Category Archives: Education

Flushables-Toilet-Trash FI

The State of the Flush!

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The State of the Flush!
Better product guidelines, marketing standards for pipe-clogging “flushables” are on the way

By Brianne Nakamura, Program Manager in the Water Science & Engineering Center at the Water Environment Federation (Alexandria, Va.).

Flushable wipes: To flush or not to flush?

While the average consumer might wash their hands of the matter without a thought, for those in the wastewater industry, the nightmares of clogged pumps and sanitary sewer overflows (SSOs) come to mind. Recently, the topic of “flushable” wipes has become front and center within the wastewater industry, as more consumers are turning to a wet wipe rather than the common dispersible toilet paper.

While flushable wipes have been on the market for years, the question of their degradability has been garnering more attention in the media and prompted state-level responses, such as the recently proposed bill in Maine requiring that products labeled “flushable” live up to their claim.

Advertising versus reality

According to the current Association of Nonwoven Fabrics Industry (INDA; Cary, N.C.) guidelines (GD3, June 2013), a “flushable” is “any product that is marketed as ‘flushable’ [that] can be flushed into the wastewater system without adversely impacting plumbing or wastewater infrastructure and operations.” Under voluntary INDA guidelines, a product must pass seven assessment tests or be clearly labeled with the “Do Not Flush” logo.

These tests include a toilet and drain-line clearance test, disintegration “slosh box” test, household pump test, settling column test, aerobic test, anaerobic test, and municipal pump test. According to INDA guidelines, if a product passes all seven tests, it should not “under normal circumstances” block toilets, drainage pipes, water conveyance, and treatment systems or become an aesthetic nuisance in surface waters. But testing and real life can have different outcomes, especially under “normal circumstances.” The U.S. Federal Trade Commission (FTC) recently announced its tentative agreement with wipe manufacturer Nice-Pak Products Inc. (Orangeburg, N.Y.), that might further define some of these issues.

Problems can’t be wiped away

For wastewater utilities, these “nondispersibles,” or anything other than human waste and toilet paper flushed down the toilet, are problematic throughout the treatment process. They cause ragging in pipes and lift stations and get caught in screens, pumps, and settling basins.

Nondispersibles wreak havoc in rainy and dry climates alike. They clog collection systems during storms and cause SSOs or, in a drought-ridden area (we’re looking at you, California), the lack of water velocity in collection systems prevents wipes from breaking down. In extreme and highly publicized cases, the accumulation of wipes and other nondispersibles can cause the formation of “fatbergs,” such as those weighing as much as 15 tons in London sewers.

Industry response to the flushables flood

Although recent media attention has increased awareness of the consequences of convenient-yet-clog-causing wipes (and other nonflushable materials), wastewater utilities throughout the country have responded with their own public education campaigns, such as “What2Flush” in California and “Don’t Flush Baby Wipes” in Maine. These initiatives, as well as the wastewater industry’s “Three P’s (Pee, Poop, and “Toilet” Paper) standard, have been informing homeowners and renters about what’s OK to flush and to not use toilets as trash cans.

The Water Environment Federation (WEF; Alexandria, Va.) has also been involved in the initiative to improve flushability requirements and educate the public. In 2010, the WEF Collection Systems Committee formed a Flushables Task Force in response to the growing concern about wipes-related problems. The WEF House of Delegates (HOD) followed suit in 2012 to involve Member Associations with the formation of the HOD Non-Dispersible Work Group.

To create a singular message, the WEF Flushable Task Group, formed in 2014 and currently chaired by Scott Trotter, has worked on several initiatives including a 2013 billing stuffer campaign with the tagline, “It’s a Toilet, Not a Trashcan!” The group also advocated for collaborative studies conducted by the Water Environment Research Foundation (Alexandria, Va.).

More recently, the Task Group, as a representative of WEF, is collaborating with four other associations representing the water sector and the nonwoven fabrics industry: INDA, the National Association of Clean Water Agencies (Washington, D.C.), the American Public Works Association (Kansas City, Mo.), and the Canadian Water & Wastewater Association (Ottawa, Ontario). The goal is to develop a new, fourth edition of guidelines (GD4) that will influence product design and support the marketing of nonwoven products as “flushable.” The guidelines are scheduled to be released in July 2016.

In addition, the collaborative effort is behind the Product Stewardship Initiative to increase public and consumer awareness about the proper disposal of wipes. The initiative seeks to improve the labelling of both flushable and nonflushable products, as well as increase the industry’s responsibility over the downstream impacts of flushable products.

WEF has been heavily involved in both GD4 and the Product Stewardship Initiative. As the awareness of the problems of flushable wipes continue to increase, both in the media and within the wastewater industry, WEF continues to support the initiatives of the Flushables Task Force. While we can’t stop consumers from flushing things down their toilets, we can stem the tide with better education and incentives for corporate responsibility.

Brianne Nakamura is a Program Manager in the Water Science & Engineering Center at the Water Environment Federation (Alexandria, Va.). She is the staff liaison for the Collection System Committee and can be contacted at bnakamura@wef.org.

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Photo caption: The WEF Flushable Task Group, formed in 2014 and currently chaired by Scott Trotter, has worked on several initiatives for better public awareness about nondispersibles, including this 2013 billing stuffer campaign.

Oahu Reuse FI

Brief Water Education


Water Reuse in Hawaii

Fresh water is our most precious natural resource. More than anything else, our natural supply of fresh water makes Hawai‘i the special place that it is. With the growth of our island state, we are pushing the limits of our available natural supply. That’s why water conservation must become part of our daily lives.

In Hawai‘i, we’ve been searching for ways to conserve our water supply. Water recycling (or reuse) is one of the most effective and proven methods for doing so. Typically, we’ve used water once and thrown it away. But now more and more people are using water over and over again.

You probably don’t realize it, but over 100 million gallons of treated water are released into the ocean everyday. It’s perfectly good water. It’s just been used before, and is commonly referred to as wastewater. But it’s only wasted if we don’t use it again.

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Why is Water Recycling Important?
The amount of water used to irrigate farm crops, golf courses, and residential and commercial landscaping is more than 70 percent of the drinking water we use. That’s about 750 million gallons a day!

When wastewater is treated for recycling, some nutrients are left in it that is good for plants. As a result, recycled water is great for irrigating most landscaping, crops and golf courses. Because of it’s nutrient content, recycled water is actually better suited than drinking water for some of the applications where drinking water gets used the most.

When recycled water is used for irrigation, more of our natural supply of drinking water is made available where we need it the most – for people to drink, for cooking, for washing, and for the ‘aina.

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Laws and Regulations Govern How Recycled Water is Produced and Used
In Hawai‘i, there are 3 classifications of recycled water based on regulatory definitions. The classifications indicate levels of purity and determine how the water is carefully monitored and the water is not recycled if it does not meet the required level of quality.

R-1 is the highest quality recycled water. This water has gone through filtration and disinfection that makes the water safe for use on lawns, golf courses, parks, and other places that people frequent. In Hawai‘i, more and more projects are using R-1 water.

R-2 is slightly lower quality recycled water. R-2 is secondary (biologically) treated wastewater that has also been disinfected. Its use requires more caution and restrictive controls than R-1 water.

R-3 is the least pure class of recycled water. R-3 quality water is wastewater that has been treated to the secondary level. It can only be used for irrigation at places where people rarely go.

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Where Recycled Water is Applied
Recycled water is utilized on most of the main islands in Hawai‘i. Golf courses, agriculture, and landscapes are irrigated with recycled water. Some of the golf courses that use water include the Experience at Koele, Ka‘anapali Golf Course, Hawai‘i Kai Golf Course, Kaua‘i Lagoons and Waikaloa Resort.

Agricultural uses include seed corn irrigation on Maui and Kaua‘i and at Hawai‘i Reserves on O‘ahu where bananas, papayas, and ornamental plants are grown. Landscape irrigation projects include Kalama Park and the Kihei Public Library on Maui, Mauna Loa Highway beautification on Moloka‘i and the Brigham Young University-Hawai‘i campus on O‘ahu.

Nutrient article FI

Turning a Pollutant into a Resource

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An overview of nutrient removal and recovery at WRRFs

By Barry Liner, Ph.D., P.E., is director of the Water Science & Engineering Center at the Water Environment Federation (WEF) Water Science & Engineering Center. Sam Jeyanayagam, Ph.D., P.E., BCEE, is chair of the WEF Nutrient Roadmap publication task force.

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Photo: Nutrient removal is an essential part of wastewater treatment to help prevent algal blooms, as shown in this 2011 satellite photo of an especially severe case in Lake Erie.

Credit: MERIS/NASA; processed by NOAA/NOS/NCCOS

In excess, nutrients can be harmful water pollutants. Nutrients are found in agricultural and home fertilizers as well as agricultural operations. Sources include confined animal feeding operations, industrial pretreatment facilities, septic systems, and water resource recovery facilities (WRRFs) as well as municipal and industrial stormwater runoff.

According to the U.S. Environmental Protection Agency (EPA), more than 100,000 mi2 of rivers and streams, close to 2.5 million ac of lakes and ponds, and more than 800 mi2 of bays and estuaries are affected by nitrogen and phosphorus pollution. Excess nutrients can lead to algal blooms, which can produce toxins and result in hypoxic zones. Algal blooms cost the tourism industry some $1 billion annually, according to EPA. These substantial impacts are the reason regulatory nutrient limits are expanding across the country.

Nutrient removal at WRRFs

Nutrient management begins with nutrient removal to meet permit requirements. WRRFs can achieve very low nutrient discharges through a variety of processes, primarily biological nutrient removal (BNR), physical separation, and chemical methods. Most technologies capable of removing both nitrogen and phosphorus utilize BNR, which relies on bacteria to transform nutrients present in wastewater. In BNR, bacteria are exposed to the influent from primary treatment. The selection of a BNR process should be based on influent flow and loadings, such as biochemical oxygen demand (BOD), nutrient concentrations, and other constituents as well as target effluent requirements.

Select species of bacteria can accumulate phosphorus, while others can transform nitrogen, and a few can do both. Achieving significant reductions in both nitrogen and phosphorus requires careful design, analysis, and process control to optimize the environment of nutrient-removing organisms. The uptake of nutrients and growth of microorganisms could be inhibited by a limiting nutrient, available carbon, or other factors, including oxygen levels.

Some nutrient removal systems rely on two separate processes for nitrogen and phosphorus removal. In some cases BNR is used to remove the majority of nitrogen and phosphorus, and then chemical methods are used to further reduce phosphorus concentrations. Mainstream nutrient treatment takes place within the typical plant process flow. However, sidestream treatment refers to liquid resulting from biosolids treatment (anaerobic digestion and dewatering) that is intercepted with an additional treatment goal — to remove nutrients from a concentrated stream and minimize mainstream impacts. Like mainstream nutrient treatment processes, sidestream treatment can also vary from biological to physical and chemical removal methods.

Nitrogen removal

Nitrogen can be removed from wastewater through physiochemical methods, such as air-stripping at high pH, but it is more cost-efficient to use BNR. Conventionally, this method utilizes the natural nitrogen cycle, which relies on ammonia-oxidizing bacteria to transform ammonia into nitrites (NO2) after which nitrite-oxidizing bacteria form nitrates (NO3) — a process called nitrification. Other species of bacteria can transform these compounds into nitrogen, a harmless gas (N2) — a process called denitrification. Nitrification can occur in the aeration basin together with BOD oxidation as they both require aerobic conditions. In contrast, denitrification takes place in an anoxic reactor with the nitrate providing the required oxygen. As denitrification occurs, nitrogen gas is produced and released safely into the atmosphere, where nitrogen gas is more abundant than oxygen. Nitrogen gas is inert and does not pollute the atmosphere.

When performing biological nitrogen removal, it is important that the activated sludge has enough available carbon to sustain denitrification. The bacteria that mediate denitrification need carbon to build new cells as they remove nitrogen. This means that utilities must make decisions on how best to use the carbon for the combinations of nutrient removal/recovery, energy generation, and/or recovery of value-added nonnutrient products.

The nitrogen removal rate is also dependent on the amount of time that sludge spends in the reactor (solids retention time), the reactor temperature, dissolved oxygen, pH, and inhibitory compounds. Optimal conditions differ for nitrification and denitrification, but both can be carried out simultaneously in the same unit if anoxic and aerobic zones exist. Some process configurations, such as oxidation ditches and sequencing batch reactors, combine nitrification and denitrification within a single tank while others incorporate two separate stages. Nitrogen removal processes can also be broken down into two categories based on whether bacteria are suspended within the wastestream or fixed to media. Examples include integrated fixed film activated sludge (IFAS) and denitrification filters.

A method of nitrogen removal that has gained favor over the past decade is deammonification, a two-step process that avoids nitrate formation. Aerobic ammonia oxidation to nitrite occurs in the first phase, then nitrogen gas is produced through anaerobic ammonium oxidation (also known as Anammox). Anammox is a biological process carried out by specialized bacteria that oxidize ammonia, and nitrite is used as an electron acceptor (oxygen source) under anaerobic conditions.

Phosphorus removal

Unlike nitrogen, phosphorus cannot be removed from wastewater as a gas. Instead, it must be removed in particulate form through chemical, biological, hybrid chemical–biological processes, or nano-processes. Nano methods involve membranes and include reverse-osmosis, nanofiltration, and electrodialysis reversal. Chemical methods (chem-P) typically utilize metal ions, such as alum or ferric chloride. These compounds bind with phosphorus and cause it to precipitate and be removed by sedimentation and filtration. Chemical methods are influenced by a number of factors including the phosphorus species, choice of chemical, chemical-to-phosphorus ratio, the location and number of feed points, mixing, and pH.

Enhanced biological phosphorus removal (EBPR or bio-P) relies on phosphorus-accumulating organisms (PAOs) capable of removing phosphorus in excess of metabolic requirements. While many factors impact the EBPR process, the two most important requirements are availability of a readily biodegradable carbon source (food) and cycling of the PAOs between anaerobic and aerobic conditions. In the anaerobic zone, PAOs take up and store carbon. The energy required for this is obtained by releasing internally stored phosphorus. In the subsequent aerobic zone, the stored carbon is assimilated and the energy is used to uptake excess phosphorus.

Consequently, the design and operation of EBPR systems must consider the availability of a readily biodegradable carbon source (such as volatile fatty acids) and the integrity of the anaerobic zone by eliminating dissolved oxygen and/or nitrate contributions from the influent, return streams, and backflow from the downstream aerobic zone. As with biological nitrogen removal, oxygen levels, solids retention time, and temperature play an important role in EBPR efficiency. It is common practice to add a standby chemical system to account for poor EBPR performance. Many existing biological nitrogen removal processes can be modified to remove phosphorus by adding an anaerobic phase.

However, economic and environmental trade-offs exist, such as greenhouse gas production in the form of nitrous oxide as well as increased energy demands. Nutrient removal techniques can also affect biogas production and dewatering. The dewatering process is negatively affected by bio-P. During anaerobic digestion, flow from the bio-P process can decrease the efficiency of dewatering and require additional polymer as a coagulant, particularly when there are fewer beneficial metal ions, such as iron and aluminum.

From removal to recovery

Beyond simply removing nutrients, WRRFs also can reclaim nutrients. Recovery not only prevents nutrients from entering waterbodies but provides a supply of these essential resources. The most straightforward way of recovering nutrients is through biosolids. EPA estimates that the approximately 16,000 WRRFs in the United States generate about 7 million tons of biosolids. About 60% of these biosolids are beneficially applied to agricultural land, with only 1% of crops actually fertilized with biosolids. However, generating solid fertilizer from biosolids is the most common method of nutrient recovery from wastewater.

Wastewater operations that have adopted the principles of becoming a utility of the future are using the nutrient removal process to produce marketable products beyond simple biosolids, including nutrients, energy, electricity, and vehicle fuels. Phosphorus used for fertilizer is a finite resource, with some estimating that demand will outpace supply within the next century. In a similar vein, ammonia is produced via the Haber-Bosch process, which consumes natural gas (a nonrenewable resource), is an energy-intensive process, and is associated with greenhouse gas emissions. Interest in recovering nutrients from wastewater has increased over the last decade. However, the maturity of nutrient recovery technologies varies, and each has its advantages and disadvantages.

Sidestream treatment of sludge and sludge liquor, where nutrients are more concentrated, is generally the preferable target for nutrient recovery, but resource recovery complexity can vary widely depending on local conditions. In addition to nutrients, there are other types of products that can be recovered, such as metals, heat, and potable or drinking water, which may bring financial rewards and benefits to help offset utility costs.

These are some nutrient-based and other resources that can be recovered at a WRRF:

  • Solid fertilizer from biosolids
    • Land application of biosolids recycles nitrogen, phosphorus, carbon, and other macronutrients.
    • Soil blends and composts are potential phosphorus recovery products.
    • Incinerator ash is also a source of phosphorus for recovery.
  • Solid fertilizer from the treatment process
    • Struvite precipitation and recovery: By this method, both phosphorus and ammonium can be simultaneously recovered, producing a high-quality fertilizer from some sidestream systems.
    • Other methods of phosphate precipitation such as brushite are also becoming common.
  • Water reuse
    • Irrigation with reclaimed water can have some nitrogen and phosphorus benefits.
  • Chemical recovery
    • Structural materials can be obtained from carbonates and phosphorus compounds.
    • Proteins and other chemicals, such as ammonia, hydrogen peroxides, and methanol, can be recovered.
    • Solids can be stored for future mining.

A roadmap to nutrient recovery

With the complexity of nutrient removal and recovery alternatives available, utility staff may wonder how to move forward to address current needs or plan for future impacts of nutrient limits. The Water Environment Federation (Alexandria, Va.) has released a Nutrient Roadmap to support the movement toward smarter and sustainable nutrient management in the context of each WRRF’s specific regulatory climate and stakeholder preference. The Roadmap provides a straightforward, high-level framework for planning, implementing, and evaluating different steps of a net-zero nutrient discharge strategy and can be found at www.wef.org/nutrientroadmap.

Barry Liner Sam Jeyanayagam

Note: The information provided in this article is designed to be educational.  It is not intended to provide any type of professional advice including without limitation legal, accounting, or engineering. Your use of the information provided here is voluntary and should be based on your own evaluation and analysis of its accuracy, appropriateness for your use, and any potential risks of using the information.  The Water Environment Federation (WEF), author and the publisher of this article assume no liability of any kind with respect to the accuracy or completeness of the contents and specifically disclaim any implied warranties of merchantability or fitness of use for a particular purpose. Any references included are provided for informational purposes only and do not constitute endorsement of any sources.

 

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From Problem to Profit

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A Fort Worth water resource recovery facility turns industrial waste challenges into energy opportunities

By Kristina Twigg and Peter V. Cavagnaro. Kristina Twigg is the Associate Editor, World Water: Stormwater Management at the Water Environment Federation (Alexandria, Virginia.). Peter V. Cavagnaro is a project development consultant at Johnson Controls Inc. (Milwaukee, Wisconsin).

The Village Creek Water Reclamation Facility in Fort Worth, Texas, lies on Trinity River’s west fork. Every day, the facility treats more than 378,541 m3 (100 million gal) of wastewater. With about 6437 km (4,000 miles) of sewers, the wastewater, carried largely by gravity, can take 8 to 12 hours to travel to the facility. Within this time, flows can become septic, and high-strength industrial wastes can be problematic for local industries to dispose of.

However, the Village Creek plant has turned the problem into an energy solution: Now the facility generates 75% of its electricity onsite.

“The plant’s co-digestion program has shifted the industrial wastes to a point in the plant where their energy can be harnessed,” said Madelene Rafalko, a senior professional engineer at the Fort Worth Water Department. “By injecting these concentrated wastes directly into the digester, the plant has decreased the amount of energy needed for aeration treatment.”

Wastes boost methane production
With the addition of co-digestion waste, the facility has doubled its gas production. However, facility staff are very selective about the wastes they bring in. “We are looking for wastes with high COD [chemical oxygen demand], which are more easily converted to methane,” said Jerry Pressley, water systems superintendent. The plant looks for wastes that produce a high gas yield with low residuals but avoid wastes with sulfides and sanitizers because they can cause process upsets, such as digester foaming, he said.

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Photo 1. The co-digestion building is where the plant receives industrial wastes. Operators ensure that the wastes do not contain chemicals that would upset the anaerobic digestion process. (Credit: Kristina Twigg)

For 10 minutes every hour, the high-strength wastes are injected into six of the plant’s 14 anaerobic digesters. The plant has been capturing digester biogas for decades and uses it to power one of two 5.2-MW turbines. These turbines generate about half of the plant’s energy, most of which is used for the plant’s aeration system.

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Photo 2. Biogas, used to generate energy via the plant’s turbines, is created in these anaerobic digesters fitted with linear motion mixers. (Credit: Kristina Twigg)
Steam heat provides return on investment
However, the Village Creak Water Reclamation Facility has also found a way to reduce the energy needed for its aeration basins.

In the process of using the turbines to generate electricity, heat is also created. The plant has harnessed this heat to make steam, which powers two of the plant’s blowers. The heat is also used to warm buildings and anaerobic digesters during winter. Even the steam itself is not wasted — it is condensed and reused.

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Photo 3. The Village Creek Water Reclamation Facility generates both energy and steam. The steam is used to power two of the plant’s aeration basin blowers. (Credit: Kristina Twigg)
“The cost savings from the steam process has paid for everything else,” Rafalko said. The project, started in 2007, has saved $3 million so far, he said.

Improvements lead to other efficiencies
While the steam process is the largest part of the plant’s energy-efficiency program, staff have also taken advantage of low-hanging fruit, such as optimizing process controls, upgrading pumps and motors, replacing its SCADA system, and installing a web-controlled lighting system. “Going through and taking measures helped us to identify maintenance needs and further energy improvements,” Pressley said.

The plant also created anoxic zones in six of its 13 aeration basins. In the presence of oxygen, bacteria convert ammonia to nitrate (NO3). Then in the anoxic zones, the bacteria can utilize the oxygen present in the NO3. This eliminates mechanical aeration in these sections of the basins, further reducing the plant’s energy needs. These improvements bring the facility one step closer its goal of net-zero energy.

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Photo 4. Using anoxic zones in the aeration basin improves energy efficiency at the Village Creek Water Reclamation Facility. (Credit: Kristina Twigg)

KONICA MINOLTA DIGITAL CAMERAKristina Twigg photo

 

 

 

 

 

 

 

Note: The information provided in this article is designed to be educational. It is not intended to provide any type of professional advice including without limitation legal, accounting, or engineering. Your use of the information provided here is voluntary and should be based on your own evaluation and analysis of its accuracy, appropriateness for your use, and any potential risks of using the information. The Water Environment Federation (WEF), author and the publisher of this article assume no liability of any kind with respect to the accuracy or completeness of the contents and specifically disclaim any implied warranties of merchantability or fitness of use for a particular purpose. Any references included are provided for informational purposes only and do not constitute endorsement of any sources.

Kihei Effluent Reuse

 


INTRODUCTION
County of Maui Wastewater Reclamation Division Logo

Kihei lies on the dry south side of Maui.  Potable water for the area must be piped over ten miles from water wells drilled into the ‘Iao Aquifer near Wailuku.  Approximately 65 percent of this water is used by the community for irrigation with the remainder ultimately ending up in the sewer system. This wastewater is then treated and disposed at the Kihei Wastewater Reclamation Facility (WWRF).

In the past, the County of Maui has had difficulty finding users for reclaimed water from the Kihei WWRF.  The primary drawback has been the high cost of conveying the treated effluent to individual users.  However, through the collective efforts of surrounding landowners, potential users and the County, an effluent reuse system consisting of storage and transmission facilities was constructed that met the needs for all parties involved. The goal of the project was to establish a reuse system that was compatible with existing activities, providing beneficial uses for the community, minimizing adverse environmental impacts and be economically feasible.

 

KIHEI WASTEWATER RECLAMATION FACILITY (WWRF)

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The Kihei WWRF is an activated sludge treatment facility that currently has a peak dry weather capacity of 8.0 million gallons per day (mgd). The facility has undergone major upgrades in its treatment capabilities with the addition of flocculation and chemical feed units, effluent filtration, ultraviolet disinfection, and renovations to the operations building. The plant is capable of producing high quality effluent, designated as R-1 by the Hawai‘i State Department of Health (DOH) Standards. Because R-1 effluent is the highest grade of reclaimed water by DOH standards, it has minimal restrictions for reuse.

The Kihei WWRF currently reclaims between 40 and 50 percent of the wastewater it treats, which is typically between 1.6 and 2.0 million gallons per day. The remaining treated effluent is discharged into injection wells located on the grounds of the WWRF, where it percolates into the ground. It is envisioned that the Kihei WWRF will eventually reclaim 100 percent of its flow as public acceptance and demand for the high quality effluent increases in the future.

PROJECT DESCRIPTION

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The County of Maui has constructed major elements of the Kihei Effluent Reuse System which includes its storage facilities and a major portion of its transmission and distribution system. These improvements have been installed in two projects: the Kihei Effluent Reuse Core System and the Kihei Effluent Reuse Distribution System, Phase I. The initial project, the Effluent Reuse Core System, qualified as an innovative project for a 100 percent low interest loan from the State Revolving Fund (SRF), administered by the Hawai‘i State DOH.

Kihei Effluent Reuse Core System

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The Kihei Effluent Reuse Core System included modifications of existing facilities at the Kihei WWRF and new improvements.  Major elements at the Kihei WWRF incorporated into the reuse system included the effluent pumping station, equipped with two 1500 gpm pumps, and the 1.8 million gallon (MG) effluent storage basin.  The existing effluent storage basin was rehabilitated and retrofitted with a polypropylene liner and floating membrane cover system to maintain the high quality of the treated effluent produced at the reclamation facility. The membrane liner and cover protect the effluent from debris and contaminants, and reduce the potential for algae growth.

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The new improvements were designed to operate in concert with the existing reclamation facilities, and are capable of functioning under expanded operating conditions as the plant capacity is increased in the future.  New improvements included the construction of an elevated 1.0 MG reinforced concrete reservoir in the hillside above the Kihei WWRF.  The elevated tank allows gravity to pressurize the system, thus eliminated the need for mechanical pumping.  The reservoir is fitted with an aluminum geodesic dome cover that eliminated the need for interior columns and footings within the reservoir, and the resulting cost savings allowed for the installation of a high quality tank lining system.  In addition, an 18-inch ductile iron pipeline was constructed to connect the storage reservoir to the reclamation facility.

The storage and transmission system was also equipped with remote pressure and flow sensors and level controls that communicate with the Kihei WWRF control station. Due to the reservoir’s remote location, level sensors at the tank utilize solar powered radio transmitters to communicate with the WWRF control station, thus eliminating the need for conventional power and communication lines. The telemetry system enables system operation and status checks through the reclamation facility’s Supervisory Control and Data Acquisition (SCADA) System. The SCADA system is programmed to start and stop the effluent pumps and to control valves that permit irrigation of the Elleair Maui Golf Club and the Monsanto Corporation’s seed corn operations.

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The Effluent Reuse Core System was put into operation prior to completion of all construction, so that it could continue to serve Monsanto Corporation’s seed corn operations and the Elleair Maui Golf Club. Cooperation between effluent consumers, the County and the contractor allowed virtually uninterrupted service during the construction period. The total project construction cost for the Kihei Effluent Reuse Core System was $3.2 million. Total project construction time was 12 months with the project substantially completed in April 1998.

Kihei Effluent Distribution System, Phase I

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Community interest in utilizing reclaimed effluent and the surplus funding available from the initial project prompted the County of Maui to extend the effluent distribution capability of the Kihei Effluent Reuse Core System. The Kihei Effluent Distribution System, Phase I was initiated during the construction phase of the Core System. Planning, design and bidding of the project was accomplished prior to the completion of construction for the Effluent Reuse Core Project.  One of the goals of the project was to complete construction of the distribution system before the completion of the Kihei Community Center, allowing the effluent to be used for the establishment of the playfields being constructed at the Center.

The Phase I Distribution System included the extension of the effluent transmission line from the Kihei WWRF in the makai direction across Pi‘ilani Highway, then northward along the proposed North-South Collector Road corridor to the Kihei Community Center site. Approximately 6,200 linear feet of 12-inch, and 1,700 linear feet of 18-inch, ductile iron pipe was installed for this project. The system serves the Kihei Community Center, Kihei Elementary and Lokelani Intermediate Schools, Haggai Institute and the Pi‘ilani Commercial Center.
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The effluent line was also outfitted with fire hydrants to aid firefighters in control of brushfires that frequently occur in the area. Per Hawai‘i State DOH standards, the fire hydrants are painted purple to identify them as part of the reclaimed water system.

The construction cost for the Kihei Effluent Distribution System, Phase I, was $682,000. Total construction time was 8 months, with substantial construction completed in December 1998. The contractor for the project was Goodfellow Brothers, Inc.

CONCLUSION

The Kihei Effluent Reuse System is the first application in Hawai‘i of an effluent reuse system pressurized by an elevated closed reservoir, making the effluent available to customers on a continuous basis.  Customers can simply connect to the system and use the effluent without the use of booster pumps.  The system has met its goal of providing the County of Maui with a system that is beneficial to the community by preserving its potable water resources, and utilizing reclaimed water for irrigation of parks, landscape areas and a golf course, and for fire protection. The reclaimed water is also used by a major agricultural operation, Monsanto Corporation, for the production of high quality seed corn that is marketed worldwide. The system has proven to be easy to operate and reliable, and has met the needs and expectations of the County.

For more information on the Kihei Effluent Reuse System, contact Steve Parabicoli, Maui County Wastewater Reclamation Coordinator at phone (808) 270-7426 or e-mail: steve.parabicoli@co.maui.hi.us.

Honouliuli WRF


BACKGROUND

BWS LogoThe ‘Ewa district on the island of O‘ahu has undergone a significant amount of development in recent years. What was once fertile agriculture land has now given way to numerous residential, commercial and industrial developments. These developments have seriously impacted the region’s available water resources in two ways: (1) by reducing the amount of recharge that the caprock aquifer receives because of reduced agricultural activity, and (2) increasing the potable water demands placed on O‘ahu’s potable water aquifers.

As more and more land is being developed, the amount of water being applied to the ground in the form of agricultural irrigation is being reduced. This reduction ofgroundwater recharge has markedly reduced the amount of water replenishing the existing aquifer. As a result of this activity, the salinity of the aquifer has been gradually rising as withdrawals from existing wells continue. This has prompted the Hawai‘i State Department of Land and Natural Resources (DLNR) to develop plans to limit new well permits and well permit renewals in the region.Development in the ‘Ewa area includes a number of golf courses that are currently pumping brackish water from the caprock aquifer for irrigation. New residential subdivisions are increasing the demand for potable water in the region, and accelerating the withdrawal of water from potable water aquifers. In addition, industrial activities at the Campbell Industrial Park also place demands on potable water aquifers. This area contains many industrial facilities that consume large amounts of potable water for their industrial processes. Recognizing these demands, the Honolulu Board of Water Supply (BWS) entered into the water recycling business in 2000 by purchasing the Honouliuli Water Recycling Facility.  Water recycling is one element of a broader BWS strategy to protect O‘ahu’s aquifers and to conserve water resources through conservation and development of new water supplies.  The facility is now irrigating golf courses that were once using brackish water, including West Loch,  ‘Ewa Villages, Hawai‘i Prince, and Coral Creek.  The facility is also providing recycled water to industries at Campbell Industrial Park.

WASTEWATER TREATMENT IN THE ‘EWA DISTRICT

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The City and County of Honolulu (City) owns and operates the Honouliuli Wastewater Treatment Plant (WWTP), which is the regional wastewater treatment facility for the ‘Ewa district. The Honouliuli WWTP is located along Geiger Road directly east of the former Naval Air Station Barbers Point. The service area of the plant encompasses a total area of approximately 76,000 acres and ranges from Red Hill along its eastern boundary up to Mililani on its northern boundary, and extends to Makakilo City, Honokai Hale, and Ko Olina on its western boundary.
Service Area of Honoluliuli WWTP

All residential, commercial, industrial and agricultural areas within these boundaries are included in the service area except for Pearl Harbor, Campbell Industrial Park and several small pockets that are served by cesspools or septic tanks. Wastewater treated at the Honouliuli WWTP is discharged into West Mamala Bay through a deep ocean outfall.

The Honouliuli WWTP was originally put into service in December 1984. The plant was initially designed to treat up to 25 million gallons per day (mgd) of wastewater to the primary level only. Over the years, the plant capacity has been expanded to meet increasing and expected future flows. The plant presently has a design average dry weather flow capacity of 38 mgd, with future plans to further expand it’s capacity to 51 mgd.

Treatment processes at the Honouliuli WWTP include preliminary treatment, primary treatment, secondary treatment, effluent screening, solids treatment and handling, and odor control.  The preliminary treatment processes include influent screens at the headworks, aerated grit removal, and preaeration facilities.  Primary treatment processes include four circular clarifiers which utilize flotation and sedimentation to remove floating and settleable solids from the wastewater.  The secondary treatment processes at Honouliuli includes two biotowers that are fed by the biotower pump station, a solids contactor and sludge reaeration tank, and two circular secondary clarifiers.  The secondary treatment facilities are currently capable of treating up to 13 mgd.  The effluent screens are located immediately upstream of the ocean outfall pipe, and ensure that no large objects are discharged through the outfall.

The solids treatment and handling processes include thickening, storage/blending, stabilization, dewatering and disposal.  Incineration was originally used at the plant to further reduce the volume of the dewatered sludge before disposal, but was taken offline in 1995 due to public concerns about air quality.  Odor control at the plant consists of four main systems, 1) headworks, 2) central system for the grit removal/preaeration tanks, primary clarifiers, gravity thickeners, blending tanks, 3) secondary treatment system, and 4) solids system.

HONOULIUILI AND 309 CONSENT ORDER

The secondary treatment facilities at the Honouliuli WWTP were constructed as a result of a State of Hawai‘i Department of Health (DOH) consent order which was signed in 1993 between the DOH and the City. The main objective of the consent order was to establish secondary treatment facilities at the plant to allow for those treated portions of the wastewater flow to be reused.  The secondary treatment facilities at Honouliuli were completed in 1996 and initial water reuse was initiated in 1998 with approximately 2 mgd being used for in-plant demands.

Additionally, in 1995, the U.S. Environmental Protection Agency (EPA), DOH, and the City entered into an agreement known as the 309 Consent Decree, which required a significant commitment by the City to improve its wastewater system.  As part of the 309 Consent Decree requirements, the City was faced with spending at least $20 million to develop an effluent reuse system that would need to recycle 10 mgd of water by July 2001. The Honouliuli WWTP was selected for implementation of the water reuse requirements because of the demands on the ‘Ewa caprock aquifer, the termination of sugar cultivation which led to the significant decrease in groundwater recharge, and the proximity of the facility to potential users of reclaimed water.

WATER RECYCLING FACILITIES

Construction of water recycling facilities within the Honouliuli WWTP commenced in January 1998 and was completed in the summer of 2000.  The facility was officially dedicated in August 2000.  Prior to its dedication, the water recycling facility was purchased by the Honolulu Board of Water Supply (BWS) in July 2000 for $48.1 million from USFilter Operating Services.

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Overview of the Recycling Facility

The entire water recycling facility is located adjacent to the City & County of Honolulu’s Honouliuli WWTP.  Water recycling components include a Reuse Pump Station, a Sand Filter Structure which includes rapid mixing tanks and chemical flocculators, Ultraviolet Light (UV) Disinfection, a Microfiltration/Reverse Osmosis Building, Storage Tanks, and a Product Delivery Pump Station.

The facility currently has a capacity of 12 million gallons per day (mgd) and produces two grades of recycled water.  R-1 water is used for irrigational uses, and Reverse Osmosis (RO) for industrial uses.  The facility is currently capable of producing up to 10 mgd of R-1 water, which is the highest level of treatment as designated by the Hawai‘i DOH.  R-1 water is currently used throughout the state of Hawai‘i for golf course irrigation, landscaping, and agriculture.  On the other hand, RO water is intended strictly for industrial uses such as boiler feed water, cooling tower make-up water, and process water for refineries.  The facility currently has an RO capacity of 2 mgd.  Both types of recycled water begin with secondary treated effluent from the Honouliuli WWTP.

THE R-1 PROCESS
The R-1 process includes the following components:

Schematic Diagram of R-1 Process

  • Rapid Mix Tanks
  • Chemical Flocculators
  • Sand Filters
  • Ultraviolet (UV) Light Disinfection
  • R-1 Transfer Pumps
  • Two 2.5 Million Gallon R-1 Storage Tanks
  • R-1 Product Delivery Pumps

Secondary effluent flows by gravity from the existing Parshall flume box into the Reuse Pump Station.  Lift pumps in the Reuse Pump Station convey effluent to the Sand Filter Structure, where polyaluminum chloride is added and rapidly mixed in one of two mixing tanks.  The effluent then flows into one of three flocculation tanks to facilitate the coagulation of suspended and dissolved particles to form larger and/or denser particles.  The effluent then flows into one of seven sand filter cells.  Filtered effluent is collected in an underdrain system to a clearwell at the rear of the Sand Filter Structure, then flows by gravity to the UV Disinfection system (consisting of 4 banks).  Disinfected effluent is then conveyed by the R-1 Transfer Pumps to one of two 2.5 million gallon storage tanks.  The R-1 effluent is then pumped to customers via the R-1 Product Delivery Pump Station.

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09_r-1_tanks

 

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THE REVERSE OSMOSIS PROCESS

The Reverse Osmosis (RO) process includes the following components:

  • Microfiltration
  • Reverse Osmosis
  • One 0.5 Million Gallon Storage Tank
  • RO Delivery Pumps

The production of RO water utilizes the membrane filtration process.  Membrane filtration consists of a permeable membrane that allow particles smaller than the membrane pores to pass through, but captures particles that are larger than the membrane pores.  In general, relatively high pressures are required to force the effluent through the permeable membrane.

The reverse osmosis process typically uses higher pressures and smaller pore sizes than microfiltration.  Consequently, reverse osmosis can remove particles with lower molecular weights than microfiltration.  Because of the high pressures involved in reverse osmosis, the process is capable of de-ionizing water and is typically used for desalination.  Microfiltration is used as a pretreatment separation process downstream of the secondary treated effluent from the adjacent Honoluliuli WWTP secondary units. Self cleaning strainers at the Reuse Pump Station remove larger-sized particles that could clog the microfilters.  The microfiltration process then removes additional residual suspended solids in the secondary effluent by utilizing a 0.2 micro hollow fiber membrane that is cleaned monthly using citric acid. This enables the reverse osmosis process to remove higher levels of ionic constituents from the effluent, thus reducing the degree of post-treatment required by RO water users to meet their water quality requirements.  The microfiltration pretreatment process also prolongs the life of the reverse osmosis membranes by reducing the amount of membrane fouling and consequent cleaning required.

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CURRENT USES OF RECYCLED WATER

The Honouliuli WRF currently supplies the City golf courses of West Loch and ‘Ewa Villages with 1 mgd each of R-1 water.  Recycled water is pumped to the West Loch course at night, while the ‘Ewa Villages course is supplied during the day.  The pumping rate to each course is 150 gallons per minute (gpm) at a pressure of 68 pounds per square inch (psi).

MORE INFORMATION

For more information about the Honouliuli Water Recycling Facility, please visit the official Honolulu Board of Water Supply Water.  Organizations interested in touring the Facility may contact the Honolulu Board of Water Supply’s Water Recycling Program at phone (808) 527-6156.

Sanitary Sewer Overflow PSA [Video]


In 2009 the following 30-second public service announcement (PSA) videos were completed with funding jointly provided by a Federal Clean Water Act Section 319(h) grant from the U.S. Environmental Protection Agency (USEPA), the Hawai‘i State Department of Health (DOH), Clean Water Branch, and Learning Education Technology.  These videos are intended to educate the public about the problem of sanitary sewer overflows, which are oftentimes caused by disposal of inappropriate objects into the sewer system.  Additional funding was provided by the City & County of Honolulu and the McInerny Foundation.  Technical assistance was provided by the Hawai‘i Water Environment Association (HWEA).

For more information see:  Sanitary Sewer Overflow Overview

Sanitary Sewer Overflow Overview


Preventing Sewage Spills
Caution SignOverflows and spills from sewer lines onto our roadways and into our streams and oceans spoil our beautiful Hawaiian environment and can endanger public health. Sewage spills are costly to clean up (increasing your sewer bills) and can even hurt our tourist industry by causing beach closures. In a typical year, there are over 400 spills statewide involving more than two million gallons of raw sewage!

Learn about the sanitary sewer system and what you can do to help prevent SEWAGE SPILLS!

A Quick Overview
Preventing sewage spills is quite simple. Spills are simply caused by clogged pipes and/or too much flow. All everyone needs to do is keep unwanted things out of our sewer pipes such as grease, trash, rainwater and tree roots.

Illustrated below are some of the causes of sewage spills and how you can help prevent these spills (click here to download a higher resolution image shown below):

Causes of Sewage Spills

More Information on Sewage Spills
Now that you have a feel for the basic ways to prevent sewage spills, take some time to learn about the fascinating details of sewage spills and your underground sewer system. By reading through the information presented below, you can learn:

  • Important sewer system terms.
  • The difference between “sanitary sewers” and storm drains.
  • Why sewage spills are a BIG problem.
  • Typical causes of sewage spills.
  • How to keep grease and oils out of the sewer system.
  • How to keep rubbish out of the sewer system.
  • What infiltration and inflow are and why it is important to keep rainwater and other excess water out of the sewer system.
  • What you should do if you see a sewage spill.
  • Where more information on your sewer system can be obtained.

Ten Terms to Help You Better Understand Your Sewer System

  1. “SEWAGE” or “WASTEWATER.” This is the “used” water that contains human wastes from toilets and water from other sources such as sinks, showers, washing machines, etc. In addition to being odorous, sewage can contain large amounts of germs that cause disease. The term “wastewater” is often used in place of “sewage” to make things sound more pleasant when discussing this unpleasant subject.
  2. “SANITARY SEWER SYSTEM,” also known as “WASTEWATER COLLECTION SYSTEM,” or “SEWERS.” These are pipes through which sewage is carried from homes and businesses to a treatment plant. The sanitary sewer system includes the main sewer lines in the streets and the branch lines to individual sewer customers called “sewer laterals.”Sewer systems are generally designed to flow by gravity through sloped pipes until it reaches either the treatment plant or a sewage pumping station (which pumps the sewage up to another higher sewer or a treatment plant).Although sewage is very unsanitary, the term “sanitary sewer” is used because the sewer pipes are separate from the pipes used for storm water drainage. This helps protect public health and the environment. In some older cities, sewage and rainwater flow through the same pipes. This can cause major environmental and public health problems because untreated or partially treated-sewage is discharged into streams, rivers and other water bodies during heavy rain.
  3. “SEWER LATERAL.” This is the sewer pipe that connects a building’s plumbing system to the main sewer line in the street. Maintenance of sewer lateral pipes located within private property is generally the responsibility of the property owner. Sewer laterals are also called “service laterals,” “house laterals,” or simply “laterals.”
  4. Sewer Cleanout“SEWER CLEANOUT.” This is a pipe rising from the sewer lateral to the ground surface with a removable cap or plug. It is used to access the sewer lateral to free blockages. A sewer cleanout is usually located just inside the property line. There may be additional sewer cleanouts at various other locations in your property.
  5. “WASTEWATER TREATMENT PLANT”or “WASTEWATER RECLAMATION FACILITY”. These are facilities where organic matter, bacteria, viruses and solids are removed from sewage through physical, biological and chemical processes. The treated wastewater (called effluent) may be disposed of by discharging it to water bodies (mainly the ocean in Hawaii), injecting it into the ground, or reusing it for irrigation or other beneficial non-potable (non-drinking) uses.
  6. Infiltration“INFILTRATION.” This refers to groundwater (water found below the ground surface) that enters sewer pipes through cracks, pipe joints, and other system leaks. Because sewers in coastal areas are typically buried deep, they are often located below the water table. Since most sewer lines do not flow full (under pressure), groundwater “infiltrating” into the sewer line is actually more of a problem than sewage leaking out of the line. Storm events can raise groundwater levels and increase infiltration of groundwater into sewer pipes. The highest infiltration flows are observed during or right after heavy rain. Too much infiltration will overload the sewers and cause spills!
  7. “INFLOW.” This is rainwater that enters the sewer system from sources such as yard and patio drains, roof gutter downspouts, uncapped cleanouts, pond or pool overflow drains, footing drains, cross-connections with storm drains, and even holes in manhole covers. Inflow is greatest during heavy rainfall and like infiltration, can cause excessive flows and sewage spills.
  8. “PATHOGENS.” These are harmful germs in raw sewage that cause diseases such as cholera, dysentery, hepatitis and gastroenteritis.
  9. Manhole Cover“MANHOLES.” Sewer manholes are underground structures used to provide access to underground sewer lines and are usually found in a street, parking area or sidewalk. Access is required to periodically inspect and clean the lines. Sewer manholes typically have heavy round covers with the words “Sanitary Sewer” on the cover.
  10. Sanitary Sewer Overflow“SANITARY SEWER OVERFLOW.”Sewage spills are technically called “sanitary sewer overflows” since it involves the overflow of sewage from the sanitary sewer system. The word “sanitary” is used only because the overflow is from the sanitary sewer system, and not because the raw sewage is sanitary! (See definition of sanitary sewer above). For simplicity, we will use the term “sewage spill” or “sewage overflow.”Sewage overflows often occur from sewer manholes in the streets. Sewage can also backup into homes through your toilets, showers and floor drains. Sewage spills are caused by sewage filling the sewer pipes behind the clog to the point where it spills out of an opening in the system (generally the lowest manhole, shower drain or other plumbing fixture).

What is the difference between “sanitary sewers” and “storm drains”?

“Sanitary sewers” collect and convey sewage to a treatment plant where the sewage can be treated. It is important to understand that sanitary sewers are a completely different set of pipes from “storm drains.”

In Hawaii and most other areas, an independent system of pipes called “storm drains” is used to only transport storm water (i.e., rainwater) to streams, bays and the ocean with little or no treatment. The separate “sanitary sewer system” (see definition above) is “sanitary” because it keeps sewage out of the storm drains and sends the sewage to a treatment plant before it is released into the environment.

Some key points to remember are:

  • Sanitary sewers have limited capacities and are not designed to dispose of storm water (i.e., rainwater) from your property.
  • Storm drainage flows are generally not treated and therefore should not contain any pollutants that could affect our streams and ocean.
  • Rubbish should not be thrown down sewers or storm drains. Because sewage is treated, sewers can handle sewage as well as certain types and limited amounts of “toxic” materials such as household cleaners.

Why are sewage spills a public health, environmental and economic problem?

Sewage spills are simply an overflow of untreated or partially-treated sewage from the sewer system (i.e., the raw sewage overflows from a sewer line before it reaches the wastewater treatment plant). The sewage can overflow from the manholes in the streets, from open cleanout lines, or from toilets and drains in your home.

Spill inside a house

In really bad situations, someone else’s sewage could spill out of your toilet or shower and flood your home! Yuck!! This may not happen to you but what you do in your home could cause it to happen to someone else living farther down the sewer line!

 

Sewage spills are a big problem because:

  • Sewage spills cause public health problems. Spills can expose people to disease-causing germs (pathogens) such as E. coli and Cryptosporidium that are present in sewage.
  • Sewage spills can pollute our streams, the ocean and other bodies of water. In addition to being a public health problem, sewage can add unwanted nutrients to our water environment and cause excessive growth of algae that disrupts the ecosystem.
  • Sewage spills can pollute the groundwater, which in many inland areas, is our source of drinking water.
  • Sewage spills hurt our economy. Sewage spills are costly to clean up and this affects our sewer bills (which almost everyone feels are already too high!). More importantly, sewage spills can cause beach closures that can have a big impact on Hawaii’s tourism-based economy.

What are the main causes of sewage spills?

Sewage spills are caused by the clogging of pipes and/or too much flow. Clogging is caused by blockages from fats, oils and grease as well as rubbish, roots and other foreign or unwanted objects in the sewer system. Too much flow is caused by infiltration and inflow (i.e., groundwater and rainwater getting into the sewer system). The following sections discuss each cause in detail.

Keeping fats, oils and grease out of the sewer system

Grease inside sewer pipe

Fats, oils, and grease, and other byproducts of cooking come from meat, lard, shortening, butter, margarine, food scraps, sauces, and dairy products. They present a significant clogging problem for sewer systems. Fats, oils and grease stick to the inner walls of sewer pipes and reduce the diameter of the pipes over time. This eventually causes clogged sewer pipes and sewage spills.

Grease ball

Clogging is further caused by chunks of grease breaking away from the pipe walls and becoming stuck further down the line. Grease balls that form when grease combines with sand, grit, and other sewage debris can even become large and hard enough to clog sewage pumps!

 

Fats, oils and grease also flow down to the wastewater treatment plants where it disrupts operations and increases maintenance costs.

 

Regulations require restaurants and other commercial food handling facilities to install large grease separation devices to protect sewers from grease problems. Folks at home need to do their part!

How should we properly dispose of grease and oils?

Everyone can do their share to prevent clogged sewers by following these simple Do’s and Don’ts:

DO’s:

  • Cooking grease in panCollect oil and grease in a container filled with absorbent material (shredded newspaper, napkins, paper towels, rags, etc.) and properly dispose of it in the garbage.
  • Scrape grease and food scraps off cooking/serving utensils and plates for proper disposal. Better yet, wipe them with used napkins and paper towels before washing.
  • Encourage friends and neighbors to practice similar habits of proper oil and grease disposal. Parents, set a good example for your kids! Kids, educate your parents!

DON’Ts:

  • Do not pour grease or oil down the drain or toilet.
  • Do not dump greasy or oily food waste into the drain. (Minimize the use of your garbage disposal and better yet, compost your vegetable scraps!)

Some other points to remember:

  • Be sure to put your oil and grease in a suitable container or bag with absorbent material. The reason for using the absorbent material is so that your grease and oils do not leak out of garbage trucks and cause a big mess. Also, remember that solid grease can turn to liquid in our hot climate so use absorbent material for solid or semi-solid fats too!
  • If you have a large amount of cooking oil, consider using a disposable automotive oil change box filled with absorbent material. For even larger quantities (several gallons or more), take your used cooking oil to a recycler (check your yellow pages).
  • On Oahu, your trash is sent to HPOWER and therefore, instead of causing a costly sewer and environmental problem, throwing your fats, oils and grease in the trash is now helping to generate power and save everyone money!

Keeping rubbish out of the sewer system

Your toilet and sewer system are only designed to dispose of human wastes and toilet paper (which quickly breaks down). Unfortunately, people use the toilet as a wastebasket out of convenience. It is a huge “out of sight, out of mind” problem because people often don’t see the mess sewer overflows cause and the problems that sewer workers need to deal with!

 

Almost any type of rubbish may restrict sewage flow, clog sewers, and cause sewage overflows. Keep the following from going down your toilet and sinks:

 

  • Paper (paper towels, facial tissue (Kleenex), paper napkins, wrappers, etc.). Only toilet tissue is okay!
  • Plastics (bags, wrappers, bottles, cotton-tip shafts),
  • Rubber (gloves, condoms, underclothes elastic, etc.),
  • Cloth and fibers (cotton balls, tampons, cigarette filters, stockings, rags, etc.).
  • Food scraps (greasy items are the worst but minimize throwing down non-greasy items too. Try to even keep out smaller food items such as tea-leaves, coffee grounds or eggshells. Garbage grinders help but its even better not to use it where possible — compost what you can and throw the rest in the trash. Place food scraps in tightly sealed bags or other containers so it does not become an odor or rodent problem.)
  • Toys, cans, sticks, pebbles and sand, and pretty much all other solids except for human wastes and toilet tissue.

Why is it a problem? Rubbish and other objects often combine with hair, grease and other debris to cause clogging of the sewer system. Even something as small as a cotton tip swab with other attached debris can cause a blockage in sewer pipes. Rags and stringy material can clog sewage pumps. Malfunctioning sewage pumps, like clogged pipes, prevent sewage from flowing through the system and are a cause of spills. Any rubbish-type items that you dump in toilets and sinks at home, work, schools, shopping centers, movie theaters, or parks can contribute to sewage spills.

Do your share to keep rubbish from clogging our sewers by following these simple Do’s and Don’ts:

DO’s:

  • Place and use a wastebasket in the bathroom to dispose of rubbish (including disposable diapers and personal hygiene products).
  • Use sink and shower drain strainers.
  • Scrape food scraps into sealed containers or bags and throw them out in the garbage.
  • Educate each other on minimizing disposal of rubbish to our sewers.

DON’Ts:

  • Don’t use the sewer as a convenient means to dispose of food scraps.
  • Don’t use the toilet as a wastebasket!!

Keeping rainwater and other excess water out of the sewer system

What is infiltration and inflow?
Infiltration and inflow are the technical terms referring to rainwater and/or groundwater that enters the sewer system through such sources as cracked pipes, leaky manholes, or improperly connected storm drains and roof gutter downspouts. Most infiltration comes from groundwater and most inflow comes from rainwater. See the definitions presented earlier for infiltration and inflow. The following figure shows typical sources of infiltration and inflow.

Inflow and Infiltration Sources
Image courtesy of King County website

Why are infiltration and inflow big problems?
In addition to causing sewage spills, the additional flow from infiltration and inflow results in the need for larger sewers and treatment plants. This raises the sewer fees that residents and businesses must pay the government or private sewer agency to build, operate and maintain the sewers and wastewater treatment plants.

Sewer systems (sewer pipes and pumping stations) are designed to handle sewage flows from houses and businesses plus some additional flow from infiltration and inflow. Sewage flow rates used to design sewers have been developed over the years based on information obtained from water usage within the household and workplace. The exact volume of groundwater and rainwater (infiltration and inflow) entering the system, however, varies with location and is virtually impossible to predict. Infiltration and inflow entering the system can be much higher than the system’s capacity when there is too much leakage due to infiltration from deteriorated sewer pipes or significant sources of rainwater inflow.

The infiltration and inflow that enters the sewer system is transported to wastewater treatment plants along with the sewage. The groundwater and/or rainwater mixed with the sewage can double and even triple the design capacity of the treatment plant. Like the sewer system, the treatment plants are generally designed and constructed to accommodate the expected sewage flows plus some infiltration and inflow, but not large volumes of groundwater and rainwater.

When large volumes of infiltration and inflow increase the wastewater flow, the sewer system is overwhelmed to the point where a sewage spill can occur. The extra flow from infiltration and inflow simply causes the sewer system capacity to be exceeded. Sewage spills pose a public health risk due to increased probability of human contact with harmful pathogens as the sewage runs down the street to the storm drains, the streams, and eventually our recreational waters. Devastating backups of sewage into homes can also occur. In addition to causing sewage spills, the high flows can also affect the ability of the treatment plant to adequately treat the wastewater.

How does this affect the sewer fees that everyone pays? In many cases, your sewer agency will deal with heavy infiltration and inflow by increasing the size of the sewer pipes, pumping stations, and treatment plants.

Constructing large sewer lines to handle high infiltration and inflow is very expensive and has its own problems associated with it. For example, large sewer pipes tend to result in sluggish flow during normal low dry weather flows. This causes the organic matter to putrefy and generate gases that are both odorous and corrosive to the sewer pipes. The corrosive gases shorten the life of the sewer lines and manholes, which increases your sewer bill even more!

At the sewage treatment plant, high infiltration and inflow can result in a significant amount of money being spent to construct facilities that are rarely used. The sewer users pay for the higher maintenance costs as well as the added construction costs. Once again, this increases your sewer bill!

Who is responsible for the infiltration and inflow problem?
Although infiltration of groundwater is a concern, the large jump in flow caused by inflow of rainwater has the greatest impact on a sewer system. Through extensive studies on sewers in the U.S., it has been found that the greatest contribution of inflow comes from private property. Common inflow sources include direct connections from rain gutter downspouts, outdoor drains, and pool/pond overflow pipes connected to the sewer lines. Uncapped cleanouts and broken house sewer laterals also cause excessive rainwater to enter the sewer system.

Although these inflow connections at your home may alleviate the inconvenience of yard flooding and puddles, they have significant impacts to the sewer system, the sewer rates, and public health. It has been estimated that as much as 40% of the total infiltration and inflow is contributed by the “private” side of the sewer. The individual sewer user therefore can play a HUGE role in minimizing sewer fees, promoting proper functioning of the sewer system (reducing spills), and protecting the environment. Your sewer agency is probably spending a lot of money replacing old defective sewer lines in the streets to reduce infiltration but individual sewer users must do their part in reducing rainwater inflow!

What can you do to prevent and reduce infiltration and inflow?
The following are important actions that sewer users can take to help reduce infiltration and inflow:

  • DownspoutInspect the rain gutters on your house to see if the downspout connects to a sewer line. Such connections are illegal (violation of the plumbing code)! If the gutter downspouts are connected to the sewer line, have them disconnected-the large amount of water from the roof can cause a sewage spill. The rainwater needs to be directed onto your lawn and/or to the storm drain system.
  • Look for and check your sewer cleanout. The cleanout is usually a small pipe, about 4-inches in diameter, outside your house that is used to access the sewer lateral for cleaning. You will normally find it near the house (where the sewer lateral comes out) and/or near the property line (where the sewer lateral connects to the main sewer line). Make sure the cap to the cleanout pipe is not missing and has not been damaged (such as by a lawn mower). Replace missing caps so that rainwater cannot get into the sewer line. Kids love to throw rocks, toys and other nasty things down an uncapped cleanout! By keeping the cleanout capped, you can also prevent unpleasant sewer odors and gases from escaping.
  • Check to see that outdoor patio, deck or yard drains are not connected to the sewer. Also, be sure that pool or pond overflow drains are not connected to the sewer. These connections are not allowed by the plumbing code. You may want to call your plumber to assist you in checking your connection. You can also try calling your sewer agency for assistance since they often have personnel that can trace lines and have a strong interest in keeping rainwater out of the sewers. If you are voluntarily taking steps to find and correct the problem, it is unlikely that you will be fined for the illegal connection(s).
  • If you live in a low area with a high water table, and/or experience a lot of settlement on your property, you may want to have your sewer line checked for cracks, separated joints, or “sags” that could cause entry of rainwater or clogging problems. Many plumbers now have miniature video cameras that can be sent down your line to check if the line has any significant damage or other problems.
  • Avoid planting trees and shrubs over or near the sewer laterals. This also applies to sewer mains that may be in yard easements. Roots can enter and damage sewers. This allows groundwater and rainwater to enter the sewer and also causes costly ongoing problems with sewer clogging, backups and spills.
  • If you have a basement sump pump to pump out groundwater or rainwater leakage, be sure that it does not connect to your sewer pipes or to a sink or floor drain in your basement. This would be another source of unwanted excess flows that can overload the sewer system.
  • If your area is experiencing flooding, NEVER try to drain the areas by removing the sewer manhole covers in the street or covers from your cleanouts. The huge amount of flow that would enter the sewer system will definitely cause a problem downstream. Notify your sewer agency if you observe or know of someone doing this.

What should you do if you see a sewage spill?

Make sure that people are kept away from the area of the overflow, typically a manhole cover. This is especially important for children and pets who may play near the overflow area (e.g. street, public park, or local stream).

SSO from manholeIf liquid is coming out of a manhole cover with “Sanitary Sewer” on it, it is probably sewage! Note that sewage is not brown or yellowish in color and actually looks like dirty gray dishwater. Especially during heavy rain, take note of and report any sewer manhole covers that you see lifting up and spilling sewage.

Report the sewer overflow immediately to the statewide Hazard Evaluation and Emergency Response Hotline (Ph. 586-4249 during working hours; Ph. 247-2191 after hours) or your sewer agency if you have their number. Quick action is required to reduce the risk of public exposure to raw sewage by stopping the overflow, monitoring its impact, and ensuring proper cleanup.

Where can I obtain more information?

For any questions on your plumbing system, call your local city or county building department. They are the experts on plumbing codes and what should or should not be connected to the sewer line.

Most plumbers would be able to assist you in locating and disconnecting illicit sources of rainwater discharge to the sewer line within private property.

For problems with the sewer lines in the road and other public property, contact your sewer agency or private wastewater service provider.

For any other questions, feel free to email HWEA at info@hwea.org. As a public service, we will do our best to respond to your questions or direct you to someone who can. HWEA can also provide or find speakers to do presentations on most topics related to wastewater treatment and water pollution control.

Keep Hawaii Spill Free!

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Impacts of the Clean Water Act in Hawaii


On October 18, 1997, the Clean Water Act (CWA) celebrated its twenty-fifth anniversary as a landmark piece of legislation which spawned tremendous changes and improvements to the water environment in our country.

The Federal government’s involvement in prevention of pollution of interstate waters actually began over 100 years ago with the enactment of the Rivers and Harbors Act of 1890, which prohibited discharges of filth and pollutants that could impede navigation into such waters. In 1899, however, the act exempted “refuse flowing from streets and sewers” in a liquid state.

Although there were increasing pollution problems as the country grew and developed, little else was done from then until the 1940s. During the industrial boom that followed World War II, the country prospered and Americans enjoyed a higher standard of living, but this was not achieved without sacrifices. As much as 7 million tons of untreated or inadequately treated wastes were dumped daily into our waterways which turned many rivers into sewers and lakes into stagnant pools. Many water bodies had become too dirty for fishing and swimming or too polluted for aquatic and wild life. From 1948 to 1970, Congress enacted six principal bills which not only toughened the controls over discharges, but also included inducements in the form of authorizations for loans and grants to states to develop comprehensive plans and standards to control the discharge of pollutants and for the construction of projects that conformed to such plans and standards.

Pollution was not, however, being effectively controlled primarily because of an unmanageable system of setting discharge limits for each individual discharger based on the impacts of its discharge on the receiving water quality. With increasing closures of beaches and fishing beds and incidents like the Cuyahoga River in Ohio catching fire, public indignation turned to outrage and Congress was spurred to action. Changes to the environmental strategy of the nation such as the establishment of the U.S. EPA (the Environmental Protection Agency) culminated in the enactment of the 1972 amendments to the Federal Water Pollution Control Act of 1948. These amendments and subsequent amendments constitute what is called the CWA. The primary goals of the CWA were to have all waters of the U.S. clean enough to be fishable and swimmable and to end all discharges of pollutants into waters.

With this act, a new era of pollution control began. The act required all dischargers to the Nation’s waters, industrial as well as municipal, to have discharge permits. It also set national uniform minimum treatment requirements which were technology based for discharges. The requirements for municipal discharges were for a minimum of secondary treatment, except for discharges into marine waters for which lower levels of treatment could be allowed if there were no impacts.

Higher levels of treatment of the effluent being discharged could be required if water quality dictated a need. Senator Edmund Muskie, one of the prime authors of this historic piece of legislation, described it as offering “Uniformity, Enforceability, and Finality”.

 

Construction Grants Program

The act, however, was not only a big stick. There was a carrot in the form of federal financial assistance to build municipal wastewater treatment plants under a Construction Grants Program. Grants of 75% of the total eligible project costs could be obtained. Since 1990 federal assistance to states have been grants to establish State Revolving Funds from which low-interest loans could be made to municipalities.

In Hawai‘i, the federal grant funds were supplemented with 10% grants from the state. Thus, the net cost to the counties was down to 15% of the cost of the facilities built. Of all the counties, the City and County of Honolulu, which had the greatest needs, benefited the most from the grants program. Great improvements to the water quality of O‘ahu have resulted from the projects that were made possible by the financial assistance.

 

Water Quality Program for Oahu

Honolulu’s efforts to resolve its water quality problems began in 1969, before the CWA, with the implementation of the WQPO. This was a study to:

  • Identify the water quality problems on O‘ahu;
  • Identify the wastes contributing to the problems and their characteristics and quantities;
  • Recommend alternative wastewater management systems to meet existing and future needs; and
  • Establish priorities and a plan of action.

The final product of this effort was a report, the Water Quality Program for O‘ahu with Special Emphasis on Waste Disposal, which was completed, coincidentally, in February 1972, the year of the CWA. The conclusion was that the design of water quality control systems should be directed toward the conservation of corals and other indigenous aquatic organisms, the protection of the aesthetic qualities of the water environment, and the protection of the various recreational uses of the waters. This was the plan that Honolulu has used to guide the course it took to alleviate the water quality problems that needed correction.

A major priority of the plan was to abate the problems associated with sewage discharges. These were discharges in Mamala Bay in the vicinity of the Sand Island, in the southeast portion of Kane‘ohe Bay, and in Pearl Harbor. The plan, however, not only covered the impacts of sewage discharges but also identified water quality problems in areas such as Honolulu Harbor, Ke‘ehi Lagoon, Kewalo Basin and Ala Wai Yacht Harbor where there were no sewage discharges and the problems were due to other contributing factors such as suspended solids, nutrients, and pesticides in non-point source discharges from agricultural and urban areas.

 

Sand Island Discharge

In 1972, the sewage from the entire urban Honolulu corridor extending from Red Hill to Niu Valley, amounting to about 62 million gallons per day (mgd), was being discharged off Sand Island through a 60-inch diameter outfall pipe about 3,700 feet offshore and at a depth of 38 feet. The discharge was raw sewage, totally untreated. It was an end-of-pipe discharge with no diffusers to spread the sewage to minimize the impact.

With no treatment preceding the discharge and all of the wastewater discharged at one single point, the debris in the sewage settled to the ocean floor. There were thick sludge deposits in the vicinity of the outfall and measurable impacts to the reef community as far away as where the Reef Runway is today. Polychaete worms and filter feeders, indicators of pollution, were abundant.

worms

 

Photograph 1: Polychaete worms in a mound of debris near the old Sand Island Outfall discharge

The aesthetics of our receiving water were marred by an ever present thick, grayish-brown plume on the ocean surface, usually heading in the direction of ‘Ewa Beach and Barbers Point. As the plume spread it impacted the Ke‘ehi Lagoon area where the nutrients in the sewage stimulated growth of seaweed. Ogo, a favored seaweed, was especially abundant in the area.

plume

Photograph 2: Slick caused by surfacing plume from old Sand Island Outfall discharging into shallow waters

During times when the trade winds were not blowing, debris from the sewage was carried toward the shore and could be found at distant recreational areas like Ala Moana Beach Park. Studies by University of Hawai‘i scientists, who had developed methods to recover viruses from seawater and to culture them, revealed that viruses from the discharge were being carried to the recreational waters.

By 1976, Honolulu had a new 78-inch diameter outfall which extended to about 1-1/2 miles offshore where the ocean was about 225 to 240 feet deep. The new outfall was designed to incorporate state-of-the-art technology that had been developed at the California Institute of Technology. The design reduced the impact of the discharge on receiving waters. Instead of discharging the sewage in one big mass from the end of the pipe, the outfall was designed with a 3400-foot long diffuser section which had 282 openings, ranging from 3 to 3.5-inches in diameter and spaced 24 feet apart. In this way the sewage was discharged in small amounts from each port and spread out over the length of the diffuser. The outfall was designed to keep the sewage from impacting the ocean bottom and nearshore recreational areas. The new outfall also kept sewage from reaching the ocean surface most of the time so that it would not be visible.

The Sand Island Wastewater Treatment Plant was not completed until 1981 and therefore raw sewage was discharged through the new outfall from 1976 until the Sand Island Wastewater Treatment Plant was operational. With the start of operation of the new outfall in 1976, even with a raw sewage discharge there was dramatic improvement to the water quality, demonstrating the efficacy of the design of the new outfall. There no longer was a visible plume on the water surface and without navigational tools a boat would not be able to locate the outfall.

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Photograph 3: The deep, blue waters show no evidence of the discharge from the new Sand Island outfall

Analyses of samples of the sands at the ocean bottom in the area of the new outfall diffuser, collected by lowering a sampler from a boat, indicated that the solids in the sewage were not settling and creating deposits. It was not, however, until about 1982 when the University of Hawai‘i’s research submarine, the Makali‘i, came back with pictures of the clean white sand right at the discharge ports that all doubts about the outfall design were erased. Other pictures also showed that the rocks that are used to anchor and protect the outfall provide relief and habitats on an otherwise barren sand bottom and attracted a new and more diverse population of aquatic biota.

starfish

Photograph 4: Clean bottom at the new Sand Island Outfall (photo credit: Makali’i)

In follow-up virus studies conducted in 1977–1978 the University of Hawai‘i researchers were not able to isolate viruses from the seawater samples taken in the same areas that were sampled in their initial study. Even doubling of the amount of seawater filtered for each sample did not result in positive readings. The only sample that tested positive was collected directly over the new outfall site.

A dramatic demonstration that the discharge was no longer affecting the areas close to the shore where recreational activities occur was the decline of the ogo that had abounded in the Ke‘ehi Lagoon area. With the nutrients in the sewage no longer available to the ogo after the new outfall went into operation, the ogo has to rely on the nutrients in runoff and while still growing in the area, it is no longer plentiful.

The CWA applied to all discharges, not only the municipal discharges. An example of a major discharge that was eliminated was the discharge of approximately 10 mgd of pineapple wastes into Kapalama Canal. With such discharges no longer permitted, it was diverted into the City and County of Honolulu’s sewer system in the mid-70’s. This discharge had caused gross pollution of the canal waters which resulted in a horrendous stench on Nimitz Highway. With the elimination of the discharge, the odors eventually disappeared.

 

Kaneohe Bay

Kane‘ohe Bay contains some of O‘ahu’s finest reefs and a rich and diverse aquatic ecosystem. As the Kane‘ohe area developed, runoff transported increasingly greater silt and nutrient loads from disturbed lands. In addition there were discharges from two secondary wastewater treatment plants, the Kane‘ohe Marine Corps Base wastewater treatment plant (WWTP) and City and County of Honolulu’s Kane‘ohe WWTP. These plants discharged into the southern end of the bay which is quite sheltered and has poor water circulation. The treatment plants added additional organic matter, suspended solids, and more importantly, nutrients into the bay. These imposed stresses resulted in high turbidity in the water column making the water murky. Excessive algal growth, deposition of solids, and the activities of bottom organisms such as filter feeders and burrowing worms were killing the coral reefs.

turbid

 

Photograph 5: Murky, turbid waters of Kane’ohe Bay prior to diversion (left) compared with clear, post diversion water (right)

Diversion of the sewage discharges to a new outfall that discharged to the open ocean off Mokapu Peninsula was recommended to correct the problems. By December 1977, the Mokapu outfall and the diversion lines from the two treatment plants to the outfall were completed and the diversion began. An extensive study of Kane‘ohe Bay was conducted from January 1976 through August 1979 and thus covered the pre- and post-diversion periods. The study showed that after the sewage diversion, clarity of the bay’s waters improved more rapidly than would have been predicted and, within a year, the water was very clear. Although the algal masses that had been smothering the coral also decreased quickly, the coral community had a more gradual recovery. Later studies about 5 years after the diversion showed the corals were recovering nicely.

 

Pearl Harbor

There were several major sewage discharges into Pearl Harbor. Two were the City and County of Honolulu’s Pearl City WWTP primary treated discharge and Waipahu WWTP secondary treated discharge. The Navy was discharging untreated, raw sewage into the harbor as well as secondary treated effluent from its Fort Kamehameha and Iroquois WWTPs near the mouth of the harbor. There were also indirect wastewater discharges from inland treatment plants into the harbor via streams that eventually emptied into the harbor. These treatment plants were the City and County of Honolulu’s Mililani and Palisades (Pearl City) plants and the Army’s Schofield plant. O‘ahu Sugar Company was discharging some of its soil laden sugar mill wastewaters into the harbor. All of these discharges had caused the harbor waters to deteriorate to such a state that in the late 1960’s, the Federal Water Pollution Control Administration, the forerunner of the EPA, to decided to conduct a study to evaluate what needed to be done to rectify the situation.

Diversion of the City and County of Honolulu’s sewage discharges to a deep ocean outfall extending about 1-1/2 miles offshore from One‘ula Beach Park in ‘Ewa Beach was required. The Navy was required to terminate its raw sewage discharge and send the sewage to the Fort Kamehameha WWTP for treatment. O‘ahu Sugar Company was required to recycle its wastewater for cane irrigation. Although no studies have been performed on Pearl Harbor to document its recovery, anecdotal information from federal employees indicate that there have been significant improvements.

 

Waivers from Secondary Treatment Requirements

Under the CWA, waivers from secondary treatment requirements can be granted by the EPA for discharges from municipal wastewater treatment plants that are into the deep ocean. The municipality must demonstrate that its discharge of the less than secondary treated effluent has no adverse impacts on the marine environment and on public health. The City and County of Honolulu has been granted waivers for its discharges from its Honouliuli and Sand Island WWTPs. Its on-going studies have continued to show that primary treatment is adequate for the discharges. A more recent $8 million study by the Mamala Bay Commission, an independent board established as a result of settlement of a lawsuit by the Sierra Club and Hawaii’s Thousand Friends against the City and County of Honolulu confirmed the results of the on-going studies. Even the State’s bacterial standards for recreational waters, the most stringent in the country were shown not to be exceeded.

 

Clear Successes

The CWA established requirements for all dischargers to clean up or eliminate their discharges. While the private sector had to fund its improvements, the Construction Grants Program of the CWA assisted and enabled the City and County of Honolulu and other municipalities across the country to implement many of the necessary pollution prevention and control projects that they otherwise may not have been able to afford. The federal construction grant funds which were made available to the State of Hawai‘i amounted to about $360 million dollars, of which the City and County of Honolulu received an estimated $260 million. Since the grant funds represented 75% of the total eligible costs of the projects, it means the total costs of Honolulu’s projects were at least $347 million. With the State contributing 10% of these project costs or about $35 million, the City and County of Honolulu’s share of the costs was only the remaining 15% or $52 million. The documented improvements in the water quality of O‘ahu that resulted from these projects have been tremendous and the CWA can be considered a clear success here in Hawai‘i as well as throughout the rest of the country.

 

Future Challenges

In the first 25 years of the CWA, the emphasis has been on the cleanup of known pollutant sources or point sources. These were easy targets and also easier to control. The Water Quality Plan for O‘ahu (WQPO) indicated that while gross pollution effects were being caused by point sources, primarily ocean or estuary discharges from the City and County of Honolulu’s wastewater treatment plants, there were other sources of pollutants. Noted were runoffs from streams and agricultural discharges. With the major point sources on O‘ahu now improved to an extent that further improvement will not provide significant benefits, it is necessary to reassess where expenditures of limited public funds should be directed.

The State Department of Health has designated several areas of O‘ahu as Water Quality Limited Segments (WQLS). These are areas where the water quality chronically does not meet the State’s Water Quality Standards and include Ala Wai Canal, Honolulu Harbor, Kahana Bay, Kane‘ohe Bay, Ke‘ehi Lagoon, Kewalo Basin, Pearl Harbor, and Waialua–Kaiaka Bay. It is noted that, except for Pearl Harbor, sewage is not being discharged in these areas and cannot be blamed for the problem. Rather, these are areas that are affected by high mass emissions of pollutants by non-point sources. Further, after intense rainstorms our coastal waters are often colored brown by sediments carried by the runoff. During these periods, although the bacterial counts are often higher than the State standards, the State Department of Health does not normally close beaches unless a sewage spill has occurred at the same time.

Water quality managers are focusing on an approach called watershed planning where all of the pollutant sources in a watershed are evaluated instead of concentrating on specific sources. By taking this comprehensive approach, water quality problems can be prioritized so that limited resources are directed where the returns will be the greatest. While this approach may seem to be logical, it can require a great deal of effort to develop a consensus on the priorities. This is a challenge that faces us all if we are to make significant future strides in water quality improvements.