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2015 PWC FI

2015 Pacific Water Conference [Photo Gallery]


 

The 2015 Pacific Water Conference

Feb 2015 HWEA Community Service - FI

2015 Pacific Water Conference Community Service [Photo Gallery]


Second Annual Pacific Water Conference Community Service Event
with Hawaii Water Environment Association, American Water Works Association, in Partnership with Livable Hawaii Kai Hui

When: Saturday, January 31 from 9am-noon
Where: Keawawa Wetland
What: Removing shrubs and invasive plants; planting native species.
Special thank you to Alyssa “Sunshine” Smith for organizing the event.

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HWEA 2015 Golf Tournament - FI

2015 Pacific Water Conference Golf Tournament [Photo Gallery]


 

February 2, 2015
Hawaii Prince Golf Course
A special thank you to: Merlita Alimagno, Anna Sasaki & Darnelle Chung, the amazing organizers of this year’s Pacific Water Conference Golf Tournament.

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SJWP 2015 FI

SJWP Hawaii State Winner – Iokua Spencer


 

Bioluminescent Bacteria as a Natural Water Pollution Indicator
Iokua Spencer

The environment I grew up in consisted of hand-me-downs, food stamps, and low-income housing.  Due to these circumstances, I go to a school for at-risk youth with dedicated teachers who do their best to help us succeed.  I became interested in learning how to make positive changes in my life through education. Contrary to the skeptics around me, I overcame the pressures of life and became inspired.

Much of our way-of-life depends upon the ocean; it’s Hawaii’s largest natural resource and attraction for our tourism industry because the ocean is a cultural and economic resource for Hawaiians. With the growth of land development, population, and industry it is important to always remember that the health of our state is tied to the health of our ocean.  In September of 2013, Honolulu harbor was devastated by a huge molasses spill. The marine environment was severely affected with the lack of oxygen.  Approximately 26,000 fish, various other marine species, and a lot of coral died.  This was a huge environmental catastrophe.  Storm water runoff from non-point pollution has also caused sedimentation and changed the ecology of Kaneohe Bay.  The incidence of mercury is increasing in Hawaii’s waters because of harbor waste such as boat cleaning products.  Mercury-laden products are used to clean surfaces and restore ship surfaces.  Society needs to be more aware of this growing problem and take steps to protect our ocean water as a critical resource.  This led to my interest in studying whether bioluminescent bacteria could be used as a water pollution indicator.

The global importance of my study was to develop a solution by creating a test kit that can be used globally to identify water pollution.  The significance being that using natural bacteria as a quick indicator, it will be environmentally safe in lieu of using chemicals. Two experiments were done and the following results were seen:

  • Experiment #1: The bioluminescence showed no change significant enough in the levels of light over time to be a reliable indicator of water pollution. However, it may also be an indicator that the beach water samples were “clean.”
  • Experiment #2: Because Vibrio fischeri* experienced death at different concentrations of mercury, this shows that mercury can be an effective indicator when used as a negative control in determining marine water pollution. This outcome proved that Vibrio fischeri can be used as an indicator of water pollutants such as mercury.

The study found that bioluminescent bacteria is a natural resource and can be used to indicate water pollution.  They confirm an idea presented on the Instructables website which suggested creating a bioluminescent bacterial lightbulb that may be used as a water pollution tester.

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* Aliivibrio fischeri is a gram-negative, rod-shaped bacterium found globally in marine environments.[1] A. fischeri has bioluminescentproperties, and is found predominantly in symbiosis with various marine animals, such as the bobtail squid. It is heterotrophic and moves by means of flagella. Free-living A. fischeri cells survive on decaying organic matter. The bacterium is a key research organism for examination of microbial bioluminescencequorum sensing, and bacterial-animal symbiosis.[2] It is named after Bernhard Fischer, a German microbiologist.[3] rRNA comparison led to the reclassification of this species from genus Vibrio to the newly created Aliivibrio in 2007.[4]

Welcome to the Updated Website!


To the Members and Friends of the Hawaii Water Environment Association:

I am so happy to be able to introduce our new website! It has been a long road of planning, surveys, reviews, meetings, iterations of changes and emails, and we finally have a great product to show for it. In a world where technology has become an integrated part of our lives, the need for change in how the Hawaii Water Environment Association communicates with our members was necessary. All of the information from the former site is still available, along with additional pages for each committee, events, and up-to-date information about the occurrences within our association. Between the late 1990’s and early 2000’s, the Lua Line newsletter was created and distributed. We wanted to keep the tradition, but morph it into an easy-to-use and read article-based website.

First and foremost I would like to thank Leland Lee, Mark Goodrowe and all of the other members who have put in so much time and effort into the old webpage. Your contributions over the years have helped in collecting old memories and files.

old webpage

HISTORY OF THE REBRAND AND WEBSITE RENEWAL:

The purpose of rebranding is to invigorate, update and refresh how the public and our members see the association. With the environment coming to the forefront of the public’s thoughts and attitudes, it is a great time to get our name out there. With the hopes to outreach publicly more, rebranding will be one of the most important first leaps. To justify the revamp of our website, we needed a clear vision and statement of who we are. Two years ago HWEA revised the Strategic Plan and Vision Statement to update our vision and mission as professionals committed to preserving and enhancing our water environment, essential to the Pacific Island Region by providing industry leadership, engage all water professionals, promote innovation, and support clean and sage water for our communities.

A survey was sent out to the membership, and the website was a high priority for change. In changing the website, the logo is a part of that for coherency. We wanted to appeal to a broader audience including those in the entire Pacific region, as well as water/wastewater professionals and the public. After many years of the same logo, updating will keep our association relevant, focusing on transference of information through digital media and hopefully bring old and new membership together.

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In the survey distributed about a year ago our members told us that above all, a calendar of events, updated information and training materials would be most important. We have incorporated many of these features, and in the next few months we hope to fill in the gaps.

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Another piece missing was a newsletter. In the survey a large majority believed that a HWEA newsletter would be of value. We hope to accomplish this through published articles under the MEDIA section at the top of the website.

About a year later and with lots of help, we now have a user-friendly website to update, maintain and hopefully help increase involvement.

ENDING REMARKS

I would like to thank our rebranding and communications committees including: Jack Tano, Jason Nakata, Carly Kaneko, Carol Zuerndorfer and a special thank you to Audrey Haerle, without their help this website would not have been possible. Also, much appreciation to Seabelo Silitshena with [100 Innovations] for the website design and dealing with a bunch of busy volunteers!

It is an honor and privilege to work with HWEA, WEF, and the members of both. As the 2015-2016 President I hope to implement a new program to help Operators and to establish a precedent for this website and its maintenance. Please let me know if you would like to be involved or have any questions or comments about the Hawaii Water Environment Association.

Emily Dong, P.E.
Hawaii Water Environment Association – 2015-2016 President

emily

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.

2015 Service FI

2015 Conference Community Service Event

 

Second Annual Pacific Water Conference Community Service Event
with Hawaii Water Environment Association, American Water Works Association, in Partnership with Livable Hawaii Kai Hui

When: Saturday, January 31 from 9am-noon
Where: Keawawa Wetland
What: Removing shrubs and invasive plants; planting native species.

Over 25 HWEA members, friends and family gathered to volunteer at the second annual Pacific Water Conference community service event with AWWA and Livable Hawaii Kai Hui. The physical labor comprised of removing invasive species and planting native species.

According to Livable Hawaii Kai Hui:

The Trust for Public Land is working with a non-profit community organization Livable Hawai‘i Kai Hui (The Hui) to protect a 5-acre property in heavily-developed Maunalua, O‘ahu. The property includes Hāwea heiau complex and a portion of Keawawa wetland. The property contains numerous petroglyphs, an ancient niu (coconut) grove, a once spring-fed well, and many ancient rock formations thought to be house structures, a Tahitian style heiau, agricultural terraces, burial sites, and Hāwea heiau. Oral and written accounts from 8 centuries ago reflect the importance of Hāwea heiau as one of the places that La‘amaikahiki’s canoe landed carrying with it one of only two pahu heiau (religious drums) – Opuku and Hāwea – used ceremonially at the royal birthing grounds of Kūkaniloko, in the piko (center) of O‘ahu. Keawawa wetland is home to approximately 9 of the remaining 300 endangered ‘alae ‘ula (Hawaiian moorhen), as well as indigenous ‘auku‘u (Black-crowned night heron), pinao (Hawaiian dragonfly), and possibly the ‘ōpe‘ape‘a (Hawaiian hoary bat) that historically lived in the area.

The Hui’s goal is to protect, restore and mālama (take care of) Hāwea heiau complex and Keawawa wetland, and to create a cultural renaissance within Maunalua through community education of the cultural and natural resources located on the property. The Hui preliminarily envisions a small entrance space where visitors can learn about the area’s importance before entering, the restoration and preservation of all cultural sites, an environment dominated by native species, a pā pahu (pahu drumming area), a fishing hale, a la‘au lapa‘au (healing and medicinal plant) garden, and a thriving native wetland ecosystem that provides additional protected habitat and nesting grounds for the endangered ‘alae ‘ula and other native species. The property will be a community owned and managed cultural heritage park that will provide educational, cultural, and recreational opportunities to the Maunalua community and the broader public.

Reference: http://hawaiikaihui.org/4.html

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2015 YP Summit Group Featured Image

2015 Young Professionals Summit


As this year’s Young Professional (YP) Committee Chair for the Hawaii Water Environment Association (HWEA) and AWWA Hawaii Section, HWEA sponsored me to attend this year’s YP Summit in Austin, Texas. This year’s summit preceded the Utility Management Conference, and it brought together young professionals from around the country from both the public and private sectors, including many involved with utility operations.

The speakers at the summit included George Hawkins, General Manager of DC Water and Sewer Authority; Kurt Vause, Engineering Division Director of Anchorage Water and Wastewater Utility; Doug Bean, Director of Utility Services at Raftelis; and Glenda Dunn of the City of Waco and a former AWWA Vice-President. While the speakers provided great insight into the water industry, their passion and charisma were their greatest means of conveying their messages to the YPs.

George Hawkins kicked off the summit with a high-energy talk about unlocking innovation. He listed his steps to doing this, which included reaching out to students, operators, financial people, vendors, utilities, and the media. Mr. Hawkins also spoke of a personal experience which he described as both the worst and best day on the job. A large storm had flooded the sewer system, causing sewage to back up into peoples’ homes, and Mr. Hawkins had to address the public about what had happened. Although he had to face angry homeowners, he was also able to explain to them why this occurred and the importance of upgrading the aging sewer system. By the end of it, he was able to get the public on his side, which helped to facilitate the subsequent construction.

Kurt Vause discussed the keys of success in public water sector management. His six keys to success included 1) it’s all about the people, 2) always work your boss – priorities first, 3) differentiate public vs. private, 4) creation of the culture, 5) process vs. policy, and 6) check your ego but not your passion. Mr. Vause also impressed upon us the importance of interpersonal and group skills and how we must identify our strengths and weaknesses. He said that we need to be able to trust the people we work with and also be prepared to tell the boss “no,” if necessary. He also relayed to us that there’s a trick called “2793,” where you have 27 words and 9 seconds to make 3 points.

Doug Bean spoke to the group after lunch, and kept everyone’s full attention during his presentation about the commoditization of water. He described public health as encompassing community, environment, and the collective benefit to society, and if the collective good helps public health, why shouldn’t the pricing also be a shared price? Mr. Bean described the differences in measuring value for public versus private organizations. Public organizations rely on public value, mission achievement, and public trust, and private organizations are measured by shareholder value, profitability, and customer loyalty. He stressed the importance of knowing who you’re working for and what its value is measured by.

The last speaker of the summit was Glenda Dunn, who spoke to us about professionalism. She stressed that emotional intelligence (EQ) is greater than IQ. Nowadays, there are four generations in the workplace, and it is a challenge to deal with the different perceptions of loyalty and work/life balance. She also discussed the various types of power: role power-authority; skills and knowledge; and relationship power. To bring the summit to a close, Ms. Dunn encouraged the YPs to “follow your bliss.” She wanted to the YPs to know that while work plays a huge role in our lives, we need to make sure that we enjoy our lives outside of work too.

The YP Summit included roundtable discussions following each presentation, and it spurred discussion about creating a positive culture within the office, what attributes make a great public utility, and how do you capture knowledge from the aging/experienced workforce before they retire.

Overall, the YP Summit was a great learning experience that allowed me to meet YPs and leaders with various backgrounds in the water industry, and I thank HWEA for giving me this invaluable opportunity to attend.

2015 YP Summit Group Pic

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.

Nutrient article photo of bloom

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

 

 

 

 

 

 

 

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