Water Resource Recovery Facilities Operate as Urban Microbiomes

June 23, 2016

Featured

John Seldon, WEF Member and Founder of Temporary Operations and Maintenance Inc.

Photo courtesy of John Seldon.

Photo courtesy of John Seldon.


John Seldon, a Water Environment Federation (WEF; Alexandria, Va.) member since 1980, is founder and president of Temporary Operations and Maintenance Inc. (Port Burwell, Ontario, Canada). During his career, Seldon has focused on optimizing municipal and industrial solids collection and dewatering systems. Since entering the wastewater field in 1973, Seldon has

  • developed and taught courses for water resource recovery facility (WRRF) operators; published articles and research reports on topics such as biosolids, regulations, and operations; written and provided presentations on wastewater operator training and accreditation;
  • presented research at many wastewater sector events;
  • worked as a WRRF manager, technical support superintendent, in wastewater equipment sales, and as a project manager;
  • joined the Ontario Association of Certified Engineering Technicians and Technologists (Etobicoke) and is a certified engineering technologist;
  • obtained certification in environmental assessment; and
  • earned a mid-career master’s degree in regional planning and resource development from the University of Waterloo (Ontario, Canada).

A water resource recovery facility (WRRF) is as integral to an urban community as the human stomach is to a person’s health. Both systems operate in a surprisingly similar way, using microorganisms to convert organic substrate and nutrients to repair or generate new cells. Each acts as essential, living infrastructure for its  interrelated communities. Both require care and upkeep — from operators for WRRFs and doctors for human systems.

Human and WRRF biomes rely on a concentration of microbes that

  • receive food through sophisticated delivery systems,
  • consume organic substrate to thrive and reproduce,
  • produce metabolic byproducts essential to protect human health,
  • can be hindered by poor quality food and aided through bioaugmentation,
  • can be harmed by exotic wastes delivered by the food supply chain, and
  • are studied and evaluated by professionals able to aid in their recovery.

The human microbiome is monitored directly by its host: when it is working properly the individual feels well and continues with work, rest, and recreation. When out of sorts, a person can seek the aid of health-care professionals. For a WRRF, operators daily evaluate its microbiome, prescribing process remedies when needed to keep the organic infrastructure well. Wastewater operators are the health-care professionals of our community WRRFs.

Human and WRRF biomes share a common ground

At the community’s core, a WRRF consists of bricks, plastic, concrete, and metal. It provides a home to aerobic, anaerobic, and facultative microbes that thrive and ensure their own survival through reproduction and population growth. In return for the home as well as the food, oxygen, and mechanical mixing that maximizes their well-being at WRRFs, microbes provide clean water and stabilized organic matter. The strategic byproducts of this are protecting watershed ecosystems and human health.

Bacteria have provided services for both humans and wastewater for millennia. As urban centers grew from villages to metropolitan cities, the burden of human and industrial wastes has been placed on receiving streams. Without wastewater treatment, source water supplies would be polluted with pathogens, toxic organic and inorganic compounds, and massive organic loading. These supplies would be unfit for drinking, compromise public health, and restrict urban dwelling and growth.

To sustain human populations and allow urban civilizations to continue growing, wastewater was directed to collection systems that convey it to WRRFs for treatment. The microbiological core of waste treatment in WRRFs is supported through aerobic and anaerobic processes.

Carbon-based substrate – food to digest

Just as humans have a variety of options for preparing their food, microbes can work in many types of activated sludge facilities from conventional setups to membrane bioreactors to sequencing batch reactors. These processes concentrate microbes in very large numbers within either or both aerated and anaerobic process steps.

The WRRF community biome has no choice in the organic substrate available, it merely receives what arrives. Excessive organic waste loading that causes a high biochemical oxygen demand may overload the WRRF biome and possibly kill off beneficial bacteria. But humans can improve and protect their microbe factories. Sewer discharge regulations help mitigate threats to the community microbiome, and operators can manage systems internally. If wastewater flows lack sufficient phosphorus or nitrogen to help bacteria survive and reproduce, nutrients can be supplemented. When a WRRF employs denitrification, a carbon source supplement like ethanol can be added.

Also, commercial companies offer probiotic supplements for bioaugmentation at WRRF community biomes. Companies supply packaged microbes to add to an activated sludge system. Augmenting the conventional activated sludge process can enhance the existing biome. Healthy conventional activated sludge aeration tanks can be a source for acquiring the most effective strains of microbes. These strains can be cultured into commercial quantities and added to other aeration cells where needed. When operators diagnose systems fully, they can supply activated sludge to neighbors or other parts of their own facility, should one area lose its biomass and microbes. This supplementation can help return the WRRF’s performance to good health much faster.

Professional care to fix microbiome failure

Just as human health suffers when its system is compromised, WRRF community biomes can fail to meet regulations when aerobic and anaerobic systems are compromised. Overloading or underloading organics in a biome system will adversely affect its performance and can result in high biochemical oxygen demand or an inability to stabilize a facility’s digested solids.

In these situations, professional operators specializing in microbiology become the diagnosticians for these systems. They can assess the biome’s operating characteristics using a number of tools. These may include reviewing basic process measurements such as settling tests, dissolved oxygen levels, average cell residence times, acidity, organic acid concentration, and alkalinity. Corrective action may include improving the microbe’s diet by enforcing the wastewater treatment system’s use bylaws and ensuring incoming wastes are free of toxins and excess organic loading. Prescribing bioaugmentation also may boost a poorly performing biome.

Just as artificial compounds such as artificial sweeteners and pesticides in food are a concern for human systems, some chemical compounds also raise concerns in WRRFs. Bisphenol A and antibiotics are two of many compounds that may be treated only partially or not at all by WRRF processes because the biome is not up to the task. Failing to treat these wastes can result in their discharge to a receiving stream that also serves as the source of water for a community.

Once identified by a professional WRRF health-care professional, the problem can be fixed by removing exotic wastes from the community microbiome food supply before wastewater ever reaches the WRRF, a good example of preventive medicine.

WRRFs sustain civilizations and protect human life

WRRFs sustain modern life through harnessing some of the smallest organisms alive, while their cousins perform much of the same lifesaving role within each human. Each system is inextricably linked to and mutually dependent on microorganisms.

A WRRF is an engineering construct that typically incorporates two centers of biome concentration with mechanical and chemical infrastructure that support the biome’s health. For WRRFs to function properly, knowledgeable operators must focus on facility operations. Professionally accredited operators with formal academic training in microbiology are essential to monitoring a WRRF’s microbiome and diagnosing corrective measures when needed to ensure its best performance.

WRRF community biomes protect the health of whole watersheds and their urban residents. Without sophisticated wastewater treatment, life as we know it would soon collapse. The work of operators is key to sustaining urban lifestyles. I propose that we spend more energy knowing the names and qualifications of the operators who are responsible for keeping a WRRF biome healthy to protect receiving streams, drinking water supplies, and public health. Perhaps instead of singing competitions, we should have publicly televised competitions to select those who are appropriately trained and talented enough to operate WRRFs or engineer and build them.

— John Seldon, WEF Member

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