EOA provides expert technical and regulatory services to Publicly Owned Treatment Plants (POTWs) for all aspects of NPDES discharge permit compliance and for developing and implementing water recycling programs. Decades of wide-ranging staff experience in the wastewater field, coupled with specialized expertise in regulatory compliance issues, allows EOA to provide exemplary cost-effective services to clients for both “one-time” and long-term ongoing projects. Our services include:
- Technical and regulatory assistance to clients for NPDES permit re-issuance and amendment
- Design and implementation of NPDES permit special studies, compliance monitoring and reporting programs, and associated data management systems
- Technical assistance and training for POTW industrial pretreatment, laboratory, and plant O&M programs
- Contributing to regional initiatives to develop TMDLs and site-specific water quality objectives
- Assisting with planning, developing, and implementing all aspects of recycled water programs for conventional and advanced systems, including physical infrastructure, administrative, monitoring, and regulatory compliance
EOA’s clients have included the Cities of Sunnyvale, San Jose, Benicia, Livermore, and Pacifica, and special districts including East Bay Dischargers Authority (EBDA), East Bay Municipal Utility District (EBMUD), Las Gallinas Valley Sanitation District, Oro Loma Sanitary District, Sewer Authority Mid-Coastside, and Carmel Area Wastewater District, and many agencies.
CASE STUDIES
Wastewater Treatment Plant Technical and Regulatory Services
City of Sunnyvale Water Pollution Control Plant
Since 1986, EOA has provided assistance to the City of Sunnyvale Water Pollution Control Plant on NPDES permit renewals, including Reasonable Potential Analyses, infeasibility studies, and negotiating permit requirements. EOA has also provided assistance on a number of special studies required by the plant’s NPDES permit, including those associated with disinfection byproducts, chronic toxicity, ammonia, cyanide, and copper & nickel. EOA provides ongoing support to the City on plant operations, laboratory and pretreatment staff training, annual report preparation (e.g., NPDES, Reclamation, Biosolids, Pretreatment, Pollution Prevention, Recycled Water), and, design and support for data management systems. We have also provided support for plant master planning and capital projects, pilot projects, and participation in regional wastewater groups and programs.
Review of California’s Water Recycling Criteria for Agricultural Irrigation
National Water Research Institute (NWRI)
EOA, Inc., working for the national Water Research Institute on behalf of the California Department of Public Health, recently completed a review of California’s water recycling regulations in response to increased interest in expanding the amount of recycled water used for agricultural purposes. It specifically addressed the risk of exposure and infection from waterborne pathogens, such as Cryptosporidium and E. coli, due to the irrigation of a wide variety of food crops using recycled water. The report was prepared by a panel of nine experts jointly led by Robert C. Cooper, Ph.D., who is Professor Emeritus of the School of Public Health at the University of California, Berkeley, and Adam W. Olivieri, Dr.P.H., P.E., and the Vice President of EOA, Inc. Key issues addressed by the panel include:
- Characterizing “safe” recycled water for use in irrigation
- Appropriate assumptions regarding an acceptable risk to public health
- Relevancy of current criteria for reducing viruses and using chlorine disinfection
- Need for a “multiple barrier” of treatment processes to remove microorganisms
- Use of turbidity as a valid parameter to assess the performance of treatment processes
- Standards used to clarify and define “secondary wastewater treatment,” which involves biological treatment processes to remove contaminants and/or bacteria
- Use of total coliform bacteria to assess the effectiveness of disinfection in reducing microorganism
- Ability of crops to take in viruses through their root systems, leaves, and other points of entry, and any associated risks to public health
The panel includes responses to each of these issues, as well as provides suggestions to refining the State’s Water Recycling Criteria. Among the conclusions, the panel stated that “current agricultural practices that are consistent with the [Water Recycling Criteria] do not measurably increase public health risk, and that modifying the standards to make them more restrictive will not measurably improve public health.” The report is available here.
Characterization of the Potential Adverse Human Health Effects
National Association of Clean Water Agencies (Formerly American Metropolitan Sewerage Agencies)
EOA evaluated the potential public health risk associated with combined sewer overflows and sanitary sewer overflows. To carry out this evaluation, a literature review was first conducted on the concentration of pathogens of public health concern in raw wastewater and stormwater. Human exposure to pathogens was defined by the volume of water that the public may be exposed to during overflow events, as well as the relative number of individuals that are likely to be exposed during those events. A series of tables and graphs representing the risks to public health associated with overflow events was developed and presented. Guidelines for risk management were then discussed based on the results of simulation modeling and the existing federal risk thresholds for recreational water quality.