wastewater treatment plant under construction

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Water and Wastewater Treatment

Ensuring safe and reliable water is available in your community

clarifier and secondary sedimentation basins

Water and Wastewater Treatment

From permitting and planning to start-up, West Yost’s water and wastewater treatment experts will take the guesswork out of your complex projects

We provide a full-service approach across the entire spectrum of water and wastewater treatment disciplines, including technical studies, modeling, regulatory and permitting assistance, advanced treatment plant design, funding assistance, and construction management. Our firm’s unique ability and experience working with clients from planning and permitting through construction bring intrinsic value to our projects and our clients.

Facility Types

  • Wastewater and Recycled Water
  • Nutrient Removal
  • Biosolids
  • Biogas Management and Energy/Heat Production
  • Organic Waste and Co-Digestion
  • Surface Water and Groundwater
  • Solids and Waste Stream Management
  • Facilities and Site Improvements

Permitting/Regulatory Compliance

  • Permit Adoption and Compliance Support
  • Water Quality Studies
  • Antidegradation Studies
  • Groundwater Monitoring
  • Biosolids Land Application Management
  • Title 22 Reports
  • Pretreatment Program Assistance
  • Regional Water Quality Control Board and State Department of Public Health Services Coordination


  • Treatment Facility Master Plans
  • Facilities Planning, Alternatives Analysis, and Feasibility Studies
  • Process Modeling/Optimization
  • Energy Management Plans
  • Condition Assessments
  • Prioritized CIP Development
  • Plant Hydraulic Modeling
  • Pilot Testing


  • New Facilities, Expansions, and Upgrades
  • Repair, Rehabilitation, and Optimization Improvements
  • Bid Phase and Construction Support Services

Operations Support

  • Process Optimization and Trouble Shooting
  • Operations Plans, Operations & Maintenance Manuals, and Standard Operating Procedures
  • Tracer Studies
  • Operations Training
  • Facility Start-Up Assistance
  • Data Management

Climate-Energy-Reliability (CER)

Process-based energy solutions for reliability, resilience, and economy

West Yost’s Climate-Energy-Reliability (CER) service develops and delivers process-based energy solutions for our water sector clients. Our team is highly experienced in deploying solutions that combine emerging technologies with science-based engineering principles to reduce energy demands, improve mechanical system performance, and enhance the resilience of your water system.

Our core goal is to reduce our clients’ dependency on non-renewable resources through a transition to reliable and renewable resources.

To achieve exceptional results for our clients, we focus on the key mission-critical functions of reliability, resilience, and economy–through the energy lens.

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Project Highlights

Ariel of water pollution control plant in Davis, California

Multi-Year Treatment Facilities Planning and Design

City of Davis, CA

For nearly 30 years, West Yost has acted as the City of Davis’s trusted advisor for its treatment planning, design, and construction needs. West Yost has completed the planning and design for a major expansion to the Water Pollution Control Plant (WPCP). In support of the City, we have continued to provide additional services with alternative analysis and providing solutions on challenging problems.

Water pollution and control facility lit up at night.

White Slough Water Pollution Control Facility Multi-Year Planning and Regulatory Compliance Support

City of Lodi, CA

West Yost has been providing wastewater treatment and disposal system planning, regulatory compliance, and engineering design services for the City of Lodi’s White Slough Water Pollution Control Facility (WPCF) since the late 1990s. This project work started with a role in the development of a flexible Wastewater Master Plan to identify the improvements needed to address Lodi’s capacity and rehabilitation needs over a 25-year planning horizon. The Plan was completed in December 2000.

Advanced water treatment upgrades

Wastewater Treatment Plant Improvements

City of Jackson, CA

West Yost designed improvements to most of the City of Jackson’s wastewater treatment plant to address new regulatory requirements and aging infrastructure. Improvements included conversion of existing oxidation ditches to simultaneous nitrification-denitrification with improved aeration control and instrumentation, construction of a new disc filter facility, conversion from chlorine disinfection to UV disinfection using inclined lamp configuration, changing from belt press dewatering to screw press dewatering, construction of a new electrical building and MCC capacity, up-sizing electrical service to the facility, and installation of a new standby generator.

Wastewater Treatment and Biosolids Facilities Master Plan

Dublin San Ramon Services District, CA

West Yost completed a comprehensive Wastewater Treatment and Biosolids Facilities Master Plan for Dublin San Ramon Services District that evaluated every aspect of the District’s wastewater treatment system and included a detailed capital improvement program to address key capacity and condition-related issues through 2035.

Secondary treatment basin with agitated wastewater.
Clarifier at Row River Treatment Plant

Row River Water Treatment Plant Expansion

City of Cottage Grove, OR

West Yost performed design services, bid support services, and construction support services to the City of Cottage Grove for the Row River Water Treatment Plant Expansion project. The project’s objective was to expand the water treatment plant’s capacity from 4 mgd to 6 mgd.

Easterly Wastewater Treatment Plant Expansion

City of Vacaville, CA

West Yost performed planning and design services for two major projects at the City of Vacaville’s Easterly Wastewater Treatment Plant (EWWTP), a $100 million Expansion/Upgrade Project and a $130 million Advanced Treatment Project. West Yost recently designed an acetic acid storage and feed system at Vacaville’s wastewater treatment plant. West Yost is also currently completing engineering services for the design of odor control systems at the Vaca Valley Lift Station and Easterly Wastewater Treatment Plant.

Basin at the Easterly Wastewater Treatment plant.

Team Spotlight

Timothy Banyai, PE

Treatment Business Sector Leader

Kathryn Gies, PE, ENV SP

Regulatory and Planning Practice Area Leader, Engineering Manager II

Preston Van Meter, PE

Principal Engineer II

Insights & Trainings

West Yost is an Equal Opportunity Employer

EEO Policy