Award-Winning Wastewater Treatment System Design Projects


Wastewater Treatment Plant Expansion and Tertiary Upgrade
City of Woodland, California

West Yost assisted the City of Woodland in expanding their Wastewater Treatment Plant (WWTP) capacity from 7.8 mgd to 10.4 mgd, while also providing new tertiary treatment facilities (oxidation, coagulation, and filtration and ultraviolet (UV) disinfection of the effluent.) The project consists of an expansion of the secondary process to achieve ammonia removal to concentrations less than 2 mg/L, new tertiary facilities, and 100-year flood protection for the main portion of the treatment facility.


Facility Study/Preliminary Design and WWTP Improvement Design
City of Galt, California

West Yost assisted the City of Galt (City) in identifying and analyzing alternatives for achieving compliance with NPDES permit requirements. West Yost prepared a Permit Compliance Action Plan that recommended alternatives. The City used this information to proceed with near-term treatment facility improvements that will also position the City to be responsive to future growth needs, as well as additional changes in regulatory requirements. The addition of filtration and ultraviolet (UV) disinfection was identified as an important first step towards achieving compliance with the City’s discharge permit. West Yost worked with the City to pilot test filters and provided the preliminary design of these new treatment processes.


Regional Wastewater Treatment Plant Planning and Design
City of Atwater, California

West Yost provided planning and design for the City of Atwater’s new Regional Wastewater Treatment Plant (WWTP). The new plant was required to increase average flow capacity to 6 mgd (expandable to 12 mgd ultimate) and comply with new regulatory requirements for advanced treatment. West Yost evaluated upgrades to existing treatment plant facilities as well as alternatives involving abandoning the existing plant and constructing new facilities on a City owned site five miles from town.


White Slough Water Pollution Control Facility Expansion/Upgrade
City of Lodi, California

West Yost has been providing wastewater treatment and disposal system planning, regulatory compliance services and engineering design for the City of Lodi White Slough Water Pollution Control Facility (WPCF) since the late 1990’s. West Yost completed design of the City’s $60 million improvement project at the WPCF, incuding tertiary filtration and UV disinfection facilities, expansion of the treatment capacity from approximately 6.5 mgd to 8.5 mgd, and the addition of process improvements to provide full ammonia conversion and partial denitrification. 


Easterly Wastewater Treatment Plant Expansion
City of Vacaville, California

In 1997, West Yost was retained by the City of Vacaville (City) to perform evaluations to expand the Easterly Wastewater Treatment Plant (EWWTP) from 6 mgd to 15 mgd average flow capacity (and from 27 mgd to 55 mgd peak flow capacity) and to provide nitrification so that effluent ammonia limits of < 2mg/L could be reliably achieved – referred to as the Expansion Project. This project included all aspects of facilities planning, design, construction services, NPDES permit assistance, and State Revolving Fund (SRF) loan coordination for a major $100 million expansion and upgrade program to the City’s EWWTP.