Land Application Permitting Assistance
City of Modesto, California

West Yost has been providing ongoing permitting assistance to the City in relation to the City’s 35 mgd wastewater treatment plant and land application system, which consists of approximately 2,500 acres of agricultural land that receives undisinfected secondary effluent, biosolids, and cannery process water flows. The majority of these regulatory support services have been related to implementation and renewal of the City’s land application permits, which currently include separate biosolids and recycled water discharge permits. The services provided by West Yost have specifically included preparation of land management spreadsheet tools, a comprehensive Report of Waste Discharge (ROWD) and Antidegradation Analysis as part of an application to renew the City’s land application permits, development of a Title 22 report, and preparation of an Annual Land Management Report. 

The spreadsheet tools for the land application areas provided the City of Modesto with an easy-to-use tool for real-time management of the City’s land application systems, such that hydraulic and nutrient loadings from treated effluent, cannery process water, and biosolids do not exceed regulatory limits or adversely impact groundwater quality.

The ROWD, Antidegradation Analysis and Title 22 Report were needed to respond to the Central Valley Regional Board’s request to update the City’s biosolids and recycled water discharge permits, which have not been significantly updated in about 20 years. The ROWD and Antidegradation Analysis included an evaluation of recent land application hydraulic and chemical (nitrogen, salt, biochemical oxygen demand) loadings, and recommendations for changes to the City’s onsite monitoring well network to allow for better evaluation of both on-site and off-site impacts to groundwater. Changes that the City prefers to have in the renewed land application permit, including monitoring and reporting changes, were also described and justified in the ROWD. West Yost’s detailed understanding of the City’s treatment process and land application system and experience with recent and complex groundwater evaluations were especially important in preparing an effective report.

West Yost was also a key team member in preparing the City’s Wastewater Treatment Master Plan, completed in 2016. West Yost’s major tasks included: preparing flow and load projections for domestic and industrial sources; evaluating current and potential future regulatory requirements; preparing water balances of the City’s pond-based secondary treatment system and land application activities; and evaluating liquid and solids treatment and disposal alternatives.