Biosolids are a by-product of the wastewater treatment process that can be used as a biofuel, a fertilizer, or to generate electricity. Transforming these solids into useful products is relatively expensive, thus a thorough evaluation of options is necessary to identify the most environmentally-friendly and cost-effective reuse methods. To this end, EWA completed development of a Biosolids Management Plan (BMP) in 2008.
EWA’s BMP establishes long-term strategies for the distribution and marketing of EWA’s biosolids. In developing the Plan, a detailed analysis of reuse markets was conducted, which included an evaluation of: interest in the product, hauling costs, tipping fees, need for product bagging, associated EWA staff time, and potential revenue. This process identified two tiers of markets. Tier I options (biofuel, contract agriculture, landfill) provide reliable and flexible outlets for biosolids in the near term while Tier II options (fertilizer distributors, soil blenders, specialty agriculture, golf courses/turf management, local communities) require more development work, are more seasonal, have a limited capacity for product use, and may offer public outreach benefits.
EWA implemented Tier I options within the first year of bringing the heat drying facility online. An agreement was made with CEMEX for use of EWA’s biosolids as a biofuel in their Victorville cement kiln. When the kiln was down for maintenance, the biosolids were hauled to Yuma, Arizona for land application.
Since 2011, EWA has been working to develop Tier II biosolids markets. After initial product trials produced positive feedback, EWA increased its outreach efforts and began marketing its biosolids as PureGreen fertilizer. The product is currently used by golf courses, nurseries, fertilizer blenders, sod farms and fertilizer distributers. In FY 2016, this produced sales revenue of about $84,000.
