Biosolids Quality and Operational Improvements

Client: Confidential Client

Project: Biosolids Quality and Operational Improvements

Project Type: Wastewater Solids Processing Support

Industry: Utilities

Location: Coatesville, PA

The 6 mgd Wastewater Treatment Plant participated in a cost-effective beneficial use program for years with low outside-the-gate expenses. Stabilization was achieved via the addition of lime to undigested solids. Over a period of years, limitations for beneficial use and field storage from poor biosolids stacking and biosolids field odors became severe. Product quality challenges resulted in up to 70% of biosolids being taken to landfill at a significant cost. Additionally, nuisance odors from liquid storage at the plant caused serious complaints from the surrounding neighborhoods.

Material Matters recognized that biosolids quality improvements were necessary to restore a near 100% beneficial use program. Plant solids data was analyzed, additional testing was requested, and product characterization was completed. After calibrating and evaluating the lime addition system, lime stabilization process recommendations were made. Plant odors were traced to the liquid storage tanks. Dissolved oxygen levels, blower type / settings, and mixing data were reviewed, and observations were made. Based on the findings, recommendations were made to improve storage tank mixing and oxygenation.

With lime addition improvements, biosolids stacking was improved and total solids were increased, making field storage of biosolids possible. Poor oxygenation and mixing in the liquid storage, where solids were becoming septic, was corrected with recommended operational changes, without costly capital improvements. Neighborhood odor complaints stopped almost immediately. Together, these improvements improved biosolids product quality (low odor, higher total solids, ability to stack) allowing for field storage and 100% beneficial use.