Biosolids Management

Of the nine Wastewater treatment plants (WWTP) owned and operated by Oxford County, the four larger mechanical plants (Woodstock, Tillsonburg, Ingersoll, and Thamesford) generate biosolids that need to be processed on a daily basis.

The other systems inventory the material within the treatment systems over long periods of time, or in the case of Drumbo WWTP, have it transported to another facility (Woodstock WWTP) on a weekly basis for processing. 

Of the four larger mechanical plants, two plants digest biosolids anaerobically (Woodstock and Ingersoll) and two digest biosolids aerobically (Tillsonburg and Thamesford).  

Woodstock WWTP generates approximately half of all the biosolids generated in Oxford County, excluding lagoons, and had traditionally landfilled this material while the other plants traditionally used a combination of agricultural land application and landfilling of the material. This changed in 2008 with the implementation of the Oxford County Biosolids Management Master Plan (BMMP) with dewatering at three of the four mechanical plants and biosolids being transported for winter storage at the Biosolids Centralized Storage Facility (BCSF) for ultimate application on agricultural land as a nutrient.

Oxford County Biosolids Management program was the winner of the 2008 Biosolids Award from the Water Environment Association of Ontario (WEAO) for small generators of biosolids.

 There are five main elements to Biosolids Management at Oxford County which include:

• enforcement of the Oxford County Sewer use by-law,
• dewatering of stabilized biosolids at each of the major Wastewater treatment plants,
• transporting of thickened biosolids from smaller plants to the nearest major Wastewater treatment plant for processing,
• land application of all biosolids on approved soil conditioning sites, and;
• centralized storage of biosolids when the material cannot be land applied.

Watch this video “Biosolids: Naturally Sustainable” created by the Water Environment Association of Ontario (WEAO) for more information.