How often are biosolids tested to ensure safety?
Water Corporation biosolids are analysed to ensure they meet the quality standards for land application. These tests are conducted by an external, quality assured laboratory and include analyses for nutrients, metals, PCBs and pathogens. The frequency of testing depends on the amount of biosolids generated by the treatment facility which can range from once each week to once each year. Perth ’s wastewater treatment plants have established a monitoring program that is as frequent as weekly (equivalent to 100 dry tonne of biosolids) for metals and solids content. In addition, the wastewater treatment plants regularly monitor other parameter of the treatment process ensuring the production of quality biosolids. Depending on the type of biosolids treatment, process monitoring may include factors such as temperature, time, pH and volatile solids reduction.
