Options for beneficial reuse of biosolids in Victoria

Abstract

This paper presents a synopsis of current biosolids management in Victoria as well as an overview of some biosolids processing technologies. Indicative capital and annual costs to upgrade wastewater sludge management facilities at Victorian wastewater treatment plants to maximise safe beneficial reuse of biosolids and sludge products are provided. The data will be particularly useful for preliminary assessment and planning purposes of biosolids management strategies for government, non-metropolitan urban water authorities and regional waste management groups. Indicative cost curves are presented for various sludge treatment and biosolids reuse options applicable to treatment plant sizes between 2000 and 200,000 ep.

Biological Wastewater Treatment in Warm Climate Regions Volume II

“…Ideal C/N ratio for sewage sludge composting should range from 26-31 (Oorschot et al, 2000). If C/N ratio is higher than this, organisms will not find enough nitrogen, have their growth limited, and the process will become slower, not reaching the temperature required for pathogen destruction.…”

“…Several studies (Oorschot et al, 2000;EPA, 1992EPA, , 1994 have shown that the addition of 30-50% of CaO on a dry weight basis (0.3 to 0.5 kg CaO per kgTS) to sludge leads to biosolids with pathogenic organisms below the detection threshold. Hydrated lime can also be used, although a significant increase in sludge temperature is not attained, therefore requiring a longer contact time.…”