Peracetic acid can be used for sludge conditioning before thickening/dewatering.
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H2S and NH3-related odor formation is prevented (peracetic acid dose ≥ 25 mg/L).
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E. coli and Salmonella are inactivated (peracetic acid dose ≥ 480 mg/L).
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Phytotoxicity can be prevented by controlling sludge amount in soil.
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No detrimental effects for macronutrient amounts or availability.
Abstract
Peracetic acid (PAA) is an environmentally friendly disinfectant and oxidizer used in several water and wastewater treatment applications. In the present study, PAA was utilized for the conditioning of municipal wastewater sludge before thickening and dewatering. It was shown that PAA can effectively prevent odor formation (i.e., H2S and NH3) and provide hygienization (using E. coli and Salmonella as indicators). Phytotoxicity can be prevented by controlling the amount PAA-conditioned sludge that is mixed in the soil to be fertilized. The required PAA dose for hygienization was relatively high (480 mg 100% PAA perL sludge) but the results indicated that other sludge stabilization processes are not necessarily required. Therefore, the proposed process involving PAA could be feasible in cases where limited land area is available for sludge processing or quick conditioning of sludge is required.
