An investigation of agricultural use potential of dewatered sewage sludge

Background: One of the useful applications of Dewatered sludge (DWS) of municipal wastewatertreatment plants (WWTPs) is its use as manure in agriculture; therefore, its quality characteristics shouldbe specified. The aim of this research was to determine biological and physicochemical characteristicsof DWS of Sari WWTP and compare them with standards, and also to investigate its potential use inagriculture.Methods: Sludge samples were taken from the sewage sludge of Sari WWTP. Sampling and analysisof samples parameters including fecal coliform, salmonella, helminth ova, carbon, nitrogen, C/N,phosphorus, organic matter, potassium, moisture, electrical conductivity, and PH, were performedduring four seasons with three replications based on the standard method.Results: The fecal coliform, salmonella, and helminth ova of the DWS were 2.37×106 ± 1.06×106MPN/1 g d.s weight, 47±12.92 MPN/4 g d.s weight, and 466±61.85 number/4 g d.s weight, respectively,therefore, the DWS of Sari WWTP was categorized in the class B of the EPA standard. The amountsof C/N, organic matter, carbon, nitrogen, phosphorus, potassium, moisture, electrical conductivity,and PH were obtained to be 12.7±1.15, 42.4±3.27%, 24.6±1.89%, 1.94±0.13%, 2.35±0.6%, 0.57±0.13%,82±3.12%, 1.34±0.21 ds/m, and 7.41± 0.45, respectively.Conclusion: The DWS of Sari WWTP has a good fertility value but it cannot be safely used in agricultureand should be improved for class A by the Processes to Further Reduce Pathogens (PFRP), especiallyby composting.

کلیدواژه ها:

Sewage sludge ، Agricultural use ، Fertilizer ، Pollution control ، Dewatered sludge