Characterisation and Application of Municipal Sewage Sludge to Agricultural Land in the Maseru Metropolitan Area

Abstract

The nutrient content and other important properties of the sewage sludge from the Wastewater Treatment Plant at Ha Ratjamose in Maseru were determined. In addition, the sludge was characterised in terms of its, pH, salinity, TDS and temperature. The sludge was found to contain 0.011 - 0.013 (wt%) PO43- and 0.018 - 0.070 (wt%)NO3- with D/R 2000 Spectrophotometer. The values for some important physical properties were found to be as follows: pH,( 6.35-6.59); conductivity,( 335- 1674μScm-1) , salinity,( 0.00-0.6) , total dissolved solids (TDS) ,( 355-1576mgL-1) and temperature ,( 24.1-25.5˚C). The sludge was found to contain considerable amounts of nutrients, but lower than those found in commercial chemical fertilizers. It was also slightly acidic, hence it can be more appropriate if applied to strongly alkaline soils or be stabilized with alkalis if it is to be applied to neutral of acidic soils.