Application of bio-drying technique for effective moisture reduction and disposal of sewage sludge in the framework of water-energy nexus

Abstract

This research was conducted to study the application of bio-drying technique for effective disposal of sewage sludge from wastewater treatment plant. Sewage sludge and bio–dried products were randomly collected from the Wupa wastewater/sludge treatment plant at the Idu Industrial area Abuja, Federal Capital Territory, Nigeria. The bio–dried product was a mixture of sewage sludge and sawdust that were bio–dried and cured before this experiment. The bacterial communities were analyzed in the laboratory using Pour Plate Technique to examine the total bacterial present in the sewage sludge bio -drying Material (SSBM) and the bacterial were later isolated using other techniques like Oxidase test, Catalase test, Grams Staining technique and Spread Plate Technique while evaporation of free water and water formation was determined by humidity gauge and moisture-oven drying method. The result shows that the moisture content of the SSBM decreased from 63.1% to 51.6%, the water evaporation was 43.56 kg, 2.86% of water generation was noticed on the 6th day and the volatile solid content decreased from 67% to 54%, the bacterial density dropped down drastically (Mesophilic - 483 × 104 cfu/g to 15 × 104 cfu/g and Thermophilic – 2.50 × 104 cfu/g to 0.10 × 104 cfu/g). The study concludes from the bacterial density grades that increase the temperature of the SSBM during the bio–drying process reshaped the bacterial communities.