Palestinian experience with enhanced pre-treatment of black wastewater from Birzeit University using a UASB septic tank system

Abstract

Successful implementation of the UASB (Anaerobic upflow sludge blanket) at pilot and full scale has produced very encouraging results that show its feasibility as a pre-treatment for black and domestic wastewaters. The economic advantages it offers, further encourages developing countries to become self-sufficient in this respect. In this contribution, the start-up of the UASBseptic tank system and its monitoring during this period was the main objective. A pilot scale UASB reactor with a liquid volume of about 400 L (h= 1.88m and φ =0.265m) was fed with the black wastewater collected from the Faculty of Commerce at Birzeit University. During the startup phase, the reactor was operated in a batch mode for six months and only shortly operated in a continuous flow node. The results obtained demonstrated that the system is quite effective in removing organic pollutants. The removal rate of the organic pollutants was mainly due to biophysical process, which is sedimentation of the particles and its microbial degradation. Although, the microbial activity was yet slow it contributed to the total COD removal efficiency. The CODtotal removal attained was approximately 80% in which the removal of CODss, CODcol, and CODdis was 68%, 23% and 52% respectively. The UASB effluent has a good transparency with an elimination rate of 80% and 85% for TSS,and VSS respectively. This would facilitates a natural post- treatment (waste stabilization ponds), where photosynthesis and pH might increase. Based on the results obtained from this research study, the UASB-septic tank system offered practical advantages compared to conventional septic tanks through its small size , biogas collection and utilization, and elimination of odour problems. Furthermore, its ease of operation encourages its application in poor rural areas of Palestine