Use of Slow Sand Filtration Technique to Improve Wastewater Effluent for Crop Irrigation

Water scarcity has resulted to urban residence to resort to using untreated wastewater to irrigate their crops. This practice raises concerns on health of the farmers and consumers of the crops. The study aimed at determining whether the effluent from Boundary Sewage Treatment Plant was up to national and international standards recommended for irrigation, if not they were further subjected to slow sand filtration of different sand sizes (0.1 and 0.05 mm) to polish the effluent. Pour plate method was used to determine total coliforms (TC), Biological oxygen demand (BOD) technique for BOD, chemical oxygen demand (COD) digestion for COD, gravimetric method for total dissolved solids (TDS) and total suspended solids (TSS). One sample t-test during dry season showed that BOD, COD, TC and TSS in the effluent were significantly higher (P<0.05) than the standards for irrigation. During wet season BOD, COD, TDS and pH were significantly not higher (P>0.05) than the compared standards for the wastewater to be used for crop irrigation. The filters improved the effluent from the treatment plant to the standards for irrigation. The sequential treatment of the raw wastewater by the Boundary Sewage Treatment Plant and the slow sand filtration technique made the wastewater to achieve the standards it can be utilized for crop irrigation.