Ph. D.

Ti: Impact of treated sewage water on soil characteristics, forage production and the surrounding inhabitants
Au: Izat Mirghani Taha
Loc: Agriculture, University of Khartoum (2001)
Ph. D. thesis
Ab: This study investigates the effect of Treated Sewage Water “TSW” on soil properties as a result of ten, twenty and thirty years of irrigation for the Green Belt plantations south of Khartoum and potentiality of the water for forage production in location 1, which represent long-time application of TSW and location 2 as control was also tested. Both locations received normal water and TSW for two successive seasons. The study also surveyed the surrounding inhabitants who have close encounters with the TSW. Tests for the TSW indicated that it has low alkalinity and medium salinity, diminishing numbers of coliforms colonies of Escherichia coli from inlet to outlet; a reduction of (103- 104) colonies from an initial (1010- 1012) per 100 ml of TSW was recorded. The average number of eggs of helminths in raw sewage was between zero and twenty, which was reduced by the treatment processes by 25.7 % in the second pond and by 99.89% at the outlet. No significant changes in soil mineral content or the texture were induced by effluent. Slightly decreasing values of pH as a result of the saline effluent were recorded but still close to neutrality. A slight increase of Organic Carbon, Nitrogen and Organic matter contents were observed. Heavy metals level was found in low concentrations because of the initial low concentration in the effluent. Forages tested belong to family Poaceae and cultivars of Sorghum bicolor “Abu Sabaien, Pioneer, Panar and Speed feed”. Irrigation by TSW resulted in relatively taller plants, plants of all cultivars looked vigorous and healthy, with less fiber content, high protein values and significantly higher dry yields compared to those irrigated by normal water at 0.05 levels of significance and no symptoms of phytotoxicity were observed. The yield of Pioneer was significantly higher than the rest of the cultivars at 0.05 levels. TSW showed no effect on soil characteristics and no serious pollution probed. Moreover, it can be safely used for the production of fodder crops of the family Poaceae. Living at a stone-throw from the treatment facility inhabitants suffered from objectionable odours, bites and nuisance from insects but they need not to fear from close encounters with the TSW because of the comparatively safe treated sewage water produced from the treatment facility in Soba.
Supervisors: Dr. Malik Nasr Malik
                         Prof. Siddig Elsheikh