Health effects of faecal sludge use as a soil improver in agriculture

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The study was to investigate the effects of the use of faecal sludge as a soil improver (nutrient potential) to crops and on the health of the farmers and their labour force. Weekly faecal sludge samples exposed to direct natural sunlight on the farms were analyzed the faecal coliforms and enterococci using the Most Probable Number and Pour Plate techniques. Nitrogen, phosphorus and potassium content of the soil before the addition of sludge, the soil—sludge mixture and at harvest were determined using the digestion and distillation, Bray’s Method and the exchangeable potassium determination methods respectively. A questionnaire survey administered to 3() farmers, which sought to obtain information on possible reactions and diseases from sludge on the farmers, was also conducted Fresh faecal sludge contained high numbers of faecal coliform bacteria (I .82 x l0). However, these coliforms reduced by 56-82 % to 9. 1 5 x I 4,00 x I 0’ after 6 to 8 weeks respectively upon exposure to natural sunlight. Additionally, at 0-20cm depth soil nitrogen, phosphorus and potassium improved by 58.75%, 1,01% and 170.89% respectively after addition of faecal sludge. Available nutrients were more at the 0-20cm depth compared to the 20- 40cm. Sixty percent of the farmers had some knowledge on the need for protective clothing use. In spite of the health hazards associated with sludge use, sludge is a valuable resource to farmers and serves as a soil conditioner and humus replenisher an asset not shared by chemical fertilizers and other soil amendment materials.
A thesis submitted to the Department of Theoretical and Applied Biology, Faculty of Biosciences, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfilment of the requirements for the award of the degree of Masters of Science (Environmental Science), 2005