Sermsook Pakkattang creator Eckhardt, Ing. Heinz Chairperson Ishibashi, Yoshinobu Examination committee Tinsley, Richard L. Examination committee Preeda Pakpian Examination Committee Royal Thai Government Scholarship donor text th Bangkok Asian Institute of Technology 1997 monographic eng

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96 leaves The application of Bangkok nightsoil and sewage sludge to agricultural land was investigated considering the nutrition value and pathogen problems. Analysis of two sewage and one nightsoil sludge, a pot study and a field study using sunflowers and grass have been conducted. The investigations showed the suitability of this sludges for reuse in agriculture. A good sludge treatment e.g. anaerobic digestion has a good influence on the sludge characteristics, such as lower numbers in fecal coliforms and no presence of parasites together with high nitrogen content ( ~ 4% N). The application of two sludges to a field study with sunflowers showed linearly relations between nitrogen application and grain yield. The application of 120 kg N/ha with sewage sludge from Huay Kwang showed the highest yield. This results are comparable to the 80 Kg N/ha application with chemical fertilizer. Nitrogen applied by sludge is not immediately available because of the required mineralization in the soil whereas available phosphorus and exchangeable potassium in the soil were raised, which proved to have certain benefitial effects on crop yield. In terms of pathogens the sludge amended soils have to be left more than three months after sludge application to reduce the fecal coliforms until less than 2 MPN per 2 gram wet weight (the lowest detectable number). The field study with grass showed a linearly relation between nitrogen application and fresh biomass yield. The liquid sludge application seemed to be most suitable. Considering aesthetic aspects the grass fields have to be left 110 days to receive a fecal coliforms free soil. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development Thesis (M.Sc.) - Asian Institute of Technology, 1997 Sewage sludge as fertilizer Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B13992 http://203.159.5.9/ait-thesis/detail.php?q=B13992 20260818170328.0