Faecal Sludge Derived Products as Fertilizer for Lettuce Cultivation in Urban Agriculture

Faecal sludge (FS) contains a significant amount of plant nutrients. After drying and composting, FS has been used as soil ameliorant in several countries. Use of FS-based compost on lettuce may meet reservations due to possible microbiological contamination. The objectives of this research are: (l) to determine the fertilizer value of different formulations of sawdust and faecal sludge compost (SDFS) pellets, (2) to compare the effect of these SDFS formulations with poultry manure, commercial compost, mineral fertilizer and non-fertilization on lettuce cultivation. The SDFS products were made by enriching and pelletized with ammonium sulphate, mineral-NPK or ammonium sulphate + muriate of potash + triple super phosphate. Lettuce was cultivated in a greenhouse and in an open field. The result showed that the fresh weight obtained from all SDFS pellets with/without enrichments were higher than those obtained from commercial compost, poultry manure, mineral fertilizer or no fertilizer. Cultivation in the open field gave higher yields than those in the greenhouse. No helminth eggs were detected in composts or lettuces. Some faecal coliforms were detected in lettuces despite fertilization treatments. A properly treated fecal sludge-based fertilizer can be a sustainable solution for lettuce production which helps urban and peri-urban agriculture.