Pit latrine faecal sludge solid waste quantification and characterization to inform the design of treatment facilities in peri-urban areas: A case study of Kanyama

摘要

The purpose of the study was to quantify waste content in faecal sludge using an appropriate method and characterise the solid wastes inherent with the faecal sludge into categories. A total of eight (8) domestic pit-latrines were analysed in the peri-urban area of Kanyama settlement in Lusaka from July to October, 2018. From each latrine, three (3) samples were obtained for analysis of solid waste and sand/grit quantities. The quantified solid waste was further characterised to generate its composition. The method of estimation involved separation of the excreta from the solid waste and grit/sand of the faecal sludge by means of washing and drying of the contents. The results indicated high content of total waste, taken as the summation of all the solid waste including grit/sand which averaged 34.2±10.3% (n=24) per wet mass of faecal sludge and 68.9±8.0% (n=24) per dry mass of faecal sludge. Characterisation of the solid waste in the faecal sludge (n=24) showed a composition of 54.4±13.3% textiles, 16.7±6.4% plastics, 8.6±9.3% others, 8.6±5.8% organic waste, 7.6±4.8% paper, 3.1±3.6% metal and 1.0±1.2% glass. The high content of waste has an implication on the handling of faecal sludge especially at the stages of desludging, treatment and disposal/re-use. The study proposed and recommended implementation of user education, improving solid waste management systems in peri-urban areas and studying the feasibility of placing some facilities like biogas digesters above ground to facilitate removal of grit, which is usually problematic with underground facilities. The study also proposed and recommended strengthening the regulation on the construction and operations of latrines, which should be supported by enacting a responsive regulatory framework to ensure all measures, are effectively implemented.