Comparative Study of Physicochemical Properties, Parasitic and Microbial Diversity of Compost Derived from Various Waste Sources

Global human population upsurge presents a serious challenge for human solid waste management. The problem is dire in Southeast Asia and Africa. Kenya is faced with “flying toilets,” where raw excrement is put in paper bags and flung at the nearest open space. The study’s objective was to progressively determine and compare the physico-chemical characteristics and microbial profile of human solid waste, cow dung, goat waste, and poultry droppings composts. The Green Toilet System developed by LIXIL ensured negligible or zero interaction between solid and liquid human wastes. Composting and daily monitoring duration was 183 days. Sample collection and analysis was carried out on day 1 and after every 21 days. Light microscopy was used for detection and quantification of parasites. Bacteria molecular analysis was carried out by amplification of conserved 16S rRNA gene. One-way ANOVA was used to determine the difference between means. Duncan’s multiple range (p < 0.05) was used to analyze individual means. Multiple sequence alignment was performed using MEGA X. Varying minimum (21.333 °C ± 0.577 °C) and maximum (58.333 ± 0.577°C) temperatures for human solid waste compost were observed. At the end of composting for human solid waste, compost color expressed as hue angle (H°) was 75.153 ± 2.514°, odor was very faint, and texture was moderately fine. There were significant differences among the means of TDS, pH, EC, C:N, OM, and moisture of all composts. Eliminated and reduced parasite burden was observed. Pathogen profile and interrelationships were elucidated. In conclusion, progressive composting plays a major role in compost microbial load reduction.