Changes in microbial pathogen dynamics during vermicomposting mixture of cow manure–organic solid waste and cow manure– sewage sludge

Purpose Microbial pathogens can lead to health problemsand disease transmission. Present study aimed to evaluatethe microbial quality and quantity of vermicompost productionand to compare to the current Iranian standards toprotect public health and environmental concerns.Method This is a pilot-scale experimental study conductedin the Public Health laboratory of Shahid SadoughiUniversity of Medical Sciences. The samples includedorganic municipal solid waste, cow manure and wastewatertreatment plant sludge which are used for vermicompostproduction. The samples are mixed as cow manure–organicwaste and cow manure–sewage sludge in two reactors.Microbial tests such as fecal coliforms (FC) and parasiteegg (Ascaris) were carried out during start, processing andcuring time with duplication analysis in 56 days. Totally, anumber of 128 samples was analyzed. Analyses wereconducted according to standard methods. Data analysiswas conducted through one-way ANOVA and Duncantests.Results The results showed a significant reduction innumber of FCs in cow manure–organic waste so that thenumber of 350,000 MPN/g in the raw sample decreased to800 MPN/g within 8-week period, also FC in the case ofcow manure–sewage sludge was achieved to 2400 from6,500,000 MPN/g. In two cocomposting cases, the parasiteeggs were completely removed in the second week.Conclusion The results showed vermicomposting as afeasible method to convert waste into fertilizer humus inagriculture which also enables to achieve Iranian class Acompost standard.