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Published on: September 13, 2022
Evaluating changes in microbial population and earthworms weight during vermicomposting of cow manure containing
Fereshteh Molavi1, Mohammad Hassan Ehrampoush1, Ali Asghar Ebrahimi1
1Environmental Science and Technology Research Center, Department of Waste Management, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, 8915173160 Iran.
Background:
Transmission of pathogens such as fecal coliforms is regarded as a significant concern about using livestock manure in agricultural applications.
Purpose:
The aim of this study was to evaluate the effects of vermicomposting on fecal coliforms in cow manure containing co-trimoxazole as a widely used drug for cow diseases in animal husbandry.
Methods:
Adaptation process of earthworms was carried out in two phases for 6 weeks; then, the main process was fulfilled in 9 weeks. The final weight of cow manure per reactor was 3.5 kg. 120 g of earthworms added to each reactor (approximately 280-300 numbers in the reactor). Co-trimoxazole was also prepared with a purity of 99% from Pakdarou Co., Iran, and added to the reactors at concentrations of 10, 20, 50, and100mg/kg. Organic carbon, total Kjeldahl nitrogen (TKN), carbon-to-nitrogen (C:N) ratio, as well as phosphorus content of the reactors were measured. Fecal coliforms and parasite eggs were counted using standard laboratory methods (i.e. the Iranian Compost Standard) for 8 weeks.
Results:
The results revealed a decrease in organic carbon, C:N ratio, and co-trimoxazole content but a rising trend in TKN and phosphorus levels. The weight of earthworms also increased at the end of the process in all reactors, except for one case. A significant reduction was observed in fecal coliforms and parasite eggs at the end of the vermicomposting.
Conclusions:
According to the results, earthworms could be active in cow manure vermicomposting including 10-100 mg/kg concentration of co-trimoxazole antibiotic. The vermicomposting seems to be an effective method for reducing fecal coliforms and parasites in cow manure. As well, co-trimoxazole in common concentration could not have any effects on the ability of earthworms. At the end of the vermicomposting, all parameters were placed within the ICS (National) - Grade 1.
