Mathematical modeling of helminth eggs inactivation in pig (Sus domestica) manure from a backyard farm

Abstract

Pathogenic organisms in pig manure can cause serious environmental and health problems. Pigs are susceptible to infection by microorganisms such as fecal coliforms, Salmonella spp., protozoa, and helminths. The latter are found in tropical and subtropical zones, where they are a source of health risk associated with poor sanitation due to contaminated water for agricultural irrigation and the inadequate final disposal of excrements on the ground. For this reason, it is necessary to treat the waste so that it complies with the maximum permissible limits established in the official regulations and is disposed of correctly. In this work, the kinetic parameters of the alkaline inactivation process were determined with different CaO concentrations (10, 15, and 20% m/m) and different time periods (0, 30, 60, 90, and 120 min). In addition, the evaluation of the product DT (ammonia dose and temperature) was carried out for the described process, for which the increase in pH and temperature after the addition of alkaline matter was studied for the inactivation of total helminth eggs in a system open. The mathematical modeling was carried out with the Hom model modified for chemical treatments. The results showed that the process used had an efficiency of 94.7% in the destruction of whole helminth eggs, of which 5.8% was carried out thanks to the ammonia dose and the resulting temperature (9,963 mg/L °C). Although the DT factor was not the leading cause of the helminth eggs inactivation it contributed favorably to the process in addition to the applied CaO dose (20%).