The present study aims to evaluate the effect of thermal pre-treatment (50, 70 Y 90 °C during 1 h) and acid pre-treatment (2.5%, 5% y 10% v/v during 1 h) in anaerobic digestion process of coffee pulp. The methodology consisted of three stages where the waste was obtained and characterized, applied pre-treatments to evaluate the solubilization degree and biogas production. The residue presented a %VS of 91.80, pH of 5.04, total COD 24.26 g/L and soluble COD 14.88 g/L. The solubilization values obtained by applying thermal pre-treatment increased to 0.92-4.98%, while applying acids pre-treatments of 2.6-18.86%. Subsequently, in the anaerobic digestion process, retention time decreased from 23 up to 14 days. The results obtained in this study demonstrate that, pretreatment is significant to increase the percentage of hydrolysis rate, however, the hydrolysis rate percentage cannot be directly related to biogas production in anaerobic digestion.
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%).
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