Application of mixed organic waste for effective septage treatment through In-vessel co-composting.

Septage management is a serious challenge in most of the low and middle-income nations. In this study, the conversion of septage into fertilizer through thermophilic composting was investigated. The complementary materials, essential for effective septage co-composting were identified through self-heating study, prior to in-vessel composting. The study revealed that the composting of septage was enhanced and the compost quality was improved by the addition of mixed organic waste (MW), due to the presence of readily available carbon and nitrogen in MW. The micropollutants, mainly personal care products (PCPs) and pharmaceutically active compounds (PhACs) present in the septage that cause serious environmental threats, can also be degraded through effective septage co-composting. Among several bulking agents investigated, coir pith enhanced the composting because of its high air-filled porosity and water holding capacity. In-vessel co-composting of septage with MW and coir pith resulted in higher temperature (>55°C) for more than 3 days. This is essential to meet the regulatory criteria for pathogen destruction. Moreover, the MW addition improved the final compost quality in terms of nutrient content. More than 80% of the micropollutants degraded through in-vessel cocomposting. A nutrient content of above 4% dry weight and a seed germination index of above 80% favoured the potential application of ripened compost as fertilizer for plants growth. [ABSTRACT FROM AUTHOR]