Assessing feasibility of sewage sludge composting in rotary drum reactor

Abstract

In a year-long study, the efficacy of a manually operated rotary drum prototype, jointly developed by CEIT Spain and IIM Mumbai, was examined for sanitized compost production in Indian conditions. The prototype, a 200-liter horizontal plastic drum made of high-density polyethylene, incorporated a perforated polypropylene pipe for passive aeration of the composting mixture. Focused on optimizing composting of sewage sludge from a Municipal MBBR, the research targeted key process variables in the rotary drum reactor to attain the thermophilic phase. Wood shavings emerged as the optimal bulking agent, with a mixing ratio of three parts dewatered sewage sludge to one-part bulking agent. A turning frequency of every 12 h proved optimal for achieving the desired temperature of around 60 °C. The study concluded that the final sludge quality met prescribed standards, showcasing the viability of the rotary drum system for efficient compost production in Indian settings.

Keywords: Bulking agent; Compost; Rotary drum reactor; Sewage sludge; Thermophilic stage.