Evaluation of biodegradation feasibility through rotary drum composting recalcitrant primary paper mill sludge

Abstract

Primary paper mill sludge (PPMS) is the major waste expelled from the pulp and paper industries contributing soil and water pollution through the recalcitrant organic and inorganic constituents. These pollutants can, however, be transformed into a high-value soil ameliorating material with nominal investment and time. Current study therefore evaluated the potential of rotary drum composting PPMS for 20 days to delineate an environmentally sustainable option. Five trials with proportions of PPMS, cow dung and saw dust: Trial 1 (10:0:0), Trial 2 (8:1:1), Trial 3 (7:2:1), Trial 4 (6:3:1) and Trial 5 (5:4:1) were performed for evaluation of degrading and nutritive ability along with the fate of pollutants for total mass of 150 kg. Trial 4 exhibited highest metabolic activity contributing higher temperature evolution and longer thermophilic phase (10 days) owing to optimum addition of innoculum and nitrogen through the cattle manure. Moreover, degradation of 16.8% organic matter was also best achieved in Trial 4 following up first-order kinetics. Furthermore, BOD, COD and C/N ratio also explains degradation to be maximum in trial 4 (6:3:1) with reduction of 59.3%, 60.1% and C/N ratio from 55.1 to 18 respectively, proving to be the essential determining factors. Phosphorus availability increased by around 67% in trial 4. PPMS can be thus transformed into a potential valued added product and safe for subsequent land application.