Comparison and toxicity assessment of co-composting process by pistachio wastes and date-palm straw combined with municipal sewage sludge

This study aimed to compare and evaluate the toxicity of co-composting process pistachio dehulling waste combined with municipal sewage sludge (PW + SS) date-palm straw (PS SS). The was evaluated over a 60-day period. During process, physicochemical parameters (temperature, humidity, pH, electrical conductivity (EC), carbon nitrogen ratio (C/N), ash, volatile organic matter (VOM)), microbial indicators (Escherichia coli, Salmonella, parasite eggs), heavy metals (copper, zinc, iron, manganese, lead, cadmium, nickel), germination index were measured. In PW SS reactor, maximum temperature reached 59 °C on 32nd day in PS 39 18th day. pH level minimum 3.2 14th then increased finally 9.5. had an increasing trend 7.1. Ash content 27.5% 19.1% SS. EC, C/N, VOM both reactors significant decreasing trend. E. coli indicator decreased from ≥ 105 zero at end process. Toxicity assessment showed that compost less toxic than compost.