Effect of Different Mass Ratios of Straws and Vegetable Wastes on Co-Composting
The effects of different raw material ratios on straws and vegetable wastes co-composting were investigated in pilot scale. The evolution of physical property (temperature, pH value, electrical conductivity (EC)) and nutrient substance (total carbon content (TC), total phosphorus content (TP), total nitrogen content (TN), C/N ratio) of composting were measured in order to research effects of different raw material ratios on the quality and maturity of composting products. Results showed that The temperature of P3 can reach above 50oC for 5 days and the time of high temperature for P3 was longer than P1 (2 d) and P2 (4 d). Compared with P1 (8.23 ms/cm) and P2 (7.63 ms/cm), the final EC value of P3 was 7.33 ms/cm which was lowest of the three piles and P3 had the lowest resistance on plants. At the end of the composting process, TC of P1, P2 and P3 have decreased about 30%, while the content of TN and TP has not changed significantly. The initial C/N ratio of P3 was 23.33, and the final C/N ratio was 12.08. Results indicated that the mass ratios of straw and vegetable waste on 7:3 was the most effective to compost and the compost quality and maturity of P3 was best among the three piles.