Influence of Nitrogen Containing Wastes Addition on Natural Aerobic Composting of Rice Straw

Problem statement: Rice straw is an agricultural residue. Typically, the rice straw can be burn in the rice field after the harvesting process. The burning can cause air pollution. Another alternative rice straw management method is animal feed. The amount of rice straw is enormus in Thailand. Another sustainable way to manage rice straw is required. Rice straw is used as main waste to compost with nitrogen containing wastes such as golden apple snail, cattle dung and urea in natural aerobic composting reactors. The golden apple snail is a pesticide and cattle dung is an animal waste. Both materials are all waste of low values. The main purpose of this study was to determine the influence of nitrogen containing wastes addition to rice straw on the performance of natural aerobic composting process in terms of the following parameters: pH, temperature, organic matter, C/N ratio, electrical conductivity and GI. The impact of this study is to reuse agriculture residue by composting. Approach: The experiments was consisted of three reactors. The reactor 1 contains the rice straws and golden apple snails while the reactor 2 contains the rice straws, golden apple snails and urea. The reactor 3 contains the rice straws, cattle dung and urea. The experiments were carried out in designed natural aerobic reactors (60 L) under controlled laboratory conditions over 60 days. The analysis was done every 5 days however the temperature was measured daily. Results: The experimental results showed that the initial C/N ratio was 30.7, 30.3 and 31.8 in the reactor 1, 2 and 3, respectively. After the 60-day period, the final C/N ratio was reduced to 17.9, 16.9 and 18.4 in the reactor 1, 2 and 3, respectively. The main nutrients (N: P: K) from all reactors achieved the standard level for Thai compost standard. The rice straw as agricultural residue was suitable for co-composting with golden apple snails and cattle dung as the nitrogen containing wastes. Conclusion: The final compost is the good quality compost according to the Thai compost standard. The moisture content is slightly higher than the Thai compost standard. The final compost can be dry in the air to reduce moisture before use. The final compost can be use as a fertilizer."