Evaluation of the effect of tween-80 and its additive amount on the maturity of cassava residue compost

Abstract

Cellulose, hemicellulose, and lignin interweave to form a dense network structure that makes lignocellulosic biomass difficult to degrade. Tween-80 is a non-ionic surfactant that can be used to promote microbial growth and increase the rate of microbial metabolism in compost. In this study, different doses of Tween-80 were presented as additives in the composting process to reduce the composting time and improve the maturity of the compost. The composting trial was conducted in a 10 L reactor for 46 days. The results showed that the addition of the chemical surfactant Tween-80 increased the temperature in the composting process and could effectively promote the degradation of lignocellulose and reduce phytotoxicity. During the composting process, the microbial population showed exponential growth followed by a gradual decline. At the end of composting, Tween-80 added at 0.35% reduced the C/N ratio to 9.61, much lower than that of the CK group at 12.3. Meanwhile, the degradation rates of cellulose and hemicellulose increased by 2.76% and 7.86%, respectively. Toxicity experiments on compost products also proved that the seed germination index of compost with 0.35% Tween-80 addition increased to 98.57%, which is 17.33% higher than that without the addition. FT-IR and TG experiments showed that the addition of Tween-80 could effectively accelerate the composting process and promote the rapid maturation of the heap. In conclusion, the addition of 0.35% Tween-80 was most conducive to promoting the rapid decomposition of organic matter in cassava residue compost and improving the maturity of the heap.