Synergistic effects of chemical additives and mature compost on reducing H_2S emission during kitchen waste composting

Additives could improve composting performance and reduce gaseous emission,but few studies have explored the synergistic of additives on H_(2)S emission and compost maturity.This research aims to make an investigation about the effects of chemical additives and mature compost on H_(2)S emission and compost maturity of kitchen waste composting.The results showed that additives increased the germination index value and H_(2)S emission reduction over 15 days and the treatment with both chemical additives and mature compost achieved highest germination index value and H_(2)S emission reduction(85%).Except for the treatment with only chemical additives,the total sulfur content increased during the kitchen waste composting.The proportion of effective sulfur was higher with the addition of chemical additives,compared with other groups.The relative abundance of H_(2)S-formation bacterial(Desulfovibrio)was reduced and the relative abundance of bacterial(Pseudomonas and Paracoccus),which could convert sulfur-containing substances and H_(2)S to sulfate was improved with additives.In the composting process with both chemical additives and mature compost,the relative abundance of Desulfovibrio was lowest,while the relative abundance of Pseudomonas and Paracoccus was highest.Taken together,the chemical additives and mature compost achieved H_(2)S emission reduction by regulating the dynamics of microbial community.

Effects of different C/N ratios on the maturity and microbial quantity of composting with sesame meal and rice straw biochar

The purpose of this paper was to study the effects of different C/N ratios on the maturity and microbial quantity of com-posting with sesame meal and rice straw biochar.Rice straw was calcined into biochar as raw materials composting with sesame meal for 30 days,referring to Chenfu Agricultural Book in Sōuthern Song Dynasty(1127-1279 A.D.).Sesame meal was used to adjust the C/N ratio of compost,and three treatments were designed in the experiment,which were C/N ratios of 15,20 and 30,respectively.The results showed that C/N ratio of 20 was beneficial for promoting the temperature rise,the removal of water,the degradation of organic carbon,and the decrease of microbial quantity.The C/N ratio of 20 was beneficial to the compost maturity(T value was 0.47,final GI was 99.67%).The results of Pearson correlation analysis showed that C/N ratio was positively correlated with moisture content,total organic carbon and negatively correlated with germination index,indicating that high C/N ratio was beneficial to water removal and total organic carbon degradation.Therefore,we suggest that the suitable C/N ratio of rice straw biochar and sesame meal is 20.At the same time,we have proved that the composting method in Southern Song Dynasty is feasible,which is of great significance to understand the development of composting in China.