The preliminary evaluation of differential characteristics and factor evaluation of the microbial structure of rural household toilet excrement in China

Abstract

Recent studies on the microbial community composition of human excrement after rural household toilet treatment are unclear regarding the effects and risks of using recycled products as fertilizers in agriculture. In this study, we used Illumina high-throughput sequencing to investigate the microbial community structure of the excrement from 50 Chinese rural household toilets on a spatial scale, and we evaluated the impact of select geochemical factors on the bacterial and fungal communities in the human excrement. Multivariate analysis showed that there was a significant spatial differentiation of the human excrement in microbial communities after all toilet treatments. Twenty dry toilet samples and thirty septic tank samples had similar bacterial (Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes) and fungal phyla (Ascomycota and Basidiomycota), differing only in the proportions of the microorganisms. For both dry toilet samples and septic tank samples, the pH and ammonium nitrogen were found to be the major driving forces affecting the changes in bacterial community structures ( p <0.05), while there was no correlation found for the fungal community with environmental factors in China ( p >0.05), except in the northern regions, where the total phosphorus was found to be significantly correlated with the fungal community ( p <0.05). Network analysis confirmed that NH 4 + -N had the most significant impact on the content of pathogens. Certain pathogens were still detected after toilet treatment, such as Streptococcus , Bacteroides , Aspergillus , and Chrysosporium , and the proportion of potential pathogenic bacteria in dry toilets was higher than that in septic tanks, suggesting that septic tanks were better than dry toilets in treating human excrement. These results provide an ecological perspective for understanding the large-scale geographic distribution of household excrement microbial communities in rural areas and for improving human excrement treatment technologies and avoiding the risks of agricultural applications. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-021-13779-9.

Effects of Partial Blackwater Substitution on Soil Potential NI-Trogen Leaching in a Summer Maize Field on the North China Plain

“…A large-scale survey revealed that the proportion of pathogenic bacteria in the effluent from septic tanks is very low [44], and ensured environmental health and agricultural application safety. While approximately 86% of the households stated that they would prefer their excreta to be used in agriculture as fertilizer [45], there is no instructional document to teach farmers how to use blackwater to fertilize, and the usual practice of farmers is to return all the collected blackwater to the field.…”

Sustainable sanitation- how can we improve sanitation systems in the global south?

“…In the process of rapid economic development and the continuous advancement of rural urbanization, the huge population and remote geographical location of rural areas have meant that they have long-term disadvantages in terms of infrastructure, science and technology, and development awareness, especially with regard to rural toilets, which are considered to be the most difficult to manage, and there is a lack of rural infrastructure in developing countries Li et al, 2021). Non-hygienic toilets, such as open toilets, in which feces cannot be safely stored quickly enough, can cause intestinal infectious diseases such as dysentery and typhoid fever, thereby increasing the risk of death from infectious diseases Gao et al, 2021). Some studies have also indicated that the contributions of total nitrogen and total phosphorus from toilet sewage accounted for 84% of the total pollutant load of rural domestic sewage (Angelakis et al, 2015).…”