Influence of various types of surfactants on gas emissions and microbiota of the liquid fraction of manure effluents

Abstract

Various surfactants are widely used in modern industrial animal husbandry. As part of detergents and pharmacological veterinary preparations, surfactants inevitably fall into manure effluents (ME), resulting in a change in the properties of ME. The study of the effect of various types of surfactants on the gas release and microbiota of the liquid fraction (LF) of ME was carried out on the example of surfactants with different biocidal activity: sodium laureth sulfate – anionactive surfactant (AS), lauryldimethylamine oxide – nonionic surfactant (NS) and benzalkonium chloride – cationic surfactant (CS). The studies were conducted under laboratory conditions. The total observation time since the introduction of additives in the LF (0,01 g per 1 liter) was 14 days. The obtained data shows changes in the dynamics of greenhouse gases (CH4 and CO2) and odor-forming substances (H2S, NH3, RSH) emission, as well as in the composition of the microbiota of biofilms and bacterioplankton, under the influence of surfactants. The dynamics of the CH4 emission differ from those of other gases. The use of CS leads to a gradual increase in CH4 emission a week after application. This may be due to increased permeability of the cytoplasmic membranes of methanogenic archaea with increased chemical resistance. The application of various types of surfactants into the LF has different effects on the dynamics of the odor-forming substances emission, and the active emission period of mercaptans becomes longer. The highest level of ethyl mercaptan was observed in the option with NS. There was no significant difference in the effect of low concentrations of various surfactants on the microbiota of LF, however the AS has a more pronounced bacteriostatic effect on set of indicators. The most tolerant to the effects of all types of surfactants were Clostridia, which dominates the microbiota biofilms and bacterioplankton. Fungi were the second most abundant in biofilms of the LF.