Comportamento de enterobactérias em sistemas de tratamento aeróbio descentralizado de resíduos sólidos orgânicos domiciliares

Abstract

Composting is an environmentally sustainable technology, involving the action of various organisms, which in turn contribute to the degradation of inorganic organic matter into inorganic matter, favoring the release of nutrients to autotrophic organisms. This research aimed to analyze the behavior of enterobacteria in aerobic treatment systems of household organic solid waste. The work was divided into five stages: contact with families; structuring and assembly of the experimental area; development and / or adaptation of aerobic biological treatment systems for household organic solid waste; collection of organic solid waste in the households of the families that joined the project; monitoring and evaluation of the aerobic biological treatment system of household organic solid waste. Household organic solid waste was collected segregated from other waste. We collected 331 kg in the study area. This type of residue presents high values of organic matter and humidity, besides the presence of pathogenic organisms. Two models of triplicate composters were adopted: CPC - Cylindrical Polyethylene Compounder and CAR - Rectangular Aluminum Compounder, distinct in configuration, aeration and homogenization accessory (crank or steering wheel) and the type of material used for making each compost was fed 26.6 kg of crushed substrates. Of this total, 80% were household organic solid waste and 20% were structuring (tailings and meal). The purpose of adding structurants was to favor aeration, the moisture content appropriate to the action of native organisms and the equilibrium of the C / N ratio. The two composter models studied met the main objectives predicted for the technology focus of this work: stabilization and sanitation of household organic solid waste. Considerable enterobacteria diversity was found during treatment. Nine genera and fifteen species were identified: Citrobacter (25.9%), Enterobacter (14.1%) Escherichia were identified. (11.7%), Klebsiella (5.9%), Marganella (1.2%) Proteus (35.4%), Providencia (1.2%), Serratia (2.3%), Salmonella (2.3%). These bacteria play an important role in the degradation of organic matter, favoring the stabilization of the material under treatment. It was found that the highest growth rates of enterobacteria were in the mesophilic phase. Variations in the density and diversity of enterobacteria followed in line with changes in the physical and chemical characteristics of the system. It is concluded that there is considerable diversity of enterobacteria in household organic solid waste, acting in the different phases of the composting system, correlating positively and negatively with physical and chemical changes.