Potential of biodigesters for the treatment of organic effluents in rural areas

Abstract

Water is essential for life and one of the most valuable natural resources, therefore, today, the rational use of water is a concern worldwide; However, this resource is increasingly scarce, since is consumed in large quantities in both rural and urban communities and only a low percentage is treated. In Paraguay, in rural areas, according to data of the permanent survey of households 2013, 29.7% of dwellings has cesspit (absorbent) and 24% with septic cesspool; however these single systems are connected to the treatment of the sewage generated in the bathroom; other waters do not receive any treatment. The basic aspects that must be considered when the water pollution is analyzed by discharge of domestic sewage: the first refers to the concentration of the coliform group that reflects the relative risk of infection; the second refers to the physical and chemical water quality, especially related to the content of organic matter in solution, suspension or in colloidal State, the presence of fats or oils, nutrients such as nitrogen and phosphorus and toxic substances such as heavy metals; and the third refers to the goals of water quality based on their applications, among which one can quote the human use, the domestic, the preservation of flora and fauna, the agricultural and the recreation. The bio-digesters are natural systems that take advantage of anaerobic digestion for the generation of biogas and fertilizers; its use is not only limited to the treatment of wastewater, but also, it can be fed with manure generated by animals, this eliminates these piles of manure by reducing outbreaks of infection, odors and flies, in addition to reducing the pollution of water resources. This research aims to design a biodigester that allows the treatment of effluents generated in rural households, this uses the methodology suggested by Marti (2008). Whereas the data provided by the EPH (2013) on average, homes in the rural area, have 4 inhabitants and two cattle. In order to be able to treat all effluent generated is recommended the implementation of two bio-digesters, one of 1.5 m3 for the treatment of Lee and another of 2.8 m3 for the treatment of other types of organic matter (manure, leaves, etc.).