Avaliação de dejetos de cachorros para fins energético e aproveitamento do biossólido

Abstract

In 2018, it was reported that in Brazil there was a population of 54.2 million dogs, which were found in homes, kennels, zoonosis control centers (CCZ), society organizations dedicated to the rescue of animals (pet ONGs) and some in street situation, it was also reported the amount of waste generated by these animals that was an average of 340 g/day of waste. The problem was exalted due to the problems related to sanitary issues and the production of greenhouse gases, but it was also realized that it was necessary to pay attention to issues related to the proliferation of zoonotic diseases. One type of treatment for the waste is the process of anaerobic digestion of organic matter present in the biomass. Given the context described, it was necessary to produce information on the potential production of CH4 from dog waste, in view of its energy recovery and proper disposal in the environment. This production can be estimated with the help of biochemical methane potential (BMP) tests that evaluate the capacity of solid or liquid substrates degradation through the generation of biogas and CH4 under standard conditions, attesting through kinetic modeling based on the maximum biogas and CH4 potential of the substrates. For this, it was proposed to determine the per capita generation of waste produced by dogs, belonging to the Kennel of the Fire Department of Pernambuco; to characterize these waste through physical-chemical tests; to evaluate the potential of CH4 and biogas production through Biochemical Methane Potential (BMP) tests in laboratory scale; test 05 kinetic models (first order, logistic, modified Gompertz, Fitzhurgh and cone) from the experimental data; and, finally, propose a more appropriate alternative sanitary management for the biosolids according to the research results. The results obtained were that the puppies have a per capita production of 215.8 g/day. The physicochemical characterization resulted in pH, electrical conductivity, moisture, total solids, COD, alkalinity and others values of 7.58, 7053 ms/cm, 67.44%, 32.56%, 4311.11 mgO2L-1 and 3103.54 mgCaCO3L-1, respectively; The methane potential found was 99.63 Nml.gSV-1 (with bicarbonate) and 123.79 Nml. gSV-1 (without bicarbonate); the dog manure produced a high concentration of methane of approximately 79%, and in relation to the kinetic parameters studied, it was realized that the Cone Model was perfectly suited for the configurations with and without bicarbonate, but in terms of complexity, the Gompertz Model would already meet very well both cases for being a simpler model, which facilitates the stages of simulation and scale up for future reactor design. With this, it was realized that dog manure is an excellent substrate for anaerobic digestion; the tested kinetic models presented excellent fits with the experimental data; the introduction of sodium bicarbonate presented a negative impact on the potential methane generation, but the bicarbonate showed positive results in the speed of biodegradation, the stabilization time of organic matter and that the biosolid obtained at the end of the process needs further studies because the residue of the research was dried at 105 °C and in real scale would require an in natura analysis.