ABSTRACT Swine wastewater have high pollution load, requiring treatment before its disposal into the environment. Methane (CH4) potentially emitted for such waste is considered 21 times more polluting than Carbon dioxide (CO2), and the nitrous oxide (N2O) is considered 310 times. In this way, projects of the Clean Development Mechanism (CDM) and energy use related to the CH4 are worldwide diffused. It was evaluated the potential greenhouse gas emissions in the influent and effluent from digesters and stabilization ponds used to treat the swine wastewaters in two commercial farms operating in full cycle, located in the municipality of Oratorios-MG, Brazil. Using the methodology “AM0006” to estimate the average potential of greenhouse gases, it was identified 55% and 23% of reduction in emissions from digesters and stabilization ponds, respectively. Thus, when comparing the two systems, in the conditions that they were operated, it can be concluded that the digestion treatment system was more suitable for the treatment of swine wastewater, when taking into account only the emission of the mentioned gases, subjects of this study.

RESUMO Considerando a importância do substrato para cama na avicultura industrial do Brasil e a enorme pressão relativa à gestão ambiental quanto ao correto emprego e manejo dos resíduos gerados pelo setor produtivo, buscou-se analisar o efeito das reutilizações de dois tipos de substratos de cama na qualidade sanitária e no desempenho produtivo dos animais. A pesquisa foi realizada em 32 aviários no Estado de Minas Gerais, e dois tipos de substratos e quatro ciclos de reutilização foram analisados. A qualidade sanitária da cama foi avaliada pela identificação das bactérias Escherichia coli eSalmonella spp., e incidência de dermatites no coxim plantar. Verificou-se que a cama de casca de café apresentou redução de 28,61 pontos percentuais na probabilidade de ocorrência de Salmonellaspp quando comparada com a cama de maravalha, porém não houve diferença significativa entre os ciclos de reutilização das mesmas. Observou-se presença de Escherichia coli em todos os ciclos de reutilização das camas, em ambos os substratos. Houve ocorrências de lesões do coxim plantar para as camas avaliadas, sendo que, somente para a cama de casca de café, o número de reutilizações influenciou na incidência dessas lesões, aumentando 30% entre o primeiro e o segundo ciclos de reutilização a partir do qual houve tendência à estabilização.

ABSTRACT Considering the importance of the substrate to bedding in the poultry industry in Brazil, and the enormous pressure on environmental management as to the correct use and management of the waste generated by the production sector, this study aimed to analyze the effect of reuses of two types of litter on sanitary qualities and productive performance of broilers. The study was conducted with litter from 32 different broiler houses, two types of substrates and four cycles of reuses. The litter sanitary quality was verified by the identification of the presence of Escherichia coli and Salmonellaspp. and the incidence of footpad dermatitis. It was observed that the coffee hulls litter presented a reduction of 28.61 percentage points in the probability of occurrence of Salmonella spp when compared to the wood shavings litter, nevertheless, no statistical difference was observed on bacterial occurrence with Salmonella spp. for litter of different types or numbers of reutilization. The presence of Escherichia coli was detected in litter of all cycles, for both types of substrate. The occurrence of footpad lesions was detected for both types of litter, and was influenced by the number of reutilization cycles of the litter. The degree of incidence was detected only for the litter with coffee hull in which there was an increase of 30% between the first and second reuse from which tended to stabilize.