Characterisation and perspectives of energetic use of dissolved gas recovered from anaerobic effluent with membrane contactor.

Biogas is a source of renewable energy, and its production and use has been validated in anaerobic-based sewage treatment plants (STPs). However, in these systems, a large amount of methane is lost as dissolved methane (D-CH4) in the liquid effluent. In this study, the characteristics and potential energetic uses of the gas recovered during the desorption of D-CH4 from anaerobic effluents with hollow fibre membrane contactors were investigated. A pilot-scale experiment was performed using sewage and two types of membrane contactors. The recovered gas contained considerable amounts of CH4, CO2, H2S, N2, and O2; therefore, a gas upgrade is required prior to its use as a biofuel. The recovery process should be energetically self-sustainable, and induce a considerable decrease in the STP carbon footprint. Recovering D-CH4 with membrane contactors could increase the energetic potential of anaerobic-based STPs up to 50 % and allow for more sustainable systems.

Ocorrência de fármacos e desreguladores endócrinos em esgoto bruto e tratado na cidade de Belo Horizonte (MG) / Occurrence of drugs and endocrine disrupters in raw and treatment sewage in the city of Belo Horizonte / MG, Brazil

RESUMO Os compostos de preocupação emergente (contaminants of emerging concern - CECs) atingem constantemente os corpos d'água via lançamento de esgoto sanitário, efluentes industriais e lixiviados de aterro, disposição inadequada de resíduos sólidos e escoamento superficial, ocasionando a poluição dos cursos d'água. Geralmente estes se encontram em concentrações da ordem de nanograma por litro ou micrograma por litro, dificultando sua análise ou onerando esse processo, demandando, assim, o desenvolvimento de técnicas de preparo e extração. Nesse contexto, destaca-se a Partição a Baixa Temperatura (EPBT), que se baseia na partição do analito de interesse entre fase aquosa e fase orgânica. Face ao exposto e à relevância do tema, o presente trabalho teve como objetivo avaliar, pelo uso da EPBT e cromatografia gasosa acoplada à espectrometria de massas, a ocorrência de 16 CECs no esgoto bruto e no tratado de Belo Horizonte (MG).

ABSTRACT Contaminants of Emerging Concern (CECs) constantly reach water bodies through the discharge of sanitary sewage, industrial effluents and landfill leachate, inadequate disposal of solid waste and surface runoff, causing the pollution of watercourses. In general, these are in concentrations of the order of mg / L or ng / L, making it difficult to analyze or burden this process, thus requiring the development of preparation and extraction techniques. In this context, it stands out the Low Temperature Patitioning Extraction (LTPE), which is based on the partition of the analyte of interest between aqueous phase and organic phase. Bearing this and the relevance of the subject in mind, the present work had the objective of evaluating the occurrence of 16 CECs in the crude and treated sewage of Belo Horizonte / MG, by using LTPE and gas chromatography coupled to mass spectrometry.