A UTILIZAÇÃO DO BIOGÁS PROVENIENTE DE MATÉRIA ORGÂNICA PARA FINS ENERGÉTICOS E MITIGAÇÕES AMBIENTAIS: UMA REVISÃO SISTEMÁTICA

Introdução: A quantidade de Resíduos Sólidos Urbanos (RSU) tem aumentado consideravelmente ao longo dos anos, isto é consequência direta de vários fatores, entre eles o crescimento populacional da humanidade. A preocupação com o meio ambiente tem ganhado destaque na sociedade, pois a mentalidade de sustentabilidade tem desencadeado uma série de possibilidades para avanços científicos e tecnológicos no sentido da preservação ambiental. Objetivo: Realizar uma revisão sistemática para identificar estratégias para inserção de biogás proveniente da matéria orgânica dos RSU como solução energética. A hipótese é que esse biogás garanta o tratamento adequado de RSU, com benefícios ambientais. Material e Métodos: Revisão sistemática feita na base de dados SCOPUS, limitando as pesquisas para artigos publicados em periódicos e revisões. Os descritores utilizados nas buscas foram: urban solid residues, sanitary landfill, biogas, cogeneration, thermodynamics, life cycle assessment. Foram utilizados seus sinônimos correspondentes, assim como os operadores booleanos AND e OR. Resultados: A estratégia de busca elaborada forneceu um total de 157 estudos. Após a triagem pela leitura dos títulos e resumos, 45 estudos foram considerados potencialmente elegíveis e lidos na íntegra. Ao término das análises, 17 artigos preencheram todos os critérios de inclusão para o estudo, sendo publicados entre os anos de 2012 e 2021. A revisão sistemática da literatura demonstrou as vantagens da utilização do biogás para fins energéticos, confirmando também a redução de impactos ambientais. Os principais tratamentos utilizados nos estudos identificados foram de origem bioquímica (e.g., digestão anaeróbia) e termoquímica (e.g., incineração). Conclusão: Identificaram-se estratégias para inserção do biogás como fonte energética, demonstrando sua viabilidade e aplicabilidade no suporte à redução de emissões e atendimento de demandas energéticas. Observou-se a importância de propostas por novas alternativas para reaproveitamento de RSU, sendo uma problemática de extrema significância. Experiências de sucesso no mundo podem ser estendidas e adaptadas para o Brasil, principalmente no momento atual de reduzida geração hidrelétrica (e consequente bandeira vermelha na fatura elétrica), com benefícios para o governo e para a população. O aproveitamento energético do biogás traz vantagens econômicas e ambientais, reduzindo a sobrecarga das concessionárias de energia elétrica.

Upaya Pemurnian Landfill Biogas Menggunakan Metode Adsroben Steel Wool

Nilai kalor yang dimiliki oleh biogas sangat mempengaruhi lamanya waktu proses pembakaran. Beberapa penelitian telah dilakukan untuk meningkatkan nilai kalor yaitu dengan menurunkan kadar zat pengotor yang terkandung bersama biogas. Dalam penelitian ini dilakukan upaya peningkatan nilai kalor biogas dengan menggunakan steel wool sebagai adsorben dengan variasi massa steel wool (500 gram dan 600 gram) dan variasi laju aliran biogas (1 lpm, 2 lpm, dan 3 lpm). Peningkatan nilai kalor biogas sebelum dan sesudah pemurnian ditentukan dengan water heating test. Hasil penelitian menunjukan peningkatan nilai kalor diperoleh pada filter dengan massa adsorben 600 gr dan laju aliran biogas 1 lpm, dimana nilai kalor meningkat sebesar 36.19%. Sedangkan filter dengan 500 gr steel wool adsroben dan laju aliran biogas 3 lpm, menghasilkan peningkatan nilai kalor terendah yaitu sebesar 4.46%. Hasil eksperimen menunjukan peningkatan nilai kalor semakin tinggi jika laju aliran biogas makin rendah melalui kolom adsorben dengan massa steel wool yang semakin tinggi.

Biological elimination of a high concentration of hydrogen sulfide from landfill biogas

Hydrogen sulfide (H2S) is one of the main contaminants found in biogas which is one of the end products of the anaerobic biodegradation of proteins and other sulfur-containing compounds in solid waste. The presence of H2S is one of the factors limiting the valorization of biogas. To valorize biogas, H2S and other contaminants must be removed. This study evaluated the performance of a pilot-scale biotrickling filter system on H2S removal from landfill biogas. The biotrickling filter system, which was packed with stainless-steel pall rings and inoculated with an H2S-oxidizing consortium, was designed to process 1 to 10 SCFM of biogas and used to determine the removal efficiency of a high concentration of hydrogen sulfide from landfill biogas. The biofiltration system consisted of two biotrickling filters connected in series. Results indicate that the biofiltration system reduced H2S concentration by 94–97% without reduction of the methane concentration in the outlet biogas. The inlet concentration of hydrogen sulfide, supplied to the two-phase bioreactor, was in the range of 900 to 1500 ppmv. The hydraulic retention times (HRT) of the two biotrickling filters were 3.9 and 0.9 min, respectively. Approximately 50 ppmv of H2S gas was detected in the outlet gas. The maximum elimination capacity of the biotrickling filter system was found to be 272 g H2S.m− 3.h− 1. During the biological process, the performance of biotrickling filter was not affected when the pH of the recirculated liquid decreased to 2–3. The overall performance of the biotrickling filter system was described using a modified Michaelis–Menten equation, and the Ks and Vm values for the biosystem were 34.7 ppmv and 200 mg H2S/L.h− 1, respectively.

Using Multi-Criteria Decision Analysis to Select Waste to Energy Technology for a Mega City: The Case of Moscow

In a mega city like Moscow, both municipal solid waste management and energy systems are managed in an unsustainable way. Therefore, utilizing the municipal solid waste to generate energy will help the city in achieving sustainability by decreasing greenhouse gases emissions and the need for land to dispose the solid waste. In this study, various Waste to Energy (WTE) options were evaluated using analytical hierarchy process (AHP) to select the most appropriate technology for the Moscow region. The developed AHP model consists of 4 levels, which assessed four WTE technologies, namely landfill biogas, anaerobic digestion, incineration, and refuse derived fuel (RDF), using four criteria and nine subcriteria. The pairwise comparison was achieved by soliciting 16 experts’ opinions. The priority weights of various criteria, subcriteria, and alternatives were determined using Expert Choice Software. The developed model indicated that landfill biogas is the preferred option with a global weight of 0.448, followed by the anaerobic digestion with a weight of 0.320 and incineration with a weight of 0.138, while the least preferred technology is the RDF with a weight of 0.094. Sensitivity analysis has shown that the priorities of WTE alternatives are sensitive for the environmental and technical criteria. The developed AHP model can be used by the decision makers in Moscow in the field of WTE.

Potential of landfill biogas production for power generation in the Valencian Region (Spain)

Landfills are one of the most common ways to dispose the solid urban waste in many countries due to their relatively simple technical requirements, operational costs and low investment. Moreover, biogas produced in landfills can be used as a renewable energy source for power generation. The Valencian Region is one of the largest solid urban waste producers in Spain, and therefore, it has an unexplored potential of landfill biogas production. This paper aims to estimate the potential of biogas landfill production for power generation in the Valencian Region. Statistical data from solid urban waste in landfills in the provinces of Alicante, Castellón, and Valencia was gathered. Then the potential of landfill biogas production was estimated by means of waste classification for each province. To provide information related to the use of landfill gas as an alternative source of energy, results presented in this work show that the Valencian Region has an important potential to use landfill biogas from solid urban waste as a renewable source for power generation, and also provide information to the regional government, academic researches, policy makers and investors.

Energy recovery from municipal solid waste of intermunicipal public consortia identified in São Paulo State

The main reasons, which this research is based on, are evidenced by the need of technical, political, economic and socioenvironmental coordination for the municipal solid waste management in Brazil and in the State of São Paulo. Most of the counties do not have adequate size to promote the management of MSW, so it’s necessary to perform a consortia to do it. Therefore, it was necessary to characterize the current State of Sao Paulo consortial arrangements considering the environment (including sanitation, waste, water resources, among others). The scale of waste generation and the total population involved in these consortia were also considered. The energy potential of municipal solid waste was evaluated considering two possible technologies: The burning of landfill biogas in engines and the incineration in plants with Rankine cycle. It was identified that the sum of consortia energy potential was 1,454,336 MWh y–1 (landfill biogas), and 2,715,925 MWh y–1 (incineration). It is intended that such results provide significant information and encourage interaction between the different agents involved in the intermunicipal arrangements. It is expected that the characterisation and calculation of energy potential will stimulate future studies about new consortia approaches that consider energy recovery in their projects.