A review on membrane concentrate management from landfill leachate treatment plants: The relevance of resource recovery to close the leachate treatment loop.

Membrane filtration processes have been used to treat landfill leachate. On the other hand, closing the leachate treatment loop and finding a final destination for landfill leachate membrane concentrate (LLMC) - residual stream of membrane systems - is challenging for landfill operators. The re-introduction of LLMC into the landfill is typical; however, this approach is critical as concentrate pollutants may accumulate in the leachate treatment facility. From that, leachate concentrate management based on resource recovery rather than conventional treatment and disposal is recommended. This work comprehensively reviews the state-of-the-art of current research on LLMC management from leachate treatment plants towards a resource recovery approach. A general recovery train based on the main LLMC characteristics for implementing the best recovery scheme is presented in this context. LLMCs could be handled by producing clean water and add-value materials. This paper offers critical insights into LLMC management and highlights future research trends.

Comparison between Aliivibrio fischeri and activated sludge microorganisms in the evaluation of the toxic pollutants of leachates from Brazilian landfills.

Ecotoxicological assessment of landfill leachate has become a priority to determine its impacts on the ecosystem. Toxicity assays with microorganisms stand out due to their quick response, low cost and ease of testing. In this context, the present study evaluated the acute toxic effects of leachates from two landfills of different ages and modes of operation to bacterium Aliivibrio fischeri and activated sludge microorganisms and the ammonia nitrogen and humic substances (HS) sensitivity to these organisms. Reductions greater than 30% in leachate toxicity were observed after ammonia removal for A. fischeri and activated sludge microorganisms. After 97% removal of HS, the greater reductions in toxicity (44.28 to 79.82%) were verified for microbial species studied, indicating that the organic compounds (measured as chemical oxygen demand, total organic carbon and humic substances) were the primary pollutants responsible for the toxicity of the leachates. Concerning the organisms studied, A. fischeri showed greater sensitivity to the leachates' pollutants compared to the activated sludge microorganisms. Nevertheless, a strong correlation was observed between A. fischeri and activated sludge microorganisms' toxicity responses, suggesting that respirometry assay can be used to determine leachate toxicity.

Submerged microfiltration membrane and activated carbon processes for recalcitrant compounds removal in oil refinery effluent as electrodialysis pre-treatment.

The combination of suspended activated carbon (AC) and submerged microfiltration (SMF) processes was applied to polish a biotreated effluent generated in a refinery industry. Preliminary results indicated that Norit 1240 W AC was more suitable than Carbomafra AC brand for total organic carbon (TOC) removal due to the highest Freundlich adsorption constant value (1.97 ± 0.42 and 0.96 ± 0.23 (mg/g)(L/mg)1/n, respectively), thus the first one was used in the combined system. Among all particle sizes of AC tested (0.041-1.01 mm), AC/SMF system was better performed, according to permeation flux, when applying granular AC instead of the powder one. On the other hand, the best response regarding TOC removal and absorbance at 254 nm (ABS254 nm) reduction were observed when applying powder AC (89% and 97%, respectively). Statistical analysis with two-sample T-test (p-value <0.05) endorsed the need of both air purge (20 L/h) and backwash strategies (8 min of permeation and 10 seconds of backwash) to diminish fouling occurrence in the SMF system. Finally, it was found that 2 g/L of Norit 1240 W PAC (0.041 mm particle size) condition fitted the effluent to further electrodialysis reversal (EDR) process (3.4 mg/L TOC) with consistent normalized permeate flux after 5 h of permeation (0.76 ± 0.1 J/J0).

Lessons and challenges for the recycling sector of Brazil from the pandemic outbreak of COVID-19.

Abstract: The 2019-2020 coronavirus pandemic imposed unprecedented challenges in Brazilian governance sectors, mostly in the waste management system. Herein, we analyse the main challenges of the recycling sector in Brazil to cope with this scenario. Understanding difficulties during the pandemic outbreak of COVID-19 can help improve waste recycling in the post-pandemic period in Brazil and other developing nations that face similar issues. The current pandemic exposed the deficiencies of this system, and some important lessons can be learned. Recommendations are drawn to advance the proper management of recyclables in the country. The Government must increase total investments in the recycling industry's infrastructure and support local recycling initiatives during a public health crisis and beyond. In sum, this paper strengthens the idea that waste segregation at the source and selective collection will not be sufficient without massive investments in the recycling sector's infrastructure. The future challenge includes strengthening the economic markets for recycled materials.

Fouling mitigation in produced water treatment by conjugation of advanced oxidation process and microfiltration.

This work explored the use of ozonation and photoperoxidation before the microfiltration process to reduce fouling. Produced water was synthesized with salt, viscosifier, and surfactant. The additives influence on membrane fouling was evaluated. Photoperoxidation process led to an overall better performance than ozonation in terms of oil removal and fouling reduction. The maximum oil removal efficiency was 86%, obtained for emulsions with salt after 2 h of treatment (COD: H2O2 ratio 1:1, UV dose of 965 J/m2). The inclusion of chemical additives impaired the oxidative power of hydroxyl radicals leading to a moderate oil removal; however, they were still able to reduce membrane fouling, mainly in oil/water emulsions with viscosifier. Higher salt concentration promoted fouling resistance and also benefited the permeate quality. Cross-flow microfiltration process integrated with photoperoxidation was able to improve the permeate flux from 84 to 182 L/m2.h after 3 h of exposure to UV radiation, resulting in a permeate with less than 10 mg/L of oil content. Graphical abstract.

Nanofiltration applied to the landfill leachate treatment and preliminary cost estimation.

The leachate treatment by nanofiltration (NF) process has received much attention over the last two decades. Previous studies focused on the investigation of the technical feasibility of NF. However, there are a limited number of works that examined leachate treatment costs. On the other hand, in a landfill management system, the economic component is an imperative factor for the decisions of all operations. Thereby, this work aimed to investigate the technical feasibility and economic parameters involved in a full-scale NF plant for the treatment of leachate previously treated by the physicochemical process. The average quality of the pre-treated leachate was 2258 ± 230 mg L-1 chemical oxygen demand (COD) and 821 ± 86 mg L-1 humic substances (HS). NF was performed using a bench-scale filtration module with commercial polymeric membranes SR100 and NP030. At the end of each filtration, a cleaning protocol was applied to recover the initial membrane permeability. The concentration of recalcitrant compounds, expressed as HS, was reduced to 84 ± 8 mg L-1 in the permeate, and COD complies with the wastewater discharge standards imposed by local legislation. The capital costs for a full-scale NF was estimated at MUS$ 0.772, and specific total cost, treated leachate per volume unit, has been estimated at US$ 8.26 m-3.

Cost estimation of landfill leachate treatment by reverse osmosis in a Brazilian landfill.

The reverse osmosis (RO) process has been increasingly applied to landfill leachate treatment. The published literature reports several studies that investigated the technical feasibility of RO. However, information about process costs is scarce. Also, companies that run leachate treatment plants do not provide actual costs. To fill this gap, this study aimed to evaluate the treatment costs of a full-scale RO for the treatment of landfill leachate located in Rio de Janeiro State, Brazil. A procedure was proposed to estimate the capital expenses (CAPEX), operational expenses (OPEX), and specific total treatment cost, the total cost per m3 of treated leachate, of the leachate treatment by membrane process, and the results obtained are discussed. The CAPEX for this full-scale RO was estimated at MUS$ 1.413, and OPEX ranged from US$ 0.132 to US$ 0.265 m-3 per year. The cost of leachate treatment has been estimated at US$ 8.58 m-3 considering the operation of the RO-unit for 20 years after landfill closure.

Evaluation of toxic potential of leachate originating from experimental landfill cells containing household waste and healthcare waste.

Two experimental cells with household solid waste and healthcare solid waste were monitored in order to evaluate the pollution potential, and its toxicity effects corresponding to the chemical substances present in the leachates generated, correlating the physico-chemical composition with the ecotoxicity results (organisms Aliivibrio fischeri and Danio rerio). From the statistical evaluation of the physico-chemical analysis results, leachate generated in the household solid waste cell presented greater or equal values than to the healthcare solid waste cell, except for the turbidity parameter. The ecotoxicity results showed the same behaviour as that obtained with the physico-chemical analysis. A significant positive correlation was verified between chemical oxygen demand, alkalinity and ammonia nitrogen parameters with the leachate toxicity. This study concluded that healthcare solid waste presented less or equal polluting potential compared with household solid waste, and the co-disposal can be considered a viable alternative in sanitary landfills.

Landfill leachate treatment in Brazil - An overview.

The management of municipal solid waste (MSW) presents an ever increasing and more complex challenge in global terms. The disposal of MSW in landfills generates leachate, a liquid highly polluting to the aquatic environment. This review describes the state-of-the-art approaches to treatments applied to leachate in Brazil, highlighting the new technologies and alternatives that are still in the research phase, and compares the leachate treatment technologies applied around the world with the current scenario in Brazil. In Brazilian landfills, along with other technologies, the biological process is commonly applied, since this is a simple and economical approach and often it is the only technique used in small municipalities. The sanitary landfills in large Brazilian cities located in the states of São Paulo and Rio de Janeiro, invest in or outsource landfill activities, where apply advanced treatment technologies, such as membrane filtration. The use of membrane filtration technology in these cases reveals similarities with leachate treatments applied in the developed countries of North America and Europe. Brazilian researchers have highlighted the need to use efficient and economically viable technologies for the treatment of leachate in Brazilian landfills. However, the current scenario of MSW management in Brazil shows deficiencies related to the monitoring of sanitary landfills and limited information is available on the performance of leachate treatment systems.

Evaluation of reduction estrogenic activity in the combined treatment of landfill leachate and sanitary sewage.

Combined treatment of urban solid waste leachate and domestic sewage has emerged in Brazil and worldwide as an alternative to minimize the difficulties of treating landfill leachate. Landfill leachate is a complex matrix of organic and inorganic substances, recalcitrant material and xenobiotic organic compounds that are considered to be highly toxic, as well as endocrine disrupting compounds (EDC) that contribute to increased estrogenic activity. Although combined treatment is feasible for removal of organic matter, ammonia and toxicity, the efficiency of the removal of estrogenic substance is poorly investigated. In this study, the activated sludge process in batch and continuous modes was used for the combined treatment of 2% and 5% leachate/sewage mixtures. Estrogenic activity was reduced in reactors in both batch and continuous modes. The activated sludge process achieved average reductions of the estradiol equivalent (EQ-E2) values in the combined treatment of 94.5, 60.8 and 66.4% for the sanitary sewage, 2% mixture leachate in sewage and 5% mixture leachate in sewage reactors, respectively, in batch mode. For continuous reactors, 86%, 72%, and 65% of reduction of EQ-E2were achieved for sanitary sewage, 2 and 5% mixture with sanitary sewage. As for EQ-E2, the increase in the concentration of leachate in the sewage mixture was detrimental to the removal of estrogenic compounds during the biological process. Therefore, a limit on the % leachate/sewage mixtures should be established to achieve efficiency in the combined treatment of leachate in a Wastewater Treatment Plant (WWTP).

Remoção da cor no tratamento combinado de lixiviado de aterro sanitário e esgoto doméstico via processo PACT® / Color removal in the combined treatment of landfill leachate and domestic sewage via PACT ® process

RESUMO Misturas diferentes de lixiviado de aterro sanitário e esgoto doméstico foram aplicadas em 16 reatores em batelada usando o processo PACT® (lodos ativados com adição de carvão ativado em pó - CAP). O objetivo do trabalho foi representar a remoção de cor utilizando dois ajustes matemáticos: o primeiro combinou as variáveis concentração de CAP (0 a 6 g.L-1) e mistura lixiviado/esgoto (0 a 10%, em volume); e o segundo, a concentração de CAP e a cor da mistura (276 a 1.199 uH). A metodologia de superfície de resposta (MSR) foi escolhida para representar a resposta dos ajustes. Os resultados indicaram que, conforme a concentração de lixiviado aumentou até 5%, a adição de CAP resultou em um maior percentual de remoção de cor. No entanto, para a mistura com 10% de lixiviado, os reatores perderam eficácia, com exceção do reator com 6 g.L-1 de CAP, que apresentou os melhores resultados de remoção de cor.

ABSTRACT Sixteen batch reactors fed with different mixtures of landfill leachate combined with synthetic wastewater were treated using the PACT® process (activated sludge process plus powdered activated carbon addition - PAC). The objective was to measure the color removal using two mathematical adjustments: the first adjustment combined the variables PAC concentration (0 to 6 g.L-1) and landfill leachate concentration in the wastewater (0 to 10%, in volume); and the second model combined PAC concentration and the influent color (276 to 1,199 uH). The response surface methodology was used to describe the response of both adjustments. The results indicated that as the proportion of leachate was increased up to 5%, higher PAC concentrations resulted in a better color removal in the reactors. When the leachate proportion was 10%, the reactors were less efficacious, except for the one with 6 g.L-1, which presented the highest color removal within the experiment.

Evaluation of the biodegradability and toxicity of landfill leachates after pretreatment using advanced oxidative processes.

Leachate from urban solid waste landfills is a complex mixture of organic and inorganic substances that cause damage to the environment, due to the high concentration of recalcitrant organic matter and toxicity. The objective of this study was to apply advanced oxidation processes (AOP), namely the dark Fenton and solar photo-Fenton processes, to young and old landfill leachates prior to biological treatment. The leachates were obtained from the Seropedica and Gramacho landfill sites, respectively, located in Rio de Janeiro State, Brazil. For the two Fenton processes, different conditions of pH (1.5, 3.0 and 5.0) and Fe2+: H2O2 ratio (1:2, 1:5 and 1:10) were evaluated. Biodegradability was evaluated using the Zahn-Wellens methodology and Aliivibrio fischeri acute toxicity tests were conducted in order to predict the toxicity in the activated sludge. The best conditions for both Fenton processes were pH of 3.0 and Fe2+: H2O2 and CODRAW:H2O2 mass ratios of 1:5 and 1:1, respectively. The solar photo-Fenton process was more effective at improving the quality for both leachates, reaching COD, TOC and abs 254 nm reductions of 82%, 85% and 96.3%, respectively, for the Seropedica landfill leachate. In the case of the Gramacho landfill leachate, the corresponding reductions were 78.2, 80.7% and 91.1%, respectively. The biodegradability results for the untreated leachates from the Seropedica and Gramacho sites were 65% and 30% respectively. The biodegradability of both leachates was improved by the Fenton processes, especially the solar photo-Fenton process, which increased the leachate biodegradability to 89% (Seropedica) and 69% (Gramacho). For both leachates, a greater reduction in the acute toxicity was achieved with the solar photo-Fenton compared to the dark-Fenton process. The Seropedica landfill leachate showed high toxicity (EC50 = 33%, 15 min), after the dark Fenton and solar photo Fenton processes, with EC50 values of 81 and 91%, respectively. In the case of Gramacho landfill leachate toxicity, the EC50 value of the raw leachate was 13%, whereas after the dark Fenton and solar photo Fenton processes the corresponding values were 54% and 59%, respectively. These results indicate that the Fenton process (especially solar photo-Fenton), was efficient in terms of increasing the biodegradability and reducing the toxicity of the leachate. This is important in relation to protecting the microbiological community in the activated sludge process.

Municipal solid waste in Brazil: A review.

The production of municipal solid waste (MSW) represents one of the greatest challenges currently faced by waste managers all around the world. In Brazil, the situation with regard to solid waste management is still deficient in many aspects. In 2015, only 58.7% of the MSW collected in Brazilian cities received appropriate final disposal. It was only as late as 2010 that Brazil established the National Policy on Solid Waste (NPSW) based on the legislation and programmes established in the 1970s in more developed countries. However, the situation with regard to MSW management has changed little since the implementation of the NPSW. Recent data show that, in Brazil, disposal in sanitary landfills is practically the only management approach to MSW. Contrary to expectations, despite the economic recession in 2015 the total annual amount of MSW generated nationwide increased by 1.7%, while in the same period the Brazilian population grew by 0.8% and economic activity decreased by 3.8%. The article describes the panorama with regard to MSW in Brazil from generation to final disposal and discusses the issues related to the delay in implementing the NPSW. The collection of recyclable material, the recycling process, the application of reverse logistics and the determination of the gravimetric composition of MSW in Brazil are also addressed in this article. Finally, a brief comparison is made between MSW management in Brazil and in other countries, the barriers to developing effective waste disposal systems are discussed and some recommendations for future MSW management development in Brazil are given.

Remoção da fração oleosa de embalagens de lubrificantes automotivos pós-consumo por drenagem gravitacional / Residual oil removal from used automotive lubricant packages by gravitational drainage

RESUMO: Este trabalho aborda a questão do gerenciamento de embalagens pós-consumo de lubrificantes automotivos, considerando as dificuldades inerentes à implementação do sistema de logística reversa - prática compulsória por força de lei (Brasil, Lei 12.305/2010) - e a ineficácia dos atuais métodos utilizados para remoção da fração oleosa residual, necessária ao reprocessamento do material plástico por reciclagem mecânica direta. Para determinar metodologia apropriada para limpeza dos frascos de lubrificantes foram conduzidos experimentos para avaliar a influência do aquecimento e da posição das embalagens durante o processo de drenagem gravitacional. O procedimento analítico realizado proporcionou a escolha de uma combinação de variáveis capaz de assegurar remoção de elevado teor do resíduo oleoso com menor gasto energético. A otimização foi feita utilizando um planejamento experimental do tipo composto central com triplicata no ponto central. Os dados obtidos nos ensaios foram analisados com recursos estatísticos e demonstraram que ambos os parâmetros avaliados interferem, de forma significativa, no processo em estudo. Os resultados apontaram aumento da eficácia do processo quando a drenagem é realizada em temperaturas superiores a 35ºC e com a embalagem inclinada em ângulos próximos a 70º em relação à horizontal. Nessas condições, percentuais de remoção de óleo residual superaram 95% após 35 minutos de drenagem.

ABSTRACT: This work addresses the management of automotive lubricants packages after lubricant use, considering the difficulties of implementing reverse logistics system - compulsory practice by virtue of Law (Brazil, Law 12,305/2010) - and the poor effectiveness of the current methods for removing residual oil from packages, which is required before reprocessing plastic material in direct mechanical recycling. Experiments were conducted in order to determine the appropriate methodology for cleaning the lubricant bottles, evaluating the influence of temperature and package position in the gravitational drainage. This analytical procedure elicited a combination of variables and conditions capable of improving the removal of oily residue with less energy. The experimental optimization was performed using a central composite model with triplicate center point. The test results were statistically analyzed and showed that both parameters have significant influence on the separation process. The data indicated that the process is more effective when the drainage is performed above 35ºC and the packaging inclined at angles close to 70º relative to horizontal. Under these conditions, the oil removal is greater than 95% after 35 minutes of drainage.

Mathematical modeling of COD removal via the combined treatment of domestic wastewater and landfill leachate based on the PACT process.

The experiments performed in this study consisted of 16 batch reactors fed different mixtures of landfill leachate combined with synthetic wastewater treated using the Powdered Activated Carbon Treatment (PACT) process. The objective was to measure the COD mass removal per liter each day for each reactor using two models: the first model combined the variables PAC concentration (0 g·L(-1), 2 g·L(-1), 4 g·L(-1), and 6 g·L(-1)) and leachate rate in the wastewater (0%, 2%, 5%, and 10%), and the second model combined the PAC concentration and the influent COD. The Response Surface Methodology with Central Composite Design was used to describe the response surface of both models considered in this study. Domestic wastewater was produced under controlled conditions in the laboratory where the experiments were performed. The results indicated that the PAC effect was null when the influent did not contain leachate; however, as the concentration of leachate applied to the mixture was increased, the addition of a higher PAC concentration resulted in a better COD mass removal in the reactors. The adjusted R(2) values of the two models were greater than 0.95, and the predicted R(2) values were greater than 0.93. The models may be useful for wastewater treatment companies to calculate PAC requirements in order to meet COD mass removal objectives in combined treatment.

Evaluation of pH, alkalinity and temperature during air stripping process for ammonia removal from landfill leachate.

The objective of this research was to evaluate the air stripping technology for the removal of ammonia from landfill leachates. In this process, pH, temperature, airflow rate and operation time were investigated. Furthermore, the relationship between the leachate alkalinity and the ammonia removal efficiency during the process was studied. The leachate used in the tests was generated in the Gramacho Municipal Solid Waste Landfill (Rio de Janeiro State, Brazil). The best results were obtained with a temperature of 60(o)C, and they were independent of the pH value for 7 h of operation (the ammonia nitrogen removal was greater than 95%). A strong influence of the leachate alkalinity on the ammonia nitrogen removal was observed; as the alkalinity decreased, the ammonia concentration also decreased because of prior CO2 removal, which increased the pH and consequently favored the NH3 stripping. The air flow rate, in the values evaluated (73, 96 and 120 L air.h(-1).L(-1) of leachate), did not influence the results.

Caracterização microbiológica de lixiviados gerados por resíduos sólidos domiciliares e de serviços de saúde da cidade do Rio de Janeiro / Microbiological characterization of leachate from domestic and hospital solid wastes from Rio de Janeiro city

O presente trabalho consistiu na caracterização microbiológica de lixiviados gerados a partir de resíduos sólidos de serviços de saúde e domiciliares para subsidiar a discussão do tratamento e disposição final diferenciados para os resíduos sólidos de serviços de saúde. Foram analisados: coliformes totais e termotolerantes; Escherichia coli, Enterococos, Salmonella e outras enterobactérias; Pseudomonas aeruginosa, bactérias heterotróficas aeróbias mesófilas, análise da suscetibilidade aos antimicrobianos e pesquisa da atividade antimicrobiana do lixiviado. Foram observadas densidades expressivas das populações microbianas em resíduos sólidos de serviços de saúde e domiciliares com valores que variaram de 10(8) a 10(9). Em ambos os lixiviados, ocorreram estirpes resistentes e sensíveis aos antimicrobianos, e nenhuma delas apresentou resistência a todos os antibióticos testados. Os resultados mostraram semelhanças entre ambos os tipos de resíduos e reforçam a recomendação de codisposição de resíduos sólidos de serviços de saúde e domiciliares em aterros sanitários.

The present paper consisted on the microbiological characterization of leachate generated from solid waste from health services and municipal solid waste. This study aimed to support the discussion about the need for differentiated treatment and disposal for the health services solid waste. The following parameters were selected: total coliforms, thermotolerant coliforms, Escherichia coli, Enterococci, trials for Pseudomonas aeruginosa, and Salmonella and other Enterobacteria, analysis of susceptibility to antimicrobials and research on antimicrobial activity of the leachate. Expressive densities were observed in microbial populations in health services and municipal solid waste, with values ranging from 10(8) to 10(9). In both wastes, resistant and susceptible strains to antimicrobials occurred and none were resistant to all antibiotics tested. Results showed similarities for both types of waste and reinforce the recommendation for health services and municipal solid waste co-disposal in sanitary landfills.

Wetlands para tratamento de lixiviados de aterros sanitários: experiências no aterro sanitário de Piraí e no aterro metropolitano de Gramacho (RJ) / Landfill leachate treatment using wetlands: experiences in Piraí municipality solid waste landfill and Gramacho metropolitan solid waste landfill

O Grupo de Resíduos Sólidos do Programa de Pós-Graduação em Engenharia Ambiental (PEAMB/UERJ) vem realizando, há cinco anos, pesquisas utilizando wetlands construídos em tratamento de lixiviados de aterros sanitários. Esses sistemas promovem a absorção de nutrientes pelas plantas e facilitam a degradação de material orgânico por microrganismos do solo e aderidos às raízes. Experiências desenvolvidas no Aterro Sanitário de Piraí mostram remoções, em termos de concentração de poluentes, de 41 por cento de DQO e 51 por cento de nitrogênio amoniacal. Os resultados obtidos no Aterro Metropolitano de Gramacho apresentam redução, em termos de carga de poluição, de 86 por cento de DQO e 89 por cento de nitrogênio amoniacal. Os sistemas implantados mostram-se boas alternativas no tratamento de lixiviados, sobretudo em regiões de clima tropical, onde as elevadas temperaturas potencializam a evapotranspiração.

The Group of Solid Waste of Environmental Engineering Program (PEAMB/UERJ) has been conducting research using constructed wetlands in landfill leachate treatment in the last five years. These systems promote the absorption of nutrients by the vegetation and facilitate the degradation of organic material by microorganisms in the soil and the ones adhered to the roots. Experiments carried out in Piraí Municipality Landfill show removal of pollutants about 41 percent of COD and 51 percent of ammonium nitrogen. The results obtained in Gramacho's landfill, present a reduction of 86 percent of COD load and 89 percent of ammonium nitrogen load. Wetlands seens to be a good alternative in the treatment of landfill leachate, especially in regions of tropical climate, where high temperatures improve effects of evapotranspiration.