Academic literature on the topic 'Grease trap waste (GTW)'

In this study, a newly established bench-scale thermophilic continuously stirred fluidized bed reactor (CSFBR) was applied for anaerobic co-digestion of food waste (FW) with grease trap waste (GTW). The performance of CSFBR regarding stability and treatment efficiency was inspected through a laboratory contrast experiment with two traditional continuous stirred tank reactors (CSTRs). In the OLR range of 3.19–7.41 g COD/L/d, the methane production rate of the thermophilic CSFBR was about as high as that of the thermophilic CSTR. Nevertheless, the thermophilic CSFBR had much lower VFAs (<1000 mg/L) and LCFA concentrations (<100 mg/L) as compared with the thermophilic CSTR. Unlike the mesophilic CSTR, there was no foaming that occurred in the CSFBR during the whole experimental period. The results all suggested that CSFBR simultaneously provided high treatment capacity and process stability in anaerobic digestion with high-lipid loading.

Fat, oil and grease are the three elements usually found in the municipal sewage systems as the results of improper disposal from the sink. These elements come from domestic and commercial kitchens. The absent or inefficient of a plumbing device known as grease trap has caused the trapped of fat, oil and grease in the sewage systems. There are two types of grease trap, namely Passive Grease Trap and Active Grease Trap. These grease types are collected and they can be recycled and used to produce an energy source, for example biodiesel. In Malaysia, the usages of passive grease traps are exercised. There are two parameters that govern the construction of the grease trap, namely retention time and flow rate. The ratio of sizing including the empirical formulations regarding the flow rate and the retention time will be discussed thoroughly in this paper. Furthermore, the understanding of the nature of the fat, oil and grease and the construction guideline for grease trap will be covered in this paper.

Abstract The aim of the study was to evaluate the effect of using biopreparations on efficiency of the co-fermentation process. Commercial bacterial biopreparations DBC Plus Type L, DBC Plus Type R5 and yeast biopreparations were used in the study. The process of cofermentation of sewage sludge with grease trap waste from a production plant that manufactured methyl esters of fatty acids was analysed in the laboratory environment under mesophilic conditions. The sludge in the reactor was replaced once a day, with hydraulic retention time of 10 days. Grease trap waste accounted for 35%wt. of the fermentation mixture. The stabilization process was monitored everyday based on the measurements of biogas volume. Addition of yeast biopreparation to methane fermentation of sewage sludge with grease trap waste caused an increase in mean daily biogas production from 6.9 dm3 (control mixture) to 9.21dm3 (mixture M3). No differences in biogas production were found for other cases (mixtures M1, M2). A similar relationship was observed for methane content in biogas.

Caixas de gordura são dispositivos para retenção de material gorduroso, de origem animal e vegetal, proveniente de pias de cozinha. Sua instalação é exigida por muitos municípios para liberação de ligações de esgoto, visando reduzir as concentrações de óleos e graxas (OG) lançadas no sistema público de coleta e tratamento. Um fator primordial para que estas caixas cumpram suas funções é o estabelecimento de rotinas de manutenção envolvendo inspeção e limpeza periódica. A instalação de locais para recebimento e pré-tratamento dos resíduos retirados das caixas de gordura pode incentivar boas práticas de operação e manutenção destes dispositivos. Diante disso, os objetivos desta pesquisa contemplam a caracterização de resíduos acumulados em caixas de gordura e a avaliação da flotação como alternativa para o seu pré- tratamento, seguido de caracterização do óleo extraído da escuma produzida no flotador. Para tanto, materiais acumulados em caixas de gorduras de fontes distintas foram caracterizados, possibilitando observar grande variação em sua composição, e elevadas concentrações de DBO, DQO, SST e OG. Para verificar o desempenho da flotação visando à redução de OG no efluente pré-tratado, foram realizados ensaios em bancadas e testados quatro produtos químicos coagulantes, sendo eles o PAC, o cloreto férrico, o tanino e o polímero catiônico. Todos apresentaram eficiências elevadas na remoção de OG, porém o produto que apresentou mais vantagens na aplicação foi o polímero. Utilizando o polímero, foram realizados ensaios para verificação do desempenho de várias dosagens associadas a três pH de coagulação diferentes e o melhor desempenho se deu com a aplicação de 30 mg/L de polímero combinada ao pH 4,3, natural da amostra. Foram também realizados ensaios utilizando diferentes relações A/S (7,5/1000, 15/1000 e 22/1000 gar/gsólidos),obtendo-se melhores remoções de OG com a utilização da relação 22/1000 gar/gsólidos. Os materiais flotados obtidos nos ensaios de avaliação da relação A/S foram caracterizados e apresentaram concentrações de ST entre 9,7 e 10,6% e de OG entre 6,1 e 6,7%. Baseado nos resultados obtidos a flotação mostra-se como alternativa com bom desempenho para o pré- tratamento dos resíduos estudados. Para avaliar a dificuldade do manuseio dos resíduos provenientes de caixas de gordura, uma planta piloto foi operada, e entre as principias dificuldades observadas estão o odor intenso, a necessidade de remoção de sólidos grosseiros e de homogeneização do resíduo no tanque de equalização. Visando reaproveitamento do resíduo flotado, foi realizada a extração do óleo com solvente de uma amostra deste material (com teor de sólidos de 8,86%), obtendo a recuperação de 30g óleo/L resíduo com acidez de 13,76 mg KOH/L. A elevada acidez indica a necessidade de purificação, se o objetivo for a produção de biodiesel.
Grease traps are devices that retain animal and vegetal fatty material from kitchen sinks. Many municipalities demand its installation in order to connect house wastewater to the public network, aiming to reduce fat, oil and grease concentration in the collecting and treatment systems. The establishment of maintenance schedule involving inspection and periodic cleaning is a key factor to the right functioning of the device. The existence of appropriated sites to receive and pretreat grease trap wastes may stimulate good practices on maintenance and operation of these devices. In this direction, the objectives of this research are the characterization of grease trap wastes and the evaluation of flotation as an alternative for its pretreatment, followed by characterization of the oil extracted from the scum formed at flotator. Therefore, grease trap wastes from different sources were collected and characterized. It could be observed a wide variation on its composition and high concentrations of BOD, COD, TSS and FOG. Lab scale tests were performed to assess flotation performance to reduce pretreated effluent FOG using four chemical coagulants: PAC, ferric chloride, tannin and cationic polymer. All of them achieved high efficiency on FOG removal, however the product that presented more advantages on application was polymer. More tests were performed using several dosages of polymer associated to three pH coagulation conditions. The combination that resulted in the best efficiency was 30 mg/L of polymer combined to pH 4.3, samples natural pH. Different A/S ratios were also tested (7.5/1000, 15/1000, 22/1000 gair/gsolids), the ratio 22/1000 gair/gsolids presented the best FOG removal efficiencies. Floated material from A/S ratio tests were characterized and presented TS concentrations between 9.7% and 10.6% and FOG was from 6.1% to 6.7%. Based on the obtained results, flotation appears as a high performance alternative for the pretreatment of studied wastes. A pilot plant was operated to evaluate problems related to grease trap waste handling. The main problems were: bad odor, the need of screening and waste homogenization in equalization tank. Aiming to reuse the floated waste, oil was extracted from a sample (8.86% solid content) using solvent, achieving the recovery of 30g oil/L waste with 13.76 mgKOH/L acidity. The high acidity points to the need of purification if biodiesel production is intended.

Tidigare undersökningar visar att fettproblematiken i de kommunala ledningsnäten är ökande. Fettet som hamnar i avloppen leder till drift- och underhållskostnader, men leder även till problem för att nå de lagar och regler som ställs på VA-huvudmännen. Vad gör huvudmännen åt detta problem? Är användningen av bioteknik en lösning? Vilka åtgärder finns mot hushållen? I denna uppsats har en litteraturstudie genomförts om fett i avlopp, en enkätstudie för att undersöka privatpersoners kunskap om matavfallssortering och även intervjuer med personer från företag inom VA. Resultaten visar att det finns indikationer på att informationen ut till privatpersoner kan förbättras från enkätstudien. Informationen som finns på kommunens hemsida som är riktad mot privatpersoner är svåråtkomlig. Fett i avlopp är ofta ett osynligt problem för allmänheten. Därför krävs informationsinsatser för att minska uppkomsten. Användandet av fettavskiljare är en effektiv åtgärd så länge de är tillräckligt dimensionerade och töms varje månad. Bioteknikens påverkan i de kommunala ledningsnäten bör undersökas vidare i en större studie.
Previous studies show that problems with fat in the municipal sewer systems are increasing. The fat that ends up in the drain leads to costs related to operation and maintenance, as well as issues with reaching the laws and rules that the owners of the water- and wastewater infrastructure needs to apply. What are the sewer system owners doing against this problem? Is the use of biotechnology a part of the solution? What actions are available towards the households? In this study we have done a literature study about fat in sewers, a survey to investigate the publics knowledge about food waste separation. We have also performed interviews with companies within the field. The results from the survey shows indications that the information to the public can be improved. The accessible information aimed towards the public on the municipality's website is hard to reach. Fat in sewers is often an invisible problem to the individuals. Because of this efforts with information is needed to lower the emergence of fat. The use of grease traps is an effective solution if they are correctly dimensioned and are emptied every month. The effect that biotechnology have on the wastewater system ought to be investigated in a larger study.

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The effluent from the kitchen sink, dishwasher, tank/washing machine, toilet bowl, shower, sink and tub when not covered are the source of many environmental problems and public health. The current management models based on conventional technologies still present technical and economic limitations. In this context, the study aimed to develop and propose a new model of management of domestic sewage and specifically the development of an alternative technology for the preliminary treatment of wastewater generated in the kitchen sink (due to its specific characteristics). The methodology included the qualitative and quantitative characterization of the generating source and domestic effluents, methods of collection, transportation and conventional treatment of domestic sewage and explanation of the advantages/disadvantages of the methods, processes and conventional technology. The results of the monitoring activities and habits of a family allowed determining the water consumption and the consequent generation of waste in each of the sources, which resulted in a correlation that will assist in the calculation of generation capacity/production of domestic sewage in homes and corresponding diagnosis. The tests performed with commercially available technologies for treating the effluent from the kitchen sink (grease trap) have identified the technical limitations of these technologies and the consequence was that the development of a new technology with innovative features called "ash for treatment of effluent from the sink kitchen with simultaneous separation of fat and settleable solids - Model UNIOESTE" innovative technology and in the process of patenting. It therefore contributes to mitigating the negative impacts that result from inadequate management of domestic wastewater using for such technological innovations resulting from intellectual activity with experimental validation. Key-words: domestic sewage, effluent from the kitchen sink, waste management, grease trap.
Os efluentes domésticos provenientes da pia da cozinha, máquina de lavar louça, tanque/máquina de lavar roupas, bacia sanitária, chuveiro, lavatório e banheira quando não tratados são fonte de muitos problemas ambientais e de saúde pública. Os atuais modelos de gestão com base de tecnologias convencionais ainda apresentam limitações técnicas e econômicas. Nesse contexto, o trabalho objetivou o desenvolvimento e proposição de um novo modelo de gestão de efluentes domésticos e especificamente o desenvolvimento de uma tecnologia alternativa para o tratamento preliminar do efluente gerado na pia da cozinha (devido às suas características peculiares). A metodologia contemplou a caracterização qualitativa e quantitativa da fonte geradora e dos efluentes domésticos, dos métodos de coleta, transporte e tratamento convencional de efluentes domésticos e explicitação das vantagens/desvantagens dos métodos, processos e da tecnologia convencional. Os resultados do monitoramento das atividades e hábitos de uma família permitiram determinar o consumo de água e a conseqüente geração de efluentes em cada uma das fontes, cujo resultado foi uma correlação que deverá auxiliar no cálculo da capacidade de geração/produção de efluentes domésticos nas residências e o correspondente diagnóstico. Os testes realizados com tecnologias disponíveis no mercado para tratamento do efluente da pia da cozinha (caixa de gordura) permitiram identificar as limitações técnicas dessas tecnologias e a conseqüência disso foi o desenvolvimento de uma nova tecnologia com características inovadoras denominada Caixa para tratamento de efluente da pia da cozinha com separação simultânea de gordura e sólidos sedimentáveis Modelo UNIOESTE , de tecnologia inovadora e em fase de patenteamento. Desta forma, contribui-se com a mitigação dos impactos negativos que resultam da gestão inadequada dos efluentes domésticos utilizando-se para tal, inovações tecnológicas resultantes da atividade intelectual com validação experimental.

This thesis investigated the technical and economic feasibilities of biodiesel produced from recycled grease trap waste (GTW) which accumulates in the wastewater system coming from food outlets and food processing sectors. The study was carried out by performing four principal tasks, these being: (1) extraction of fats, oils and grease (FOG) from GTW and investigation of its characterisation as a potential feedstock for biodiesel production; (2) development of an analytical methodology for the quantitative analysis of free fatty acid ethyl ester profiles; (3) optimisation of the process parameters for the synthesis of biodiesel from the extracted FOG via esterification and transesterification reactions; (4) scaling-up the laboratory-based process using a process simulator, and evaluating the economic feasibility of producing biodiesel from GTW. The GTW investigated in this study was provided by Peats Soil and Garden Supplies Ltd. Pty., (Adelaide, South Australia). The provided GTW was collected from the floating grease layer in a storage tank in which the lipid content was concentrated due to its lower density (approximately 51 wt%). Lipid extraction was then performed at ambient temperature (25ºC), employing hexane (HEX) and diethyl ether (DEE) as the solvents. A 97% lipid yield was obtained under the optimum operating conditions, these being: 1:1 DEE to GTW ratio (v/w); 300 rpm stirring speed, and 5 hr reaction time. Due to the high level of free fatty acids (>80 wt%) in the extracted oil, the esterification reaction was then conducted to reduce the FFA level in the feedstock. Two approaches, an esterification reaction with the use of the co-solvent acetone, and an esterification reaction without acetone were investigated and optimized. The optimal conditions for both reactions were determined using response surface methodology (RSM) based on central composite design (CCD). Optimum conditions for the esterification reaction without acetone were found to be 6:1 ethanol to oil molar ratio, 3 hr reaction time, 75ºC reaction temperature, and 3 wt% H₂SO₄ loading per FOG weight. In the presence of acetone, the optimal conditions were 35% v/v acetone to FOG, 6:1 ethanol to oil molar ratio, 3 hr reaction time, and 3 wt% H₂SO₄ loading. The ester yields obtained were 81 wt% and 80 wt%, respectively. The crude oil obtained from the previous pre-treatment was then subjected to a transesterification reaction to convert the remaining glycerides to ethyl esters. Two approaches, which were specified by the priority of the added components, were investigated to determine the optimal operating parameters. The results showed that a 96.7 wt% ester yield could be obtained under the optimum conditions, which were; 4:1 ethanol to oil molar ratio, 1 hr reaction time, 65ºC reaction temperature, and 1 wt% KOH loading. Importantly, approximately 30% of the excess ethanol could be reduced when ethanol and the base catalyst were heated first, while the extracted oil was added later at a specific rate. It was also found that the characterization of the GTW-derived biodiesel obtained satisfied most of the performance and compositional parameters required by the Australian Biodiesel Standard. After obtaining the optimal process parameters, two simulation models were constructed using Aspen Plus® V8.8 to generate the equipment and utility data required for the economic evaluation. Those simulation models were classified by the use of the co-solvent acetone in the esterification reaction. The result showed that the minimum production price of GTW-derived biodiesel was US$1,337.5/t, obtained through the process without using acetone. It can be concluded that the production of biodiesel from recycled greases is technically feasible and the economic aspect is also promising, although further studies need to be conducted to produce a biodiesel fuel which all satisfies the current mandatory standards.
Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Chemical Engineering, 2018

Fat, oil, and grease residues, food particles, solids and some kitchen wastewaters are collected in grease traps which are separate from the municipal wastewater stream. Grease traps are emptied periodically and grease trap waste (GTW) is hauled for treatment. This dissertation focuses on anaerobic co-digestion of un-dewatered (raw) GTW with municipal wastewater treatment sludge (MWS) at wastewater treatment plants. In particular, this research focuses on the biochemical methane potential of un-dewatered GTW as well as the stability and performance of anaerobic co-digestion of MWS and un-dewatered GTW. A set of modified biochemical methane potential tests was performed to determine the methane potential of un-dewatered GTW under mesophilic conditions (35 °C). Methane potential of un-dewatered GTW in this study was 606 mL CH₄/g VS [subscript added] which is less than previously reported methane potentials of 845 - 1050 mL CH₄/g VS [subscript added] for concentrated/dewatered GTW. However, the methane potential of un-dewatered GTW (606 mL CH₄/g VS [subscript added]) was more than two times greater than the 223 mL CH₄/g VS [subscript added] reported for MWS digestion alone. A comprehensive study was performed to determine the stability and performance of anaerobic co-digestion of MWS with un-dewatered GTW as a function of increasing GTW feed ratios. The performance of two semi-continuously fed anaerobic digesters at 35 °C was evaluated as a function of increasing GTW feed ratios. Anaerobic co-digestion of MWS with un-dewatered GTW at a 46% GTW feed ratio (on a volatile solids basis) resulted in a 67% increase in methane production and a 26% increase in volatile solids reduction compared to anaerobic digestion of MWS alone. On the other hand, anaerobic co-digestion of un-dewatered GTW resulted in a higher inhibition threshold (46% on VS basis) than that of dewatered GTW. These results indicate that using un-dewatered GTW instead of dewatered GTW can reduce the inhibition risk of anaerobic co-digestion of MWS and GTW. Recovery of the anaerobic digesters following upset conditions was also evaluated and semi-continuous feed of digester effluent into upset digesters yielded of the biogas production level of the undisrupted digestion. Finally, a mathematical model was used to describe the relationship between methane potential and GTW feed ratio on a VS basis. The results of this research can be used to predict methane production and identify suitable GTW feeding ratios for successful co-digestion of un-dewatered GTW and MWS.
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Grease trap waste and water hyacinth is a major problem of sewer clods and impedes water flow, a factor in flooding. Both of which can be proceeded for use as soil amendments. This research had two objectives: 1) to study the appropriate characteristics of the ratio between grease trap waste and water hyacinth for compost production and 2) to study the efficiency of compost from the growth rate of kale. The results of the analysis revealed that moisture, organic carbon, pH, conductivity, C/N ratio, nitrogen, phosphorus, and potassium are conformed to organic fertilizer standards of the Announcement by the Department of Agriculture: Criteria for organic fertilizers 2014, Thailand. Comparison of compost quality from macronutrients revealed that the ratio between grease trap waste and water hyacinth (2:1) was of the highest quality. Comparing the average growth rate of kale by plant height, a number of leaves, leaf width, leaf length, and fresh weight, found that the efficiency of compost containing grease trap waste and water hyacinth (2:1) affected the maximum growth rate of kale. In conclusion, the study found that the utilization of residues can reduce costs for waste management and increase resource renewal, which contributes to sustainability in future.

Food processors and retailers are under increasing regulatory and market pressure to manage their food waste in an environmentally responsible way. This study analyzes the climate change impacts of several alternatives available for the management of the several food wastes generated in this sector. Four food chain wastes are selected: whey, apple pomace, grease trap waste and bakery waste. Four treatment pathways were analyzed: landfill, anaerobic digestion, land application and animal feed. The results of the analysis showed significant differences among the pathways with climate change impact varying from −621 kgCO2e/t to 1924 kgCO2e/t. Landfilling of food waste resulted in the highest impacts and diversion to feed animals resulted in net benefits. The moisture content of the waste proved to be an important factor while the bio-degradability and nutrient value also had an influence. The combined impacts of diverting food waste from one disposal pathway to an alternative pathway were also considered and data is provided on the optimal pathways for each food waste alternatives.