RESUMO Este trabalho foi realizado com o intuito de se avaliarem a codigestão dos dejetos de bovinos leiteiros e óleo de descarte, por meio das produções específicas de biogás, reduções dos teores de sólidos totais (ST) e voláteis (SV), da demanda química de oxigênio (DQO) e fibra em detergente neutro (FDN). Utilizaram-se 28 biodigestores batelada, abastecidos com substratos contendo 4% de ST e compostos por dejetos de bovinos leiteiros, óleo de descarte (nas doses de 0; 2; 4; 6; 8; 10 e 12% dos STs do substrato e representado pelo resíduo de frituras que foi doado por pastelaria), inóculo e água para diluição. As máximas reduções de SV, DQO e FDN, além das produções específicas de biogás, foram obtidas por modelos quadráticos de predição, estimando-se, assim, as doses ideais de inclusão de óleo. As maiores reduções de DQO, SV e FDN foram de 82,88; 47,53; 51,28 e 49,48%, alcançadas com as inclusões de 5,74; 5,93, 4,77 e 6,45% de óleo de descarte, respectivamente. A inclusão de 4,63% de óleo permitiu alcançar a produção de 0,25 litro de biogás por g SV adicionado, que foi superior em 13% ao rendimento observado nos substratos sem inclusão de óleo. A adição de óleo em substratos contendo dejetos de bovinos leiteiros nas doses entre 4,4 e 6,5% aumenta as produções de biogás e as reduções de sólidos.
This study aimed to obtain the best dose of waste cooking oil inclusion for the co-digestion of substrates prepared with dairy cattle and swine manure in order to maximize solids reductions and biogas yield. Analyses of total solids (TS), volatile solids (VS), and neutral detergent fiber (NDF) were performed during the loading and unloading of digesters, while biogas yield was measured twice a week. The maximum reduction in VS (51.4%) was reached with the inclusion of up to 54.6g waste cooking oil.kg manure-1. Maximum NDF degradation occurred with inclusions of up to 69.4g waste cooking oil.kg manure-1. Inclusions of up to 64g of waste cooking oil.kg manure-1 provided specific biogas yield of 291.4 and 251.0L biogas.kg VS-1 added to substrates with swine and cattle manure, respectively. Adding oil at doses between 45.1 and 69.4g waste cooking oil kg manure-1 to substrates composed of cattle or swine manure maximizes reductions of solids and fibrous constituents and enhances specific biogas yield. Furthermore, swine manure supports higher doses of waste cooking oil.
The different organic matter fractions of residues significantly impact the degradability of organic material in composting windrows. Based on that, this study aimed to find out the organic matter fractions that most impact the breakdown rate during composting, besides proposing models to estimate the solids reductions in sheep bedding composting windrows. To that end, 24 sheep beddings from different locations and varied composition were composted so as to ensure the representativeness of the sample. The models found for reduction in total (TS) and volatile (VS) solids as a function of compostable organic matter (COM) and organic matter resistant to composting (OMRC) were not significant. Lignin had correlation coefficients of ¡0.6, ¡0.89, and ¡0.84 in relation to temperature, TS reduction, and VS reduction, respectively. The hemicellulose: lignin ratio was the parameter most correlated with temperature (0.69), TS reduction (0.91), VS reduction (0.92), and nitrogen (0.5), which led to more significant predictive models. It can be concluded that the hemicellulose:lignin ratio is the parameter that most impacts the breakdown of organic matter and nitrogen losses in sheep bedding composting windrows.
The objective of this study was to determine the optimal inclusion doses of crude glycerin in anaerobic co‐digestion with dairy cattle manure processed at 10, 17, and 24 days of retention in order to maximize reductions in solid and fibrous constituents and increase the productions of biogas and methane. Semi‐continuous digesters were fed with daily loads of substrates containing doses of 0, 5 and 10% (based on total solids, TS) of crude glycerin and dairy cattle manure. The highest specific productions of biogas and methane with the 10‐day HRT were also achieved in substrates with 0% glycerin, reaching values of 0.91 and 1.27 L/g of TS and solids (VS) added, respectively. In substrates retained for 17 and 24 days the values were maximal with addition of glycerin doses between 2.7 and 3.6% resulting in yields of 1.72 and 2.42 L of biogas per gram of TS added and 2.37 and 3.31 L of biogas per gram of VS added, respectively. For methane production, the optimal inclusion doses of crude glycerin with HRTs of 10, 17, and 24 days were 0.0, 3.7, and 3.3%, generating 0.70, 1.43, and 1.86 L of methane per gram of VS added. The inclusion of crude glycerin in co‐digestion with dairy cattle manure is not recommended for digesters operated with retention time of 10 days. However, when substrates remain for 17 or 24 days this inclusion promotes reductions of solids constituents while maximizing the specific productions of biogas and methane. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1305–1311, 2018
Objetivou-se com este estudo avaliar o efeito da hidrólise alcalina sobre o comportamento da temperatura e as reduções dos sólidos e da fração fibrosa no processo de compostagem da cama obtida durante a terminação de ovinos. O experimento foi conduzido em delineamento inteiramente casualizado com três tratamentos e cinco repetições (leiras) e com os seguintes tratamentos experimentais: 1 - apenas cama da criação de ovinos; 2 - cama da criação de ovinos acrescida de 0,8% dos sólidos totais (ST) de cal hidratada; tratamento 3: cama da criação de ovinos acrescida de 1,6% dos ST de cal hidratada. A eficiência do processo de compostagem foi avaliada pelas reduções de ST, sólidos voláteis (SV), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e hemicelulose, além da temperatura. Foram observadas diferenças (P<0,05) entre os tratamentos para as características mensuradas durante o processo de compostagem, com exceção da temperatura e o FDA que não diferiram entre os tratamentos testados. Foram observadas reduções (P<0,05) de 28,10 e 35,32% de ST e 34,32 e 42,48 % de SV para as doses 0 e 1,6% de cal hidratada, respectivamente. As maiores reduções (P<0,05) observadas foram de hemicelulose, sendo encontrados valores de 29,07 e 44,14% para as doses de 0 e 1,6% de cal hidratada, respectivamente. Concluiu-se que a hidrólise alcalina com 1,6% de cal hidratada foi eficiente no tratamento da cama de ovinos, permitindo um aumento significativo nas reduções de sólidos totais, sólidos voláteis e fibra durante o processo de compostagem.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.