Showing papers on "Hydraulic retention time published in 1983"
01 Jan 1983
89 citations
TL;DR: In this paper, a laboratory scale anaerobic filter packed with synthetic high surface area trickling filter media was used to treat a low strength domestic wastewater averaging 288 mg 1−1 COD.
86 citations
TL;DR: In this article, the effects of temperature (35° and 55°C), influent Volatile Solids (VS) concentration (So = 50·4 and 62·5 kg VS m−3) and hydraulic retention time (HRT = 5, 10, 15 and 25 days) on CH4 production from swine manure were evaluated using 3-dm3 laboratory scale fermentors.
85 citations
TL;DR: The effect of liquid-solids separation pretreatment on methane production from mesophilic (30°C) anaerobic digestion of dairy cattle manure was investigated in the laboratory.
40 citations
TL;DR: In this article, a kinetic model was presented to describe the interactions among microbial reactions that are important in single-sludge treatment systems for nitrification/denitrification, which was used in a series of computer simulation experiments to delineate the effects of process variables on efficiency of nitrogen removal in an intermittently aerated, completely mixed, single sludge configuration and showed the importance of solids retention time, aeration fraction, influent organic matter concentration, and dissolved oxygen control strategy to good nitrogen removal.
Abstract: A kinetic model is presented to describe the interactions among microbial reactions that are important in single-sludge treatment systems for nitrification/denitrification. This model describes the aerobic processes of organic carbon oxidation and nitrification and the anaerobic process of denitrification. It was used in a series of computer simulation experiments to delineate the effects of process variables on efficiency of nitrogen removal in an intermittently aerated, completely mixed, single-sludge configuration. The effects of the following variables on nitrogen removal were studied: aeration fraction, solids retention time, hydraulic retention time, dissolved oxygen control, and the influent concentration of organic matter. Important interactions were observed between the solids retention time, aeration fraction, and influent organic matter concentration and were investigated in additional simulation experiments. Results of these experiments show the importance of solids retention time, aeration fraction, influent organic matter concentration, and dissolved oxygen control strategy to good nitrogen removal. Knowledge of the nature of the interactions among these variables is directly applicable to design and operation of single-sludge biological treatment systems for concurrent removal of organic matter and nitrogen.
24 citations
TL;DR: In this paper, a two-stage, unified anaerobic fermenter-filter model operating in a horizontal flow mode for a period of 114 days at room temperature (approximately 21°C) at a COD loading of 1·16 kg m−3 day−1 and a hydraulic retention time of 9·5 days in the fermenter.
22 citations
TL;DR: A fermenter which combined a fully mixed phase for cellulose degradation and a fixed‐film phase with pre‐immobilized bacteria for converting fatty acids to CH4 in one vessel, was devised.
Abstract: Cellulose degradation to methane under continuous fermentation conditions was compared using Cellulose degradation to methane under continuous fermentation conditions was compared using fully mixed, fully mixed with solids return, sludge-blanket, and fixed-film fermenters. In fully mixed fermenters, a decrease in hydraulic retention time (HRT) of two weeks or less caused the washout of anaerobes capable of converting volatile fatty acids to methane, while at increased feeding rates over 1 g/L day the rapid growth of cellulolytic anaerobes upset the balance between acid formation and its conversion to methane. Circulation of cellulose and difficulty in settling of cellulose with attached bacteria imposed problems in the use of other types of fermenters. On the basis of information obtained from this study, a fermenter which combined a fully mixed phase for cellulose degradation and a fixed-film phase with preimmobilized bacteria for converting fatty acids to methane in one vessel was devised. Using this fermenter, a mixed culture converted cellulose to methane at 4.8 g/L day ata HRT of six days as compared to 0.7 g/L day at a HRT of 28 days in the fully mixed fermenter.
20 citations
TL;DR: In this article, a two-stage digestor was used to produce biogas with 52% methane from anaerobic fermentation of the alcohol stillage derived from sugarcane molasses.
Abstract: The production of biogas with 52% methane from anaerobic fermentation of the alcohol stillage derived from sugarcane molasses has been studied using a two-stage digestor. Gas productivity of 0.4 m3/KgCOD day with four days of hydraulic retention time was much better than the reported holding times between 10 to 15 days with a single digestor.
14 citations
TL;DR: In this article, anaerobic digestion of acidified citrus peel press liquors by completely mixed and upflow UASB processes were compared. But the results showed that UASb was stable and achieved 95% removal of COD.
Abstract: Anaerobic digestion of acidified citrus peel press liquors by completely mixed and upflow anaerobic sludge blanket (UASB) processes are compared. Completely mixed digestion was overloaded at a hydraulic retention time of 10.7 d (organic load 7.41 g COD/1.d), whereas UASB digestion at a retention time of 7 d (11.15 g COD/1.d) was stable and achieved 95% removal of COD.
12 citations
TL;DR: In this article, various modifications of the anaerobic process applied to low concentration, screened, piggery wastewater and compares maximum gas generation rates, minimum hydraulic retention time (HRT) and minimum volumes, maximum removal efficiency and minimum maintenance requirements for a number of systems.
11 citations
Journal Article•
TL;DR: In this article, the effect of liquid-solid separation pretreatment on methane production from the anaerobic digestion of cattle manure was investigated in the laboratory, and the results support the concept that a liquid solid separation pre-treatment step could significantly reduce the volume of digester required for a farm with no decrease in biogas production.
Abstract: The effect of liquid-solid separation pretreatment on methane production from the anaerobic digestion of cattle manure was investigated in the laboratory. Screening out the coarse solid fraction from the waste before digestion had a minimal effect on the rate of biogas production for equal volatile solids loading rates at a 16-day hydraulic retention time. For a 12-day hydraulic retention time, a significant increase was found in the biogas production rate per litre of digester or per gram volatile solids added for the screened manure over the unscreened manure. The results support the concept that a liquid-solid separation pretreatment step could significantly reduce the volume of digester required for a farm with no decrease in biogas production.