Showing papers on "Hydraulic retention time published in 1986"
TL;DR: In this paper, a landfill leachate is treated by activated carbon adsorption, after mixing with chemical manufacturing wastewaters, by sequencing batch reactors (SBRs).
Abstract: A landfill leachate is treated, after mixing with chemical manufacturing wastewaters, by activated carbon adsorption. Biotreatment of the combined wastewater in sequencing batch reactors (SBRs) reduced the carbon requirement by 90%. Excellent treatment efficiency was consistently achieved under a variety of operating conditions: wastewater TOC, feed rate, hydraulic retention time, MLSS, organic loading, temperature, and cycle time. The SBR performance was unaffected when wastewater feeding was suspended during weekends and holidays. Results obtained in 1-L SBRs were reproduced in 12-L and 500-L units. The experimental data served as the basis for design of a full-scale SBR-adsorption system. The integrated wastewater treatment system would produce a better quality effluent at a lower overall cost. Biodegradation rates for some of the more persistent wastewater constituents were enhanced in batch bioreactors which were supplemented with strains of bacteria isolated from the landfill site.
45 citations
TL;DR: In this article, an anaerobic digester, operated semi-continuously in order to retain high concentrations of biomass in the digester was used to treat wool scouring wastewater, and preliminary studies of enzymatic pretreatment of the scouring effluent showed that significantly improved treatment rates and or efficiencies could be achieved.
28 citations
TL;DR: In this article, a synthetic medium containing 9 g/l sucrose was hydrolyzed in a hybrid reactor, and a viable anaerobic cell count of 109 organisms/ml was obtained in the reactor fluid.
Abstract: A synthetic medium containing 9 g/l sucrose was hydrolyzed in a novel hybrid reactor. A minimum hydraulic retention time (HRT) of 9.9 h, with a gas production rate of 1.07 m3/m3·d, was obtained without continuous neutralization. A viable anaerobic cell count of 109 organisms/ml was obtained in the reactor fluid. The results showed that both pH and temperature significantly influenced the type and concentration of the various metabolites formed. These include ethanol, formic, acetic, propionic and butyric acids as primary metabolites and caproic acid as secondary metabolite. From the results obtained, it is suggested that to obtain the energetically most favourable products, a substrate pH of 6.5 and a temperature of 35°C must be used in anaerobic acidogenic digesters.
18 citations
TL;DR: In this paper, the removal of total Kjeldahl nitrogen (TKN) was found to increase rapidly at higher TKN food to microorganisms (F/M) ratios at BOD F/M ratios below 0·6 kg kg−1 day−1 nitrification manifested itself through accumulation of oxidised forms of nitrogen.
15 citations
TL;DR: In this article, a two-stage digestion of cheesewhey was studied using two anaerobic rotating biological contact reactors, and the results indicated that two stage digestion is a feasible alternative for treating whey.
14 citations
TL;DR: The purpose of this study was to assess the applicability of the anaerobic biofilter process to treat low strength organic wastewater such as domestic sewage and found that 75% of nitrogen could be removed when the circulation ratio was more than 1:2.
12 citations
TL;DR: In this article, a mesophilic fixed-film reactor was used to feed 12°C anaerobic digestion in a laboratory scale (4 l) fixed film reactor fed with screened dairy manure and achieved a methane production rate of 0.27 l CH 4 l −1 day −1 obtained at 1 day hydraulic retention time.
11 citations
TL;DR: In this paper, a one-phase and a two-phase anaerobic digestion system was studied using screened dairy manure as feed material, and the results indicated that the methane production rate and yield for the two phase system were similar to those of the one phase system.
11 citations
TL;DR: In this article, the degradation of leucocephala was performed in a multi-stage digester with separate compartments, which achieved a methane content of 78-80% in a batch fermentation for 80 days with input volatile solids of 40-44 g.
10 citations
TL;DR: In this article, a laboratory-scale fixed-film reactor receiving a mixture of screened dairy manure and winery waste was studied at 35°C and a hydraulic retention time of 4 days.
9 citations
TL;DR: In this article, the nitrogen removal capability of the continuously fed intermittently decanted (CFID) process was evaluated using synthetic feed, and the specific denitrification rate ranged from 0.014 to 0.037 g N g SS−1 day−1.
TL;DR: In this article, three inclined tubular digester of 13- to 15-litre volume were operated at temperatures between 20 and 30°C with hydraulic retention times of 10-50 days on pig slurry of 10%, 5% and 2·5% Total Solids content.
TL;DR: In this paper, a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge was developed, which indicated that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time.
TL;DR: In this article, first-order kinetic models were developed for substrate removal and biomass generation in parallel aerated lagoons at various organic loads and it was found that lagoon performance should be interpreted against volumetric organic load rather than against hydraulic residence time or surface load.
TL;DR: In this article, the authors used the concept of the air diffuser performance to predict the power economy, defined as the amount of BOD removed per unit power consumption, and the effluent quality of the activated sludge process under various operating conditions.
TL;DR: In this paper, an anaerobic filter and the upflow upflow sludge blanket (UASB) were modified to develop a feasible alternative anaerobically wastewater treatment method, where polypropylene rings were used in the reactor as the floating media to maximize solids retention time.
TL;DR: An integrated process involving the production of biogas and the recovery of proteins by anaerobic digestion of piggery manure has been studied, yielding a solid biomass with reduced coliform counts and a protein content of about 14%.
Abstract: An integrated process involving the production of biogas and the recovery of proteins by anaerobic digestion of piggery manure has been studied. the digestion, effected in a 616 L downflow stationary fixed film reactor, resulted in a biogas production rate of approximately 0.86 m3 per m3 reactor per day (35°C, hydraulic retention time 7.2 days). Treatment of the digested effluent by flocculation, decantation and/or sieving yielded a solid biomass with reduced coliform counts and a protein content of about 14%.
TL;DR: A laboratory investigation has been undertaken to asses the effects of two operating parameters, mean cell residence time (MCRT) and anoxic hydraulic retention time (HRT), on the performance of an anoxic/oxic activated sludge system.
Abstract: A laboratory investigation has been undertaken to asses the effects of two operating parameters, mean cell residence time (MCRT) and anoxic hydraulic retention time (HRT), on the performance of an anoxic/oxic activated sludge system. The performance of the system was evaluated in terms of its COD, nitrogen, and biomass characteristics. An activated sludge system is capable of producing a better effluent, in terms of COD and nitrogen characteristics, when it is operated in an anoxic/oxic fashion. A longer MCRT and an adequate anoxic HRT are desirable in the operation of an anoxic/oxic activated sludge system. For the wastewater used in this investigation, the anoxic/oxic unit was capable of producing an effluent with the following characteristics when it was operated at MCRT = 20 days, total system HRT = 10 h, and anoxic HRT = 3–5 h: COD = 15 mg/L; VSS = 10 mg/L; TKN = 1.30 mg/L; NH3 − N = 0.60 mg/L; and NO2 + NO3 − N = 5.0 mg/L. A uniform distribution of biomass is achievable in an anoxic/oxic activated sludge system because of the intensive recirculation/convection maintained. The provision of an anoxic zone in the aeration tank promotes a rapid adsorption of feed COD into the biomass without an immediate utilization for cell synthesis. This, in turn, results in a high microbial activity and a lower observed biomass yield in the system. A tertiary treatment efficiency is achievable in an anoxic/oxic activated sludge system with only secondary treatment operations and costs. A conventional activated sludge system can be easily upgraded by converting to the anoxic/oxic operation with minor process modifications.
TL;DR: In this paper, the feasibility of this treatment is examined, using digesters of the CSTR-type similar to those used in the conventional secondary sludge biomethanization, and an optimization study is carried out to determine the operating parameters, hydraulic retention time and organic load.
TL;DR: In this article, the effects of wastewater strength on the performance of an anaerobic filter were investigated with a bench-scale filter unit using both high and low strength synthetic wastewater (3,000 mg/l of TOC).
TL;DR: In this article, an anaerobic plate-column reactor, developed to retain a high concentration of biomass, was studied using starch-containing synthetic wastewaters with regard to its start-up profile and the effects of TOC-loading rate, hydraulic retention time (HRT), and temperature in a steasy state.
01 Jan 1986-Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering
TL;DR: In this paper, an anaerobic rotating biological contactor (AnRBC) and a completely mixed stirred tank reactor (CSTR) were used to study the attached growth and suspended growth phase systems, respectively.
Abstract: Performance of an attached growth methane phase was compared to that of a completely mixed methane phase in a two‐phase anaerobic process. An anaerobic rotating biological contactor (AnRBC) and a completely mixed stirred tank reactor (CSTR) were used to study the attached growth and suspended growth phase systems, respectively. In the methane phase, the hydraulic retention time (HRT) was varied from 10 to 72 hours and the pH was maintained either at 6.0 or at 7.5. The attached growth methane system was observed to be more efficient than the suspended growth methane process In methane production per gram of total organic carbon (TOC) removed.
01 Jan 1986
TL;DR: In this paper, the feasibility of producing reasonably high methane rates from three different organic farm wastes was demonstrated using batch and semi-continuous fermenters using batch-and continuous-firm fermenters.
Abstract: Bench-scale studies using batch and semi-continuous fermenters have demonstrated the feasibility of producing reasonably high methane rates from three different organic farm wastes.
TL;DR: In this article, the development of an innovative two-phase methane fermentation process that provided a mesophilic methane yield of about 0·5 SCM/kg VS (8 SCF/lb VS) added from digestion of a municipal industrial sludge at a system hydraulic residence time (HRT) of about 6 days compared with a yield of 0·22−0·31 SCM / kg VS (3·5−5·0 SCF / lb VS) obtained from single-stage conventional ‘high-rate’ digesters operated at HRTs