• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7443-7450
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• 2014

To resolve shortcomings of high-rate anaerobic processes, such as high upward flow velocity, this study sought to improve the structure of the high-rate anaerobic reactor and evaluate its performance. The improved reactor was manufactured by adjusting the diameter and dividing the reactor into three parts. The evaluation of the structurally improved reactor revealed that the reactor could stabilize a single circuit, and prevent the accumulation of solid matter and leakage of microbes, thereby stabilize the microbes. In the process of anaerobic digestion, an increase in pH and alkalinity within the reactor was presumably attributed to bicarbonate created in the process of organic matter decomposition and due to the re-dissolution of some biogas. To maintain a high rate of organic matter removal, the reactor should be operated with more than 9 hrs of HRT and an organic matter load of under $10.kgTCODcr/m^3{\cdot}d$. The methane gas generated in the anaerobic digestion process showed a high content of 65~83 % at the organic matter load of over $7.7kgTCODcr/m^3{\cdot}d$. per removal of CODcr. The methane quantity was generated at $0.10{\sim}0.23m^3CH_4/kgCOD_{rem}$, showing that it was smaller than the theoretical methane generation amount (0.35) in the STP state. In the latter part of high-rate anaerobic process, an advanced treatment process was required to remove nitrogen.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.10
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• pp.730-736
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• 2013

This study was conducted to examine the effects of the salt concentration in seafood wastewater on the high-rate anaerobic digestion process. In the general high-rate anaerobic process test, the TCODcr removal efficiency at 6 hr or more HRT was 81.1~0.7%, and the optimal HRT for seafood wastewater process was found to be 6 hr or more. The methane content in the biogas was 70.1~76.8% during the operation, and was hardly affected by the change in the influent load. The results of the anaerobic digestion efficiency according to the salt concentration showed that the removal efficiency of TCODcr was 83.4~89.2% below a $4,000mgCl^-/L$ salt concentration, and mid-70% at a $5,000mgCl^-/L$ salt concentration. Therefore, the salt concentration had to be kept below $4,000mgCl^-/L$ to ensure stable treatment efficiency. Below a $3,000mgCl^-/L$ salt concentration, the methane generation was 0.2999~0.346$m^3CH_4/kgCODrem.$, which was similar to the theoretical methane gas generation in STP condition ($0.35m^3CH_4/gTCODrem.$). The methane content in the biogas was 64.7~73.3% below a $3,000mgCl^-/L$ salt concentration, but decreased with an increase in the salt concentration, to 50.1~56.9% at a $4,000mgCl^-/L$ concentration.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.4
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• pp.31-44
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• 1985

The application of anaerobic attached microbial films in the expanded bed process has recently been examined at high temperatures ($55^{\circ}C$) and with particulate matter. Extrapolation of the kinetics suggested that waste activated sludge (WAS) could be efficiently digested at hydraulic retention times as short as six hours in the expanded bed process. This would represent a 99 percent digester reactor volume reduction and would introduce interesting solids management alternatives if such a high rate process were developed. This paper presents a summary of a 1.5 year study of the feasibility of such a process. Three continuously fed $55^{\circ}C$ laboratory reactor systems were used to define the kinetics and the site of reactions-control completely mixed reactors were compared to the expanded beds (AAFEB) with and without a hydrolysis unit preceding the attached film unit. Well defined laboratory-generated WAS was compared to actual WAS from a domestic sewage treatment facility. Sixty percent of the biodegradable organics were converted in an AAFEB at a 15-hour hydraulic retention time without hydrolysis, whereas greater than 95 perccent of the biodegradable organics were stabilized in a two-stage system consisting of a 3-day HRT hydrolysis reactor followed by a 15-hour HRT AAFEB. The limitations of this high rate process and its potential application are discussed.

• New & Renewable Energy
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• v.1 no.2 s.2
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• pp.60-72
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• 2005

The effect of alkaline pre-treatment on the solubilization of waste activated sludge(WAS) was investigated, and the biodegradability of WAS, pretreated WAS, [PWAS], food waste and two types of mixture were estimated by biochemical methane potential [BMP] test at $35^{\circ}C$. The biodegradability of PWAS and mixture waste were significantly improved due to the effect of alkaline hydrolysis of WAS. An alkaline pre-treatment was identified to be one of the useful pre-treatment for improving biodegradability of WAS and mixture waste. In high-rate anaerobic co-digestion system coordinate with an alkaline pre-treatment in process, the digesters were operated at the HRT of 5, 7, 10 and 13 days with a mixture of FW $50\%\;and\;PWAS\;50\%,\;$In term of $CH_4$ content, VS removal and specific methane production [SMP] which are the parameters in the performance of digester, the optimum operating condition was found to be a HRT of 7 days and a OLR of 4.20g/L-day with the highest SMP of 0.340 L $CH_4/g$ VS.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.981-987
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• 2000

Upflow anaerobic sludge blanket(UASB) reactor was operated for treating swine wastewater containing high ammonia nitrogen to assess their performance and toxicity of free ammonia concentration. In the reactor, chemical oxygen demand(COD) removed about 70% at $2.6kgCOD/m^3.day$ of organic loading rate(OLR) and 3 days of hydraulic retention time (HRT), while it was decreased when OLR and HRT was maintained $7kg\;COD/m^3.day$ and 2 days, respectively. Also UASB reactor was evaluated the activity of methane producing bacteria(MPB) according to change of free ammonia concentrations, MPB activity of applied sludge in the 500 and $1000mg-N/{\ell}$ of free ammonia concentration was inhibited by 4% and 40%, respectively. This clearly showed that free ammonia concentration less than $500mg-N/{\ell}$ showed no inhibition to MPB in anaerobic treatment of organics, UASB reactor was stabilized easily less than $1000mgVSS/{\ell}$ due to degradation of organic solids by the high activities of anaerobes.