• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.47-55
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• 1999

Recently, the treatment of that wastes according to increase of food waste has been a great problem of modern society for long time. This study was aimed to evaluate possibility for food waste and sewage sludge mixture treatment using pilot scale two-phase anaerobic digester. Pilot scale two-phase anaerobic digestion system was performanced at 1 : 9 mixture ratio of food waste and sewage sludge infield. The detention time of digester was 20days. The average COD and VS removal efficiencies in organic loading rate $3.03kg\;TCOD/m^3-day$ were 57.7 and 47.7%, and the gas production rate and methane content were $0.4m^3/kg$ VS-day and 65.3%, respectively. TS, VS and VS/TS(%) of mixing tank were 4.44%, 2.59% and 58.34%, respectively and TS. VS and VS/TS(%) of digester in steady state were 3.32%, 1.39% and 41.90%, respectively, Through this study. it was possible to accomplish effective mixture treatment of the sewage sludge and food waste.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.712-718
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• 2005

Stepwise reductions of glucose and Orange II concentration were observed from the experiment of both white-rot fungi such as T. versicolor and P. chrysosporium. As a result, typical removal patterns in those dual substrate system were categorized through several distinctive steps: initial lag period, primary and secondary carbon consumption periods. Also, based on the total removal amounts of Orange II, COD and Color during the experimental period, similar removal extent were observed from both species experiments, within the maximal error range of 5%. However, it was refereed that the internal steps of Orange II removal on enzymatic level should be different between two species: Enzyme Lac showed good affinity for Orange II removal in T. versicolor, however in P. chrysosporium enzyme LiP represented more close affinity to the similar experimental condition. Thus, even though the superficial removal amount of calcitrant Orange II at different fungal species was merely similar, removal pathway of enzymatic levels and intermediates produced during the fungal decomposition would be different.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.2
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• pp.97-103
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• 2017

In this study, variations of hydrogen production were investigated with food waste fermentation in the presence of heavy metals. Hydrogen production was 79.48 mL/g COD with fermentation of food waste. In the presence of 1 mg/L of zinc, the hydrogen production was decreased about 60%. When the copper is present, the production of hydrogen is severely inhibited, while the coexistence of copper with zinc relaxes the inhibition of copper and restores hydrogen production. Butyric acid or acetic acid was observed as the main species during hydrogen production. Klebsiella sp., Clostridium sp., and Dysgonomonas sp. were mainly appeared in the samples not containing heavy metals. However, Enterococcus sp. extremely influenced the hydrogen production activities of samples containing zinc or copper.

• Membrane Journal
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• v.11 no.4
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• pp.170-178
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• 2001

PVC microfiltration membrane was prepared by phase immersion method and applied to membrane bioreactor (MBR) contained activated sludge. The hydrophilicity of membrane and the pore size increase with the amount of additive(PVP) ducting the preparation of membrane. Permeation characteristics and the membrane fouling behavior were investigated by varying the internal environment in MBR using the prepared membranes. When there is a sludge bulking in MBR caused by microorganism, membrane fouling was accumulated. The cake layer resistance, R$_{c}$, of membrane increased in the order of CP-0 > CP-1.0 > CP-1.5. Rc increased up to 3.5~7 fold where the sludge bulking occurred in MBR. CP-1.5 seems to be appropriated membrane on the basis of the surface characteristics and the flux. The average flux of all the test membrane was 12(${\pm}$2) L/$m^2$hr whereas the COD removal efficiency was 98.8%. The ratio of bulking sludge and the type and the size of microorganism in operating MBR accelerate the membrane fouling and flux decline. It is concluded that the characteristic of membrane filtration depends on the hydrophilicity of membrane, the internal environment of MBR reactor and the growth factor of sludge.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.99-106
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• 2021

The purpose of this study was to evaluate the performance of novel process with thermal hydrolysis and separation as pre-treatment of anaerobic digestion (AD). The dewatered sludge was pre-treated using THP, and then separated. The separated liquid used as substrate for AD and separated solid was returned on THP(Thermal Hydrolysis Process). The degree of disintegration (DD, based on COD) using only THP found 45.1-49.3%. The DD using THP+separation found 76.1-77.6%, which was higher than only THP. As result from dual-pool two-step model, the ratio of rapidly degradable substrate to total degradable substrate found 0.891-0.911 in separated liquid, which was higher than only THP. However, the rapidly degradable substrate reaction constant (kF) of only THP and THP+separation were similar. This results found that dewatered sludge was disintegrated by THP, and then rapidly degradable substrate of hydrolyzed sludge was sorted by separation.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.144-152
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• 1993

A bacterium which degrades efficiently synthetic detergents was isolated from the polluted waters, activated sludge of wastewater treatment plants or polluted soil. This bacterium showed considerably higher growth rate in the agar plate containing $2,000{\mu}g/ml$ of synthetic detergents than any other isolated strains, was identified as a Pseudomonas fluorescens or strains similar to it. The strain was named as a Pseudomonas fluorescens S1. Optimum pH and temperature for the growth of the Pseudomonas fluorescens S1 were pH 7.0 and $30^{\circ}C$, respectively. The strain was resistant to streptomycin and gentamycin, but sensitive to kanamycin. The strain was greatly resistant to zinc chloride, lead nitrate and copper sulfate, but unable to grow in the presence of relatively low concentrations of mercury chloride and silver nitrate. This strain utilized benzene, catechol, cyclohexane and xylene as a sole carbon source. The strain was well grown in the medium containing ABS 10,000${\mu}g$/ml. Degradation of ABS was 55% and 60% at 20${\mu}g$/ml and 100${\mu}g$/ml of ABS, respectively. Benzene ring was degraded 45% in 100${\mu}g$/ml of ABS. During the incubation of the strain in the medium containing ABS 100${\mu}g$/ml and COD 10,000${\mu}g$/ml for 4 days, degradation of ABS and COD were reduced to 40${\mu}g$/ml and 3,200${\mu}g$/ml, respectively. Total amino acid content of the Pseudomonas fluorescens S1 grown with 1,000${\mu}g$/ml of ABS was 115mg/g cell, whereas its content was decreased in the bacterium grown without synthetic detergent by 9.4%.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.13-23
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• 2014

A lab-scale Anaerobic Baffled Reactor (ABR) was applied to treat a primary sludge taken from a municipal wastewater treatment plant. In this experiment, acidogenic reaction was promoted by operating the ABR with short hydraulic retention time (HRT) to produce sufficient volatile fatty acids (VFA) instead of production of methane. The performance of ABR on the VFA production and total solids reduction was observed with different operating conditions with 2, 4, 6, and 8 days of HRT. Corresponding organic loading rates were 6.7, 3.4, 2.2, and $1.6kgCOD_{cr}/m^3{\cdot}day$. As HRT increased the removal rate of TCOD was also increased (82.5, 84.2, 96.9, and 95.9 % in average for HRT of 2, 4, 6, and 8 days, respectively) because the settlement of solids was enhanced in the baffle by the decrease of upflow velocity. At HRT of 2 days the average concentration of VFA in the effluent was measured at $1,306{\pm}552$ mgCOD/L corresponding to 107 % increment as compared to the VFA concentration in the influent. However, as HRT increased VFA concentraiotn was decreased to $143{\pm}552$ mgCOD/L at HRT of 8 days. The reduction rates of total solids were 12.2, 26.5, 24.8, and 43.0 % for HRT of 2, 4, 6, and 8 days. As HRT increased the hydrolysis of organic particulate matters in the reactor was enhanced due to the increasing of solids retention time in the baffle zone with low upflow velocity in long HRT condition. Consequently, we found that a primary sludge became a good source of VFA production by the application of ABR process with HRT less than 4 days and the 12-26 % of total solids reduction was expected at these conditions.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.4
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• pp.201-209
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• 2016

Theoretical maximum methane yield of glucose at STP (1 atm, $0^{\circ}C$) is 0.35 L $CH_4/g$ COD. However, most researched actual methane yields of anaerobic digester (AD) on lab scale is lower than theoretical ones. A wide range of them have been reported according to experiments methods and types of organic matters. Recent year, a MET (Microbial electrochemical technology) is a promising technology for producing sustainable bio energies from AD via rapid degradation of high concentration organic wastes, VFAs (Volatile Fatty Acids), toxic materials and non-degradable organic matters with electrochemical reactions. In this study, methane yields of food waste leachate and sewage waste sludge were evaluated by using BMP (Biochemical Methane Potential) and continuous AD tests. As the results, methane production volume from the anaerobic digester equipped with MET (AD + MET) was higher than conventional AD in the ratio of 2 to 3 times. The actual methane yields from all experiments were lower than those of theoretical value of glucose. The methane yield, however, from the AD + MET occurred similar to the theoretical one. Moreover, biogas compositions of AD and AD + MET were similar. Consequently, methane production from anaerobic digester with MET increased from the result of higher organic removal efficiency, while, further researches should be required for investigating methane production mechanisms in the anaerobic digester with MET.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.737-742
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• 1999

This study was conducted for the two purposes; one was removal of dissolved humic acid, the well-known precursor of trihalomethanes (THMs), by physicochemical treatment processes such as ozone oxidation, coagulation and activated carbon adsorption. The other was qualitative identification of by-products in chlorination of the dissolved humic acid. When ozone oxidation was applied to remove the dissolved humic acid, pH was abruptly decreased. It was indicated that humic acid was not perfectly converted to $CO_2$ and $H_2O$, but to low fatty acid. In coagulation process, the coagulant was polyaluminumchloride which was widely used for drinking water treatment in recent years. With the dosage of 160 mg/L, total organic carbon(TOC), $COD_{Cr}$ and color were removed with 23%, 24% and 5% respectively. Color was effectively removed by ozone oxidation process, which was the first order reaction, with the reaction rate constant of $0.067min^{-1}$. In activated carbon adsorption process, preozonation process could remove more effectively the dissolved humic acid than that without preozonation. When the dissolved humic acid and sodium hydrochloride were reacted with 1 mg-NaOCl/mg-TOC, only trihalomethanes were detected.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.523-533
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• 2000

A two-phase anaerobic reactor with submerged membrane system was developed for increasing acidogen concentration and methane recovery. The membrane used was mixed esters of cellulose of $0.5{\mu}m$ pore size and $0.8m^2$ of effective surface area. The methanogenic reactor comprised of UASB (Upflow Anaerobic Sludge Blanket) and AF (Anaerobic Filter). COD removal efficiency was 70~80% and the methane content in the biogas increased up to 90% for the submerged membrane system in the anaerobic reactor. As the cake resistance of membrane caused a serious problem, stainless steal prefilters (40, 53, $63{\mu}m$) and air backwashing methods were applied to minimize the cake resistance effectively. Among the tested prefilters. the $63{\mu}m$ prefilter showed the best performance for reduction of cake resistance and a successful long-tern operation. By cleaning with alkali first and acidic solution later. the permeate flux decreased by long term operation was recovered to 89% of that with a new membrane.