• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.21-24
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• 2012

In this study, Anaerobic Membrane Bioreactor(AnMBR) treating food waste leachate was operated to investigate treatment efficiency of anaerobic process, operational parameters and production of biogas. AnMBR was operated under the condition of filtration type of inside-out mode. AnMBR was operated under the condition that range of permeate flux was from 15 to 20 LMH and range of transmembrane pressure was from 1 to $3 kgf/cm^2$. It was not good that AnMBR was performed under direct connection between anaerobic reactor and external UF module. so, this connection method changed to indirect connection using buffer tank was placed between anaerobic reactor and UF external module. TCOD and SCOD values were that influent were about 113 g/L, 62 g/L and effluent were 25 g/L, 12 g/L, respectively. also TCOD and SCOD removal efficiency were 77% and 81%, respectively. but after added UF process, COD and SCOD removal efficiency was increased to 93% and 86%, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.2
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• pp.59-66
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• 2016

The purpose of this study was to review of technical, economical feasibilities regarding Integrated Two-Phase Anaerobic Digestion(ITPAD) method. In order for that, operation conditions and data with 24tpd capacity of operating ITPAD plant were analyzed. The result showed that VS removal efficiency was 73.7% and total amount of biogas was generated $1,239m^3/day$ on the average that represents $54.4m^3/ton$-input of generation efficiency. ITPAD had advantages in terms of required area and energy for heating which were analyzed 15.9%~47%, 11.6%~17.8% lower respectively compared to Conventional Separated Two-Phase Anaerobic Digestion(CSTPAD) method. Thus, it is considered the ITPAD has comparatively high feasibility to be expanded and commercialized to dispose high concentration organic matter of waste such as food waste and its leachate.

• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.247-256
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• 2006

This study has been conducted for the process of food wastes disposal using surplus capacity of established sewage treatment plant by co-digestion of fermented food wastes and sewage sludge after thermophilic acid fermentation of food wastes. The co-digestion of thermophilic acid fermented food wastes and sewage sludge was performed by semi-continous method in mesophilic anaerobic digestion reactor. It showed great digestion efficiency as the average SCOD and VS removal efficiency in organic loading rate 3.30g VS/L.d. were 74.2% and 73.6%, and the gas production rate and average methane content were 0.440 L/g $VS_{add}.d$ and 66.5%, respectively. Based on the results of this study, the co-digestion of thermophilic acid fermented food wastes and sewage sludge in sewage treatment plant is able to improve treatment efficiency of anaerobic digestion reactor and to dispose food wastes simultaneously, and was proved excellent economical efficiency comparing with any other treatment methods.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.1
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• pp.15-25
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• 2020

Biogas production potential was experimentally estimated for mono- and co-digestion of cow manure and waste grass. The two organic wastes were mixed at five different ratios (100:0, 75:25, 50:50, 25:75, 0:100) on the volatile solids basis, and were assessed using biochemical methane potential (BMP) test. Thee reaction temperatures, 25℃, 30℃ and 35℃, were applied as well, resulting in 15 different combinations for the test. The results showed that both higher temperature and waste grass mixing ratio resulted in higher methane yield and maximum methane production rate. Based on the experimental results, a theoretical farm- or community-scale (240 or 2400 ㎥) anaerobic digester was designed to evaluate the energy balance associated with mono- and co-digestion of the wastes at different temperatures. Although the energy production increased as the temperature and the waste grass mixing ratio increased, the net energy gain, energy production subtracted by energy consumption for heating and maintenance, was estimated to be the highest at 30℃, followed by at 35℃ and 25℃. Therefore, it is advised that both the experimental methane production and the detailed design parameters must be considered for the optimization of the net energy gain from these wastes.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.2
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• pp.72-78
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• 2006

Effect of organic loading rate on digester performance was evaluated under the conditions of same surface area/reactor volume ratio and different reactor diameter. At the low loading rate of $0.4\;kg\;COD/m^3{\cdot}d$, high rate of organic removal could be obtained regardless of reactor diameter. It can be estimated that reactor configuration can not affect reactor performance at the low loading rate. However, different performance depending on reactor diameter was observed at the organic loading rate of $6\;kg\;COD/m^3{\cdot}d$. That is, volatile acid accumulation and low COD removal efficiency was observed in reactor having 6.4 cm diameter, while volatile acid was not accumulated at all and high COD removal efficiency was observed in reactor having 3 cm diameter. Such a difference of reactor performance depending on reactor diameter can be explained that sludge bed can be fluidized by evolved gas bubble in narrow reactor while sludge bed can not be fluidized by evolved gas bubble only in wide reactor. At a high organic loading rate of $20\;kg\;COD/m^3{\cdot}d$, it can be judged that there is no relation between reactor configuration and reactor performance because all reactors showed very low COD removal efficiencies regardless of reactor diameter. Sludge bed fluidization is one of the most important factors in achieving efficient start-up of anaerobic digester. Narrow and tall type reactor is favorable condition for making sludge bed fluidization at a constant surface area/reactor volume ratio. Thus, it can be judged that reactor configuration and sludge bed fluidization have great influence to reactor performance.

• Journal of Dairy Science and Biotechnology
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• v.27 no.1
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• pp.13-18
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• 2009

We confirmed methane production and reduction of pollution during anaerobic digestion of milk waste and analyzed the economic potential of using milk waste as a renewable energy source. The milk waste sludge was obtained from the Pasteur milk factory and processed by anaerobic digestion to produce methane. The methane production from two completely mixed tank reactors with an effective capacity of 6 ${\ell}$, 15 days of hydraulic retention time (HRT), and a mid-temperature of $35^{\circ}C$ averaged 4.11 ${\ell}$/day. The total chemical oxygen demand (TCOD) during production decreased from an initial 31,416 mg/${\ell}$ to 13,500 mg/${\ell}$, showing a maximum TCOD removal efficiency of 60%. When HRT was reduced to 12 days, methane production increased by 44% under a high-temperature condition of $55^{\circ}C$. An economic analysis based on these results was applied to a Korean milk factory of typical size and demonstrated that the installation of an anaerobic digester could provide sufficient economic profit.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.343-348
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• 2010

The surface of low density polyethylene (LDPE) film was oxyfluorinated under different reaction conditions to introduce hydroperoxide groups and change surface characteristics. Hydroperoxide functional groups created by oxyfluorination were used as active sites for graft polymerization with hydrophobic monomer, acryl amide (AM), and hydrophilic monomer, methyl methacrylate (MMA) to carry out the second modification of the LDPE film surface. The surface properties of the OFPE films and grafted OFPE films were characterized by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method, ATR-IR, contact angle measurement and DSC. From the results of DPPH method, the amount of hydroperoxide groups on the oxyfluorinated LDPE film continuously increased as the total pressure in the oxyfluorination and the partial pressure of fluorine gas increased. The water contact angle and surface free energy measurements showed that hydrophilic liquid (water) contact angle on LDPE film surface decreased with hydrophilic AM grafting and hydrophobic liquid (methylene diiodide) contact angle on LDPE film surface decreased with hydrophobic MMA grafting. These were attributed to AM or MMA monomer grafting and the wettability of LDPE filmsurface to hydrophilic and hydrophobic liquids were improved.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.3
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• pp.104-110
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• 2001

In this study, the effect of physico-chemical variables on sludge conditioning was determined to enhance dewaterability of effluent produced from the thermophilic anaerobic digestion of food waste. The gas production rate and methane content during the anaerobic digestion of food waste were $1.1m^3/kg$ VS and 63%, respectively, and the biodegradability of volatile solids was 87.5%. The concentrations of CODcr, TKN and TP of effluent from digestor were 18,500mg/L, 2,800mg/L, and 582mg/L, respectively. At the jar test to screen the flocculant for the dewatering of effluent from digestor, $FeCl_3$ and strong cationic polymer were effective on making flocs in the effluent. The condition of flocculation of effluent were 500mg/L of $FeCl_3$ and 50-100 mg/L of strong cationic polymer, respectively. As the result of measuring of dewaterability potential of effluent to determine the mixing ratio between $FeCl_3$ and polymer by capillary suction time(SCT), optimum condition was 500mg/L of $FeCl_3$ and 80mg/L of strong cationic polymer.

• Clean Technology
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• v.15 no.1
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• pp.9-15
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• 2009

Catalytic hydrodechlorination of PCBs (polychlorinated biphenyls) included in the transformer oil was carried out to detoxify PCBs and to recycle the treated oil. Catalysts such as 0.98 wt% Pt and 0.79 wt% Pd on ${\gamma}$-alumina (${\gamma}-Al_2O_3$) support, 12.8 wt% Ni on ${\gamma}-Al_2O_3$, and 57.6 wt% Ni on silica-alumina ($SiO_2-Al_2O_3$) support were used for the catalytic hydrodechlorination. Various supercritical fluids such as carbon dioxide, propane and isobutane were used as reaction media. The effects of reaction temperature, reaction time, catalysts, and supercritical fluids on the catalytic hydrodechlorination were examined in detail. The detoxification degree increased in the order of Ni > Pd > Pt. This is possibly due to higher metal loading and larger metal size of the Ni catalyst. Below $175^{\circ}C,\;scCO_2$ was found as the most effective reaction media for the catalytic hydrodechlorination of PCBs included in the transformer oil.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.615-624
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• 2005

The cPCR technique was used to monitor rumen fermentation and attachment of Fibrobacter succinogenes to cellulose at different pH in the in vitro culture medium. The target fragments of 16S rDNA(445 bp) were amplified from genomic DNA of F. succinogenes with specific primers and internal controls(205 bp) were constructed. Cell counts were estimated from the amounts of genomic DNA, which was calculated from cPCR results. F. succinogenes in pH 6.8 and 6.2 showed apparently higher attachment than in pH 5.8 during all incubation time. There were some difference between pH 6.8 and 6.2 in the degree of attachment, but the different was not significant (P>0.05). Cellulose degradation increased in process of incubation time and the increasing rate was higher when initial pH was higher. The pH in culture medium decreased regardless of initial pH in course of incubation time. After 24 h of incubation, medium pH was dropped by 0.24, 0.58 and 0.16 units from original medium pH 6.8, 6.2 and 5.8, respectively. More gas was produced at higher initial pH in the same manner as in cellulose degradation. In summery, Initial pH of rumen culture in vitro significantly influenced cellulose digestion, gas production, pH change and bacterial attachment. Especially, low pH(5.8) resulted in much lower bacterial attachment and fiber digestion compared to higher medium pH.