• Journal of Environmental Science International
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• v.20 no.6
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• pp.767-773
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• 2011

The objectives of this research are to investigate the proper coagulation conditions which are a type and doses of coagulants, mixing conditions (velocity gradients and mixing times), pH and so on through Jar-test, to evaluate the flux variations, permeate, backwashing according to characteristics of pretreatment of the wastewater by means of MF membranes for river maintenance water reuse. The effluent water from B-city K-sewage treatment plant are used for this research. Turbidity and suspended solids(SS) are 14.2 NTU and 10.4 mg/L respectively. This condition causes fouling for membrane process. The flux decline could be reduced when coagulation pretreatment was carried out. Optimal coagulations PAC which are commonly used in the sewage treatment plant was observed in this research. The results indicate that an optimal coagulation dose and pH are 80 ppm and pH of 7 respectively, but coagulation efficiency was lower at strong acid or strong base. Results showed that continuous and steady operations in membrane separation process by means of the effective removal of organic matter and turbidity with coagulation pretreatment of sewage secondary effluent were achieved.

• International journal of advanced smart convergence
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• v.5 no.2
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• pp.18-23
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• 2016

Cell walls of microalgae consist of a polysaccharide and glycoprotein matrix providing the cells with a formidable defense against its environment. Anaerobic digestion (AD) of microalgae is primarily inhibited by the chemical composition of their cell walls containing biopolymers able to resist bacterial degradation. Adoption of pre-treatments such as thermal, thermal hydrolysis, ultrasound and enzymatic hydrolysis have the potential to remove these inhibitory compounds and enhance biogas yields by degrading the cell wall, and releasing the intracellular algogenic organic matter (AOM). This paper preproposal stage investigated the effect of different pre-treatments on microalgae cell wall, and their impact on the quantity of soluble biomass released in the media and thus on the digestion process yields. This Paper present optimum approach to degradation of the cell wall by ultra-sonication with practical design specification parameter for ultrasound based pretreatment system. As a result of this paper presents, a microalgae system in a wastewater treatment flowsheet for residual nutrient uptake can be justified by processing the waste biomass for energy recovery. As a conclusion on this result, Low energy harvesting technologies and pre-treatment of the algal biomass are required to improve the overall energy balance of this integrated system.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.851-858
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• 2012

This study conducted a result analysis on operation of 26 Rural Community Sewage Treatment Plant (RCSTP) newly constructed in Yeong-yang, Bong-hwa and An-dong areas which are located at the upper region of An-dong Dam and Im-ha Dam. Based on operation result, an analysis on characteristics of sewage in each area and the treatment efficiency of the installed treatment process was conducted. The result of analysis on characteristics of sewage has shown the difference in concentration of the sewage according to area characteristics. Sewage in areas with frequent occurrence of agricultural water and livestock wastewater had high concentration. It is important to select the most suitable treatment process when selecting a treatment process for RCSTP according to properties of sewage in each area. As a result of operation, the disposal efficiency for organic matter and suspended solids was stable with less fluctuation, but the disposal efficiency for nitrogen and phosphorus showed high fluctuation. This signifies that it is necessary to pay attention to operation condition management of nitrogen and phosphorus when operating RCSTP.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.872-878
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• 2009

Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to develop and apply the modified intermittently aeration mode as process control conditions for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 6.3, 4.5, 10.0, and 1.3 mg/L. The modified mode decreased the nitrification capability more than the conventional mode in the application period. Nitrate in the anaerobic condition can have a negative effect on biological phosphorus removal. In the decreasing nitrate levels, the modified mode increased the biological ability of removal phosphorus more than the conventional mode in this study. Therefore, newly developed APID process with modified intermittent aeration mode can be one of the useful processes for stable organic matter and nutrients removal.

• Environmental Engineering Research
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• v.24 no.3
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• pp.495-500
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• 2019

Bioremediation of bacterial algae is one of wastewater treatment by utilizing symbiosis of bacterial algae, which is relatively inexpensive and safe for the environment. The aims of this research were: (1) to investigate initial characteristic of boezem water of Kalidami Surabaya, (2) to investigate the effect of potassium (K) element and carbon source addition toward the reduction of $NH_3-N$ content and organic matter in $KMnO_4$ of boezem water. The research conducted in a laboratory in batches without adding aeration. The initial stage of this research was conducting alga culture until it was obtained chlorophyll-a algae concentration of $3.5{\pm}0.5mg/L$. The best result of range finding test was a comparison of boezem water volume with algal which were about 25%:75%. The research conducted in duplo over 18 d. The result of the research can be concluded that boezem water of Kalidami Surabaya for the parameter of pH, temperature, $NH_3-N$, dissolved oxygen, chemical oxygen demand, biological oxygen demand, and number of $KMnO_4$ show that it enables to do bioremediation of bacterial algae. Decrease efficiency occurred in a reactor with the addition of element K 3% and source C. $NH_3-N$ and $KMnO_4$ final content 0.164 mg/L and 30 mg/L, respectively.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.707-714
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• 2007

A laboratory experiment was performed to investigate nitrogen removal by the soil column. The addition of 20% waste oyster shell to the soil accelerated nitrification in soil column. The $NO_3^--N$ concentration in the effluent decreased with the decrease of HRT(Hydraulic Retention Time). When methanol and glucose added as carbon sources, the average removal rates of T-N(Total Nitrogen) were 82% and 77.9%, respectively. The $NO_3^--N$ removal by methanol supplementation in soil column can likely be attributed to denitrification. In continuous removal of nitrogen using the soil column, the COD(Chemical Oxygen Demand) and $NH_4^+-N$ removed simultaneously in organic matter decomposing column. The greater part of $NH_4^+-N$ was nitrified by the percolated through nitrification column, and the little $NH_4^+-N$ was found in the effluent. The T-N of 87.4% removed at HRT of 36 hrs in denitrfication column. Because of nitrified effluents from nitrification column are low in carbonaceous matter, an external source of carbon is required.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.141-148
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• 2017

The oxidation ditch (OD) is one of the most widely used processes for treating municipal wastewater. However, the microbial communities in the OD systems have not been well characterized, and little information about the shift of bacterial community during the startup process of the OD systems is available. In this study, we investigated the bacterial community changes during the startup period (over 100 days) of a full-scale OD. The results showed that the bacterial community dramatically changed during the startup period. Similar to the activated sludge samples in other studies, Proteobacteria (accounting for 26.3%-48.4%) was the most dominant bacterial phylum in the OD system, but its relative abundance declined nearly 40% during the startup process. It was also found that Planctomycetes proliferated greatly (from 4.79% to 13.5%) and finally replaced Bacteroidetes as the second abundant phylum in the OD system. Specifically, some bacteria affiliated with genus Flavobacterium exhibited remarkable decreasing trends, whereas bacterial species belonging to the OD1 candidate division and Saprospiraceae family were found to increase during the startup process. Despite of the bacterial community shift, the organic matter, nitrogen, and phosphorus in the effluent were always in low concentrations, suggesting the functional redundancy of the bacterial community. Moreover, by comparing with the bacterial community in other municipal wastewater treatment bioreactors, some potentially novel bacterial species were found to be present in the OD system. Collectively, this study improved our understandings of the bacterial community structure and microbial ecology during the startup of a full-scale wastewater treatment bioreactor.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.329-334
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• 1998

This study was conducted in order to investigate removal rate of organic matter, nitrogen and phosphorus to reduce environmental polluation with treatment to attach combined septic tank to 3 stage soil filter after mixing anaerobic treated water of livestock wastewater and low concentrated wastewater generated in farm house. Because anaerobic filter bed was packed in combined septic tank and a microorganism was accumulated in combined septic tank with increasing hydraulic retention time(HRT), if HRT $4{\sim}12day$, CODcr was removed $63.4{\sim}84.0%$. Also, $NH_4\;^+-N$ and $PO_4\;^{3-}-P$ were removed $3.9{\sim}5.4%$ and $18.3{\sim}29.0%$, respectively. In being re-treated by 3 stage soil filter, although hydraulic loading rate was gradually increased, CODcr, $NH_4\;^+-N$ and $PO_4\;^{3-}-P$ were removed above 90% due to filtration, adsorption, ion exchange, and action of soil microorganism. Generally, the attached treatment of combined septic tank and 3 stage soil filter did suitably treat livestock wastewater to water standard of discharge applied from '96 year, in view of decreasing pollution loading amount and recycling of agricultural water.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.253-258
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• 2004

There have been several problems in treating shipbard sewage due to special environmental conditions of ship, such as limited space, rolling and pitching, change of temperature and so on It was suggested that Sequence Batch Reactor (SBR) might be suitable process for overcome these problems in terms of small size, high capacity of treating wastewater and full automation. In this study a SBR process was employed for biological treatment of organic wastes in the shipboard sewage. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. Afore than 95％ of chemical oxygen demand(COD) were removed. In addition, about 97％ of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93％. A disturbance operation caused by the treatment of Methylene Blue Active Substances(MBAS) was not observed.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.583-588
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• 2004

This research examined the treatment efficiency and methane production rate in treating slurry-type swine waste using UASB (upflow anaerobic sludge blanket) reactor. The UASB reactor was operated at an organics volumetric loading rate (VLR) of $2.6-15.7kgCOD/m^3/day$. A stepwise increase of the VLR resulted in a temporary deterioration in the COD removal rate in UASB reactor but recovered quickly. The COD removal rate were 65-70% for VLR up to $5 kgCOD/m^3/day$. When organics VLR was $10kgCOD/m^3/day$, the COD removal rate decreased sharply and there was loss of 17.537g of the seeding biomass due to sludge washout. This result indicated that the UASB system cannot be adapted to more than $10kgCOD/m^3/day$ of VLR. As the organic load increased from 2.6 to $15.7kgCOD/m^3/d$, the biogas production rate varied from 3.2 to 10.8 L/d and the methane conversion rate of the organic matter varied from 0.30 to $0.23m^3CH_4/kg\;COD_{removed}$. The methane content showed the range of 70.1-81.5% during the experimental period. The volatile solids (VS) removal efficiency was similar at the low VLR (< $5 kgCOD/m^3/day$), but it decreased sharply at the high VLR (> $5 kgCOD/m^3/day$). The VS reduction rate was, moreover, large those of COD. The result shows that hydraulic retention time above 2 days is essential in case of treating wastewater containing 1% of solids.