• Environmental Engineering Research
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• v.23 no.3
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• pp.229-241
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• 2018

Microalgae are likely to become a part of our everyday diet in the near future as they are considered to be rich in proteins, carbohydrates, and high density lipoproteins. They will play a pivotal role in the food cycle of many people around the globe. Use of microalgae in treating wastewater is also one of the disciplines which are luring researchers as this contributes to a sustainable way of exploiting resources while keeping the environment safe. In addition, microalgal biomass also has the potential to be used as a feedstock for producing biofuel, bio fertilizers, pharmaceuticals, nutraceuticals and other bio-based products. This review presents the different value-added products obtained from microalgal biomass and the applicability of these products commercially.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2239-2245
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• 2000

For the treatment of wastewater being discharged in large quantities as in these modern times, qualitative and quantitative concepts should be introduced in consideration of the recycling. In view of a qualitative concept, high rate aeration process is known as the most effective process up to now. However, Lee suggested UHR process showing the superiority over high rate process in treatment rate and quantity. Therefore, this study was performed to investigate the basic sphere of design and treatment quality, such as applicable $BOD_5$-loading and influent wastewater concentration of UHR process, based on Lee's suggestions1). Consequently, this process showed applicable $BOD_5$-loading of $2.2{\sim}7.0kg-BOD_5/kg-MLSS{\cdot}day$, exceeding three times or more of high rate process with maximum applicable loading of $2.25kg-BOD_5/kg-MLSS{\cdot}day$. Meanwhile, with the range of influent wastewater concentration from 200 to 450 mg/L. it showed the treatment rate from 94.7 to 97.3%, it indicated very good condition. In view of quantitative concept of treatment, UHR process is considered an epoch-making treatment process being superior to existing ones.

• Journal of Environmental Health Sciences
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• v.34 no.6
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• pp.452-458
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• 2008

This study was undertaken to establish the biological reaction characteristics of the marine products industry wastewater which contains high concentrations of organic matter and saline. As the S/I is varied from 0.3 to 1.2, the results were follows : the observed ultimate anaerobic biodegradability varied from 72.0 to 88.0%, the first order reaction rate varied from 0.1735 to $0.3420\;day^{-1}$ and the second order reaction rate varied from 0.0132 to $0.0295\;day^{-1}$. When S/I was 0.9, the first order reaction rate had a maximum value, but the variations of the second order reaction rate were less than 1st-order reaction rate. When the operation time exceeded 2 days the gas production rapidly increased. The source of this rapid increase was due to that the activity of the granular sludge used in this study being faster than that of conventional sludge. Under aerobic condition, the characteristics of organic matter were as follows: the marine industry wastewater used in this study contained about 81% of biodegradable matter, and it was divided into readily biodegradable COD(Ss), slowly biodegradable COD(Xs), soluble COD(Si) and inert suspended COD (Xi). The percentages of each COD were 87.3%, 23.9%, 6.4% and 12.4% respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.11-17
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• 1996

Photosynthetic bacteria, strains KN 1-1, KN 2-1 and KN 2-3 were isolated from nature, and were studied for swine wastewater treatment. Growth of those photosynthetic bacteria were increased to 2~3 fold in organic-acid added medium(sodium acetate 1g, sodium propionate 1g and sodium butyrate 1g in Lascelles basal medium $1{\ell}$) than cultivation in Lascelles basal medium, and amount of bacteriochlorophyll a were increased to 1.5~2 fold. Chemical Oxygen Demand(COD) in swine wastewater using photosynthetic bacteria, strains KN 1-1, KN 2-1 and KN 2-3 were reduced 80%, 89% and 75%, respectively.

• Environmental Engineering Research
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• v.25 no.3
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• pp.309-315
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• 2020

Slaughterhouse wastewater (SWW) is characterized as one of the most harmful agriculture and food industrial wastewaters due to its high organic content. The emissions of SWW would cause eutrophication of surface water and pollution of groundwater. This study developed a pilot scale anaerobic-aerobic slaughterhouse wastewater treatment process (AASWWTP) to enhance the chemical oxygen demand (COD) and total nitrogen (TN) removal. The optimum supernatant reflux position and ratio for TN removal were investigated through the modified Box-Behnken design (BBD) experiments. Results showed that COD could be effectively reduced over the whole modified BBD study and the removal efficiency was all higher than 98%. The optimum reflux position and ratio were suggested to be 2 alure and 100%, respectively, where effluent TN concentration was satisfied with the forthcoming Chinese discharge standard of 25 mg/L. Anaerobic digestion and ammonia oxidation were considered as the main approaches for COD and TN removal in the AASWWTP. The results of inorganic nutrients (K⁺, Na⁺, Ca²⁺ and Mg²⁺) indicated that the SWW was suitable for biological treatment and the correspondingly processes such as AASWWTP should be widely researched and popularized. Therefore, AASWWTP is a promising technology for SWW treatment but more research is needed to further improve the operating efficiency.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.57-64
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• 2019

We investigated influence of connected influent on the treatability of a wastewater treatment plant (WWTP), recently accepting effluent from a sludge carbonization facility. Based upon the pollutant loading rates (kg/d) of each connected influent, food waste leachate and livestock wastewater contributed to high BOD and COD loadings, while sludge carbonization facility effluent certainly contributed to T-N and $NH_3-N$ loadings. The nitrification rate in aerobic tank decreased to 55% with the carbonization facility effluent entering to the WWTP, while it was 89% with no carbonization facility effluent entering. The sludge carbonization facility effluent may need to be pretreated to reduce T-N and $NH_3-N$ loadings before entering to the WWTP for further treatment.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.120-131
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• 1998

This study was performed to define the physicochemical characteristics of food waste and food wastewater, and to find the effect of moisture content variation and salinity variation on aerobic composting for food wastes. In moisture content variation experiment, the samples of 2-1, 2-2, 2-3 and 24 were prepared by the moisture content of 83.8%, 70.9%, 64.8% and 45.1%, respectively. In salinity variation experiment, the samples of 3-1, 3-2, 3-3 and 3-4 were prepared by the salinity of 0.99%, 1. 69%, 1.75% and 2.34%, respectively. In both experiments, aerobic composting reactors were operated by the mode which was composed of half an hour's stirring and 2 hour's aeration per day, for 45 days. The followings are the conclusions that were derived from this study. 1. In the study of physicochemical characteristics of food waste and food wastewater, the values of pH were 4.19 and 3.96, the values of salinity were 0.91% and 1.17%, and the values of conductivity were 7.6 mS/cm and 18.2 mS/cm, respectively. 2. In food waste, the moisture content was 60.3%, organic compound content was 96.1%, total carbon was 48.0%, total nitrogen was 1.5%(therefore, C/N ratio was 32), and the concentration of total phosphorus was 1.34 mg/kg. 3. The time of temperature ascending was delayed, the highest temperature was lowered, the duration period of high temperature was shortened by the increasing of moisture content. In the higher moisture content, anaerobic condition was formed, bad smell was released, insects were gathered and multiplicated, and the reaction rate of composting was reduced. 4. In moisture content experiment, C/N ratios were changed from the range of 31.2-34.8 at the beginning phase to that of 20.4-28.4 at the last phase. 5. In salinity experiment, the reduction rate of volume was increased(40.3%) when the salinity was decreased(0.99%). Also, the reduction rate of mass was increased(51.8%) when the salinity was decreased(0.99%). This fact denotes that salinity hinders the process of composting. 6. the concentrations of total nitrogen and total phosphorus were increased from 0.74% to 1.10%, and from 0.82 mg/kg to 3.44 mg/kg, respectively when the salinity was decreased from 2.34% to 0.99%.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.3
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• pp.110-116
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• 2002

The aim of this study was to analyze food waste treatment cost and to estimate effect of by-product, such as wastewater and foreign materials, on amount cost. In cost analysis, man power and facility capacity are fixed, whereas operation cost, by-product treatment and et, al. are varied by treatment methods. The rate of by-product treatment cost in amount cost are between 5% and 39%. The methods which consume large electric power or generate much wastewater showed higher rate of by-product treatment cost in range of 14 to 39%. On the other hand, the methods which have simple process showed lower rate in range of 5 to 11%. Thus, this study recommend that by-products should be treated in sewage treatment facilities or landfill sites to prevent illegal disposal of by-products or to reduce burden of by-product from private sectors.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.2
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• pp.55-61
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• 2010

This study was carried out to analyze national and regional distribution of the organic wastes generation and build their distribution maps including food wastes, paper and wood wastes, wastewater and slaughterhouse wastes. The information for the annual waste production was modified using statistics from Ministry of Environment (MOE). Based on waste generation resources data, we established database architecture table about waste generation. The distribution maps for food wastes were built up in both national and regional scales and distribution maps for paper and wood wastes, wastewater and slaughterhouse wastes were also produced, respectively. The distribution maps of waste generation graphically provide the information regarding biomass resources to policy-makers, farmers, general users and it is highly expected to be utilized for policy-making of environmental-friendly agriculture and bioenergy.

• Environmental Engineering Research
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• v.13 no.3
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• pp.155-161
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• 2008

This study examined effects of the fermented leachate of food waste (FLFW) on nitrogen and phosphorous removal for domestic wastewater containing a low carbon-to-nitrogen (C/N) ratio in sequencing batch reactor (SBR). When the FLFW was not supplied in the process, release of phosphorus and excessive intake was not observed at both anaerobic and aerobic stages. On the other hand, when the FLFW was gradually added, active release of phosphorus and intake of phosphorus was noticed at an anaerobic stage and aerobic stage, respectively, resulting in improved phosphorus removal efficiency. The removal efficiency of nitrogen and phosphorus was increased from 75% and 37% (R-1, control test) to 97% and 80% (R-4, the highest substrate ratio test), respectively. In addition, although activity of the nitrogen oxidizing microorganisms was reduced when the reaction temperature was decreased to $10^{\circ}C$, the phosphorus removal efficiency was shown to increase with the addition of FLFW, indicating an independence from temperature. Overall, this study suggests that an efficient nutrients removal process can be successfully employed into a SBR when the FLFW is added to a wastewater which has a low C/N ratio.