• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.231-239
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• 1994

A reed-sand-filter system was used to purify swine wastewater economically. Reeds (Phragmites communis Trin) were planted on the sand / gravel bed of a 20/30cm layer depth. After the input of waste-water up to a depth of l0㎝, the effluent was monitored for pollutants on the 1st, 3rd, 5th and 7th day thereafter. As swine wastewater stayed longer, the pollutants in the effluent such as T-N, $PO_4^{3-}$, COD and BOD were removed more effectively. The sand-filter system with reeds showed a superior removal efficiency to that without reeds. Especially in summer, the former showed greater purification rates than the latter, being 30% greater in T-N, 37% in $PO_4^{3-}$, 42% in COD and 30% in suspended solids. The seasonal purification efficiency was in the decreasing order of July, October and April. Reeds took up 40.1g N, 10.8g $P_2O_5$, 38.9g $K_2O$, 2.8g CaO, 2.1g MgO per square meter of the above surface area.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.264-272
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• 2007

Runoff of non-point pollutants has affected bad influence to water quality of river as reaching within short time. For this reason, reducing them prior to reaching aquatic systems or treating them after collection from discharge process of pollutants are desirable for efficient treatment of pollutants. This study was carried out to develop an ecotechnological method to prevent further aggravation of water quality by non-point source through vegetation filter strips. This study has placed a focus on improving infiltration capacity of soil for the optimum condition of vegetation filter strips. Therefore, we used titled soil filter strips instead of vegetation filter strips in this study. The three types of soil tilter strips were used in a bench scale experiment before applying to the field. The reduction efficiency of pollutants in soil filter strips (SS $84.5{\sim}92.5%$, BOD $67.9{\sim}80.6%$, T-N $43.4{\sim}76.6%$, T-P $40.6{\sim}87.4%$, Cu $28.3{\sim}48.1%$ Fe $92.1{\sim}97.7%$, Pb $81.4{\sim}97.3%$) was much higher than that of the controled group. And non-point pollutants reduction efficiency by soil filter strip's forms was estimated to be distinguishing in order of bio material, mixture of sand and gravel and lastly the whole gravel. In the event, the whole reduction efficiency of pollutants on the soil filter strips disclosed good results.

• Applied Biological Chemistry
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• v.20 no.2
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• pp.228-235
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• 1977

The yeast strain was isolated from food industry waste water and its identification and biological characteristics were investigated. The optimum condition for cultivations and its activities for the reduction of B.O.D. on the food industry waste water were also confirmed. The results are as follows; 1) The isolated was identified as Candida curvata. 2) Candida curvata grew well in all of the experimented media, so and it can be regarded as a useful strain in the treatment of food industry waste water. 3) There was only a slight difference in the induction period between sterilized cultivation and unsterilized cultivation. But in the ice cream waste water, the period was considerably longer in unsterilized cultivation. 4) Specific rate of growth of Candida curvata in sugar waste water was 0.50/hr, ice cream waste water 0.50/hr, and beer waste water 1.0/hr. 5) Increasing of innoculum reduced the induction period in unsterilized cultivation. 6) The amount of dried yeast from sugar waste water were $175mg/{\ell}$, ice cream waste water $628mg/{\ell}$, and beer waste water $857mg/{\ell}$. Crude protein content in the dried yeast from sugar waste water were 52%, ice cream waste water 54%, and beer waste water 54%. 7) The rate of BOD reduction in sugar waste water were 49%, ice cream waste water 80%, and beer waste water 64%.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1090-1097
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• 2006

The anoxic activated sludge process was applied to the treatment of industrial box-mill wastewater, which exhibited the high removal efficiencies of $90{\sim}94%$$ TCOD_{Mn}$ and $58{\sim}81%$ Color. For the design of industrial anoxic activated sludge process, Monod bio-kinetic coefficients of box-mill wastewater were estimated as follows: $K_{max}$(maximum specific substrate removal rate)=0.52 $day^{-1}$, $K_s$(half saturation constant)=314 mg/L, $K_d$(decay coefficient)=0.274 $day^{-1}$, y(microbial yield coefficient)=0.908 mg/mg, and ${\mu}_{max}$(maximum specific growth rate)=0.472 $day^{-1}$. Space loading factors for the design analysis were practically determined as the values of F/M ratio=$0.043{\sim}0.07$ kg-$TCOD_{Mn}$/kg-SS-day, BOD space loading=$0.18{\sim}0.3$ kg-$TCOD_{Mn}/m^3-day$, and ${\theta}_x=6.8{\sim}26.4$ day when considering the relationship of these loading factors with growth dynamics of microorganisms, the F/M ratio that is inversely proportional to ${\theta}_x$ should be equivalent to ${\mu}_{max}$ in units, but exhibited the significant difference between theses two values. Therefore, it is considered that high safety factors are requested in the design of anoxic activated sludge process that is based on Monod bio-kinetics of microorganism.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.780-786
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• 2010

The bacterial community structure in biological reactor in wastewater treatment system was investigated by denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization (FISH). Samples were collected at different three points in wastewater treatment system. Through treatment processes, BOD (biochemical oxygen demand) and COD (chemical oxygen demand) of was removal efficiency was 83.1~98.6%, 67.2~85.2% respectively. Microbial community of aerobic tank and oxic tank were similar but anoxic tank was different (RRP group was increased about tripple) by DGGE and FISH in sludge (2007 October and 2008 January). Samples in 2007 October and 2008 January were dominant ${\alpha}$-Proteobacteria and CF group respectively. Sludge in 2008 April were different comparing former results dominant others as 65~80%. Others group was dominant. Eubacteria by FISH with the probe EUB338 was about $1.7{\sim}7.6{\times}10^9\;cells/mL$. It could be successfully observed bacterial community in biological wastewater system.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.67-76
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• 2021

Biogasification is a technology that produces environmentally friendly fuel using methane gas generated in the process of stably decomposing and processing organic waste. Biogasification is the most used method for energy conversion of organic waste with high moisture content, and is a useful method for organic waste treatment following the prohibition of direct landfill (2005) and marine dumping (2013). Due to African Swine Fever (ASF), which recently occurred in Korea, recycling of wet feed is prohibited, and consumers such as dry feed and compost are negatively recognized, making it difficult to treat food waste. Accordingly, biogasification is attracting more attention for the treatment and recycling of food waste. Korea's energy consumption amounted to 268.41 106toe, ranking 9th in the world. However, it is an energy-poor country that depends on foreign imports for about 95.8% of its energy supply. Therefore, in Korea, the Renewable Energy Portfolio Standard (RPS) is being introduced. The domestic RPS system sets the weight of the new and renewable energy certificate (REC, Renewable energy certificate) of waste energy lower than that of other renewable energy. Therefore, an additional incentive system is required for the activation of waste-to-energy. In this study, the operation of an anaerobic digester that treats food waste, food waste Leachate and various organic wastes was confirmed. It was intended to be used as basic data for preparing the waste-to-energy incentive system through precise monitoring for a certain period of time. Four sites that produce biogas from organic waste and use them for power generation and heavy gas were selected as target facilities, and field surveys and sampling were conducted. Basic properties analysis was performed on the influent sample of organic waste and the effluent sample according to the treatment process. As a result of the analysis of the properties, the total solids of the digester influent was an average of 12.11%, and the volatile solids of the total solids were confirmed to be 85.86%. BOD and CODcr removal rates were 60.8% and 64.8%. The volatile fatty acids in the influent averaged 55,716 mg/L. It can be confirmed that most of the volatile fatty acids were decomposed and removed with an average reduction rate of 92.3% after anaerobic digestion.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.398-404
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• 1984

This study was attempted to investigate variation of the bacterial flora in waste water treatment of fish meat paste plant by batch and continuous culture. The results of the experiment are as follows : 1. The removal rate of BOD in waste water treatment by activated sludge of continuous culture was above $90\%$. 2. In the process of nitric acidification of protein waste water, $NH_4-N\;and\;NO_2-N$ increased untill the lapse of 48 hours from culture, but $NO_3-N$ showed little change. 3. In activated sludge obtained from acclimation by batch culture for 10 days, bacteria good in capacity of nitric acidification were not appeared. 4. Among 120 strains of isolated bacteria, the most predominantly appeared bacterial flora were Enterobacteriaceae ($28\%$) and Pseudomonas spp. ($25\%$), In the latter term of aeration during which ammonia originates in abundance, Pseudomonas spp. was decreased but Enterobarteriaceae was increased. 5. Fifty percent of the isolated strains were able to grow in $0\%,\;3\%$ NaCl and $75\%$ artificial sea water, Therefore, it is suggested that sea water can be used as dilution water instead of tap water during the treatment of waste water.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.372-381
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• 2005

This study was conducted to test the efficiency of water quality improvement using the dissolved air flotation (DAF) technique in a shallow eutrophic reservoir. The application of DAF was followed by the addition of a chemical coagulant (poly aluminum chloride; PAC). The experiment was conducted in the mesocosm scale (wide ${\times}$ length ${\times}$ depth: 6 m ${\times}$ 6 m ${\times}$ 3 m). Suspended solids (SS) and volatile SS (VSS) concentration decreased by 54 ${\sim}$ 71% and 57 ${\sim}$ 79% of the initial concentrations, respectively. Total phosphorus and Chl- a concentration also decreased by 74 ${\sim}$ 92% and 54 ${\sim}$ 98%, respectively. BOD decreased by>86% while COD decrease ranged 29 ${\sim}$ 63%. Dissolved inorganic P (DIP) and dissolved total P (DTP) concentration decreased by 34 ${\sim}$ 88% and 62 ${\sim}$ 88%, respectively. After DAF application further onto the sediment, DIP-release rates from the sediment decreased by 17% (0.82 ${\to}$ 0.68 mg $m^{-2}$$day^{-1}$ in the oxic condition and 23% (2.27 ${\to}$ 1.76 mg $m^{-2}$$day^{-1}$) in the anoxic condition, compared to the release rate from the untreated sediment. DTP-release rate from both the oxic and anoxic sediments also decreased by 33% (5.62 ${\to}$ 3.78 mg $m^{-2}$$day^{-1}$) and 20% (6.23 ${\to}$ 4.99 mg $m^{-2}$$day^{-1}$), respectively. These results suggest that the DAF application both to the water column and onto the sediment be effective to improve water quality by removing particulate matters in the water column as well as reducing P-release from the sediment.

• The Korean Journal of Ecology
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• v.27 no.6 s.122
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• pp.375-381
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• 2004

We investigate the biological treatment of processed-leachate from SUDOKWON landfill site in Korea by the reed (Phragmites australis)-bed with a continuous flow system. The reed individuals showing superior growth in processed-leachate experiment were selected among the reeds of thirteen natural habitats by means of the comparisons between the removal rates of nutrient salts, eco-physiological responses and growth. The reed-beds (combination of the reed individuals showing superior growth with helper microorganisms) were continuously supplied with processed-leachate. We monitored the effluents that passing through the reed-beds during the experiment period. After five weeks, analysis results of effluent from each reed-bed were as follows; chromaticity, total nitrogen, total phosphorus, biological oxygen demand, chemical oxygen demand, total dissolved solid and salinity decreased $29.5{\sim}36.9\%,\;49.4{\sim}67.2\%,\;42.1{\sim}94.6\%,\;74.5{\sim}88.8\%,\;15.6{\sim}20.8\%,\;17.5{\sim}35.4\%\;and\;15.3{\sim}34.7\%$, respectively. These results represented the substantial improvement of water-quality after passing through reed-bed in a continuous flow system.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.581-589
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• 2005

Recently, membrane processes have been replacing the conventional processes for waste water treatment to produce better quality of effluent and to meet more stringent regulations because of water shortage. However, using membrane processes for water treatment has confronted with fouling and difficulty in treating dissolved organic pollutants. In this study, membrane process equipped with crossflow microfiltration is combined with coagulation process using alum and PAC to improve permeability and treatment efficiency. The effects of coagulant dosage and optimum membrane operating conditions were investigated from measurement of permeate flow, cumulative volume, total resistance, particle size, dissolved organic pollutant, dissolved aluminium and quality of effluent. Characteristic of PAC coagulation was compared with that of alum coagulation. PAC coagulation reduced membrane fouling because of forming larger particle size and increased permeate velocity and cumulative volume. Less dissolved organic pollutants and dissolved aluminum made decreasing-rate of permeate velocity being lowered. At using $0.2\;{\mu}m$ membrane, cake filtration observed. At using $0.45\;{\mu}m$ membrane, there was floc breakage due to shear stress occurred born circulating operation. It made floc size smaller than membrane pore size, which subsequently to decrease permeate velocity and to increase total resistance. The optimum coagulation dosage was $300{\pm}50\;mg/L$ for both alum and PAC. PAC coagulation was more efficiently used with $0.2\;{\mu}m$ membrane, and the highest permeate flux was in using $0.45\;{\mu}m$membrane. The greatest efficiency of treatment was as follows; turbidity 99.8%, SS 99.9%, $BOD_5$ 94.4%, $COD_{Cr}$ 95.4%, T-N 54.3%, T-P 99.8%.