• Journal of the Korea Organic Resources Recycling Association
• /
• v.7 no.2
• /
• pp.57-64
• /
• 1999

The purpose of this study is to establish effective conditions for controlling $CH_4$, $N_2O$ emission from organic Waste / wastewater treatment processes. Continuous and batch experiments were conducted to treat the micro algae from polluted and eutrophicated lakes through the thermophilic oxic process. The microalgae used were mainly Microcystis sp.(collected from eutrophic lake) and Chlorella sp. (cultured in laboratory) Wasted cooking oil was added by aid-heating source. Physico-chemical components of sludges and microalgae were analyzed. In batch experiments, air supply was changed from 50ml/min to 150ml/min. The temperature. water content and drained water were affected by the air flow rate at initial stage. However, there was almost no influence of air flow rate on them in middle and last stages. At air flow rate of 100ml/min, the degradation rate of organic material was higher than that at other air flow rates. $CO_2$ concentration in exhaust was proportional to the strength of aeration, especially at initial stage when degradation was active. $CH_4$ with low concentration was detected only at starting stage when air diffusion was not enough. $N_2O$ production was not affected by variation of air supply. In continuous experiments no matter what the dewatering methods (with PAC and without PAC) and media (wood chip and reed chip) were changed, $N_2O$ was almost not affected by variation of injected air. Result showed that the reed chips using for lake purification could be used as media for thermophilic oxic process in lake and marshes area. $CO_2$ concentration was not so much affected by the change of dewatering methods and media types. $CH_4$ was not detected in the experimental period. So it can be shown that the thermophilic oxic process had been well operated in wide handling conditions regardless of media and dewatering methods.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.5
• /
• pp.398-404
• /
• 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 Food Science and Technology
• /
• v.35 no.1
• /
• pp.103-110
• /
• 2003

Stable production of fermented kanjang containing 1.8% (v/v) ethanol was obtained within four days using traditional kanjang containing 4% added glucose in packed-bed bioreactor systems filled with immobilized Zygosaccharomyces rouxii and Candida versatilis on porous alumina ceramic bead carrier at $28{\pm}0.5^{\circ}C$ and aeration rate of 0.05 vvm. Specific rates of alcohol production for Z. rouxii and C. versatilis were 0.0033 and 0.0031/day, respectively, and those of glucose consumption were both -0.0087/day in the batch type of alcoholic fermentation. In semi-continuous alcoholic fermentation at a dilution rate of 0.25/day, specific rates of alcohol production for Z. rouxii and C. versatilis were 0.0045 and 0.0029/day, and those of glucose consumption were -0.01 and -0.008/day, respectively, using identical bioreactor system. Similar specific rates of alcohol production were observed both in the batch or semi-continuous process and in the continuous one at the dilution rate of 0.25/day. Sensory characteristics of all alcoholic-fermented kanjang by Z. rouxii, C. versatilis, and a mixture of both yeasts (2:1, w/w) were shown to be significantly superior to those of home-made kanjang as revealed through organoleptic evaluation tests (p<0.05).

• Journal of the Korea Organic Resources Recycling Association
• /
• v.17 no.3
• /
• pp.71-81
• /
• 2009

Food waste has been actively used as a composting material in order to reduce the environmental pollution load and to enhance the recycling of resources. In this study, the longterm effects of continuous application of food waste compost to soils on both the crop production and the soil properties were examined to ensure the safety of food waste compost in agricultural use. In addition, we collected the preliminary data for establishing standard application rate of food waste compost for agricultural utilization. Based on conventional nitrogen application rate of chemical fertilizer for crop cultivation, pig manure compost $(24g\;N\;kg^{-1}$, $8g\;P_2O_5\;kg^{-1}$, and $10.4g\;K_2O\;kg^{-1})$ and food waste compost ($20g\;N\;kg^{-1}$, $20.1g\;P_2O_5\;kg^{-1}$, and $6.5g\;K_2O\;kg^{-1}$) were applied to the upland soil in $2{\times}2{\times}2m$ lysimeter in which lettuce (Lactuca sativa var. crispa), Chinese cabbage (Brassica campestris subsp. napus var. pekinensis), red pepper (Capsicum annuum), and potato (Solanum tuberosum) were grown continuously. The crops grown in soils to which food waste compost applied showed better growth responses than the control, whereas some variations were observed in the crops grown in chemical fertilizer treated soils. Continuous application of food waste compost increased the contents of organic matter, nitrogen, and phosphorus, which resulted in improving soil aeration.

• Korean Journal of Food Science and Technology
• /
• v.17 no.1
• /
• pp.25-32
• /
• 1985

Low-temperature in-bin paddy drying has been examined to study the limitations of this drying method under Korean weather conditions, the initial moisture content of the paddy, the bulk depth and the airflow rate. The results are reported and discussed with regard to drying time, energy requirements and costs, uniformity in the moisture content of the dried kernels and, finally, the quality of the paddy. The tests carried out during the paddy-drying period in 1981 and 1982 have shown that under Korean weather conditions paddy can be dried to safe storage conditions by continuous aeration with ambient air. Depending upon the initial moisture content of the kernels(19.2%-25.5% w.b.), the bulk depth(1.1-3.5m) and the airflow $(3.0-6.9m^3\;air/m^3\;paddy/min)$ the paddy could be dried within 5 to 17 days. The energy requirements and energy costs are shown to be considerably lower than for conventional high-temperature drying. No significant changes in the quality in terms of milling yield, cracking ratio, acid value and germination were observed.

• Journal of Animal Environmental Science
• /
• v.14 no.3
• /
• pp.183-192
• /
• 2008

This study was carried out to investigate the temperature, water balance, evaporation and physicochemical properties during the composting with pig slurry at a scraper system. The pig slurry was composted on farm trial using continuous aeration with turning machine for 5 month. A compost facility of rectangular concrete bin with dimension of 53 m (length) ${\times}$ 4.6 m (width) ${\times}$ 2 m (height) was bedded with sawdust. The environmental parameters were monitored in period of 5 months. The results were as follows ; 1. During the composting period, the temperature was varied in the range $50{\sim}70^{\circ}C$. The temperature of compost pile was highest in middle layer and lowest in under layer. Temperature difference between middle and under area of compost pile was $5{\sim}20^{\circ}C$. 2. The water content of compost pile varied $50{\sim}68%$. In the period of 50% of water content of compost pile, the temperature of compost was $20{\sim}30^{\circ}C$ and was not successfully composted. 3. In this study, total evaporation was 90% during composting. The amount of slurry per $1m^3$ sawdust by this method was $3.16m^3$ without treatment of effluent output. 4. The chemical properties of produced compost was high, but suitable for plant growth. Concentration of T-N, T-C in the final compost were 1.62, 34%, respectively.

• Korean Journal of Environmental Biology
• /
• v.20 no.2
• /
• pp.158-164
• /
• 2002

Some of synthetic chemicals can net as an endocrine disrupting substance in higher animals. Dioxins, DDT, PCBs and bisphenol A (BPA) are classified into endocrine disruptors and aye under a strict control in many countries. This research was designed to compare the clastogenic effects of BPA to those of ionizng radiation to establish the relaltive effectiveness of BPA by means of Tradescantia micronucleus assay. For the uptake of the BPA through the stems, groups of fresh cuttings of Tradescantia BNL 4430 weve placed in BPA solutions of 0 to 4 $\mu$M for 6 hours under continuous aeration. The other groups of the cuttings were irradiated with 0 to 0.5 Gy of gamma- rays. The frequencies of micronucleus showed a positive dose- response relationship in the range of 0 to 0.5 Gy, and a clear concentration-response relationship in the experimental range of BPA concentrations. By comparing the two experimental results, it is possible to estimate the BPA concentration and its equivalent radiation dose for a fixed value of MCN frequency. BPA of $ll.8\mu{M}$ can give rise to 53.3 MCN/100 tetrads, which is the same frequency induced by 25 cGy of gamma- rays. It is of biological importance that clinical symptoms start to develop after a whole body exposure to radiation higher than 25 cGy. The results indicate that the pollen mother cells are an excellent biological end- point for toxicity test of suspected endocrine disrupting chemicals such as bisphenol A, cotylphenol and nonylphenol.

• Membrane Journal
• /
• v.15 no.2
• /
• pp.114-120
• /
• 2005

The purpose of this study is to obtain practical information about membrane coupled $ A_2O$ system for muncipal wastewater treatment. A flat-plate microfiltration (MF) module with a pore size $0.25\;{\mu}m$ was submerged into the aeration basin and treated water was filtrated through the membrane by continuous suction with low pressure. The system was operated with synthetic wastewater to find operational parameters of internal recycle ratio and maximum MLSS showing best water quality and long-term stability. The internal recycle was defined as type 1 for aerobic to anoxic tank and type 2 for anoxic to anaerobic tank, respectively When the flux was maintained at $0.015\;m^3/m^2/hr$ (15 LMH) with 2Q type 1 internal recycle ratio, the optimal operational setting were 10 internal recycle ratio for type 2 and maximum MLSS of 11,000 mg/L among tested conditions. At this condition, removal efficiencies of BOD, CODcr, T-N and T-P showed $97.3\%,\;94.2\%,\;64.0\%,\;63.0\%$, respectively.

• Clean Technology
• /
• v.23 no.4
• /
• pp.345-356
• /
• 2017

The composting is a biological process that converts organic matter into useful resources such as fertilizers. It is a continuous transition of microbial communities to adapt changes in organic matter and environmental conditions (carbonation rate, temperature, humidity, oxygen supply, pH, etc.). Most of the composting plants are located in the proximity of the residential areas. It is a general scenario where government authorities receive complaints from the local residents due to release of odor from the composting, and has become a social problem in Korea. Identification of dominant microorganisms, understanding change in microbial communities and augmentation of specific microorganism for composting is vital to enhance the efficiency of composting, quality of the compost produced, and reduction of odor. In this paper, we suggest the optimum operation conditions and methods for compost depot to reduce odor generation. The selection of the appropriate microorganisms and their rapid increase in population are effective to promote composting. The optimal growth conditions of bacteria such as aeration (oxygen), temperature, and humidity were standardized to maximize composting through microbial degradation. The use of porous minerals and moisture control has significantly improved odor removal. Recent technologies to reduce odor from the composting environment and improved composting processes are also presented.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.17 no.3
• /
• pp.55-70
• /
• 2009

The long-term effects and the soil environmental changes were examined to ensure the safety of food waste compost in agricultural use. Based on conventional nitrogen application rate of chemical fertilizer, Pig manure compost with $24g\;N\;kg^{-1}$, $8g\;P_2O_5\;kg^{-1}$, and $10.4g\;K_2O\;kg^{-1}$ and food waste compost with $20g\;N\;kg^{-1}$, $20.1g\;P_2O_5\;kg^{-1}$, and $6.5g\;K_2O\;kg^{-1}$ were applied to the paddy soil in $2{\times}2{\times}2m$ lysimeter in which paddy rice (Oryza sativa L. var Chucheong) were grown. The rice grown where food waste compost applied showed better growth responses than control, whereas less yield rate than chemical fertilizer applied. The contents of organic matter, nitrogen, and phosphorus after experiment were increased with compost applied. In addition, it improved soil aeration by the application of food waste compost, while little difference was observed in the quality of surface, infiltrated, and ground water compared to chemical fertilizer applied or control.