• 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.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.357-362
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• 2017

Acetate, propionate, butyrate are the major soluble volatile fatty acids metabolites of fermented food waste leachates. This work investigate the effects of volatile fatty acid on the growth rate and $NH_4-N$, $PO_4-P$ removal efficiency of mixotrophic microalgae Chlorella vulgaris to treat digested food waste leachates. The results showed that acetate, propionate and butyrate were efficiently utilized by Chlorella vulgaris and microalgae growth was higher than control condition. Similar trends were observed upon $NH_4-N$ and $PO_4-P$ consumption. Volatile fatty acids promoted Chlorella vulgaris growth, and nutrient removal efficiencies were highest when acetate was used, and butyrate and propionate showed second and third. From this work it could be said that using mixotrophic microalgae, in this work Chlorella vulgaris, fermented food waste leachates can be treated with high efficiencies.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.2
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• pp.91-97
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• 2005

The purpose of this research is malodor reduction of food waste leachate by some microorganism. In oder to observe the efficiency of malodor reduction by different microorganisms, 300ml of food waste leachate was fermented by the addition of 10% precultured seed microorganism such as marine algae of Spirulina plantensis, Chlorella vulgaris, the yeast Saccharomyces cerevisae and bacteria Bacillus cereus for 10 days. During the fermentation the change in pH, salinity and sensory evaluations were tested. As the results, the pH values of samples in the beginning were 3.5~4.0. After fermentation they are increased to the level 4.9~7.4. The salinity values of the samples fermented by Spirulina plantensis and Chlorella vulgaris were lowered rapidly. By the sensory evaluation, the efficiency of malodor reduction by Chlorella vulgaris of the marine microalgae showed almost inodorous degree of ordor 1.

• Journal of Applied Biological Chemistry
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• v.51 no.4
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• pp.155-159
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• 2008

A local isolate of Aspergillus niger was cultivated under optimal growth conditions on wheat bran in solid state fermentation. Filter paperase from fermented bran was separately extracted with different solvents to test the recovery of the enzyme. Among solvents tested, distilled water served as the best leachate, thus the conditions were further optimized with distilled water. After two washes of fermented bran with distilled water for 1.5 h each under stationary conditions at 1 g wheat bran: 5 mL distilled water, the maximum recovery of 13.5 $Ug^{-1}$ of wheat bran was obtained.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.11-17
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• 2015

This study performed acid fermentation pre-treatment to improve production efficiency of methane that is produced as a product in case of anaerobic fermentation by using food waste leachate, and attempted to confirm the acid fermentation optimum through the BMP test by using pre-treated food waste leachate to increase the yield of methane. As a result of the BMP experiment by using acid fermented food waste leachate, the highest yield of methane of 0.220 L/g VS was confirmed in the HRT three-day condition, and in the initial BMP test by pH, pH 6 was 19,920 mg/L that the highest VFA and acetic acid/TVFA(76.2%) were shown. At this time, it was confirmed that the yield of methane was mostly within 10 days that was reduced to around one-third compared to the general methane fermentation (within 30 days). As the yield of methane was 0.294 L/g VS, it showed a high efficiency of around 1.3 times compared to the control group.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.397-402
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• 2006

The treatment characteristics of leachate produced from pretreatment facilities like composting and feeding were investigated in a mesophilic anaerobic treatment. Experiments were performed in two phase which were acidification and methane fermentation. The acidification step was optimized for OLR from 1 to $4.5kg\;COD/kg\;VS{\cdot}day$ without adding NaOH. As experiment dates became longer, the solubilization ratio of particles increased up to 30% over 70 days. TVA was generated up to maximum 9,970mg HAc/L at OLR of $2kg\;COD/kg\;VS{\cdot}day$. But TVA was generated to minimum 6,519mg HAc/L at OLR of $4.5kg\;COD/kg\;VS{\cdot}day$. The acidification ratio was analyzed from 10.9% to 3.8% at OLR of $2kg\;COD/kg\;VS{\cdot}day$ and $4.5kg\;COD/kg\;VS{\cdot}day$ respectively. After 55 days, salt contents in the acid fermenter were accumulated and stabilized at the concentration of 3,150mg/L. Sodium ion($Na^+$) concentration was stabilized at 1,300mg/L. At methane fermentation step, biogas was generated up to 750ml and 937.5ml at the feeding volume of 20ml and 25ml respectively for acid fermented liquid during 25 days. About 80% of total biogas was generated during early 15 days and 95% were generated during 18 days respectively. After 25 days of the BMP test, acetic acid was removed approximately 97% and 98%, in case of those two experimental conditions.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.31-37
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• 2010

Livestock manures have a potential to be a valuable resource with an efficient treatment. In Korea, 42 million tons of livestock manure were generated in 2008, and 84 % of them were used for compost and liquid fertilizer production. Recently recycling of livestock manure for biogas production through anaerobic digestion is increasing, but its utilization in agriculture is still uncertified. In this study, there was applied co-digestate to the paddy for rice cultivation based on N supplement. Co-digestate was fertilizer fermented with pig slurry and food waste combined with the ratio of 70:30(v:v) in its volumetric basis. For assessing the safety of co-digestate, it was monitored the contents of co-digestate for seasonal variation, resulted in no potential harm to the soil and plant by heavy metals. The results showed that soil applied with co-digestate was increased in exchangeable potassium, copper and zinc mainly due to the high rate of pig slurry in co-digestate applied. Considering high salt content due to the combination with food waste, strict quality assurances are needed for safe application to arable land though it has valuable fertilizer nutrient. Leachate after treatment showed that the concentration of nitrate nitrogen washed out within two weeks. Considering the salt accumulation results in soil, it is highly recommended that the application rate of co-digestate should not exceed the crop fertilization rate based on N supplement. With these results, it was concluded that co-digestate could be used as an alternative fertilizer for chemical fertilizer. More study is needed for the long-term effects of co-digestate application on the soil and water environment.