• Journal of the Korea Organic Resources Recycling Association
• /
• v.25 no.4
• /
• pp.31-39
• /
• 2017

From July to August 2013, liquid fertilizers produced at 180 liquid manure public resource centers and liquid fertilizer distribution centers were collected. The maturity of liquid fertilizers was measured using the mechanical maturity measurement device. The nutrient contents (nitrogen, phosphorus, and potassium), physicochemical properties, and heavy metal content of 46 liquid fertilizers were investigated in this study. We used a matured liquid fertilizer with a total number of 46, with number of 7 for Gyeonggi-do, 3 for Chungcheongbuk-do, 2 for Chungcheongnam-do, 13 for Jeollabuk-do, 5 for Jeollanam-do, 3 for Gyeongsangbuk-do, 11 for Gyeongsangnam-do, 1 for Daejeon, and 1 for Jeju-do. The physicochemical properties were as follows: pH 8.0, EC 11.6 mS/cm, SS 5,188 mg/L, TKN 847mg/L, ${{NH_4}^+}-N$ 317 mg/L, ${{NO_3}^-}-N$ 170 mg/L, Org-N 360 mg/L, TP 193 mg/L, and TK 2,557 mg/L. The total amount of NPK was 3,596 mg/L. The total amount of N-P-K was as follows: a number of 2 at 1,000-2,000 mg/L (4%), a number of 17 at 2,000-3,000mg/L (37%), a number of 11 at 3,000-4,000mg/L (24%), and a number of 16 at 4,000mg/L or more (35%). Thus, 41% of the mature liquid fertilizers were below the official standard of commercial fertilizer (livestock manure liquid fertilizer) (0.3% of the total amount of N-P-K). Most of the N-P-K total amount showed non-uniform characteristics of low nitrogen and low phosphoric acid due to the potassium concentration. The average heavy metal content in the matured liquid fertilizer was as follows: As, not detected; Cd, 0.01 mg/kg; Hg, not detected; Pb, 0.02 mg/kg; Cr, 0.14 mg/kg; Cu, 6.89 mg/kg; Ni, 0.44 mg/kg; and Zn, 20.70 mg/kg. Thus, the official standard of commercial fertilizer was satisfied in all categories, indicating a safe level.

• Microbiology and Biotechnology Letters
• /
• v.38 no.4
• /
• pp.461-466
• /
• 2010

In this study the feasibility of simultaneous electricity generation and treatment of swine farm wastewater using microbial fuel cells (MFCs) was examined. Two single-chamber MFCs containing an anode filled with different ratio of graphite felt and stainless-steel cross strip was used in all tests. The proportion of stainless-steel cross strip to graphite felt in the anode of control microbial fuel cell (CMFC) was higher than that of swine microbial fuel cell (SMFC) to reduce construction costs. SMFCs produced a stable current of 18 mA by swine wastewater with chemical oxygen demand (COD) of $3.167{\pm}80\;mg/L$ after enriched. The maximum power density and current density of SMFCs were $680\;mW/m^3$ and $3,770\;mA/m^3$, respectively. In the CMFC, power density and current density was lower than that of SMFC. CODs decreased by the SMFC and CMFC from $3.167{\pm}80$ to $865{\pm}21$ and $930{\pm}14\;mg/L$, achieving 72.7% and 70.6% COD removal, respectively. The suspended solid (SS) of both fuel cells was also reduced over 99% ($4,533{\pm}67$ to $24.0{\pm}6.0\;mg/L$). The concentration of nutritive salts, ${NH_4}^+$, ${NO_3}^-$, and ${PO_4}^{3-}$, dropped by 65.4%, 57.5%, and 73.7% by the SMFC, respectively. These results were similar with those of CMFC. These results show that the microbial fuel cells using electrode with mix stainless-steel cross strip and graphite felt can treat the swine wastewater simultaneously with an electricity generation from swine wastewater.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.7
• /
• pp.495-503
• /
• 2012

The water quality of Gul-po Stream, the subject of this study, has been deteriorating because of the inflow of domestic sewage and the industrial wastewater due to industrialization and the problems relating to the structure of river including slow flow rate and the covering of river. In particular, the domestic sewage from small-medium sized factories by the river and large-scale industrial complex by the upper and middle streams of the river, and the domestic sewage from increasing population due to the regional development are the main pollution sources. Thus, this study aims to survey the water quality and the sediment affecting Gul-po Stream; monitor the state of pollution in water body; assess the yield of sediment and investigate the water quality of river and the problems arising from sediment; and then suggest reasonable ways to improve the situation. The findings from surveying pollution load shows the discharge increases up to average 72.8 times from the upper stream to the downstream of Gul-po Stream, and pollution load increases up to: SS 111 times, BOD 150 times, COD 145 times, the nutrient T-N 222 times and T-P 312 times on an average basis. As for the pollution concentration range, ignition loss is 1.29~12.43%; COD is 4,015~37,547 kg/day; T-N and T-P 94.8~352.5 kg/day and 81.8~372.3 kg/day, respectively. As for the releasing rate of sediment, T-N is -14.46~$156.61mg/m^2/day$; T-P is -11.53~$26.10mg/m^2/day$, indicating the likelihood of internal contamination due to the elution of sediment. This study is expected to be used as basic data to manage Gul-po Stream basin.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.17 no.3
• /
• pp.203-218
• /
• 2011

Long-term trends and distribution patterns of water quality were investigated in the Yeoja Bay of South Sea, Korea from 1976 to 2010. Water samples were collected at 3 stations and physicochemical parameters were analyzed including water temperature, salinity, hydrogen ion concentration (pH), dissolved oxygen (DO), chemical oxygen demand (COD), suspended solids (SS) and nutrients. Spatial distribution patterns of temperature, pH and DO were not clear among stations but the seasonal variations were distinct except ammonium. The trend analysis by principal component analysis (PCA) during 31 years revealed the significant variations in water quality in the study area. Spatial water qualities were discriminated into 2 clusters by PCA; station cluster 1 and 2~3. Annual water qualities were clearly discriminated into 4 clusters by PCA. By this multi-variate analysis, the annual trends were summarized as the followings; water temperature, COD and SS tended to increase from late 1970's, decreased salinity, and increased phosphate from 1991 to 2001 and increased dissolved inorganic nitrogen. Water quality was showed by the input of fresh water same as those of Kyoungin coastal area, Asan coastal area, Choensoo bay, Gunsan coastal and Mokpo coastal area in the Yeoja Bay.

• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.5
• /
• pp.577-583
• /
• 2007

To overcome certain disadvantages of past typical control techniques for toxic contaminants emitted from various industrial processes, the current study was conducted to establish a thermal catalytic system using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst and to evaluate catalytic thermal destruction of five chlorinated hydrocarbons[chlorobenzene(CHB), chloroform(CHF), perchloroethylene (PCE), 1,1,1-trichloroethane(TCEthane), trichloroethylene(TCE)]. In addition, this study evaluated the catalyst poison effect on the catalytic thermal destruction. Three operating parameters tested for the thermal catalyst system included the inlet concentrations, the incineration temperature, and the residence time in the catalyst system. The thermal decomposition efficiency decreased from the highest value of 100% to the lowest value of almost 0%(CHB) as the input concentration increased, depending upon the type of chlorinated compounds. The destruction efficiencies of the four target compounds, except for TCEthane, increased upto almost 100% as the reaction temperature increased, whereas the destruction efficiency for TCEthane did not significantly vary. For the target compounds except for TCEthane, the catalytic destruction efficiencies increased up to 30% to 97% as the residence time increased from 10 sec to 60 sec, but the increase of destruction efficiency for TCEthane stopped at the residence time of 30 sec, suggesting that long residence times are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Conclusively, the current findings suggest that when applying the transition-metal catalyst for the better destruction of chlorinated hydrocarbons, VOC type should be considered, along with their inlet concentrations, and reaction temperature and residence time in catalytic system. Meanwhile, the addition of high methyl sulfide(1.8 ppm) caused a drop of 0 to 50% in the removal efficiencies of the target compounds, whereas the addition of low methyl sulfide (0.1 ppm), which is lower than the concentrations of sulfur compounds measured in typical industrial emissions, did not cause.

• Journal of Animal Environmental Science
• /
• v.15 no.2
• /
• pp.147-154
• /
• 2009

The purpose of this study was to determine the effect of re-establish the amount and major compositions of slurry from swine farms. The results obtained in this study was summarized as follow; The quantity of wastewater produced from the average volume of pig slurry was $4.64{\ell}$ /head/day and $4.68{\ell}$ in spring, $4.70{\ell}$ in summer, $4.70{\ell}$ in autumn, and $4.49{\ell}$ in winter. The average moisture content of slurry was 95.5%. And the composition of pig slurry contents of N, $P_2O_5$ and $K_2O$, were 0.27, 0.20 and 0.17% in slurry, respectively. The water pollutant concentration in slurry of swine farms, $BOD_5,\;COD_{MN}$, SS, T-N and T-P, was $21,856mg/{\ell},\;33,883mg/{\ell},\;41,253mg/{\ell},\;2,869mg/{\ell}$ and $565mg/{\ell}$, respectively.

• Journal of the Korean Society for Environmental Technology
• /
• v.19 no.6
• /
• pp.503-513
• /
• 2018

In order to continuous watershed management and improve water quality at Yeong-san river system, we analyzed and evaluated data on the monitoring of small stream in city and county boundaries within the watershed. In-period monitoring is estimated to be more frequent in the second quarter than the first quarter, so it should be considered when evaluating the target water quality by setting the target water quality. A small stream in the Yeong-san river system has higher concentration in the downstream area than the upstream area. As a result of calculating the load of the measuring point, Y.b B3(Pungyeongjeongcheon) and Y.b E1(Sampocheon) were high. The result of correlation analysis by monitoring point in order to evaluate the correlation between BOD and T-P items, BOD was highly correlated with COD and TOC, and was affected by emission of pollutants related to organic matter. T-P was highly correlated with SS and COD, and was affected by rainfall. This study will provide basic data and direction for designing efficient and scientific method for water quality management by analyzing accumulated water quality data by conducting long-term monitoring.

• Korean Journal of Ecology and Environment
• /
• v.37 no.1 s.106
• /
• pp.112-121
• /
• 2004

A study was performed to examine the effects of UV-disinfected reclaimed water on microorganism concentration during rice culture. Four treatments were used and each one was triplicated to evaluate the changes of microorganism concentrations: stream water irrigation (STR), biofilter effluent irrigation (BE), UV-disinfected water irrigation with dose of 6 mW ${\cdot}$ s $cm{-2}$ (UV-6), and UV-disinfected water irrigation with dose of 16 mW ${\cdot}$ s $cm{-2}$ (UV-16). The indicator microorganisms of interest were total coliform (TC), fecal coliform (FC), and E. coli. The biofilter effluent from 16-unit apartment sewage treatment plant was used as reclaimed water and flowthrough type UV-disinfection system was used. Concentrations of indicator microorganisms in the treatment plots ranged from $10^2$ to $10^5$ MPN/100 mL during 24 hours after irrigation in May and June, where initial irrigation water for transplanting reparation was biofilter-effluent without UV-disinfection. It implies that initial irrigation using only non-disinfected reclaimed water for puddling in paddy field can be health-concerned because of more chance of farmer's physical contact with elevated concentration of microorganisms. The concentrations of microorganisms varied widely with rainfall, and treatments using UV-disinfected water irrigation showed significantly lower concentrations than others and their levels were within the range of paddy rice field with normal surface water irrigation. The mean concentrations of STR and BE during growing season were in the range of 4 ${\times}\;10^3$ MPN/100 mL for TC, and 2${\times}\;10^3$ MPN/100 mL for FC and E, Coli, While mean concentrations of UV-S and UV-lS were less than 1${\times}\;10^3$ MPN/100 mL for all the indicator microorganisms. Overall, UV-disinfection was thought to be feasible and practical alternative for agricultural reuse of secondary level effluent in Korea.

• Korean Journal of Ecology and Environment
• /
• v.35 no.2 s.98
• /
• pp.92-102
• /
• 2002

This study was conducted to compare filtering abilities of three species of freshwater mussels (Cobicula fluminea, Corbicula leana and Unio douglasiae) and to evaluate their filter feeding effects on water quality change in experimental enclosure systems. Mussel feeding in both laboratory and enclosure resulted in decrease of particulate material, such as chlorophyll, total P, SS. In the treatment with 600 individuals of mussels, chllorophyll concentration and net primary productivity decreased from $87.3{\pm}4.5\;{\mu}g/L$ and $106.3{\pm}8.8\;{\mu}gC\;L^{-1}\;hr^{-1}$ to nearly the same level as the mussel-free enclosure ($25.0{\pm}0.5\;{\mu}g/L$ and $15.6{\pm}13.3\;{\mu}gC\;L^{-1}\;hr^{-1}$, respectively)(P< 0.05, n = 6, ANOVA). In concert with the decrease of chlorophyll concentration, not only was the transparency enhanced from 0.48 m to 1.2m but also the suspended solids and total phosphorus decreased from $22.0{\pm}1.0\;mg/L$ to $7.5{\pm}0.5\;mg/L$ and $133{\pm}0.8\;{\mu}g/L$ to $70{\pm}0.0\;{\mu}g/L$, respectively (P<0.001, $r^2$>0.71, n = 11). Although slight decrease of SRP concentration and the increase of inorganic nitrogen ($NH_3-N$ and $NO_2-N$) were observed in the mussel addition enclosure, there was no statistical difference between two enclosures. Based on the filtering rate on phytoplankton and nutrient release rate in forms of feces and pseudofeces, Corbicula leana appeared to be the most efficient filter-feeder among three mussel species. These results inidicate that Cobicula play an important role in controlling particulate sestons and thus it could be applied as a biocontroler for the water quality management in lakes and reservoirs with algal blooms.

• Korean Journal of Remote Sensing
• /
• v.39 no.5_1
• /
• pp.655-667
• /
• 2023

Algal bloom outbreaks are frequently reported around the world, and serious water pollution problems arise every year in Korea. It is necessary to protect the aquatic ecosystem through continuous management and rapid response. Many studies using satellite images are being conducted to estimate the concentration of chlorophyll-a (Chl-a), an indicator of algal bloom occurrence. However, machine learning models have recently been used because it is difficult to accurately calculate Chl-a due to the spectral characteristics and atmospheric correction errors that change depending on the water system. It is necessary to consider the factors affecting algal bloom as well as the satellite spectral index. Therefore, this study constructed a dataset by considering water quality, hydrological and meteorological factors, and sentinel-2 images in combination. Representative ensemble models random forest and extreme gradient boosting (XGBoost) were used to predict the concentration of Chl-a in eight weirs located on the Nakdong river over the past five years. R-squared score (R²), root mean square errors (RMSE), and mean absolute errors (MAE) were used as model evaluation indicators, and it was confirmed that R² of XGBoost was 0.80, RMSE was 6.612, and MAE was 4.457. Shapley additive expansion analysis showed that water quality factors, suspended solids, biochemical oxygen demand, dissolved oxygen, and the band ratio using red edge bands were of high importance in both models. Various input data were confirmed to help improve model performance, and it seems that it can be applied to domestic and international algal bloom detection.