• Environmental Engineering Research
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• v.25 no.3
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• pp.324-334
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• 2020

Tannery wastewater is known to contain high concentrations of organic compounds, pathogens, and other toxic inorganic elements such as heavy metals, nitrogen, sulfur, etc. Biological methods such as aerobic and anaerobic processes are unsuitable for tannery wastewater treatment due to its high salinity, and electrochemical oxidation offers a promising method to solve this problem. In this study, raw tannery wastewater treatment using DSA® Ti/RuO₂, Ti/IrO₂ and Ti/BDD electrodes with continuous flow systems was examined. Effects of current densities and electrolysis times were investigated, to evaluate the process performance and energy consumption. The results showed that a Ti/BDD electrode is able to reach higher treatment efficiency than Ti/IrO₂, and Ti/RuO₂ electrodes across all parameters, excluding Total Nitrogen. The main mechanism of tannery wastewater oxidation at a Ti/BDD electrode is based on direct oxidation on the electrode surface combined with the generation of oxidants such as °OH and Cl₂, while at DSA® Ti/RuO₂ and Ti/IrO₂ electrodes, the oxidation mechanisms are based on the generation of chlorine. After treatment, the effluents can be discharged to the environment after 6-12 h of electrolysis. Electrooxidation thus offers a promising method for removing the nutrients and non-biodegradable organic compounds in tannery wastewater.

• Journal of Korean Society on Water Environment
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• v.32 no.2
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• pp.191-196
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• 2016

This study aimed to evaluate SBR operation cycle for removing the high-concentration organic matter of distillery wastewater in the ginseng processing plant. The experiment was conducted with the use of a laboratory scale SBR reactor and distillery wastewater as the influent. The results indicated an increase in pH from 4.08 to 7.59 of distillery wastewater after aeration for 2 hours. Also, the optimum SBR operation cycle for the removal of organic matter and nitrogen was 2 hr of aeration and 6 hr of anaerobic conditions. Adjustment of proper pH through aeration time is most critical in the SBR operation for distillery wastewater treatment. In this study, we presented an efficient method for distillery wastewater treatment.

• KSBB Journal
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• v.28 no.3
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• pp.157-164
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• 2013

Depending on season, mixed wastewater can show great deviations in terms of the influent ratios of tannery and seafood-wastewater. Increases in the ratio of tannery wastewater in influent water also result in increases in the concentration of chromium, which decreases the ratio of BOD/T-N so that the removal efficiency of organic and nitrogen pollutants in biological wastewater treatment deteriorates. No substantial differences occur in the ratios of Eubacteria/total bacteria as the ratio between tannery wastewater and seafood wastewater changes in the influent water. In contrast, the cell numbers and activities of Eubacteria and total bacteria significantly decline with increasing ratios of tannery wastewater in the influent water. Stable removal of organic and nitrogen pollutants by biological wastewater treatments leads to dominance of Proteobacteria groups in all biological treatment basins. In aeration and oxic basins, ${\gamma}$-Proteobacteria account for approximately 21% of the Eubacteria groups, at $1.9{\times}10^9{\sim}2.0{\times}10^9$ cells/mL, while in an anoxic basin, ${\beta}$-Proteobacteria account for approximately 19% of the Eubacteria groups, at $1.3{\times}10^9$ cells/mL. However, a substantial decline in dominance of approximately 11% occurs for ${\gamma}$-Proteobacteria in aeration and oxic basins and about 1% for ${\beta}$-Proteobacteria in an anoxic basin. Mixed wastewater that undergoes extensive property changes of the influent water shows an efficiency of biological treatment that is greatly influenced by the ratio of dominant Proteobacteria groups.

• KSBB Journal
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• v.23 no.1
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• pp.83-89
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• 2008

Food wastewater derived from the three-stage methane fermentation system developed in this lab contained high concentration organic substances. The organic wastewater should be treated through advanced wastewater treatment system to satisfy the "Permissible Pollutant Discharge Standard of Korea". In order to treat the organic wastewater efficiently, several optimum operation conditions of a modified $UV/TiO_{2}$ photocatalytic system have been investigated. In the first process, wastewater was pre-treated with $FeCl_{3}$. The optimum pH and coagulant concentration were 4.0 and 2000mg/L, respectively. Through this process, 52.6% of CODcr was removed. The second process was $UV-TiO_{2}$ photocatalytic reaction. The optimum operation conditions for the system were as follows: UV lamp wavelength, 254 nm; wastewater temperature, $40^{\circ}C$; pH 8.0; and air flow rate, 40L/min, respectively. Through the above two combined processes, 69.7% of T-N and 70.9% of CODcr contained in the wastewater were removed.

• The KSFM Journal of Fluid Machinery
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• v.17 no.3
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• pp.41-45
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• 2014

The biological aerated filter (BAF) reactor is regarded as an effective biological wastewater treatment method. It can remove pollutants by carrier filtration and biodegradation. Due to its advantages, which include high biomass retention, tolerance to toxicity, excellent removal efficiency, and slurry separation, BAF has been widely used to remove COD, $NH_4{^+}-N$, phosphorus, and other harmful organic substances. In this study, the BAF reactor was used to remove organic contaminants of domestic wastewater of Korea at both the benchand pilot-scale. The main objectives of this study are to: (i) investigate the removal efficiency of organic contaminants (ex. COD, nitrate, phosphorus) in BAF reactors at both scales; (ii) characterize the small-scale wastewater treatment plant using the BAF reactor. The concentration of COD in the influent increased from 69 to 246 mg/L. During the operation period, the final effluent concentration of COD remained maximum 4.0 mg/L, and the average removal efficiency was above 88%. The present study investigated the removal efficiencies of COD, TN, TP and $NH_4{^+}-N$ from smelting wastewater by BAF system. When treating wastewater in both bench and pilot-scale reactors, the BAF worked well.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.57-65
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• 2008

Wastewater containing strong organic matter is very difficult to treat by utilizing general sewage treatment plant. but the wastewater is adequate to generate biomass energy (bio-gas; methane gas) by utilizing anaerobic digestion. EcoDays Plug Flow Reactor (E-PFR), which was already proved as an excellent aerobic wastewater treatment reactor, was adapted for anaerobic food wastewater digestion. This research was performed to improve the efficiency of bio-gas production and to optimize anaerobic wastewater treatment system. Food wastewater from N food waste treatment plant was applied for the pilot scale experiments. The results indicated that the efficiency of anaerobic wastewater treatment and the volume of bio-gas were increased by applying E-PFR to anaerobic digestion. The structural characteristics of E-PFR can cause the high efficiency of anaerobic treatment processes. The unique structure of E-PFR is a diaphragm dividing vertical hydraulic multi-stages and the inversely protruded fluid transfer tubes on each diaphragm. The unique structure of E-PFR can make gas hold-up space at the top part of each stage in the reactor. Also, E-PFR can contain relatively high MLSS concentration in lower stage by vertical up-flow of wastewater. This hydraulic flow can cause high buffering capacity against shock load from the wastewater in the reactor, resulting in stable pH (7.0~8.0), relatively higher wastewater treatment efficiency, and larger volume of bio-gas generation. In addition, relatively longer solid retention time (SRT) in the reactor can increase organic matter degradation and bio-gas production efficiency. These characteristics in the reactor can be regarded as "ideal" anaerobic wastewater treatment conditions. Anaerobic wastewater treatment plant design factor can be assessed for having 70 % of methane gas content, and better bio-gas yielding and stable treatment efficiency based on the results of this research. For example, inner circulation with generated bio-gas in the reactor and better mixing conditions by improving fluid transfer tube structure can be used for achieving better bio-gas yielding efficiency. This research results can be used for acquiring better improved regenerated energy system.

• Environmental engineer
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• s.167
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• pp.50-53
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• 2000

The Wastewater from livestock farms shows the high organic concentration which was over 3,000mg/L of BOD concentrationin swine wastewater especially. Also the nitrogen concentration and red tide phenomena with phosphorous. Most of the livestock facilities

• Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.205-214
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• 2007

Surface water and sediment samples collected from the Mokpo coast of Korea were analyzed for molecular markers of organic municipal wastewaters, i.e., 11 fecal sterols including coprostanol (Cop) and nonylphenolic compounds (NPs), to characterize the main routes of these wastewaters to the coast and to assess contamination levels. Concentrations of Cop ranged from 94 to 7,568 ng/L in surface water and from 43 to 38,108 ng/g dry weight in sediments. Concentrations of NPs [nonylphenol (NP) and nonylphenol mono- and di-ethoxylates ($NP_{1-2}EOs$)] ranged from 123 to 4,729 ng/L in surface water and from 4 to 2,119 ng/ng dry weight in sediments. The levels of these compounds were much higher at stations near the rivers that pass through the urban center of Mokpo and the outfall of the wastewater treatment plant (WWTP). The spatial distribution of Cop levels was statistically similar to that of NPs (r=0.809 and 0.982 in surface water and sediments, respectively), indicating that these compounds may have similar discharge points, transport, mixing, and deposition in the study area. These results suggest that considerable amounts of organic wastewater compounds are discharged through rivers and WWTP effluent to the Mokpo coast.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.57-65
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• 1998

In this research, Effect of C/N ratio on nutrient removal in intermittently aerated activated sludge system(IAASS) was investigated with dormitary, building and swine wastewater. Three types (2-stage, 4-stage, modified) of IAASS were operated. Time interval of aeration/nonaeration in IAASS was 1hr/1hr. In treatment of Dormitary wastewater(BOD/T-N ratio : 4.4), Building wastewater (BOD/T-N ratio : 3.14) and swine wastewater(BOD/T-N ratio : 3.84), Nitrogen removal efficiency of 80, 70 and 90.4% was achieved, respectively. Nitrogen removal in IAASS was a great influenced on influent C/N ratio, efficient nitrogen removal was achieved at BOD/T-N ratio over 4. In IAASS operation, $\Delta $BOD mg/L/$\Delta $ nitrogen mg/L ratio was about 4-6. Simultaneous removal of organic, nitrogen and phosphorus in IAASS can achieved. And influent organic was efficiently utilized in denitrification. IAASS could be one of the best alternative process for the retrofit of conventional activated sludge system for the removal of nutrients.

• Journal of Industrial Technology
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• v.16
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• pp.51-60
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• 1996

This research was performed for the fundamental data using a advanced treatment process of piggery wastewater. Characteristics of influent wastewater was divided with various methods in fixed biofilm batch reasctor. Fractons of organic were divided into readily biodegradable soluble COD(Ss), slowly biodegradable COD(Xs), nonbiodegradable soluble COD($S_I$), and nonbiodegradable suspended COD($X_I$). Experimental results were summerized as following : i) biodegradable organics fraction in piggery wastewater was about 88.1 percent, and fraction of readily biodegradable soluble COD was about 66.1 percent. ii) Fractions of nonbiodegradable soluble COD was 11~12 percent, and soluble inert COD by metabolism was producted about 6~8 percent. iii) Active biomass fraction of attached biofilm was about 54.7 percent, and substrate utilization rate and maximum specific growth rate of heterotrophs were $8.315d^{-1}$ and $3.823d^{-1}$, respectively.