• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.1
• /
• pp.9-14
• /
• 2009

In this research, a polyester manufacturing company (i.e. K Co.) in Gumi, South Korea was investigated regarding the release of high concentrations of 1,4-dioxane(about 600 mg/L) and whether treatment prior to release should occur to meet with the level of the regulation standard (e.g., 5 mg/L in 2011). The pilot-scale (reactor volume, 10 $m^3$) treatment system using Photo-Fenton Oxidation was able to remove approximately 90% of 1,4-dioxane under the conditions that concentrations of 2,800 ppm $H_2O_2$ and 1,400 ppm $FeSO_4$ were maintained along with 10 UV-C lamps (240 ${\mu}W/cm^2$) illuminated during aeration. However, the effluent concentration of 1,4-dioxane was still high at about 60 mg/L. Thus, further investigation is needed to see whether the bench scale (reactor volume, 8.9 L) of activated sludge could facilitate the decomposition of 1,4-dioxane. As a result, 1,4-dioxane in the effluent has been decreased as low as about 2~3 mg/L. Consequently, Photo-Fenton Oxidation coupled with activated sludge process can make it possible to efficiently decompose 1,4-dioxane to keep up with that of the regulation standard.

• Journal of Korean Society on Water Environment
• /
• v.26 no.5
• /
• pp.871-879
• /
• 2010

To figure out the removal efficiency of indicator and pathogenic bacteria by unit processes of a sewage treatment plant using activated sludge process, analyses were done for incoming sewage, influent and effluent of primary clarifier, aeration tank, secondary clarifier and final discharge conduit of the plant. A matrix of bacterial items (average of bacterial reduction [log/ml], p value of paired t-test, number of decreased cases of twenty analyses, removal percentage only for decreased cases) between incoming sewage and final effluent of the plant were heterotrophic plate counts (1.54, 0.000, 20, 95.01), total coliforms (1.38, 0.000, 19, 83.94), fecal coliforms (0.90, 0.000, 20, 94.84), fecal streptococci (0.90, 0.000, 20, 98.08), presumptive Salmonella (0.23, 0.561, 7, 99.09), and presumptive Shigella (1.02, 0.002, 15, 92.98). Total coliforms, fecal coliforms, heterotrophic plate counts, and fecal streptococci showed highest decrease through secondary clarifier about 1-log (p<0.001) between 88% and 96%, and primary clarifier represented the significant (p<0.05) decrease. However, final effluent through discharge conduit showed higher total coliforms and fecal streptococci than effluent of secondary clarifier (p<0.05). In addition, final effluent once violated the water quality standard while effluent of secondary clarifier satisfied the standard. Hence some control measures including elimination of deposits in discharge conduit or disinfection of final effluent are necessary.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.2
• /
• pp.970-976
• /
• 2013

An evaluation of the organic matter removal efficiency showed high removal efficiencies of 91.1~96.3% and 91.4~97.5% for TCODcr and TBOD5, respectively, for 9hr or longer of HRT. However, the removal efficiencies decreased to 86.9~90.5% and 88.0~90.9%, respectively for 6hr of HRT. $NH_3$-N showed a high removal efficiency of 95% or higher for 9hr or longer of HRT. The total nitrogen removal efficiency was 67.6~76.7% for 9~12hr of HRT, and it decreased to 50% for 6hr of HRT, which seems to be due to the insufficient carbon source required for denitrification. The T-P removal efficiency was 32% on average. To comply with the legal standards, a chemical phosphorus removal process is needed after the reactor.

• Journal of Korean Society of Water and Wastewater
• /
• v.24 no.3
• /
• pp.267-276
• /
• 2010

Many plants have been improved to adapt the target of the biological treatment processes changed from organics to nutrients since the water quality criteria of effluent was reinforced and included T-N and T-P for the municipal wastewater treatment plant. To meet the criteria of T-N and T-P, the conventional biological reactor such as aeration tank in activated sludge system is changed to the BNR (biological nutrient removal) processes, which are typically divided into three units as anaerobic, anoxic and oxic tank. Therefore, the solid separation process should be redesigned to fit the BNR processes in case of the application of the DAF (dissolved air flotation) process as an alternatives because the solid-liquid separation characteristics of microbial flocs produced in the BNR processes are also different from that of activated sludge system as well. The results of this study revealed that the microbial floc of the anaerobic tank was the hardest to be separated among the three steps of the unit tanks for the BNR processes. On the contrary, the oxic tank was best for the removal efficiency of nutrients as well as suspended solid. In addition, the removal efficiency of nutrients was much improved under the chemical coagulation treatment though coagulation was not indispensable with a respect to the solid separation. On the other hand, in spited that the separation time for the microbial floc from the BNR processes were similar to the typical particles like clay flocs, over $2.32{\times}10^3$ ppm of air volume concentration was required to keep back the break-up of the bubble-floc agglomerates.

• Journal of the Korean Applied Science and Technology
• /
• v.31 no.4
• /
• pp.669-678
• /
• 2014

The amount of waste water generated from the domestic sources is consistently increasing in proportion to economic growth, and the conventional activated sludge process is widely being used for general waste water treatment. But the ministry of environment becomes stringthent treatment standards of N and P (less than 20mg/L of N, 2mg/L of P) to prevent the eutrophication of lake water, and therefore highly advanced treatment technology is required not only in the existing treatment plants where the activated sludge process is being used, but also in newly constructed treatment plants for the treatment of N and P. This study is aimed at highly operating the engineering technology method was developed by domestic to eliminate N and P at the same time. Experiments were conducted in the treatment plant located in Yong In city. The bioreactor was started from the principal equipment for the elimination of N and P and the elimination of organic compounds. It consists of an internal recycle piping from the end of the aerobic tank to the anoxic tank and external recycle piping from the final settling basin to the denitrification tank. By experiment of 4 types separate inflow of waste water to the denitrification tank and the anaerobic tank, and changes in staying time at the anoxic tank and the aerobic tank, the elimination of organic compounds in each type and the relationship in the efficiency between the elimination of N and P were researched.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.4
• /
• pp.569-575
• /
• 2002

Two bacterial strains capable of degrading trichloroethylene (TCE), isolated form soils contaminated with various chlorinated alkenes, were identified as Alcaligenes odorous N6 and Nocardia sp. Hl7. In addition, four KCTC strains, including three strains of Pseudomonas putida and one strain of Sphingomonas chlorophenolica, exhibited an ability to degrade toluene. A. odorans N6 and Nocardia sp. H17 degraded 84% of the initial amount of TCE in a basal salts medium (BSM), containing 0.2 mM TCE as the sole source of carbon and energy, in a day. The optimal pH for growth was within a range of 7.0-8.0. A mixed culture of the four toluene-degrading isolates degraded 95% of 0.2 mM TCE with 1.5 mM toluene as an inducer, whereas no TCE was degraded by the same mixture without an inducer. When a mixed culture of all 6 isolates was used, the degradation efficiency of 0.2 mM TCE was 72% without an inducer, in a day, and 82% with toluene as an inducer. In a continuous treatment, 1,000 mg/1 of TCE in an artificial wastewater was completely removed within 18 h when an activated sludge was used along with the microbial mixture, which was 27 h laster than when only an activated sludge was used. Accordingly, it would appear that such a microbial mixture could be effectively applied to the biological treatment of wastewater containing TCE with or without an inducer.

• Journal of Environmental Health Sciences
• /
• v.20 no.2
• /
• pp.22-27
• /
• 1994

This study is to discuss the factors influenced on the removal efficiency of a high-strength organic wastewaters investigated using the polypropyrene media which appropriate to attach microorganism in the tube type fixed biofilter reactor. The results obtained in the experiment were as follows: 1. The kinetics of reaction rate (k') were 0.125, 0.135, 0.155 varing initial COD 720, 1280, 1630 mg/l in batch reactor. 2. In the range of pH 4.0 ~12.0 was obtained the removal efficiency of COD higher than 85%. It was proved that variation of pH (4.0 ~12.0) was nothing to do with the removal efficiency of substrate in continuous reactor. 3. Temperature to obtain removal efficiency of COD higher than 85% was 10 ~ 40$\circ$C. Removal efficiency of COD was no less than those at high temperature. 4. In the continuous reactor, the volumetric loading of COD for removal efficiency higher than 95% had to be 0.5~1.5 kg COD/m$^3$.d below. And then the HRT was 8 hrs. 5. In comparison with the activated sludge process, the tube type fixed biofilter process was excellent in removal efficiency of substrate and sludge production rate.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.6 no.4
• /
• pp.275-282
• /
• 2018

This study examines the ways to address environmental issues by utilizing activated loess to reduce the amount of cements that emit a large amount of carbon dioxide during the process of manufacturing, and by reusing the polysilicon sludge produced as a result of manufacturing polysilicon, one of the components for solar power generation panels. The findings of the experiment showed that the optimal replacement ratio of the polysilicon sludge is 20%, 35% for W/B, and 20% for the ratio of the fine aggregate addition. As it is deemed that utilizing the polysilicon sludge for reinforced concrete may lead to rebar corrosion due to the $CI^-$ contained in the sludge, it can be considered to use for unreinforced concrete or bricks.

• KSBB Journal
• /
• v.22 no.3
• /
• pp.129-133
• /
• 2007

This study represents that a removal efficiency of organic matters in wastewater is activated by a sludge process using new mixed microbial population. In case of mixed microorganisms, removal rates of suspended solid (SS), biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were over 90 percent under experimental condition, and removal efficiency of organic matters, sludge density index (SDI) and capillary suction time (CST) in mixed population were higher than that in not-mixed microorganism, while total kjeldahl nitrogen (TKN) and total phosphorus (T-P) which indicate a degree of eutrophication were removed easily in both case. From these results, we may propose that an application of the mixed microbial population is useful to treat domestic wastewater including a great deal of organic matters.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.412-416
• /
• 1993

In this paper, fuzzy-neural network is proposed to identify the Activated Sludge Process(A.S.P) in sewage treatment such as "IF-THEN" type fuzzy rules and using various learning methods and improved complex method, the performance index of the identified model is improved. The proposed FNN has the neural network structure of which the connection weights have particular meanings for obtaining fuzzy inference rules and for tuning membership functions. And based on the identified model, graphic simulator which can analize nonlinear characteristics of A.S.P and generate control strategy for A.S.P is being developed.developed.