• Journal of Environmental Science International
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• v.12 no.4
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• pp.427-437
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• 2003

An evaluation of the application of SBR and biofilm en small sewerage system was conducted. A newly developed small sewerage system, using SBR, was successfully applied to the nutrient treatment using municipal wastewater. The system was consisted of 6 compartments. Two systems, with SBR (A type) or without SBR (B type), were compared by several parameters (COD, SS, T-N, NH$_4$$\^$+/-N, NO$_3$$\^$-/-N, NO$_2$$\^$ -/-N, alkalinity, pH, DO) in all experimental periods. Also, the time variation of several parameters (DO, pH, NH$_4$$\^$+/-N, NO$_3$$\^$-/-N NO$_2$$\^$-/-N) was examined in a SBR applied sewerage system. T-N removal efficiency of B type Was higher than that Of A type by the effect of nitrification and denitrification even though the COD removal efficiencies were similar. In aeration stage, the pH was decreased from 6.4 to 6.3 within 1 h and increased to 6.65 at the end of aerobic stage, and pH was decreased to 6.2 in non-aeration stage, and these phenomena were explained. The effects of nitrification and denitrification were compared in A type and B type sewerage system, and the typical nitrification and denitrification were observed in B type sewerage system.

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.17-21
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• 1993

Characteristics of a downflow anaerobic packed bed reactor with raschig ring ceramics as a packing were measured and discussed for the basic evaluation of the process. A synthesized glucose substrate wastewater were used as a feed and process characteristics such as pH, biogas production, composition of produced gas, COD removal and VSS were measured with the hydraulic retention time (HRT) changing from 0.25 to 2 days. As a result, this type of reactor was applicable in continuous operation within the given HRT range and the transient period approaching the steady state was about 20 days. The content of methane in produced gas increase with HRT was always high above 50% enough to use as energy source. The COD removal efficiency increased gradually as HRT increased. The axial profile of VSS concentration in the reactor usually showed the maximum at the lower region and the minimum at the middle. The VSS concentration at the upper region and the exit appeared similarly. However, at 0.25 day of HRT, the VSS concentration of effluent became higher than that of the upper region. Therefore the optimum HRT of this reactor occurred about 0.5 day, at which the production of methane began to be just stabilized and loss of VSS and COD removal were resonable.

• Advances in environmental research
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• v.3 no.4
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• pp.293-306
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• 2014

The present study primarily focuses on the evaluation of the comparative effect of chemical coagulation and ultrasonication for elimination of aromatic amines (AAs) present in anaerobically pretreated textile wastewater containing different types of dyes including azo dyes. Color and COD reduction was also monitored at the optimized conditions. The production of AAs was measured spectrophotometrically in the form of total aromatic amines (TAAs) and also verified with high performance liquid chromatography (HPLC) selectively. A composite coagulant, magnesium chloride (MC) aided with aluminium chlorohydrate (ACH) in an equal ratio (MC + ACH) was utilized during the coagulation process, which yielded 31% of TAAs removal along with 85% of color and 52% of COD reduction. At optimized power (200 W) and sonication time (5 h), an appreciable TAAs degradation efficiency (85%) was observed along with 51% color reduction and 62% COD removal using ultrasonication. The chromatographic data indicate that sulphanilic acid and benzidine types of aromatic amines were produced after the reductive cleavage of utilized textile dyes, which were effectively mineralized after ultrasonication. The degradation followed the first order kinetics with a correlation coefficient ($R^2$) of 0.89 and a first-order kinetic constant (k) of $0.0073min^{-1}$.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1035-1042
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• 2005

Granular Activated Carbon(GAC) is widely used in drinking water treatment. At S and B Water Treatment Plant, GAC is used in place of granular media in conventional rapid filters(GAC Filter-Adsorber) for removal of Disinfection By-products(DBPs). The primary focus of this study is on the performance of existing filter-adsorber, and their operation. It was found that F/A process removed turbidity as effective as sand system. The ratio of Hydrophobic DOM (HPO) and hydrophilic DOM (HPI) fraction in the raw water at S and B WTP was similar. Filter Adsorber presented earlier DOC breakthrough and steady state condition which was contributed by biodegradation during operation period. The removal efficiency of DBPs were used to evaluate the filter performance. The DBPs concentration of F/A treated water was below treatment goal level (THM < $80\;{\mu}g/L$, HAA < $60{\mu}g/L$). The removal efficiency of THM decreased rapidly during operation period. However, HAA were removed steadily regardless of the influent concentration of HAA. These results indicate that the removal of THM depend upon the adsorption mechanism while the removal of HAA depend upon biodegradation as well as adsorption. The decrease of adsorption capacity and characteristic value of GAC may be attributed to the effect of high organic loading, residual free chlorine, coagulants, manganese oxidants and frequently backwashing. This study has confirmed that Filter adsorber process can be considered as effective alternatives for the removal of DBPs, especially HAA.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.403-409
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• 2007

This study was carried out to recommend the systematic improving practice for the effective operation of septic tank, and the evaluation of its BOD and nutrient removal efficiency depending on process, the survey of characteristics of FRP material, and the suggestion of optimum septic tank model within sewage treatment area. The average BOD concentration and BOD removal efficiency of septic tank which was carried out the cleaning periodically in 63.9 mg/L and 77.8%, shows good quality better than the septic tank which was not carried out the cleaning regularly. Maximum load of tensile, flexural and compressive strength increased in proportion to its thickness, and the contents standard 25% of glass fiber required upgrade over than 30%. Configuration and performance for the optimum of the septic tank suggests that over $0.75m^3$ of the effective total volume, adding to over $0.25m^3$ a man for more than 5 men of the treated person, retention time should be within one day. Improving plans about facility and materials quality of the septic tank have an obligation that protective wall ought to install on the concrete bottom and side faces to prevent crumble or transform from loading of the ground or upper part of the structure on the tank setting. And it is eliminated the uneffective resisting pressure and it keeps off circulate imperfect products by strengthening of the test methods such as stretching strength, pressing strength, glass fiber contents and thickness.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.652-656
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• 2004

Both surface wash and backwash are considered as one of the most important methods that can improve the filtration efficiency in the existing water treatment plant. This study has mainly focused on the improvement of filtering efficiency by controlling surface wash and backwash time, and water level before backwash (when drained up to the trough, when drained up to 10 cm above filter bed, and when drained below 10 cm filter bed). Filtration efficiency was shown a little bit of differences depending on the operating conditions like surface wash injection pressure, the distance control between filter bed and the facility, and the types of surface wash. When the water level before backwash was reached up to 10 cm below filter bed after draining, however, the filtration velocity and the turbidity removal efficiency in the filter bed was improved. When the surface wash followed by backwash is longer, it showed a similar result. Because the proper adjustment of surface washing time makes filtration efficiency higher, therefore, it is necessary to set up the backwash time moderately.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.483-490
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• 2009

The aims of this study were to evaluate the removal efficiency for various pollutants in urban storm runoff by a filtration device, and to determine design parameters depending on filter media properties. Appropriate selection of filter media will affect the size and life time of the filtration device. Sets of column tests were performed in order to evaluate the removal efficiency by perlite and a synthetic resin. An investigation of surface properties including CEC (cation exchange capacity) and zeta-potential suggested that the perlite had a superior adsorption capability for cationic pollutants. TCODcr and turbidity were analyzed to investigate the removal characteristic of particulate pollutant. In both columns, the particles in the collected storm runoff was almost completely capture with a small EBCT (empty bed contact time) of 2.5 minutes. Complete clogging at the EBCT of 2.5 minutes occurred after 630 minutes in the perlite column and 810 minutes in the resin column. The removal efficiency of TCODcr and turbidity at the EBCT of 2.5 minutes decreased to below 70% due to an wall effect. The removal efficiency for dissolved pollutant (SCODcr) was negligible due to the insufficient contact time for adsorption. The removal of heavy metals (Cu, Zn, Pb) was mostly ascribed to the filtration of particles containing metals, since the relationship between CEC and the removal efficiency was not apparent. The result of this study would be valuable for the application of filtration device to control of urban storm runoff.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.719-726
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• 2009

One of the alternative runoff management measures is on-site runoff mitigation, such as rainwater retention tank and infiltration facilities especially the latter that is possible to manage simultaneously runoff quality and quantity as a perspective of water-cycle. This study was conducted to develop a particle separator, inclined-pipe settling system, that could improve particle removal efficiency of road runoff as a pre-treatment device of stormwater infiltration. Solid particles larger than $100{\mu}m$ are separated by simple sedimentation; however, the significant amount of pollutants with a diameter less than $100{\mu}m$ remain in suspension. Without any treatment in that case of the runoff into infiltrate, groundwater would be deteriorated and also infiltration rate would be decreased by clogging. Therefore, we suggest optimal design parameters (inclined angle, pipe length, and surface loading rate) of inclined-pipe settling system which can be designed to effectively remove particles diameter smaller then $70{\mu}m$. Thus, the results showed TSS removal efficiency more than 80% with a particle diameter between $20{\mu}m$ and $70{\mu}m$, 100% above particle diameter $70{\mu}m$ for the inflow rate $0.018 m^3/m^2{\cdot}hr$ with pipe inclined at angle $15^{\circ}$.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.341-348
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• 2007

The efficiency of powdered activated carbon (PAC) for removing taste and odor (T&O) in drinking water supplies is dependent on the contact time, quality of mixing, and the presence of competing compounds. All of these are strongly influenced by the stage in the treatment process at which the PAC is added. In conventional water treatment plants (WTPs), PAC is commonly added into the rapid mixing basin where chemicals such as coagulants, alkaline chemicals, and chlorine, are simultaneously applied. In order to prevent interference between PAC and other water treatment chemicals, alternative locations for addition of PAC, such as at transmission pipe in the water intake tower or into a separated PAC contactor, were investigated. Whatever the location, addition of PAC apart from other water treatment chemicals was more effective for geosmin removal than simultaneous addition. Among several combinations, the sequence 'chlorine-PAC-coagulant' produced the best result with respect to geosmin removal efficiency. Consequently, when PAC has to be applied to cope with T&O problems in conventional WTPs, it is very important to prevent interference with other water treatment chemicals, such as chlorine and coagulant. Adequate contact time should also be given for adsorption of the T&O compounds onto the PAC. To satisfy these conditions, installation of a separated PAC contactor would be the superior alternative if there is space available in the WTP. If necessary, PAC could be added at transmission pipe in the water intake tower and still provide some benefit for T&O treatment.

• Journal of Environmental Science International
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• v.23 no.8
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• pp.1409-1418
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• 2014

Foundry has an important economic value in the industry. However, the generation of air pollutants like particulate and odor are serious. Due to the unavoidable usage of molding sand, particulate occurs in almost all the processes. That accounts for the majority of respirable dust in the size less than $10{\mu}m$ As well as particulate, over 22 species of odor-causing gases and VOCs including hydrogen sulfide and ammonia are occurred. Therefore, the development of equipment that can simultaneously remove TVOC and particulate is regarded as an essential research. In this study, the spraying absorbent system was connected with the shear bag filter for the purpose to remove TVOC and particulate simultaneously. Maximization of process efficiency for the affective factors like the powder combination and injection method is conducted. The experiment was performed at the de-molding process of one foundry plant. Through these devices, the removal efficiency of more than 95% for TVOC was achieved with the absorbent that composed by 800 mesh Activated carbon (80%) and 300 mesh zeolite (20%). Also, the durability and economic evaluation were assessed. In the result of Durability assessment, the available recovery to maintain the deodorizing effect at 90% was counted to 350 degree.