Koo-Ho Kwon

Biological removal characteristics of phenol with filtration bio-reactor

AbstractA laboratory scale bio-reactor equipped with a filter module was examined for the separation of activated sludge, where the effluent was withdrawn by mesh filtration. The synthetic wastewater containing phenol was fed into the reactors, and the removal performance was evaluated under the following conditions: 7 or 14 d of HRT, room temperature (ca. 20°C), synthetic wastewater containing 5,000–20,000 mg/L of phenol, 262 mg/L of NH4-N, 43.7 mg/L of PO4-P, maximum phenol loading rate: 1.43 kg/m3/d, feeding the synthetic wastewater for 5 or 10 h (Run-1) or feeding at once (Run-2), and filtration once a day. The reactors maintained high concentrations of MLSS (10,000–15,000 mg/L), and the filtration was carried out stably in a short time. When the synthetic wastewater containing 5,000 mg/L of phenol was fed into the reactor at 7 d of HRT (0.7 kg/m3/d of phenol loading rate), in the operation of Run-1, the removal rates for phenol, NH4-N, and D-TN were above 99.9, 98, and 96%, respectively. Similar resu...

Optimization of phosphorus reduction in BNR process for urban watershed management

The removal of the phosphorus contained in wastewater can be carried out by physic-chemical or by biological phosphorus removal (EBPR) process. Currently, the biological phosphorus removal process has been attracting attention. Because of its low capital and operational costs compared with those of chemical precipitation processes. According to the U.S. Environmental Protection Agency (EPA), TP eff . concentration decrease to 0.3 mg/l by using the biological treatment [1,2]. Therefore, in this study, we experimented with enhancing the BNR process by injecting an external carbon source into the anaerobic phase. Afterwards, when the phosphorus was released or accumulated in poly-p accumulating organisms (PAOs), we measured the behavior of cations. When the BNR process is injected with an external carbon source in the anaerobic phase was operated, the removal efficiency of TP in the effluent was 94.48% at the maximum, and Org-P, which is difficult to remove by chemical treatment only, was removed considerably. Likewise, some of the external carbon source affected the nitrogen removal. By estimating the metal cations concentration in the anaerobic phase, K + , Mg 2+ was used as a parameter to control the amount of external carbon which had to be injected. Our results showed that TP treatment with BNR met the criteria of effluent quality and is a cost-effective and environmentally sound alternative when compared with chemical treatment.

The Recovery of Carbon Source from Municipal Primary Sludge using Pilot Scale Elutriated Acidogenic Fermentation

Pilot scale study was carried out to produce Volatile Fatty Acids with primary sludge from municipal wastewater treatment plant. An acid fermenter was operated at pH 9, 35℃, SRT of 3.5-4.25d, using a final effluent as elutriating water(Mode-Ⅰ) and pH 9, SRT 5d, temperature of 35℃(Mode-Ⅱ), 55℃(Mode-Ⅲ), using a primarily treated water as elutriating water. Although solubilization rate was enhanced with the increase of temperature, the VFAs production rate was decreased. The VS reduction was shown approximately 56%, and the sludge volume reduction was 93%. The optimal conditions for solubilization was obtained at pH 9, 35℃ and SRT of 5d.

Removal of phosphite and sulfate from electroless nickel–phosphorus plating bath with hydrotalcite for the management of watershed

Abstract This study was focused to remove both and for the improvement of efficiency in electroless nickel–phosphorus plating process with hydrotalcite-like compound (HT). The adsorbed amount, q e, of which was main component was low and had little influence on the adsorption of and . and were similar in the adsorption behaviors of the adsorption isotherm and the influence of solution pH. The q e was increased with the increase of water temperature, because the was decreased with the increase of water temperature. On the coexisting adsorption, the q e of was decreased with . The ion selectivity of HT was in the order of  >   >   ≫  at pH 10. The results indicated that the HT-Cl is a useful adsorbent for and removal in the exhausted electroless nickel-phosphorous plating bath.

Particle removal properties of stormwater runoff with a lab-scale vortex separator

ABSTRACT A lab-scale vortex separator, based on a swirling motion to remove settleable particles, was used to remove suspended solids in urban stormwater runoff. However, the treatment is limited to the removal of large settleable particles. The synthesized stormwater runoff was made with tap water and the addition of road sediment. The vortex separator has internal components designed to enhance vortex separation by minimizing the turbulence, increasing the efficiency, and preventing captured pollutants from washout. As the flow continues to spiral down around the inlet baffle, a low energy vortex motion directs settleable particles into the protected sediment storage zone. Advanced vortex separation provided an extendable and stabilized flow path while protecting the captured pollutants for a wide range of flow rates. The range of the inflow rate was 30–115 l/m, and the size of the influent particles varied from 75 to 200 μm. Overall removal efficiencies of 51.8% for SS, 26.6% for COD, 70.5% for TP, and...

Recycling of sewage sludge using microwave pretreatment and elutriated acid fermentation

AbstractThis work elucidates the effects of pretreatment on primary and secondary sludge using microwave irradiation before the application of elutriated acid fermentation (EAF) systems conducted under different temperature conditions. The EAF used water to elutriate volatile free acids generated in the fermenter which thickened the sludge generated. The results of this study focus on sludge reduction conducted under different temperatures. The SCOD production utilizing a microwave pretreatment method (MW) followed by EAF, with 35°C after the microwave as pretreatment, and from only the EAF at 35 and 55°C was 0.33, 0.11, and 0.22 g SCODprod./g VSfed. Volatile fatty acids (VFAs) production was found to be similar to that of the results of SCOD production. Coliforms and Escherichia coli were not detected after pretreatment with microwave irradiation for time over 5 min.

Contaminant loads of CSOs at the urban area in Korea

AbstractCombined sewer overflows (CSOs) were examined in an urban catchment with three areas of 11.9, 19.9, and 57.7 ha located in northern Daegu city in Korea. A total of two non-rainfall run-off events were monitored and a variety of water quality parameters were analyzed. During the non-rainfall run-off, most water quality parameters, particularly organic pollutants, were fluctuated accordingly to the discharge of sewage flow. Event mean concentrations (EMCs) during the storm water run-off were shown higher than EMCs of non-rainfall events. The loading rates of overflows against total flow particularly, SS load was 14 times higher. Total CSOs emissions were expected to be around 1.38 to 5.18 kg/ha per event. Few obvious first flush phenomenons were observed due to the inflow of unknown sources and dilution with incessant duration of rainfall.

Waste sludge reduction with a pilot-scale membrane bioreactor for point source pollution management

Abstract It is an important subject to reduce the amount of waste sludge from small-/middle-scale wastewater facilities for the establishment of point source pollution management. In this work, we focused on the development of sludge decomposition system which did not increase organic loading ratio into wastewater treatment units. The excess sludge produced from wastewater treatment plant of a food factory was decomposed by an aerobic digestion technology with a membrane bioreactor (MBR) system. It was composed of digestion tank (500 L) and a membrane filtration unit (350 L). Sludge was decomposed under the following conditions: 25 g L−1 of MLSS, 36.9 d of HRT, average temperature 32.3°C, and 0.565 kg-SS m−3 d−1 of sludge loading rate. The system decomposed 77.2% of the fed sludge to inorganic carbon, and all of average TOC, CODMn and CODCr in the effluent were less than 50 mg L−1. However, the effluent contained T–N and T–P at 200 mg N L−1 and 150 mg-P L−1, respectively. The quinone profile analysis indi...