• 상하수도학회지
• /
• 제23권3호
• /
• pp.363-369
• /
• 2009

In order to evaluate primary clarifier performance on TSS(Total Suspended solids) removal, four different sampling sets were collected as part of this study; (1) weekly test, (2) the diurnal sampling, (3) the settling velocity distribution sampling. Primary effluent TSS($TSS_{PE}$) and non settleable TSS($TSS_{NON}$) concentrations were averaged 160 and 75.5 mg/L, respectively. These data suggest approximately 85 mg/L TSS can be removed more. Average $TSS_{NON}$, $TSS_{PE}$, and Dispersed TSS(DTSS) concentrations(75.5, 160, and 104 mg/L, respectively) suggest that 28.5 mg/L of TSS difference attributable to poor flocculation, whereas 56 mg/L of TSS difference attributable to poor hydraulics within primary clarifier. In this study, equations for maximum TSS removal efficiency and effluent TSS concentration were suggested and compared with experimented data.

• 한국수자원학회논문집
• /
• 제52권11호
• /
• pp.947-950
• /
• 2019

이 논문의 주요 특징은 초기강우 유입 시 일차 침전지 처리효율을 개선하기 위한 운전제어 전략을 제공하는 것이다. 최근 IoT 기술과 센싱 기술이 발전함에 따라 하수처리시설 운전제어를 위한 기반이 개선되고 있으며, 온라인 측정결과를 활용한 일차침전지 처리효율 개선에 따라 미처리 하수의 하천 유출을 최소화하고, 하수처리시설 운영효율 개선에기여할 수 있다.

• 한국물환경학회지
• /
• 제26권5호
• /
• 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.

• 상하수도학회지
• /
• 제18권6호
• /
• pp.715-723
• /
• 2004

The quantity of residuals generated from water treatment plants depends upon the raw water quality, dosage of chemicals used, performance of the treatment process, method of sludge removal, efficiency of sedimentation, and backwashing frequency. Sludge production by the physical separation of SS occurs under quiescent conditions in the primary clarifier, where suspended solids are allowed to settle and to consolidate on the clarifier bottom. Raw primary sludge results when the settled solids are hydraulically removed from the tank. The relative solid and liquid fractions of a slurry are most commonly described by the solids concentration, expressed as mg/L or percent solids. The purpose of the present investigation is to estimate a suitability on the design capacities of residuals treatment facilities by the quantity of dewatered sludge generated from water treatment plants.

• 상하수도학회지
• /
• 제25권5호
• /
• pp.777-782
• /
• 2011

The residual treatment facilities in WTP(water treatment plant) play an important role in solid-liquid separation. At present, it is difficult to solve problems related with thickening and dewatering of WTP sludge, and discharging waste water to river. The quantity of residuals generated from water treatment plants depends upon the raw water quality, dosage of chemicals used, performance of the treatment process, method of sludge removal, efficiency of sedimentation, and backwashing frequency. Sludge production by the physical separation of SS(Suspended Solid) occurs under quiescent conditions in the primary clarifier, where SSs are allowed to settle and to consolidate on the clarifier bottom. Raw primary sludge results when the settled solids are hydraulically removed from the tank. In this study, Drawing characteristics of the sludge thickening in the thickener of Water Treatment Plants was simulated by Using CFD(Computational Fluid Dynamics.

• 물과 미래
• /
• 제29권6호
• /
• pp.141-154
• /
• 1996

열 유동 현상을 규명하기 위한 연구로서 2차원 연직 좌표계의 수체 유동 컴퓨터 프로그램을 개발하였다. 이러한 연구의 구체적인 목적은 일차침전조 같은 폐수나 용수처리 및 상수원 호소에서의 수체유동에 대한 기작을 파악하고자 함이다. 이렇게 개발한 컴퓨터 프로그램 성능을 문헌에 나타난 수치해석 및 실험 자료와 성공적으로 비교, 검증하였다. 첫 번째 검증 문제는 응축열 방출에 따른 수체유동해석에 대한 것이며 두 번째 문제는 캐나다 온타리오주 사리나시에 있는 일차침전조에 대한 수치해석 실험 결과이다. 이렇게 개발된 컴퓨터 프로그램은 2차원 호소의 전도와 같은 특성규명에 응용하였으며 주요 변수로는 유량, 바람의 속도 그리고 온도 분포 등을 고려하였다. 나아가서 호소의 전도 현상과 같은 유동 특성을 규명하기 위한 연구의 일환으로서 바람의 속도나 온도 분포에 따른 수치해석을 시도하였다. 결과는 물리적으로 일관성 있게 나타났으며 수체 유동 특성 규명을 위한 유용한 도구로서 가능성을 보였다.

• 한국물환경학회지
• /
• 제23권1호
• /
• pp.19-26
• /
• 2007

The lab-scale BNR processes fed with Municipal Wastewater Before or After Primary Clarifier (MWBPC or MWAPC) were operated to observe the behavior of particle organic matter in terms of nitrification and denitrification efficiency. As a result of the fractionation of the COD from MWBPC or MWAPC using an aerobic respirometric serum bottle reactor, the total mass of biodegradable organic matter from MWBPC is about 52% greater than the mass from MWAPC. Batch reactors were operated to observe the effect of the Particulate Organic Matter (POM) on substrate utilization for denitrification. Although the consumption of POM for denitrification was observed, the increment of the Specific Denitrification Rate (SDNR) was not great. In terms of the effect of POM on nitrification at different HRTs, activate sludge reactors were operated to determine the optimal HRT when MWBPC and MWAPC were fed relatively. All reactors showed a great organic matter removal efficiency. Reactors fed with MWAPC had obtained the nitrification efficiency above 90% when the HRT of 4 hr, at least, was maintained, while reactors fed with MWBPC had same efficiency when the HRT longer than 5 hr was kept. Three parallel $A^2/O$ systems fed with MWBPC or MWAPC relatively were operated to investigate the effects of POM on BNR processes with varying the HRT of an anoxic reactor. For all systems, the efficiency of organic matter removal and denitrification, respectively, was great and about the same. In case of denitrification efficiency, system with MWAPC had 1.5% lower than system with MWBPC at the same HRT of anoxic reactor of 2 hr, and the increasing the HRT of the anoxic reactor by 1 hr in systems fed with MWBPC resulted in a 3.5% increment. The denitrification rate was similar while the consumption of organic matter in systems fed with MWBPC was higher than system fed with MWBPC. It suggests that POM in MWBPC was not be used significantly as a substrate for denitrification in system with the HRT of 3 hr of an anoxic reactor.

• 한국환경과학회지
• /
• 제19권5호
• /
• pp.647-653
• /
• 2010

The objectives of this research are to evaluate and compare the oxygen transfer coefficients($K_{La}$) in both a general bubbles reactor and a micro-nano bubbles reactor for effective operation in sewage treatment plants, and to understand the effect on microbial kinetic parameters of biomass growth for optimal biological treatment in sewage treatment plants when the micro-nano bubbles reactor is applied. Oxygen transfer coefficients($K_{La}$) of tap water and effluent of primary clarifier were determined. The oxygen transfer coefficients of the tap water for the general bubbles reactor and micro-nano bubbles reactor were found to be 0.28 $hr^{-1}$ and 2.50 $hr^{-1}$, respectively. The oxygen transfer coefficients of the effluent of the primary clarifier for the general bubbles reactor and micro-nano bubbles reactor were found be to 0.15 $hr^{-1}$ and 0.91 $hr^{-1}$, respectively. In order to figure out kinetic parameters of biomass growth for the general bubbles reactor and micro-nano bubbles reactor, oxygen uptake rates(OURs) in the saturated effluent of the primary clarifier were measured with the general bubbles reactor and micro-nano bubbles reactor. The OURs of in the saturated effluent of the primary clarifier with the general bubbles reactor and micro-nano bubbles reactor were 0.0294 mg $O_2/L{\cdot}hr$ and 0.0465 mg $O_2/L{\cdot}hr$, respectively. The higher micro-nano bubbles reactor's oxygen transfer coefficient increases the OURs. In addition, the maximum readily biodegradable substrate utilization rates($K_{ms}$) for the general bubbles reactor and micro-nano bubbles reactor were 3.41 mg COD utilized/mg active VSS day and 7.07 mg COD utilized/mg active VSS day, respectively. The maximum specific biomass growth rates for heterotrophic biomass(${\mu}_{max}$) were calculated by both values of yield for heterotrophic biomass($Y_H$) and the maximum readily biodegradable substrate utilization rates($K_{ms}$). The values of ${\mu}_{max}$ for the general bubbles reactor and micro-nano bubbles reactor were 1.62 $day^{-1}$ and 3.36 $day^{-1}$, respectively. The reported results show that the micro-nano bubbles reactor increased air-liquid contact area. This method could remove dissolved organic matters and nutrients efficiently and effectively.

• 한국전산유체공학회지
• /
• 제2권1호
• /
• pp.93-108
• /
• 1997

This paper describes several computational results on the various energy and environmental problems using Patankar's SIMPLE method. The specific problems included in this study are : pollutant and flammable material dispersions in open and confined areas, buoyancy-driven flow in a lake, primary clarifier for water and waste water treatment, hood ventilation in workplace. cyclone combustor and Dow chlorination reactor. A control-volume based finite-difference method is employed together with the power-law scheme. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, says SIMPLER and SIMPLEC. The Reynolds stresses are closed using the standard or RNG κ-ε models. A nonequilibrium turbulent reaction model is developed for the application of the chlorination process in the Dow thermal reactor. Other important empirical models and physical insights appeared in this study are presented and discussed in a brief note. The computational method developed in this study is considered, in general, as a viable tool for the design and determination of the optimal operating condition of various environmental engineering system of interest.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권7호
• /
• pp.73-80
• /
• 2013

Fine suspended solids from coal mine drainage were treated in the treating plant, using two different pilot-scale inclined clarifiers: radial and lamella types. Suspended solids in the mine drainage were monitored along with other geochemical factors, and metal contents. Fe and Mn are the main chemical components in the drainage, which exist predominantly as total metal forms, whereas dissolved portion is negligible. The raw mine drainage is subject to physical and chemical treatment using $CaCO_3$ and NaOH, therefore the suspended solids are thought to be composed of Fe and Mn precipitates, possibly $Fe(OH)_3$, along with carbonate precipitates. The elemental composition of precipitates are confirmed by SEM-EDS analysis. As nearly all the dissolved ions were precipitated in the primary process by $CaCO_3$, no further aeration or prolonged oxygenation are of necessity in this plant. Adoption of inclined clarifier proved to be effective in treating fine suspended solids in the current plant. Successful application of the inclined clarifier will also be beneficial to improve the current treating process by excluding the current application of chemical agent in the first stage. The final effluents from the pilot plant meet the national standards and the low dissolved Fe and Mn contents are expected not to cause secondary precipitation after discharge.