• Journal of Korean Society of Water and Wastewater
• /
• v.32 no.6
• /
• pp.559-572
• /
• 2018

The aim of this study was to evaluate pretreatment methods for 27 pharmaceuticals and personal care products (PPCPs) in various sewage samples using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) and online solid-phase extraction with LC-MS/MS. Extraction efficiencies of PPCPs in the solid phase under different experimental conditions were evaluated, showing that the highest recoveries were obtained with the addition of sodium sulfate and ethylenediaminetetraacetic acid disodium salt dehydrate in acidified conditions. The recoveries of target compounds ranged from 91 to 117.2% for liquid samples and from 61.3 to 137.2% for solid samples, with a good precision. The methods under development were applied to sewage samples collected in two sewage treatment plants (STPs) to determine PPCPs in liquid and solid phases. Out of 27 PPCPs, more than 19 compounds were detected in liquid samples (i.e., influent and effluent) of two STPs, with concentration ranges of LOQ-33,152 ng/L in influents and LOQ-4,523 ng/L in effluents, respectively. In addition, some PPCPs such as acetylsalicylic acid, ibuprofen, and ofloxacin were detected at high concentrations in activated sludge as well as in excess sludge. This methodology was successfully applied to sewage samples for the determination of the target compounds in STPs.

• Journal of Environmental Science International
• /
• v.27 no.4
• /
• pp.233-240
• /
• 2018

The purpose of this study was to confirm the applicability of aerobic granular sludge (AGS) in the advanced sewage treatment process. Simulated influent was used in the operation of a laboratory scale reactor. The operation time of one cycle was 4 h and the reactor was operated for six cycles per day. The volume exchange ratio was 50%. The influent was injected in divisions of 25% to increase the removal efficiency of nitrogen in every cycle. As a result, the removal efficiencies of $COD_{Cr}$ and TN in this reactor were 98.2% and 76.7% respectively. During the operation period, the AGS/MLVSS concentration ratio increased from 70.0% to 86.7%, and the average $SVI_{30}$ was 67 mL/g. The SNR and SDNR were 0.073-0.161 kg $NH_4{^+}$-N/kg MLVSS/day and 0.071-0.196 kg $NO_3{^-}$-N/kg MLVSS/day respectively. These values were higher or similar to those reported in other studies. The operation time of the process using AGS is shorter than that of the conventional activated sludge process. Hence, this process can replace the activated sludge process.

• Journal of environmental and Sanitary engineering
• /
• v.19 no.3 s.53
• /
• pp.1-12
• /
• 2004

This study was conducted to evaluate the variation characteristics of influent and effluent quality from sewage treatment facilities using activated sludge processes and to assess the impact caused by discharge of treated sewage on the receiving water Monthly data of five water quality items (BOD, COD, SS, T-N, T-P) were used to understand the water quality at three sewage treatment plants in Seoul for five years from 1999 to 2003. Concentration differences of water quality parameters were observed between upstream and downstream site at the sewage treatment plant outfall to investigate the impact of discharge in Tan stream and Han river basin. 1. Due to the effect of continuous improvement in sewer system, the concentrations of influent went on increasing generally. 2. Effluent concentrations of BOD, COD and SS showed the trend of a little decreasing, but the trend of increasing in T-N and T-P. 3. In Tan stream basin, the impact of sewage treatment plant discharge was not observed directly, because concentration of discharge was lower than stream water's. But discharges from sewage treatment plants affected water quality at downstream site in Han river, concentration of T-P especially.

• Resources Recycling
• /
• v.24 no.2
• /
• pp.46-54
• /
• 2015

In this study, an applicability of thermal pretreatment for primary and secondary sludge, which are generated in a sewage treatment plant, was evaluated. The efficiency and charateristics was investigated with each sludge after pretreatment under the condition of $100{\sim}220^{\circ}C$ for 30 minutes. As the result, it was found that $SCOD_{Cr}$, $NH_4{^+}$, VFAs concentrations increased as the pre-treatment temperature increased. For COD solubilization, it was also highly dependent on an increase of temperature resulting in acceleration on hydrolysis and acid fermentation. In the BMP (Biochemical Methane Potential) experiment, for the primary sludge, it showed the higher biogas production rate at a temperature of $220^{\circ}C$, however, the effect was insignificant (5.6%). Whereas, for the secondary sludge, the increase on biogass production rate was 38.8% ($180^{\circ}C$) and this means that the secondary sludge is more suitable for an applicability of thermal pretreatment.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.6
• /
• pp.737-744
• /
• 2007

Recently, one of the most interesting topic in the field of wastewater treatment is the disposal of excess sludge. The new concept of excess sludge reduction with recirculation of solubilized sludge via effective microorganisms for cell disruption within the wastewater treatment process has been developed in this study. The alkalophiles for degradation of sludge cell wall were isolated as Exiguobacterium sp., which could be more effectively solubilized sludge in the anaerobic condition. The SCOD of solubilized excess sludge by Exiguobacterium sp. was up to about 2,000mg/L and average TN and TP concentration of solubilized component were 117mg/L and 58mg/L, respectively and C/N ratio was more than 17. To investigate the effects of solubilized sludge by alkalophiles on excess sludge reduction and nutrient removal efficiency, the pilot plant of $DF^{(S)}-MBR$ process, combined with membrane bioreactor and sludge solubilization tank, was operated. In the control run(without sludge solubilization), the daily sludge production was about 4.54 kgMLVSS/day. However, in the $DF^{(S)}-MBR$(with sludge solubilization), the daily sludge production was decreased to 1.39kgMLVSS/day. The effluent quality satisfied the effluent regulation in both cases. Furthermore, the $DF^{(S)}-MBR$ showed relatively better TN removal efficiency in spite of high influent loading. So we concluded that the solubilized excess sludge by alkalophiles was effectively degraded in the MBR process as the carbon source and 70% of sludge reduction efficiency can be achieved.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.9
• /
• pp.636-643
• /
• 2011

Sludge solubilization using sonification has been increasingly used for sludge volume reduction along with enhancing digestion efficiency during anaerobic biogas production. In this study, either electric field or ultrasonification or in combination with were investigated using three types of sludge (return, excess and mixed at G sewage treatment facility) for the most efficient solubilization. As a the closed loop, 200 L of sludge was continuously passing through the solubilization system at an average flow rate of $0.7m^3/h$, which is equivalent to 3.5 times treated per hour for up to 84 times (24 h). Only implying electric field showed no variation for sCOD/tCOD before and after treatment on sludge solubilization regardless of types of sludge. However, employing the ultrasonic or combined system could both increasingly solubilize sludge with regard to the number of passing-through, which more enhanced by the combined. In addition, VSS/TSS was lowered to in the range of 2 and 6% while its particle size, diameter (0.9) and diameter (0.5) were more minimized than that of raw sludge. For return sludge, ultrasonification was more efficiently facilitated for solubilization, whereas electric field-ultrasonification was more preferably applied for excess and mixed sludge. It is concluded that depending on types of sludge, solubilization system must be selectively applied for the most efficient break-up of them.

• Journal of Korean Society on Water Environment
• /
• v.20 no.3
• /
• pp.290-295
• /
• 2004

In this study, ozone was adopted for the reduction and stabilization of waste sludge from the municipal sewage treatment plant. The waste sludge used in the experiments was primary sludge, excess sludge and a mixture of the two. The sludge cells and flocs were disrupted by ozonation resulting in the reduction of TSS and VSS concentrations. In the case of the primary sludge with a concentration of 20 gTS/L, the TSS and VSS concentrations were reduced 28%, 33% and the TCOD concentration was reduced 20% respectively. The consumption of ozone was $0.18gO_3/gSS$. In the case of the excess sludge with a concentration of 7.5 gTS/L, the TSS and VSS concentrations were reduced 37%, 41%, and the TCOD concentration was reduced 19% respectively. The consumption of ozone was $0.33gO_3/gSS$. In the case of the mixed sludge of 9.3 gTS/L, the TSS and VSS concentrations were reduced by 45%, 53%, and the TCOD was reduced 26% respectively. The desirable consumption of ozone was $0.27gO_3/gSS$. As ozonation proceeded, the level of SCOD increased due to the release of intracellular materials. However TCOD was reduced due to mineralization resulting from the transformation of organic materials to inorganic materials.

• Journal of Environmental Science International
• /
• v.21 no.11
• /
• pp.1379-1388
• /
• 2012

Odor from sewage treatment plants have the potential to cause significant annoyance and to impact the amenity. In this study, odor emission characteristics at unit process of 48 sewage treatment facilities in 39 plants were evaluated using composite odor concentration and hydrogen sulfide ($H_2S$) concentration. The values of composite odor concentration (geometry mean) and $H_2S$ concentration (median) for sludge treatment processes are higher than those for the other treatment processes. The composite odor concentration and $H_2S$ concentration are distributed over a wide area in each process. Composite odor concentration (dilution ratio) was found to have the significant correlation with $H_2S$ concentration (p=0.000<0.05). The $H_2S$ concentration accounted for 67.1% of composite odor concentration.

• Clean Technology
• /
• v.12 no.2
• /
• pp.67-77
• /
• 2006

A simple dual sludge process, called as $KNR^{(R)}$ (Kwon's Nutrient Removal) system, was developed for small sewage treatment. It is a hybrid system that consists of an UMBR (Upflow multi-layer bioreactor) as anaerobic and anoxic reactor with suspended denitrifier and a post aerobic biofilm reactor, filled with pellet-like media, with attached nitrifier. To evaluate the stability and performance of this system for small sewage treatment, the pilot-scale $KNR^{(R)}$ plant with a treatment capacity of $50m^3/d$ was practically applied to the actual sewage treatment plant, which was under retrofit construction during pilot plant operation, with a capacity of $50m^3/d$ in a small rural community. The HRTs of a UMBR and a post aerobic biofilm reactor were about 4.7 h and 7.2 h, respectively. The temperature in the reactor varied from $18.1^{\circ}C$ to $28.1^{\circ}C$. The pilot plant showed stable performance even though the pilot plant had been the severe fluctuation of influent flow rate and BOD/N ratio. During a whole period of this study, average concentrations of $COD_{cr}$, $COD_{Mn}$, $BOD_5$, TN, and TP in the final effluent obtained from this system were 11.0 mg/L, 8.8 mg/L, 4.2 mg/L, 3.5 mg/L, 9.8 mg/L, and 0.87/0.17 mg/L (with/without poly aluminium chloride(PAC)), which corresponded to a removal efficiency of 95.3%, 87.6%, 96.3%, 96.5%, 68.2%, and 55.4/90.3%, respectively. Excess sludge production rates were $0.026kg-DS/m^3$-sewage and 0.220 kg-DS/kg-BOD lower 1.9 to 3.8 times than those in activated sludge based system such as $A_2O$ and Bardenpho.

• The Korean Journal of Mycology
• /
• v.36 no.2
• /
• pp.116-122
• /
• 2008

Fungal floras were investigated for the lysimeter soil treated with municipal sewage sludge (MSS), pig manure compost (PMC), industrial sewage sludge (ISS), leather processing sludge (LS), and alcohol fermentation processing sludge (FS). Fungal populations were higher in the FS, ISS, LS, or MSS-treated soil than in the chemical fertilizer-treated soil. Isolated fungi from the sewage sludge were identified as Penicillium spp., Gliocladium spp., Acremonium spp., Trichoderma spp., Aspergillus spp., Blastomyces spp., and Phoma spp.