This study evaluates the potential of various coagulants to enhance the efficiency of total phosphorus removal facilities in a sewage treatment plant. After analyzing the existing water quality conditions of the sewage treatment plant, the coagulant of poly aluminium chloride was experimentally applied to measure its effectiveness. In this process, the use of poly aluminium chloride and polymers in various ratios was explored to identify the optimal combination of coagulants. The experimental results showed that the a coagulants combination demonstrated higher treatment efficiency compared to exclusive use of large amounts of poly aluminium chloride methods. Particularly, the appropriate combination of poly aluminium chloride and polymers played a significant role. The optimal coagulant combination derived from the experiments was applied in a micro flotation method of real sewage treatment plant to evaluate its effectiveness. This study presents a new methodology that can contribute to enhancing the efficiency of sewage treatment processes and reducing environmental pollution. This research is expected to make an important contribution to improving to phosphorus remove efficiency of similar wastewater treatment plant and reducing the ecological impact from using coagulants in the future.

This study explored effects of a sludge-based biochar addition on nitrogen removal of membrane bioreactor (MBR) for wastewater treatment. The membrane fouling reduction by the biochar addition was also investigated. A dose of 3 g/L of the biochar was applied to an MBR (i.e., BC-MBR) and treatment efficiencies of organic matter and nutrient were analyzed. The MBRs with powdered activated carbon (i.e., AC-MBR) and without any additives were also operated in parallel. The average removals of COD and TN were improved with the biochar addition compared to those with the control MBR. Interestingly, operational duration was also increased with biochar addition. The CLSM analysis revealed that biomass amounts of BC-MBR and AC-MBR were reduced by more than 40%, and thickness of the biofilm attached to the membrane surface also was decreased. The physical properties of biochar surfaces were compared with a commercial powdered activated carbon. The specific surface area with 38 m2/g and pore volume with 0.13 cm3/g of the biochar were much smaller than those of the powdered activated carbon, which were 1100 m2/g and 0.67 cm3/g, respectively. Manufacturing conditions for the biochar production needs to be further investigated for enhancing physical properties for adsorption and biological improvement.

The intensive development of the petrochemical industry globally reflects the necessity of an efficient approach for oily sludge and wastewater. Hence, for the first time, the current study utilized magnetic waxy diesel sludge (MWOPS) to synthesize activated carbon coated with TiO2 particles for the removal of total petroleum hydrocarbons (TPH) and COD from oily petroleum wastewater (OPW). The photocatalyst was characterized using CHNOS, elemental analysis was performed using X-ray fluorescence spectroscopy (XRF), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HR-TEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectrometer (FTIR), Raman, energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), MAP thermo-gravimetric analysis/ differential thermo-gravimetric (TGA–DTG), Brunauer–Emmett–Teller (BET), diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM). The optimization of synthesized highly porous AC/Fe3O4/TiO2 photocatalyst was conducted considering the impacts of pH, temperature, photocatalyst dosage, and UVA6W exposure time. The results demonstrated the high capacity of the MWOPS with inherent magnetic potential and desired carbon content for the removal of 91% and 93% of TPH and COD, respectively. The optimum conditions for the OPW treatment were obtained at pH 6.5, photocatalyst dosage of 250 mg, temperature of 35 °C, and UVA6W exposure time of 67.5 min. Moreover, the isotherm/kinetic modeling illustrated simultaneous physisorption and chemisorption on heterogeneous and multilayer surfaces. Notably, the adsorption efficiency of the AC/Fe3O4/TiO2 decreased by 4% after five adsorption/desorption cycles. Accordingly, the application of a well-designed pioneering photocatalyst from the MWOPS provides a cost-effective approach for industry manufacturers for oily wastewater treatment.

해당 연구는 산업 폐수에서 염료를 효율적으로 제거하기 위한 고급 박막 나노복합체(TFN) 기반 나노여과막을 개 발하여 효과적인 폐수 처리 방법을 제시합니다. 최근 연구의 동향을 보면, 나노카본, 실리카 나노스피어, 금속-유기 프레임워 크(MOF) 및 MoS2와 같은 혁신적인 재료를 포함하는 TFN 막의 제조에 중점을 둡니다. 주요 목표는 염료 제거 효율을 향상 시키고 오염 방지 특성을 개선하며 염료/염 분리에 대한 높은 선택성을 유지하는 것입니다. 이 논문은 넓은 표면적, 기계적 견고성 및 특정 오염 물질 상호 작용 능력을 포함하여 이러한 나노 재료의 뚜렷한 이점을 활용하여 현재 나노여과 기술의 제 한을 극복하고 물 처리 문제에 대한 지속 가능한 솔루션을 제공하는 것을 목표로 합니다.

There are two primary sludge drying methods such as the direct heating microwave method and the indirect heating steam one. In this study, the drying treatment facility at sewage treatment plant A applied both of these drying methods. The research aimed to investigate the optimal operation approach for the drying facility, considering the input sludge and the moisture content data after the drying process. Moisture content and removal rate data were executed at the research facility from January 2016 to December 2018. First, the microwave, a direct heating drying method, performed intensive drying only on the outer surface of the sludge by directly applying heat to the sludge using far infrared rays, so effective sludge drying was not achieved. On the other hand, the steam method of the indirect heating method used steam from a gas boiler to maximize the utilization of the heat transfer area and reduce energy of the dryer, resulting in an effective sludge drying efficiency. The sludge moisture content brought into the sludge drying facility was about 80%, but the moisture content of the sludge that went through the drying facility was less than 10% of the design standard. Therefore, the steam method of the indirect heating method is more effective than the microwave method of the previous direct heating method and is more effective for maintenance It has proven that it is an efficient method of operating construction facilities.

This paper aims to review the odor removal performance and operating parameters of pilot and full-scale chemical scrubbers, bioscrubbers, biofilters, and biotrickling filters for odor control in wastewater treatment plants. Based on the performance of full-scale facilities installed in wastewater treatment plants, empty-bed residence times were the shortest for bioscrubbers (7.5±2.5s), followed by chemical scrubbers (20±8.1s), biotrickling filters (22.2±26.2s), and biofilters (48±30s). The removal efficiencies of complex odors by biofilters, biotrickling filters, bioscrubbers, and chemical scrubbers were 97.7±1.9%, 87.7±15.6%, 89.0±9.0%, and 70.0%, respectively. The investment cost was the lowest for biofilters, followed by biotrickling filters, bioscrubbers, and chemical scrubbers. In addition, the operating costs of these deodorization technologies were in the following order: biofilters < bioscrubbers and biotrickling filters < chemical scrubbers. However, most studies on odor control for wastewater treatment processes have been conducted on a laboratory scale with model odors (single odorous compound or mixtures of 2-3 odorous compounds). Therefore, field research to develop deodorization technologies for wastewater treatment plants should be more actively conducted to accumulate data for the design and operation of full-scale deodorizing systems.

The odors emitted from wastewater treatment plants are not only a health and hygiene problem, but can also lead to complaints from residents and have wider social ramifications such as bringing about falling property values in the surrounding area. In this paper, based on the data measured at domestic and overseas wastewater treatment facilities, the concentrations of complex odors and odorous compounds were compared for each treatment/process: primary treatment, secondary treatment, and sludge treatment processes. Odor compounds that contribute greatly to complex odors were summarized for each process. In addition, the characteristics of odor wheels for each wastewater treatment process, which provide both chemical and olfactory information regarding odors, were reviewed. For domestic wastewater treatment facilities, the complex odor concentrations (unit, dilution factor) of the primary and secondary treatment processes were 4.5-100,000 (median, 32.1) and 2.5-30,000 (median, 10.7), respectively. However, the complex odor concentrations in the sludge treatment process were 3.0-100,000 (median, 118.7), which was more than three times higher than that in the wastewater treatment process. In the wastewater treatment process, those odor compounds making the greatest contributions to complex odors were sulfur-containing compounds such as hydrogen sulfide, dimethyl sulfide, and dimethyl disulfide DMS. In order to properly manage odors from wastewater treatment plants and minimize their impact, it is important to understand the status of odor emissions. Therefore, the compositions and concentrations of odors from wastewater treatment processes and odor wheel information, which are reviewed in this paper, are used to evaluate the potential risk of odor from wastewater treatment facilities in order to derive strategies to minimize odor emissions. Moreover, the information can be usefully used to introduce the best available technology to reduce odors emitted from wastewater treatment facilities.

본 연구에서는 분리막 생물반응기(membrane bioreactor, MBR)에서 발생되는 생물막오염 완화에 탁월한 효과를 가진 분리막을 개발할 목적으로, 친수성 산소 기능기가 많은 탄소나노구체(carbon nanosphere, CNS)를 합성한 뒤, 이를 첨가 제로 활용하여 친수성과 다공성 기공 구조를 갖는 고성능 한외여과막을 제조하였다. CNS는 막 표면에 초승달 모양의 기공을 형성하였고, CNS 함량을 4.6 wt%까지 증가시킴에 따라 최대기공 크기보다 큰 결함을 야기하지 않으면서 평균 표면 기공 크 기를 약 40% 증가시키는 것으로 나타났다. 또한, CNS 복합막의 다공성 기공 구조는 CNS의 등방성 형태와 상대적으로 낮은 입자 수밀도 덕분에 CNS 첨가에 따른 고분자 용액의 점도 급등이 방지됐기 때문이라고 판단된다. 그러나 너무 다공성이 커 지게 되면 기계적 물성이 저하되므로, 기공구조와 기계적 성질을 포함한 종합적인 고려를 했을 때 CNS2.3이 가장 우수하다 고 관측되었다. CNS2.3은 CNS0에 비해 수투과도가 2배 이상 높을 뿐만 아니라, MBR 공정에서 분리막 세정이 요구될 때까 지의 운전 시간도 5배 이상 연장시킨 것으로 확인되었다.

The discharge of industrial oily wastewater and oil spill accidents has resulted in significant environmental pollution, creating an urgent need for the treatment of oily wastewater. Nanofiber membranes, known for their high stability, flux, and efficiency, are widely employed in oil–water separation. This study systematically compared the performance of polyacrylonitrile/ graphene oxide (PAN/GO) composite nanofiber membranes prepared through immersion and electrospinning methods for oily wastewater treatment. Experimental findings demonstrated that immersion-prepared membranes achieved high flux (772.9 ± 2.9 L·m−2·h−1, n-hexane/water mixture) and efficiency (98.8%) at a GO concentration of 1.0 g/mL. On the other hand, electrospinning-prepared membranes exhibited superior flux (1500.3 ± 4.4 L·m−2·h−1, n-hexane/water mixture) and efficiency (99.6%) at a higher GO concentration (1.5 g/mL). This membrane displayed excellent stability, maintaining their exceptional performance even after ten cycles of separation. This study compared the advantages and disadvantages of the two methods for preparation of PAN/GO composite nanofiber membrane, offering valuable guidance for practical applications.

The disposal of organic pollutants is one of the important research topics. Some of the studies in this field are based on the degradation of organic pollutants with a catalytic agent. The cobalt tetraoxide/peroxymonosulfate system is an important catalytic system used for the radical degradation of organic pollutants. To increase the catalytic efficiency of such reactions, graphitization of activated carbon used as a support solid and nitrogen doping to the carbon structure are commonly used methods. In this study, cobalt tetraoxide production, N-doping and graphitization were carried out in a single step by heat treatment of activated carbon doped with the phthlocyanine cobalt (II) complex. The catalytic performance of the catalyst/ peroxymonosulfate system was investigated by changing the pH, catalyst, and PMS concentration parameters on rhodamine B and 1,3,5 trichlorophenol, which were used as models. It was seen that the catalysts had 97% activity on rhodamine B in 16 min and 100% on 1,3,5 trichlorophenol in 6 min. It was observed that the catalysts continued to show high catalytic activity for five cycles in reusability studies and had a very low cobalt leaching rate. These results are in good agreement with previously published studies. In line with these results, the synthesized N-doped graphitic carbon/Co3O4 catalyst can be used as an effective catalyst for wastewater treatments.

Large amounts of waste and wastewater from aquaculture have negatively impacted ecosystems. Among them, shrimp aquaculture wastewater contains large amounts of nitrogen contaminants derived from feed residues in an aerobic environment. This study isolated candidate strains from adult rockworms to treat shrimp aquaculture wastewater (SAW) in an aerobic environment. Among 87 strains isolated, 25 grew well at the same temperature as the shrimp aquaculture with excellent polymer degradation ability (>0.5 cm clear zone). Six isolates (strains AL1, AL4, AL5, AL6, LA10, and PR15) were finally selected after combining strains with excellent polymer degradation ability without antagonism. 16S rRNA sequencing analysis revealed that strains AL1, AL4, AL5, AL6, LA10, and PR15 were closely related to Bacillus paramycoides, Bacillus pumilus, Stenotrophomonas rhizophila, Bacillus paranthracis, Bacillus paranthracis, and Micrococcus luteus, respectively. When these six isolates were applied to SAW, they reached a maximum cell viability of 2.06×105 CFU mL-1. Their chemical oxygen demand (CODCr) and total nitrogen (TN) removal rates for 12 h were 51.0% and 44.6%, respectively, when the CODCr/TN ratio was approximately 10.0. Considering these removal rates achieved in this study under batch conditions, these six isolates could be used for aerobic denitrification. Consequently, these six isolates from rockworms are good candidates that can be applied to the field of aquaculture wastewater treatment.