Chemical Industry Zone Research Articles

Distribution characteristics, source analysis and risk assessment of polycyclic aromatic hydrocarbons in sediments of Kuye River: a river in a typical energy and chemical industry zone.

This study systematically analyzed the distribution characteristics, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in Kuye River sediments, located in an energy and chemical industry base in northern Shaanxi, China. The results that revealed the concentrations of 16 PAHs in the sediment ranged from 1090.04 to 32,175.68ng∙g-1dw, with the four-ring PAHs accounting for the highest proportion. Positive matrix factorization analysis (PMF) revealed the main sources of PAHs as incomplete fossil fuel combustion, biomass combustion, and traffic emissions. The total toxic equivalent concentration of BaP, risk quotient, and lifetime carcinogenic risk of PAHs suggested moderate to high contamination of PAHs in the area. The higher incremental lifetime carcinogenic risk (ILCR) indicated that PAH ingestion was the primary route of impact on public health, with children potentially being more susceptible to PAH exposure. This study can provide valuable theoretical support for implementing pollution prevention measures and ecological restoration strategies for rivers in energy and chemical industry areas.

An optimization method of multiscale storage tank target detection introducing an attention mechanism

Under the combined action of the expansion of the chemical industry zone and urban boundaries, urban areas exposed to danger are also increasing. As containers for chemical storage, storage tanks are potential sources of hazards. Conducting target detection for hazard risk analysis is essential. YOLOv5, a single-stage algorithm with good performance, accurately identifies most storage tanks with clear contours and evident positions; however, the identification effect is not good for storage tanks with small targets or unclear boundaries. This study proposes an optimized model based on the YOLOv5 model. First, the Coordinate Attention (CA) mechanism is introduced to make the model focus on the effective information of the target. Second, to improve the detection effect of small targets, the model adds a small target detection head and performs multiscale target detection. Finally, the EIOU loss function is employed instead of the CIOU loss function in the original model to improve the algorithm’s accuracy and speed. Experimental results show that the optimized model significantly improves the detection effect on small targets compared with the original YOLOv5 model. The number of small targets detected by the optimized model is significantly increased compared with the original model, and the size of the smallest targets detected by the optimized model is reduced by about twice compared with the original model. The model’s accuracy, recall rate, and mean average precision (mAP@0.5) are improved, which can be better applied to the detection of storage tanks.

Characteristics of air pollution complex in a typical chemical industrial development zone in eastern China

VOCs (volatile organic compounds) have an important impact on the atmospheric environment, climate and human health. In a typical chemical industrial development zone in eastern China, 123 kinds of VOCs were on-line monitored simultaneously at three sites using the GC-FID/MS system for one year. The seasonal and diurnal variations of composition and concentration of VOCs were compared and analyzed systematically. The VOCs features existed significant differences at the three sites, which were greatly affected by the types and emissions of surrounding enterprises. The alkanes appeared as the major pollutants at the site adjacent to petrochemical processing enterprises (site A), while OVOCs were the majority at the other two sites, which were around by the fine chemical enterprises (site B and C). The TVOC concentrations presented seasonal differences at the three sites, which showed higher values in summer (468.6 μg/m3) at site A, in winter (409.2 μg/m3) at site B，and in autumn (298.9 μg/m3) at site C, respectively. The isopentane (16.8%) and ethylene oxide (17.9%) made up the largest proportion of the VOCs at site A and B, respectively. While it was more susceptible to the effects of dichloromethane, 1,2-dichloroethane and chloromethane at site C. Three pollution events of ethylene oxide, isopentane and dichloromethane were analyzed and traced based on the prevailing wind and the change of concentration at the three sites. Further analysis of the impact of VOCs on the formation of secondary pollutants of O3 and PM2.5 found that the contribution of local O3 (28.1 %) in summer was significantly larger in the study area than that in non-industrial area. The multiphase chemical reactions were more likely to occur in autumn, which promoted the formation of secondary PM2.5, showing the correlation coefficient of 0.73 between the secondary organic aerosol formation potential of VOCs and PM2.5.

Relationship between chemical industrial environment and allergic skin diseases.

This study is an exploration of the relationship between chemical industrial environment and allergic skin diseases. In this retrospective analysis, 200 patients with allergic skin diseases who worked or lived in a chemical industrial zone and were admitted in our hospital between January 2018 and January 2020 were enrolled as Group A. Besides, 500 patients with allergic skin disease who lived in Zhenhai New District, five kilometers away from the chemical radiation zone, were selected as Group B. The specific immunoglobulin E (IgE) levels were determined by Western blotting. The allergen positivity, as well as allergen positivity between different age, sex and body mass index (BMI) were compared between the two groups. The positive food-specific allergen IgE antibody (sIgE) and positive inhalational sIgE were compared between the two groups. The positive rate of total IgE and inhalational sIgE in Group A was higher than that in Group B (P<0.05), while there was no significant difference in positive rate in food sIgE between the two groups (P>0.05). In Group A, the differences in positive rates of total IgE, food-induced sIgE and inhalational sIgE were not significant between patients with different ages, sexes and BMI (P>0.05). There was no significant difference between the two groups in sIgE positive rates of wheat, mango, soybean/peanut/cashew nut combination, limb/beef combination, crab/shrimp/fish combination, milk and egg white (P>0.05). The positive rates of inhalational sIgE in tree combination and dust mites/household dust mites combination in Group A were higher than those in Group B (P<0.05), but had no significant difference between the two groups in the positive rates of inhalational sIgE in Humulus japonicus, mold combination 1, cockroach, cat/dog hair combination, and ragweed/artemisia combination (P>0.05). Chemical industrial environment is closely associated with allergic dermatosis, and the positive rate of total IgE and inhalational sIgE increases significantly in patients living there.

A novel two-step approach for multi-plant indirect HENs design

Implementing interplant heat integration indirectly via intermediate fluid circuits is a reliable and promising means of enhancing the overall energy efficiency and reducing the carbon emissions of a chemical industrial zone. Although optimization-based sequential and simultaneous synthesis methods have been developed for interplant heat integration, obtaining optimal multi-plant indirect heat exchanger networks (HENs) remains a challenge due to the problem's size and complexity. Under this content, a two-step method is proposed based on the decomposable structural features of the HENs. In the first step, a mathematical model incorporating superstructure representation and pinch location technique is developed to optimize interplant intermediate stream allocation, by which the optimal configuration of intermediate fluids is determined by balancing utility targets and intermediate stream cost with pumps and pipelines. This approach enables multiple HENs synthesis to become independent, and in the second step, a compact MINLP model is proposed for the cost-optimal HEN design in each plant. The effectiveness and advantages of the proposed method are demonstrated by the better results obtained within reasonable computing times for three literature examples, particularly an industrial-scale problem.

Emission characteristics, environmental impacts and health risk assessment of volatile organic compounds from the typical chemical industry in China

To study the volatile organic compounds (VOCs) emission characteristics of industrial enterprises in China, 6 typical chemical industries in Yuncheng City were selected as research objects, including the modern coal chemical industry (MCC), pharmaceutical industry (PM), pesticide industry (PE), coking industry (CO) and organic chemical industry (OC). The chemical composition of 91 VOCs was quantitatively analyzed. The results showed that the emission concentration of VOCs in the chemical industry ranged from 1.16 to 155.59 mg/m3. Alkanes were the main emission components of MCC (62.0%), PE (55.1%), and OC (58.5%). Alkenes (46.5%) were important components of PM, followed by alkanes (23.8%) and oxygenated volatile organic compounds (OVOCs) (21.2%). Halocarbons (8.6%-71.1%), OVOCs (9.7%-37.6%) and alkanes (11.2%-27.0%) were characteristic components of CO. The largest contributor to OFP was alkenes (0.6%-81.7%), followed by alkanes (9.3%-45.9%), and the lowest one was alkyne (0%-0.5%). Aromatics (66.9%-85.4%) were the largest contributing components to SOA generation, followed by alkanes (2.6%-28.5%), and the lowest one was alkenes (0%-4.1%). Ethylene and BTEX were the key active species in various chemical industries. The human health risk assessment showed workers long-term exposed to the air in the chemical industrial zone had a high cancer and non-cancer risk during work, and BTEX and dichloromethane were the largest contributors.

Analysis of risk factors of precocious puberty in children

BackgroundThe purpose of this study is to explore the related factors of precocious puberty in children.Methods1239 children who underwent physical examination in our hospital from January 2020 to December 2022 were analyzed, including 198 precocious children and 1041 normal children. According to the age of 198 precocious children and 1041 normal children, 205 normal children were selected, and the remaining 836 normal children were excluded. They were divided into precocious group and normal group. The general data of the two groups were recorded. Logistic regression was used to analyze the influencing factors of precocious puberty in children.ResultsThere were statistically significant differences (P < 0.05) between the two groups in sex, bone age, daily exercise time, E2, FSH, LH, leptin, mother’s menarche time, living environment, consumption of nutritional supplements, consumption of foods containing pigments and preservatives, consumption of high-protein foods, and sleeping time. The multifactor logistic regression analysis shows that the risk factors of children’s precocious puberty included gender (female), bone age (> 10 years old), and daily exercise time (< 0.9 h), E2 (≥ 66.00pmol/L), FSH (≥ 6.00U/L), LH (≥ 3.50U/L), leptin (≥ 8.00 µ G/L), mother’s menarche time (< 12 years old), living environment (chemical industry zone), consumption of nutritional supplements (often), consumption of high-protein food (often), and sleep time (< 10 h).ConclusionIn conclusion, children’s gender, bone age, exercise habits, E2, FSH, LH, leptin, mother’s menarche time, living environment, eating habits, sleep time and other factors are closely related to precocious puberty in children. Reminding parents to actively prevent related factors in clinical work is helpful to prevent the occurrence of precocious puberty in children.

Metagenomic and Metatranscriptomic Analysis of Nitrogen Removal Functional Microbial Community of Petrochemical Wastewater Biological Treatment Systems

Petrochemicals are one of the pillar industries of China. Despite this, the treatment of petrochemical wastewater has long been seen as a massive challenge in the field of water pollution control, hindering the high-quality and sustainable development of the petrochemical industry. The majority of petrochemical enterprises and zones are located near rivers or seas, so their wastewater discharges can easily cause watershed or regional water ecological risks. Specifically, nitrogen pollution in petrochemical wastewater poses a significant threat to water ecological safety and human health. Sludge samples were collected from a petrochemical wastewater A/O nitrogen removal process line in a chemical industry zone in Shanghai. Metagenomic and metatranscriptomic methods were used to analyze the community structure of microorganisms, the functional characteristics of nitrogen removal bacteria, and the key nitrogen metabolism pathways in different sludges during the period when effluent water quality was stable and fluctuating. During the study, it was found that the nitrite and nitrate removal was relatively stable in this process, but ammonia oxidation fluctuated easily. In the study of microbial communities, it was found to be a nitrification-denitrification pathway that primarily removed nitrogen from the A/O process, and no genes related to ANAMMOX were detected. Approximately 90% of the functional genes responsible for removing nitrogen were responsible for denitrification, whereas only 0.17% of them were involved in the conversion of ammonia nitrogen in the nitrification process. Moreover, the abundance of ammonia-oxidizing bacteria in the process was extremely low, and the main genus was Nitrosomonas. It is likely that this is the main cause of fluctuations in ammonia nitrogen concentration in effluent due to water quality shocks in the process line.

Toxicity evaluation of polycyclic aromatic hydrocarbons (PAHs) in soils of coal chemical industry areas, North China.

Objectives of this study were to investigate the concentrations, distributions, toxicities, and risk assessment of 16 polycyclic aromatic hydrocarbons in surface soils surrounding a coal chemical industrial zone in the southeast of Shanxi province, China. A total of 52 topsoil samples were collected from different land-use areas: cereal agriculture, roadsides, and parkland. Results show that the total PAHs (∑16PAHs) ranged from 3.87 × 103 to 116 × 103µg kg-1 and that the total carcinogenicity PAHs (∑BPAHs) ranged from 3.11 × 103 to 94.2 × 103µg kg-1, with the highest concentration of ∑16PAHs noted in the RS samples, followed by PS and AS. The entire risk quotient of all PAH maximum permissible concentrations (RQ∑PAHMPCi) was greater than 1.0, and the minimum concentration entire risk quotient (RQ∑PAHNCi) of 84.3% of all samples was higher than 800. The value of the total toxicity equivalent concentration of PAH (PAHBapeq) for areas surrounding the coal chemical industrial zone was higher than the value of the standard level, and the incremental lifetime cancer risk (ILCR) far exceeds the U.S. EPA's risk standard. The toxic properties of PAHs indicated that the soils in the survey areas have a high risk to human health and the environment.

Mobile monitoring of VOCs and source identification using two direct-inlet MSs in a large fine and petroleum chemical industrial park

Mobile monitoring with direct-inlet MS (DI-MS), one of the most direct and effective ways to track emission sources, can effectively serve air quality management in chemical industrial parks (CIPs). Mobile monitoring using a high mass-resolution proton-transfer-reaction time-of-flight MS (HMR-PTR-TOFMS) and single-photon ionization time-of-flight MS (SPI-TOFMS) was conducted in a large fine and petroleum CIP in eastern China for three days. The high mixing ratios of aliphatic hydrocarbons (AHs), aromatics, oxygenated VOCs (OVOCs), and nitrogenous VOCs (NVOCs) were found in the northeast, middle, north, and northeast of the fine chemical industrial zone (FCIZ), respectively. OVOCs were the most abundant VOC group in this area. Abnormal emissions of aromatics were universal throughout the CIP. We discovered 38 characteristic VOCs by the HMR-PTR-TOFMS, mainly including C6-C10 aromatics, C2-C6 carbonyls, C2-C3 organic acids, and some NVOCs. The time series and spatial distribution of the TVOCs obtained by the two DI-MSs are generally consistent. A comparison of the speciated VOCs at the TVOC peak points illustrates that the characteristic VOCs obtained by different instruments differed significantly: PTR-TOFMS showed an advantage in measuring aromatics and OVOCs; SPI-TOFMS showed an advantage in measuring aromatics and some Ahs; offline GC–MS showed an advantage in measuring AHs, aromatics, some OVOCs, and halohydrocarbons. Similarities were compared between five positive matrix factorization (PMF) model-based fingerprints of VOCs in a previous study and observed profiles of VOCs from mobile monitoring. The emission sources of the five fingerprints were identified and validated: two were widely distributed, one was a chemical reagent production factory, one was an acrylic fiber production plant, and one was a pesticide factory. This study demonstrated methods for analyzing mobile monitoring data, characterizing the VOCs in the fine and petroleum CIP, correlating the results of stationary observation and mobile monitoring, and integrating the source tracing system with DI-MSs.

Occurrence of antibiotic resistome in farmland soils near phosphorus chemical industrial area

Heavy metal pollution of soil surrounding phosphorus chemical industry has been a long-concerned problem; however, the occurrence of antibiotic resistance genes (ARGs) in farmland soils in its vicinity remains unexplored. In this study, variations of heavy metals, ARGs, mobile genetic elements (MGEs), and microbiome in surface soils of farmland along the prevailing downwind direction of a phosphorus chemical industrial zone were investigated. Cadmium (Cd) contents in soils close to the industrial zone (≤ 500 m away) were statistically higher than those at greater distances (1000 to 4000 m). A comparable ARG diversity was observed across soils, while the relative abundance of ARGs decreased markedly with increasing distance in the range of 1000 m. The soil in closest proximity to the industrial zone (20 m away) exhibited divergent compositions of ARGs, MGEs, and bacterial community from the other soils at farther locations (500 to 4000 m away). Variation partitioning analysis revealed that Cd and MGEs levels were the primary factors controlling ARG distribution. Structural equation modeling further indicated that the direct effect of Cd on ARG abundance was stronger than its indirect effect via affecting MGEs and microbiome. The observed prevalence of ARGs in farmland soils highlights the necessity of including resistome in the framework for environmental risk assessment of phosphorus chemical manufacturing.

Benzene extraction in environmental samples based on the mixture of nanoactivated carbon and ionic liquid coated on fused silica fiber before determination by headspace solid-phase microextraction-gas chromatography

In this study, the mixture of nano activated carbon (NAC) and ionic liquid (3-triphenylphosphonio-propane-1-sulfonate; C21H21O3PS) was coated on fused silica fiber of SPME holder (NAC-IL-FSF/SPME). Then NAC/IL was used for determining of benzene in soil and vegetables samples (1.0 g, n=50) surrounding a chemical industry zone. After benzene adsorption on NAC-IL based on head space solid phase micoextraction (HS-SPME), the concentration of benzene was simply determined by introducing probe to injector of gas chromatography with flame-ionization detection (GC-FID). All effected parameters such as the sorbent mass, the amount of sample, the temperature, and the interaction time were optimized in glass chromatography vials by static procedures. The benzene vapor was absorbed from soil and vegetables samples with NAC-IL-FSF/SPME holder for 10 min at 80oC (10 mg of NAC and 0.1 g of ionic liquid in 0.5 mL of acetone coated on FSF). Then the benzene was desorbed and determined by GC-FID spectrometry. The extraction efficiency and absorption capacity of adsorbent were obtained 98.5% and 127.2 mg g-1, respectively. The high surface area of NAC and favorite interaction of aromatic chain in IL (π-π), caused to efficiently remove of benzene vapor by HS-SPME procedure as compared to other nanostructures.

Occurrence of bisphenol-A and its brominated derivatives in tributary and estuary of Xiaoqing River adjacent to Bohai Sea, China.

The chemical industrial zone located along the Xiaoqing River wetlands adjacent to Bohai Sea is one of the largest production bases for brominated flame retardants in China. Herein, high levels of bisphenol-A, tetrabromobisphenol-A (TBBPA), tribromobisphenol-A, dibromobisphenol-A, and monobromobisphenol-A were detected in sediment, soil, and water samples of this zone in the range of below method detection limit (<MDL)-5.45 × 106 ng/kg dw, <MDL-8.37 × 104 ng/kg dw, and <MDL-5.59 × 102 ng/L, respectively. They were mainly buried in sediments as their highest levels in sediment samples. The small concentration fluctuation between water samples retrieved in the upstream and downstream zones is likely attributed to seawater backflow. The nearby chemical factories were point pollution sources and the less brominated analogs are largely from debromination of TBBPA. High pollution levels and the ecological risks of these pollutants along the Xiaoqing estuary to Bohai Sea need to be further assessed in future studies.

Comparison of molluscicidal cost and effectiveness between 5% niclosamide ethanolamine salt granules and 26% suspension concentrate of metalaldehyde and niclosamide ethanolamine salt

To compare the molluscicidal effects and cost-effectiveness of 5% niclosamide ethanolamine salt granules (NEG) and 26% suspension concentrate of metalaldehyde and niclosamide ethanolamine salt (MNSC) . Two plots with high Oncomelania hupensis snail density were selected as research areas in Nanjing Chemical Industry Zone, and 5% NEG (40 g/m2) and 26% MNSC (40 g/m2) were used by the spraying method for snail control in the two plots, and their molluscicidal effects and cost-effectiveness were investigated and statistically analyzed. There was no significant difference between 5% NEG and 26% MNSC in the molluscicidal effects. The cost of 5% NEG was 1.25 times higher than that of 26% MN-SC per ten thousand square meters in snail control. The cost of 5% NEG is higher than that of 26% MNSC per ten thousand square meters in snail control. Their molluscicidal effects are similar.

Major Dangerous Sources Classification Based on Pattern Recognition Method

The important method of managing major dangerous sources in chemical industrial zone was classified according to the possibility of risk. This paper presented a model of classifying major dangerous sources based on pattern recognition method. The model was simulated by a computer program in matlab9.0 platform, and the experimental results proved that the accuracy of pattern recognition classifier was over 95%. With pattern recognition method, major dangerous sources classification was effective and accurate in comparison with conventional assessment method, which provided a new approach to risk assessment of major dangerous sources in chemical industrial zone.

Phylogenetic analysis of bacterial community composition in sediments with organic contaminants from the Jiaojiang estuary in China

The aim of this study was to investigate the bacterial community composition, the concentration of organic contaminants, and their relationship in the sediments of Jiaojiang estuary. Sediments were collected from seven stations and the environmental parameters were analyzed. The results showed that the site closest to the chemical industry zone was the most polluted. Bacterial communities were determined using 16S rRNA clone libraries and phylogenetic analysis. These results revealed that there were 13 known bacterial phyla in the sediments and that Proteobacteria were the dominant group. Using these data, we assessed the correlation between bacterial communities and organic contaminants using cluster, multidimensional scaling, and redundancy analyses. These showed that there was no simple relationship between organic contaminants and bacterial community diversity in the sediments, but polycyclic aromatic hydrocarbons were more influential than the other pollutants and negatively affected Chloroflexi.

Investigation of Ground-Level Ozone and High-Pollution Episodes in a Megacity of Eastern China.

Differential Optical Absorption Spectroscopy (DOAS) was used for the long-term observation of ground-level ozone (O3) from March 2010 to March 2013 over Shanghai, China. The 1-hour average concentration of O3 was 27.2 ± 17.0 ppbv. O3 level increased during spring, reached the peak in late spring and early summer, and then decreased in autumn and finally dropped to the bottom in winter. The highest monthly average O3 concentration in June (41.1 ppbv) was nearly three times as high as the lowest level recorded in December (15.2 ppbv). In terms of pollution episodes, 56 hourly samples (on 14 separate days) in 2010 exceeded the 1-hour ozone limit of 200 μg/m3 specified by the Grade II of the Chinese Ambient Air Quality Standards (CAAQS, revised GB 3095-2012). Utilizing the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the primary contribution to high ozone days (HODs) was identified as the regional transportation of volatile organic compounds (VOC) and high concentrations of O3 from the chemical industrial zone in the Jinshan district of Shanghai. HODs showed higher concentrations of HONO and NO2 than non-episode conditions, implying that HONO at high concentration during HODs was capable of increasing the O3 concentration. The photolysis rate of HONO was estimated, suggesting that the larger number of OH radicals resulting from high concentrations of HONO have a considerable impact on ozone concentrations.

Online hydraulic calculation and operation optimization of industrial steam heating networks considering heat dissipation in pipes

Constructing industrial parks with DH (district heating) systems has become a main way to develop modern industry, which requires strict security and reliability of heating networks. Industrial steam heating networks are usually ring-shaped with multiple heating sources, and the working conditions would be changeable due to the high frequency and a wide range of load variation of heating consumers. Under a specific working condition, low steam velocity for a long time (namely “steam stagnation”) in certain pipes will result in CIWH (condensation-induced water hammer) which will threaten the security of the whole DH system. In this paper, a hydraulic calculation model is built to study the steam flow regime considering heat dissipation and condensation in pipes, an operation optimization method is proposed to help eliminate steam stagnation through optimizing the heat load distribution of each heating source, a general software system entitled “HEATNET” is presented to realize online hydraulic calculation and operation optimization for arbitrary structured heating networks. The practical application of HEATNET in Shanghai chemical industry zone shows that heat dissipation and condensation in pipes would influence the overall hydraulic calculation of steam heating networks and it can prevent CIWH and improve the security and reliability of steam heating networks.

Heavy metal pollution in soils from abandoned Taizhou Chemical Industry Zone in Zhejiang province

Heavy metal (HM) pollution in soils from an abandoned Taizhou Chemical Industry Zone (TCIZ) was investigated. By analysing soils, including sediments, collected from the study zone, the main pollutants were quantitatively identified and their spatial distribution patterns were clearly displayed. Eleven types of HM pollutants were obtained and the results indicated a significant correlation in most of the elements of the soil and sediment. A pollution index Pi was employed to classify the degree of contamination and characterize the main pollutant, which was controlled with the evaluation standard value instead of background one. As was characterized to be one of the main pollutants with the mean concentrations at the pollution source, in the surrounding area, and in the sediment of 603, 20.4, and 22.5 mg/kg, respectively. Our study suggested that the contaminated area of TCIZ may necessitate remediation before it can be considered for reuse. Pollution index method could be a useful tool for assessing soils quality to provide comparable criteria.

Polychlorinated Biphenyls in the Centralized Wastewater Treatment Plant in a Chemical Industry Zone: Source, Distribution, and Removal

Polychlorinated biphenyls (PCBs) could be dissolved in wastewater or adsorbed on particulate. The fate of PCBs in wastewater is essential to evaluate the feasibility of wastewater treatment processes and the environmental risk. Here dissolved and adsorbed concentrations of twenty concerned PCB congeners and total PCBs have been measured in the centralized wastewater treatment plant of a chemical industry zone in Zhejiang, China. It was found that the dyeing chemical processes were the main source of PCBs, which contributed more than 13.6%. The most abundant PCB was PCB-11 in the liquid and solid phase of each treatment stage, accounting for more than 60% of the total 209 PCBs. Partitioning behavior of PCBs between the dissolved and adsorbed phases suggested that Di-CBs were the dominant isomers (&gt;70%) and more than 89.8% of them was adsorbed on the particles and sludge. The total removal efficiency of∑209 PCBs was only 23.2% throughout the whole treatment process. A weak correlation was obtained between the individual PCB concentration and their log Kowin primary sedimentation, anaerobic hydrolysis, aerobic bioprocess stage, and the whole treatment process.