Dioxide Disinfection Research Articles

Disinfection of drinking water for poultry

Relevance. The problem of biological safety of drinking water remains relevant in livestock farming. The quality of water depends on the primary composition of the microflora of the source; with further transportation, the water is additionally contaminated with microorganisms. Infected water contributes to nutritional contamination of animals, the development of various pathologies of the gastrointestinal tract, the death of livestock, and a decrease in production indicators and enterprise profits. Currently, various methods of water purification have been proposed, but the search for the most effective methods and means of water disinfection continues. The purpose of the work is to evaluate the effectiveness of the drug “Di-O-Clean” as a source of chlorine dioxide for the disinfection of drinking water in industrial poultry farming.Methods. The methodology included bacteriological studies of 80 drinking water samples taken from various poultry farm facilities in different seasons of the year, a sanitary assessment of the poultry watering system after the use of “Di-O-Clean”.Results. As a result of the water tests, coliform bacteria and Pseudomonas aeruginosa were found. There was an increase in the number of microorganisms in the water of the storage tank and poultry watering system by 2.4 times compared to the amount of the initial microflora in the well water. The sanitary quality of water depends on the season of the year; the most unfavorable values of water assessment indicators were recorded in the spring. Production tests have shown that water disinfection with “Di-O-Clean” is effective, affordable, safe and economically feasible. Chlorine dioxide disinfection technology makes it possible to minimize or eliminate the transmission of infections through drinking water, raise healthy livestock and maintain the biological safety of the enterprise as a whole.

Disinfection-residual bacteria (DRB) after chlorine dioxide treatment: Microbial community structure, regrowth potential, and secretion characteristics

This study investigates the effects of chlorine dioxide (ClO2) disinfection on the community structure, regrowth potential, and metabolic product secretion of disinfection-residual bacteria (DRB) in secondary effluent (SE), denitrification filter effluent (DFE), and ultrafiltration effluent (UE). Results show that ClO2 effectively reduces bacteria in SE and UE, achieving log removal values exceeding 3 at 1 mg/L within 30 min. A salient positive correlation (R2 > 0.95) exists between changes in total fluorescence intensity and disinfection efficacy. Post-treatment, Acinetobacter abundance increased in SE, while Pseudomonas decreased in DFE and UE. At lower ClO2 concentrations, Staphylococcus, Mycobacterium, Aeromonas, and Lactobacillus increased in DFE, but decreased at higher concentrations. After storage, bacterial counts in disinfected samples exceeded those in the control group, surpassing 105 CFU/mL. Despite an initial decline, species richness and evenness partially recovered but remained lower than control levels. Culturing DRB for 72 h showed elevated extracellular polymeric substances (EPS) secretion, quantified as total organic carbon (TOC), ranging from 5 to 27 mg/L, with significantly higher EPS in the disinfection group. Parallel factor analysis with self-organizing maps (PARAFAC-SOM) effectively differentiated water sample types and EPS fluorescent substances, underscoring the potential of three-dimensional fluorescence as an indirect measure of ClO2 disinfection efficacy.

Comparison of chlorine and chlorine dioxide disinfection in drinking water: Evaluation of disinfection byproduct formation under equal disinfection efficiency

Disinfection efficiency and disinfection byproduct (DBP) formation are two important aspects deserving careful consideration when evaluating different disinfection protocols. However, most of the previous studies on the selection of disinfection methods by comparing DBP formation were carried out under the same initial/residual dose and contact time of different disinfectants, and such a practice may cause overdose or underdose of a certain disinfectant, leading to the inaccurate evaluation of disinfection. In this study, a comprehensive and quantitative comparison of chlorine (Cl2) and chlorine dioxide (ClO2) disinfection was conducted with regard to their DBP formation under equal disinfection efficiency. The microbial inactivation models as well as the Cl2 and ClO2 demand models were developed. On such basis, the integral CT (ICT) values were determined and used as a bridge to connect disinfection efficiency and DBP formation. For 3-log10 and 4-log10 reductions of Pseudomonas aeruginosa, ClO2 had 1.5 and 5.8 times higher inactivation ability than Cl2, respectively. In the premise of equal disinfection efficiency (i.e., the ICT ratios of Cl2 to ClO2 = 1.5 and 5.8), the levels of total organic chlorine, total organic bromine, and total organic halogen formed in the Cl2 disinfection were significantly higher than those formed in the ClO2 disinfection. Among the 35 target aliphatic DBPs, trihalomethanes (THMs) and haloacetic acids (HAAs) were the dominant species formed in both Cl2 and ClO2 disinfection. The total THM levels formed in Cl2 disinfection were 14.6 and 30.3 times higher than those in ClO2 disinfection, respectively. The total HAA levels formed in Cl2 disinfection were 3.5 and 5.4 times higher than those in ClO2 disinfection, respectively. Formation of the target 48 aromatic DBPs was much favored in Cl2 disinfection than that in ClO2 disinfection, and the formation levels was dominated by contact time. This study demonstrated that ClO2 had significant advantages over Cl2, especially at higher microorganism inactivation and lower DBP formation requirements.

Study on the disinfection effect of chlorine dioxide disinfectant (ClO2) on dental unit waterlines and its in vitro safety evaluation

BackgroundEnsuring the safety of dental unit waterlines (DUWLs) has become a pivotal issue in dental care practices, focusing on the health implications for both patients and healthcare providers. The inherent structure and usage conditions of DUWLs contribute to the risk of biofilm formation and bacterial growth, highlighting the need for effective disinfection solutions.The quest for a disinfection method that is both safe for clinical use and effective against pathogens such as Staphylococcus aureus and Escherichia coli in DUWLs underscores the urgency of this research.MaterialsChlorine dioxide disinfectants at concentrations of 5, 20, and 80 mg/L were used to treat biofilms of S. aureus and E. coli cultured in DUWLs. The disinfection effectiveness was assessed through bacterial counts and culturing. Simultaneously, human skin fibroblast cells were treated with the disinfectant to observe changes in cell morphology and cytotoxicity. Additionally, the study included corrosion tests on various metals (carbon steel, brass, stainless steel, aluminum, etc.).ResultsExperimental results showed that chlorine dioxide disinfectants at concentrations of 20 mg/L and 80 mg/L significantly reduced the bacterial count of S. aureus and E. coli, indicating effective disinfection. In terms of cytotoxicity, higher concentrations were more harmful to cellular safety, but even at 80 mg/L, the cytotoxicity of chlorine dioxide remained within controllable limits. Corrosion tests revealed that chlorine dioxide disinfectants had a certain corrosive effect on carbon steel and brass, and the degree of corrosion increased with the concentration of the disinfectant.ConclusionAfter thorough research, we recommend using chlorine dioxide disinfectant at a concentration of 20 mg/L for significantly reducing bacterial biofilms in dental unit waterlines (DUWLs). This concentration also ensures satisfactory cell safety and metal corrosion resistance.

Evaluation of combined disinfection methods of infectious myonecrosis virus (IMNV) in seawater using Pacific white shrimp (Penaeus vannamei)

The global spread of infectious myonecrosis virus (IMNV) poses a serious threat to the shrimp aquaculture industry and urgent actions are needed to control its transmission and prevalence. Aquaculture water serves as an important route of IMN transmission, and disinfection of aquaculture water is crucial to ensure the health and stable production of shrimp. In this study, we introduced the purified IMNV into seawater and then subjected the seawater to different disinfection treatments (PMS, PMS + PVP-I and ClO2 + PVP-I) before culturing shrimp. By performing RT-qPCR tests on both the seawater and Pacific white shrimp (Penaeus vannamei) samples, we evaluated the effectiveness of the different disinfection methods in eradicating IMNV from the seawater. The results showed that peroxymonosulfate (PMS) could effectively reduce the viral load of IMNV in seawater samples. The combined disinfection approach (10 ppm) of PMS disinfection (combined with povidone‑iodine) followed by a standing time of at least 2 days, or 10 ppm chlorine dioxide disinfection (combined with povidone‑iodine) followed by a standing time of at least 4 days, were found to be successful in the efficient disinfection of IMNV. This research provides a method to effectively remove IMNV from marine aquaculture water, thereby contributing to reducing the risk of IMN disease transmission and providing a sound basis for the sustainable and healthy development of the shrimp aquaculture industry.

Occurrence and fate of N-nitrosamines in full-scale domestic wastewater treatment plants and their impact on receiving waters along the Lijiang River, China

Domestic wastewaters contaminated with N-nitrosamines pose a significant threat to river ecosystems worldwide, particularly in urban areas with riparian cities. Despite widespread concern, the precise impact of these contaminants on receiving river waters remains uncertain. This study investigated eight N-nitrosamines in wastewater treatment plants (WWTPs) and their adjacent receiving river, the Lijiang River in Guilin City, Southwest China. By analyzing thirty wastewater samples from five full-scale WWTPs and twenty-three river water samples from Guilin, we quantified the mass loads of N-nitrosamines discharged into the surrounding watershed via domestic effluents. The results revealed that N-nitrosodimethylamine (10–60 ng/L), N-nitrosodiethylamine (3.4–22 ng/L), and N-nitrosopyrrolidine (not detected–4.5 ng/g) were predominant in influents, effluents, and sludge, respectively, with the overall removal efficiencies ranging from 17.7 to 65.6% during wastewater treatment. Cyclic activated sludge system and ultraviolet disinfection were effective in removing N-nitrosamines (rates of 59.6% and 24.3%), while chlorine dioxide disinfection promoted their formation. A total of 30.4 g/day of N-nitrosamine mass loads were observed in the Lijiang River water, with domestic effluents contributing about 31.3% (19.4 g/day), followed by livestock breeding wastewater (34.5%, 12.0 g/day), and unknown sources (24.7%, 7.5 g/day). These findings highlight the critical role of WWTPs in transporting N-nitrosamines to watersheds and emphasize the urgent need for further investigation into other potential sources of N-nitrosamine pollution within watersheds.

Exploration of risk analysis and elimination methods for a Cr(VI)-removal recombinant strain through a biosafety assessment in mice

Though recombinant strains are increasingly recognized for their potential in heavy metal remediation, few studies have evaluated their safety. Moreover, biosafety assessments of fecal-oral pathway exposure at country as well as global level have seldom analyzed the health risks of exposure to microorganisms from a microscopic perspective. The present study aimed to predict the long-term toxic effects of recombinant strains by conducting a subacute toxicity test on the chromium-removal recombinant strain 3458 and analyzing the gut microbiome. The available disinfection methods were also evaluated. The results showed that strain 3458 induced liver damage and affected renal function and lipid metabolism at 1.0 × 1011 CFU/mL, which may be induced by its carrier strain, pET-28a. Strain 3458 poses the risk of increasing the number of pathogenic bacteria under prolonged exposure. When 500 mg L−1 chlorine-containing disinfectant or 250 mg L−1 chlorine dioxide disinfectant was added for 30 min, the sterilization rate exceeded 99.9 %. These findings suggest that existing wastewater disinfection methods can effectively sterilize strain 3458, ensuring its application value. The present study can serve a reference for the biosafety evaluation of the recombinant strain through exposure to the digestive tract and its feasibility for application in environmental pollution remediation.

Production of reactive species during UV photolysis of chlorite for the transformation of micropollutants in simulated drinking water

Chlorite (ClO2−) is a dominant product during chlorine dioxide (ClO2) disinfection. This study investigated the mechanism for UV photolysis of ClO2− and the production of reactive species. The apparent quantum yield of ClO2− is 1.21 ∼ 1.29 mol einstein−1 by UV photolysis at 254 nm at pH 7. UV photolysis primarily transforms ClO2− to ClO2, and then to HOCl/OCl−, ClO3− and Cl−. Both ClO2 and HOCl/OCl− are major reactive chlorine species, which maximum concentrations are 8.4 and 11.0 μM, respectively, at 50 μM ClO2− and pH 7. Meanwhile, hydroxyl radical (HO) and chlorine atom (Cl) are also formed with the concentrations of 3.1 × 10−14 and 7.8 × 10−15 M, respectively. The abatement of structurally diverse pharmaceuticals and personal care products (PPCPs) by UV/ClO2− is compound specific, depending on their reactivity toward ClO2, HOCl/OCl− and HO. The first-order rate constants of PPCPs primarily relying on ClO2 and HOCl/OCl− range from 0.043 to 1.533 min−1 and from 0.240 to 2.071 min−1, respectively, while those relying on HO range from 0.012 to 0.020 min−1. As for phenolics, phenol and bisphenol A (BPA) are completely removed within 15 min and ClO2 plays a dominant role. Natural organic matter (NOM) inhibits the degradation of phenol and BPA in UV/ClO2−, while chloride and bicarbonate shows slight impacts. The transformation pathways of BPA in the UV/ClO2− system initiate with electron transfer, and then hydroxylation, carbonylation, chlorination, and coupling reactions. The formation of disinfection byproducts (DBPs) and total organic chlorine (TOCl) is not significant during UV/ClO2− treatment, and over 90% TOCl are unknown DBPs. This study improves the understanding of the water chemistry of UV photolysis of ClO2−.

Simultaneous removal of chlorite and coexisting emerging organic contaminants by sulfite: Kinetics and mechanisms

The inevitable formation of chlorite (ClO2–) and the ineffective degradation of some emerging organic contaminants (EOCs) during chlorine dioxide disinfection have aroused increasing concern about their adverse effects on human health. In this study, the kinetics and mechanisms of simultaneous removal of ClO2– and coexisting EOCs by sulfite (S(IV)) were investigated. Under aerobic conditions, ClO2– and coexisting EOCs could be effectively removed by S(IV) at pH 6.5–7.5, and their removal rates decreased as pH increased. ClO3– was generated in this process but its amount decreased with increasing pH. Many lines of evidence verified that the reaction of ClO2– with HSO3– and H+ generated SO3•− and ClO•, and the generated ClO• was rapidly quenched by S(IV) to form OCl– and SO3•−. Subsequently, SO3•− quickly reacted with O2 to form SO5•−, which was further transformed into SO4•−. SO4•− was the dominant reactive oxidant contributing to the degradation of coexisting EOCs and the formation of ClO3–. Using S(IV) to simultaneously control ClO2– and coexisting EOCs in water treatment is a promising approach because its performance was slightly affected by the water matrix.

Feasibility assessment of alternative environmentally friendly disinfection technique for reverse osmosis-based desalination process

In the seawater reverse osmosis (SWRO) process, the chlorine-based disinfection method poses significant incidental problems, such as producing disinfection by-products and damaging the SWRO membrane surface directly. Chlorine dioxide can control the biofouling layer and relatively stable disinfection approach during the operation. Major two perspective views, such as process stability (water flux and salt rejection) and membrane surface functionality, we evaluated chlorine dioxide feasibility as an alternative disinfection. Standard SWRO performance was evaluated at various operation conditions (inlet pressure and flow rate) using a customized SWRO system. For the stability of the chlorine dioxide disinfection approach, the chemical exposure test was conducted within the concentration and time-variant. While full total 30 days of long-term operation with continuous chlorine dioxide (0.5 mg/L) stripping during the SWRO desalination process, water flux and salt rejection rate maintain 26.7 L.min−1 and 99.7 % respectively.

Changes in molecular dissolved organic matter during coagulation/sedimentation and chlorine and chlorine dioxide disinfection by non-target (or unknown) screening analysis

River water is a major water supply source, and its quality is strongly affected by seasonal changes in dissolved organic matter (DOM) and anthropogenic discharge. This study uses unknown screening analysis with Orbitrap mass spectrometry to investigate differences in molecular DOM in upstream and downstream areas of Phong River, Thailand, in addition to changes caused by coagulation/sedimentation, disinfection byproducts (DBPs), and formation by chlorine (Cl2) and chlorine dioxide (ClO2) in the dry season and after the first rainfall in the wet season. Among 2000 DOM features in the river, DOM with carbon, hydrogen, and oxygen (CHO features) was the most abundant class followed by CHO features with other heteroatoms such as N, NS, and S. CHO features with a relatively higher degree of oxidation (high carbon oxidation state, Cos) and highly oxygenated (high oxygen to carbon ratio, O/C) characteristics decreased preferentially via coagulation and sedimentation by polyaluminium chloride. Approximately 130 Cl-containing (CHOCl) features increased or were newly formed after Cl2 and ClO2 disinfection, respectively. Only 14 Cl2-CHOCl and four ClO2-CHOCl features were commonly formed in all water samples, while many unique DBPs were identified in each disinfection; therefore, reactions of unique DBP precursors in each water sample can produce unique DBPs. Additionally, around 100 CHO DBPs were also found after both Cl2 and ClO2 disinfection. Both Cl2 and ClO2 selectively reacted with CHO features with a relatively higher degree of oxidation (high Cos). Cl2 disinfection produced more oxygenated (high O/C) and oxidized (Cos) DBPs than ClO2 disinfection. Several hundred DBP precursors of Cl2 electrophilic substitution were found not only from natural sources but also from wastewater discharge or runoff.

The transformation mechanism of ofloxacin (OFL) by chlorine dioxide disinfection in water distribution system: kinetics, byproducts and toxicity

Abstract There is a research gap on the transformation of ofloxacin (OFL) in water supply systems under the action of ClO2. The degradation kinetics of OFL under different ClO2 concentrations, pH and pipe materials, and formation of intermediates, as well as the toxicity of water in water supply systems were first studied. The results showed that the degradation of OFL in PE pipe and deionized water increased with the increase of ClO2 concentration, and the reaction of OFL followed the second-order kinetic model. The removal rate of OFL in deionized water was faster than that in PE pipe. The degradation rate of OFL in PE tube and deionized water were positively correlated with pH. In addition, degradation efficiency of OFL in different pipes followed: cast iron pipe > stainless steel pipe > PE pipe. The detection of OFL intermediates showed that the cleavage of piperazine groups were the main and initial products in the degradation process of OFL. In addition, the decarboxylation intermediates of quinolone groups were also detected. The aquatic toxicity test showed that the degradation of OFL by ClO2 would increase the toxicity of water, therefore, the decrease of OFL may not mean the decrease of water toxicity.

Effects of Organic Compounds with Different Biochemical Characteristics on Disinfectant-Resistant Microbes in Chlorine Dioxide Disinfection Water

Effects of Organic Compounds with Different Biochemical Characteristics on Disinfectant-Resistant Microbes in Chlorine Dioxide Disinfection Water

Synthesis and characterization of a phosphotungstic acid composite carrier and its application in solid chlorine dioxide disinfectant.

Chlorine dioxide (ClO2) is an antimicrobial compound used in water. The short release time of existing solid chlorine dioxide disinfectants significantly inhibits their bactericidal efficiency. We propose a novel approach in which attapulgite was introduced into phosphotungstic acid and SBA-15 to achieve the slow-release of chlorine dioxide disinfectant tablets. The emphasis of the study lies in slow release of chlorine dioxide and reducing the escape of chlorine dioxide gas to increase the reaction time and improve disinfection efficiency. When dissolved in water the decrease rate of chlorine dioxide within 15 days after mixing SBA-15/HPW with sodium chlorite is 78.6%. Moreover, the sterilization efficiency of Escherichia coli reaches 100% within 5 minutes, and the killing rate of Staphylococcus aureus exceeds 99.999% within 10 minutes. The research solved the storage and transportation problems of ClO2 and resulted in a solution for the disinfection of water requiring long-term disinfection.

Effects of Chlorine Dioxide Disinfection on the Profile of the Super Antibiotic Resistance Genes in a Wastewater Treatment Plant

In order to study the effects of chlorine dioxide (ClO2) disinfection on the super antibiotic resistance genes (SARGs), the final effluents before and after chlorine dioxide were sampled throughout one year in a wastewater treatment plant (WWTP). The bacteria and extracellular nucleic acid were collected using microporous membrane filtration and nucleic acid adsorption particles, respectively. A total of 9 SARGs was detected through a quantitative real-time polymerase chain reaction (qPCR). The results revealed that both intracellular and extracellular NDM-1, MCR-1, and MEC-A could be positively detected in the samples. Overall, ClO2 disinfection enhanced the relative abundance of the iSARGs (P<0.05), exhibiting a seasonal pattern, and increasing in the spring, summer, and autumn. In spring, it improved the most, up to twice the abundance. No SARGs were detected positive in the winter, either intracellularly or extracellularly. There was no significant variation in the concentrations of eSARGs before and after ClO2 disinfection. Therefore, ClO2 disinfection cannot effectively remove iSARGs and eSARGs in the final effluent from the WWTP.

Effects of reductive inorganics and NOM on the formation of chlorite in the chlorine dioxide disinfection of drinking water

Chlorine dioxide (ClO2) disinfection usually does not produce halogenated disinfection by-products, but the formation of the inorganic by-product chlorite (ClO2–) is a serious consideration. In this study, the ClO2– formation rule in the ClO2 disinfection of drinking water was investigated in the presence of three representative reductive inorganics and four natural organic matters (NOMs), respectively. Fe2+ and S2– mainly reduced ClO2 to ClO2– at low concentrations. When ClO2 was consumed, the ClO2– would be further reduced by Fe2+ and S2–, leading to the decrease of ClO2–. The reaction efficiency of Mn2+ with ClO2 was lower than that of Fe2+ and S2–. It might be the case that MnO2 generated by the reaction between Mn2+ and ClO2 had adsorption and catalytic oxidation on Mn2+. However, Mn2+ would not reduce ClO2–. Among the four NOMs, humic acid and fulvic acid reacted with ClO2 actively, followed by bovine serum albumin, while sodium alginate had almost no reaction with ClO2. The maximum ClO2– yields of reductive inorganics (70%) was higher than that of NOM (around 60%). The lower the concentration of reductive substances, the more ClO2– could be produced by per unit concentration of reductive substances. The results of the actual water samples showed that both reductive inorganics and NOM played an important role in the formation of ClO2– in disinfection.

Low chlorine impurity might be beneficial in chlorine dioxide disinfection

Chlorine dioxide (ClO2) is a prevalently used disinfectant alternative to chlorine, due to its effectiveness in pathogen inactivation and low yields of organic halogenated disinfection byproducts (DBPs). However, during ClO2 generation, chlorine is inevitably introduced into the obtained ClO2 solution as an “impurity”, which could compromise the merits of ClO2 disinfection. In this study, drinking water disinfection with ClO2 containing 0‒25% chlorine impurity (i.e., at Cl2 to ClO2 mass ratios of 0‒25%) was simulated, and the effect of chlorine impurity on the DBP formation and developmental toxicity of the finished water was evaluated. With increasing the chlorine impurity in ClO2, the chlorite level kept decreasing and the chlorate level gradually increased; meanwhile, an unexpected trend from decline to rise was observed for the total organic halogenated DBPs, with the minimum level appearing at 5% chlorine impurity. To unravel the mechanisms for the variations of organic halogenated DBPs with chlorine impurity, a quantitative kinetic model was developed to simulate the formation of chlorinated, brominated, and iodinated DBPs in the ClO2-disinfected drinking water. The modeling results indicated that reactions involving iodide accounted for the decrease of organic halogenated DBPs at a relatively low chlorine impurity level. In accordance with DBP formation, ClO2 with 5% chlorine impurity generated less toxic drinking water than pure ClO2, while significantly higher developmental toxicity was induced until the chlorine impurity reached 25%. For E. coli inactivation, the presence of chlorine impurity enhanced the disinfection efficiency due to a synergistic effect of ClO2 and chlorine. Therefore, disinfection practices with ClO2 containing low chlorine impurity (e.g., <10%) might be favored (i.e., there is no need to eliminate low chlorine impurity in the ClO2 solution), while those containing high chlorine impurity should be concerned.

Reaction law of high purity chlorine dioxide and typical substances in raw water

Great concern has been risen due to the harmful by-product formation in chlorine dioxide disinfection. To control the by-product formation, we need to know the factor that make a great contribution to generate by-product in drinking water treatment. The Fe2+, Mn2+, organic matter and algae are the most presenting matters that could cause the formation of chlorite; thus, they were selected as factors in the study. The results showed that the amount of by-product chlorite produced increased along with the increase of the concentrations of organic matter, algae and Fe2+ in water, but the presence of Mn2+ didn’t impact on the formation of chlorite. In addition, the interaction between Fe2+ and Mn2+ was observed, but no obvious interaction between other factors was found. So when the concentration of above factors exceed the standard, the chlorine dioxide is not recommended in any step of the water treatment.

Degradation of Triclosan by Co-exposure to Chlorine Dioxide and UV Irradiation

This study investigated the effect of water quality parameters during simultaneous chlorine dioxide disinfection and low pressure ultraviolet (LPUV) irradiation on TCS degradation.The TCS degradation by the co-exposure process was sensitive to chlorine dioxide dosage, concentration of TCS, pH, and NOM.The removal efficiency increases as the pH increases.Neutral and slightly alkaline environments is conductive to promote TCS elimination, The removal rate within 1 minute of pH 5 was only 95.02%.The smaller the removal rate of TCS was decreased as the concentration of humic acid increasing. The higher the concentration of TCS lead to the lower the experimental removal. 2, 4-DCP was generated during UV/ClO2, ClO2 and UV, however, the production of 2, 8-Cl2DD was not detected during UV/ClO2 process.

Design and application of sewage treatment process in expressway service area

In order to improve the efficiency, impact resistance and purification effect of sewage treatment in service areas, the composition and quantity of sewage water quality in expressway service areas were studied. A highway service area in Yunnan Province uses a combined process for sewage treatment, and the scale has been reached 4000m3/d. The specific process is “multi-point water inlet A/O process + denitrification sand filter + phosphorus removal filter + chlorine dioxide disinfection + activated carbon filter”.The actual effluent quality meets the”Discharge standard of pollutants for municipal wastewater treatment plant” (GB18918-2002). And the first-class standard meets the requirements of “The reuse of urban recycling water-Water quality standard for urban miscellaneous water consumption” (GB/T18920-2002). The engineering practice proves that it is completely feasible to use this combined process to treat sewage in the highway service area, which can be used for reference and reference by similar projects.