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To alleviate the problems of eutrophication and blue algae accumulation in water, biochar was prepared from blue algae dehydrated using polymerized ferrous sulfate(PFS) to absorb phosphate in water, and the biochar was activated using steam to adjust the pore structure. The preparation conditions of blue algae biochar were optimized using the response surface method. The optimal results were as follows:the dosage of PFS was 458 mg·L -1 , the carbonization temperature was 433℃, and the mass ratio of biochar precursor to steam was 1:11. Biochar without PFS(F 0 H 11 -433) and biochar with PFS(F 458 H 11 -433) were characterized using X-ray diffraction(XRD), Fourier-transform infrared spectroscopy(FTIR), zeta potential, and Raman spectra(Raman) were used to study whether blue algae biochar and PFS had a synergic effect on phosphate removal. The results showed that:compared with F 0 H 11 -433, iron oxide appeared on the surface, the zero point of charge(pH pzc ) increased from 4.41 to 6.19, and the disorder and defect degree of biochar was increased in F 458 H 11 -433. The pseudo-second-order model and Langmuir model were suitable for describing the adsorption process of F 458 H 11 -433, and the saturated adsorption capacity was 31.97 mg·g -1 . F 458 H 11 -433 had excellent phosphorus removal efficiency in actual lake water, and the residual phosphate content of effluent was less than 0.025 mg·L -1 . In the presence of several common anions, it still showed excellent selective adsorption. After five cycles, the phosphate removal of F 458 H 11 -433 still reached 75.78%, indicating that F 458 H 11 -433 had the characteristic of being renewable. Combined with the material characterization results before and after adsorption, the phosphorus removal mechanism of F 458 H 11 -433 mainly involved electrostatic attraction and ligand exchange.

The internal source pollution of sediment is the main factor leading to the repetition of black-odorous river channels. In order to prevent this situation, a river channel in the Binhu District of Wuxi City was used as an experimental site. In-situ CaO 2 combined with a biochar covering technology was used to repair the black odorous river sediment in this channel. The effects of this technology on the quality of mud water, sedimentary volatile sulfide (AVS) and phosphorus forms, microorganisms, and restoration of black odorous sediment were investigated. The results showed that CaO 2 combined with biochar coverage could significantly increase the dissolved oxygen (DO) concentration and redox potential (ORP) of the muddy water system. The DO concentration and ORP in the overlying water were maintained above 2 mg·L -1 and 50 mV, respectively. The removal rates of interstitial water ammonia-nitrogen (NH 4 + -N), chemical oxygen demand (COD), and total phosphorus (TP) reached 43.40%, 41.18%, and 50.97%, respectively. The removal rate of AVS in the sediment reached 37.03%. The high-throughput sequencing showed that the relative abundance of anaerobic microorganisms in the sediment was significantly reduced, and that nitrogen and sulfur removal microorganisms appeared (e.g., Thermomonas , Dechloromonas , Proteus hauser , Desulfomicrobium , and Thiobacillus ). Phosphorus in the sediment was converted into Fe/Al-P and Ca-P. Therefore, in-situ CaO 2 combined with biochar coverage had a good repairing effect on black odorous sediment.

This study was carried out in the ozone (O 3 ) and biological activated carbon (BAC) section of a drinking water plant to investigate the effects of O 3 on microbial and effluent disinfection by-products (DBPs) in BAC during drinking water treatment. The water quality, dissolved organic matter (DOM) characteristics, microbial activity, and DBPs formation at different O 3 concentrations were analyzed. Results showed that the effect of O 3 on microorganisms is mainly that it increased the utilization efficiency of DOM. However, excessive O 3 increased the amount of organic matter such as protein and microbial metabolites (SMPs) in the effluent. When the O 3 concentration increased from 0 mg·L -1 to 2.0 mg·L -1 , the survival rate of microorganisms in the BAC decreased from 95.10% to 62.60%. However, since O 3 transforms organic matter into a biodegradable substance, we found that microbial activity increased by 62.52% and that the biofiltration of the BAC was enhanced. When the O 3 concentration was further increased to 4.0 mg·L -1 , the microbial survival rate decreased to 49.9% and the protein and SMPs produced by the microorganisms increased. This resulted in an increased formation of carbon-containing DBPs (C-DBPs) and nitrogen-containing DBPs (N-DBPs) by 41.93% and 7.18%, respectively. In summary, an appropriate dosage of O 3 was beneficial for removing DOM by O 3 -BAC, but we found that an excessive O 3 concentration caused the formation of new DBPs precursors.

Disinfection byproduct(DBP) precursors during the wastewater regeneration processes were separated into hydrophilic fraction(HPI), hydrophobic fraction(HPO) and transphilic fraction(TPI) with macroporous resin. DBP precursors in these water samples were characterized with fluorescence excitation emission matrix, Fourier transformation infrared and nuclear magnetic resonance, and were further tested for their DBP formation potential(DBPFP) after chlorination. The results indicated that main DBP precursors in sewage were humic acid and aliphatic hydrocarbons, and were mainly dominated by HPI. Primary treatment(sedimentation) could effectively remove hydrophobic humic acid through the mutual exclusion between HPO and water. The removal of humic acid would lead to the obvious reduction of carbonaceous disinfection byproduct formation potential(C-DBPFP). In addition, nitrogenous disinfection byproduct formation potential(N-DBPFP) was found to be increased due to the increase of DON/DOC value. Although secondary treatment(biotreatment) was effective in removing humic acid and aliphatic hydrocarbons, it could produce a large amount of soluble microbial products(SMP), which led to the enhancement of HPO percentage. And the accumulation of SMP resulted in the significant increase of C-DBPFP and N-DBPFP. Humic acid and hydrophobic SMP could be removed by the advanced treatment(cloth filtration), leading to the reduction of HPO percentage and the increase of HPI percentage. The decrease of humic acid and hydrophobic SMP would cause the reduction of C-DBPFP and N-DBPFP in the advanced treatment.

In order to control the non-point source pollution from road runoff in Wuxi City effectively, a multilayer biofiltration system was designed to remove a variety of pollutants according to the characteristics of road runoff in Wuxi, and the experimental research was carried out to study the effect on rainwater pollution purification. The results show that the system has a good performance on removing suspended solids (SS), organic pollutant (COD), nitrogen and phosphorus: all types of multilayer biofiltration systems have a high removal rate for SS, which can reach 90%. The system with activated carbon (GAC) has higher removal rates for COD and phosphorus. The system with zeolite (ZFM) has a relatively better removal efficiency for nitrogen. The addition of wood chips in the system can significantly improve the system efficiency for nitrogen removal. Between the two configurations of layered and distributed wood chips, configurations of distributed wood chips reach higher COD, phosphorus and nitrogen pollutants removal efficiencies since they can reduce the release of wood chips dissolution.

Kinetics on degradation efficiency of medroxyprogesterone (MPA) by ozonation was investigated in this paper. And the operating parameters such as MPA initial concentration, ozone dosage, pH and radicals scavenger (HCO3-) were further discussed. Results showed that MPA could be degraded effectively by ozonation, with a first-order kinetics in continuous ozone aeration system and a second-order kinetics in semibatch ozone aeration system, when the initial concentrations of MPA were 3, 5, 10 mg x L(-1). The increases of pH and the addition of HCO3- would bring negative effects to the degradation of MPA. The degradation efficiency of MPA decreased from 89.8% to 54.8% with pH increase from 3.10 to 9.02, and the rate constant k decreased from 0.1463 L x (mg x min)(-1) to 0.049 5 L x (mg x min)(-1) and the degradation efficiency decreased 22.2 percentage points with the addition of HCO3-, in semibatch aeration system.

A runoff retention and filtration pilot system was designed and the long-term purification effect of the runoff was monitored. Runoff pollution characters in 2 typical events and treatment effect of the pilot system were analyzed. The results showed that the runoff was severely polluted. Event mean concentrations (EMCs) of SS, COD, TN and TP in the runoff were 361, 135, 7.88 and 0.62 mg/L respectively. The runoff formed by long rain presented an obvious first flush effect. The first 25% flow contributed more than 50% of the total pollutants loading of SS, TP, DTP and PO4(3-). The pilot system could reduce 100% of the non-point source pollution if the volume of the runoff was less than the retention tank. Otherwise the overflow will be purification by the filtration pilot system and the removal rates of SS, COD, TN, TP, DTP and PO4(3-) reached 97.4% , 61.8%, 22.6%, 85.1%, 72.1%, and 85.2% respectively. The system was stable and the removal rate of SS, COD, TN, and TP were 98.6%, 65.4%, 55.1% and 92.6%. The whole system could effectively remove the non-point source pollution caused by runoff.

Degradation of algal toxin Microcystin-RR (MC-RR) by ozonation processes was investigated. The degradation rate of MC-RR reached 83.0% at ozone/MC-RR dosage of 6, and the degradation efficiency was decreased with increase of pH or NOM contents. Ozonation byproducts of MC-RR under different ozone dosages were detected by HPLC-MS to elucidate degradation mechanisms and pathways. The results showed that MC-RR degradation by attacking of ozone and hydrogen radicals mainly involved in substitution and cleavage of the Adda conjugated diene structure, cleavage of the peptide bond between Mdha and Ala. And Adda degradation pathway exerted a dominant position during the process.

Degradation and byproducts of microcystin-LR (MC-LR) under different ozone dosages were investigated, and, the pathway and mechanism for the degradation of MC-LR were also elucidated according to the molecular weight of 8 degradation byproducts during ozonation process in this paper. The results showed that there were two pathways for the degradation of MC-LR by ozone. The first one is that the diene structure in Adda side chain was attacked and cleaved, which was named as Adda degradation pathway. The second one is that the pathway of Mdha and Ala degradation, which was that the peptide bond between Mdha and Ala was attacked and cleaved. Adda degradation pathway was dominant and mainly responsible for the degradation of MC-LR byozone. The removal of MC-LR by ozone could reach 92% when O3:MC is 6.

Ozonation was applied to investigate the removal efficiency of 6 odorous organic compounds in eutrophic water from Taihu Lake (Wuxi). The results showed that the ozonation process could be described by first order kinetic model and the overall kinetic rates of the odorous compounds were determined by their chemical characteristic and structure, which could be ranked: beta-Ionone (3.3 x 10(-3) s(-1)) > beta-Cyclocitral (2.8 x 10(-3) s(-1)) > 2,4-Decadienal (2.7 x 10(-3) s(-1)) > Neryl Acetone (2.2 x 10(-3) s(-1)) > Geosmin (1.4 x 10(-3) s(-1)) > 2-Methylisoborneol (5.6 x 10(-4) s(-1)). Ozonation of eutrophic water led to the formation of a series of aldehydes, ketones, alcohols and esters. The influence of bicarbonate and natural organic carbon on odorous compounds ozonation were further investigated, results showed that the bicarbonate could restrain the effect of ozonation by cutting down the radical pathway and natural organic carbon in the water by competition with target compounds.