Outbreak of blue-green algae posesa threat todrinking water safety. Coagulation is a key technology for algae removal in waterworks, andiron salt is one of the most commonly used coagulants. To further explore the mechanism of iron salt for removing algae, Microcystis aeruginosa and algal organic matters were selected as the target pollutants. The effect of crystal transformation of the main hydrolysis products on removal efficiency and coagulation process was investigated. The results indicated thatthe transformationof crystalline state, crystalline phase, and crystal form of hydrolysis products were mainly affected by the coagulant dosage and pH value. With the increase of dosage and pH, the main hydrolysis product FeO(OH) was replaced by amorphous Fe(OH)₃(PDF#22-0346), and then converted to Fe₃O₄. Amorphous Fe(OH)₃ finally transformed into quasicrystalFe (OH)₃(PDF#38-0032). The surface characteristics of algal flocs were affected by the crystalline state and crystal form change of hydrolysis products. The maximum S_BET and V_t values of algal flocs were observed at a dosage of 0.7mmolFe/L, which werebeneficial to adsorb algal organic matters andresulted in the optimal treatment efficiency. Within the range of 0.1~0.5mmolFe/L, the crystal transformation of the main hydrolysis products had a more significant effect on algae removal efficiency, particle size and growth rate of algal flocs.

This study investigated the impacts of pipeline environmental factors (hydraulic shear force, temperature, darkness/light conditions, pipe materials) and continuous flow conditions on odor production characteristics of three typical odor-producing algae: Microcystis aeruginosa, Pseudanabaena galeata, and Oscillatoria. Key findings revealed that hydraulic shear force significantly promoted 2-MIB release in chain-forming Pseudanabaena galeata and filamentous Oscillatoria, with rupture rates exceeding 90% under high shear conditions. In contrast, spherical Microcystis aeruginosa exhibited structural tolerance with rupture rates below 30%. Temperature markedly influenced β-cyclocitral production in Microcystis aeruginosa, reaching 40ng/L at 30℃. Although low temperature induced cell rupture, it suppressed metabolic activity, resulting in lower odorant concentrations. Darkness and pipe materials showed limited effects, only slightly increasing rupture rates (<5%) and odorant concentrations (<8ng/L). Continuous flow experiments demonstrated accelerated 2-MIB release in Pseudanabaena galeata and Oscillatoria under high flow velocity, achieving peak concentrations (up to 85ng/L) within 0.5hours-significantly faster than batch experiments. The study identifies hydraulic shear force and temperature as primary control factors for odor production, providing scientific guidance for odor management in water distribution systems.

The release of iron in drinking water distribution systems (DWDSs) poses a severe threat to water supply safety. By establishing a static simulation experimental system to systematically investigate the coupled effects of fulvic acid (FA), sulfate ions (SO₄^2-), and alkalinity (Alk) on iron release in DWDSs and the changes of pipe scale micromorphology, crystalline composition, and elemental speciation. Based on principal component analysis (PCA), a prediction model for iron release was developed, quantitatively characterizing the relative importance of various influencing factors and their interaction intensities. Results showed that under conditions of FA=4mg/L, SO₄^2-=240mg/L, and Alk =100mg/L CaCO₃, iron release reached the maximum of 4.82 and 3.60mg/L for steel and cast iron pipes, respectively. SO₄^2- and FA were positively correlated with iron release, while alkalinity showed negative correlations. The relative influences of these factors followed the order: alkalinity > SO₄^2- > FA.

Graphene oxide-chitosan (GO-CS) composite materials were prepared using the hydrothermal method, and a single-stage autotrophic nitrogen removal reactor was constructed for continuous experiment. Batch experiments were conducted to evaluate its concentration-response characteristics, and molecular biology method was applied to elucidate the succession patterns of microbial communities. The effect of GO-CS addition on the performance of single-stage autotrophic nitrogen removal was systematically investigated. The results showed that 20mg/L GO-CS promoted anaerobic ammonium oxidation by facilitating electron transfer; at a concentration of 50mg/L, the activity of AnAOB was inhibited which might be there were other reactions which competing for the use of GO-CS as an electron transfer; and after long-term exposure to 100mg/L GO-CS, AnAOB achieved adaptive recovery by increasing the secretion of extracellular polymeric substances (EPS) and regulating functional genes.

In order to improve the water pollution control level in the basin and solve the shortcomings of existing optimization emission reduction technologies, a data driven theory-based optimization emission reduction model for river pollution was developed with the combination of Bidirectional Long and Short Memory Network (Bi-LSTM) algorithm and Bayesian Optimization (BO) algorithm considering the receiving water body as the research object. The developed optimization emission reduction model was then applied to Songhua River basin from Baidu Town and Sandao to Hongkeli section. The results show that the Bi-LSTM algorithm can effectively train the spatial neural network architecture, and improve the study accuracy of water quality spatial relationship. The reduction rates of TN in Baidu Town and Sandao are [14.12%, 38.84%] and [15.01%, 38.98%], respectively, and TP hardly needs to be reduced under the water quality standard III. While the reduction rates of TN and TP in Baidu Town are [19.08%, 39.72%] and [0.00%, 41.93%], and the ones in Sandao are [18.43%, 40.09%] and [0.00%, 36.24%], respectively under the water quality standard II. The optimal reduction strategies can be obtained by the developed optimization emission reduction model under different reduction scenarios to provide decision support for accurate reduction and intelligent control of river pollution.

The accuracy of particulate organic matter (POM) detection in sewage was established as the fundamental basis for the systematic characterization of water pollution features. A multi-dimensional synergistic pretreatment system was developed, through which efficient fragmentation and solubilization of POM were achieved by coupled energy field interactions—alkaline hydrolysis (chemical energy), thermal treatment (thermal energy), and ultrasonic cavitation (mechanical energy). This integrated approach was found to enhance sample homogeneity, thereby optimizing spectroscopic detection outcomes. Based on single-factor experimental results, Box-Behnken response surface methodology (RSM) was employed to conduct multi-parameter collaborative optimization of critical control parameters (pH, temperature, and ultrasonic energy) in the composite pretreatment process. The results indicated that: significant differential impacts of the treatments on POM disruption efficiency were observed. Ultrasonic treatment contributed more to TCOD detection accuracy (A_COD was improved from 60.8%±14.9% to 93.3%±3.7%) and total carbohydrate (TCHO) detection accuracy (A_CHO was increased from 59.1%±9.6% to 97.9%±2.8%), while alkaline treatment showed superior optimization effects on total protein (TPN) detection accuracy (A_PN was enhanced from 32.7%±9.7% to 82.7%±3.9%); Optimal process parameters were obtained through RSM model optimization: pH=13.3, T=66.5℃, t=5min, under which enhanced detection accuracies of 96.1% for TCOD, 98.7% for TPN, and 97.5% for TCHO were achieved. The synergistic pretreatment method was demonstrated to have broad applicability across various wastewater scenarios, including primary pipeline sewage, influent of wastewater treatment plants, and effluent from biochemical reactors, effectively reducing detection duration while maintaining robust universality.

A one-year study was carried out to investigate the changes in water quality parameters such as water temperature, residual chlorine, turbidity, pH, UV₂₅₄, dissolved organic carbon (DOC) and trihalomethanes(THMs) along the main pipe of a regional water supply system in Suzhou (2km sampling interval). The results of spatial scale analysis showed that the concentration of THMs at the end of the water supply pipe network at 8~10km was at a relatively high level; the results of time scale analysis showed that the concentration of THMs at the end of the water supply pipe network reaches the highest peak in June, with the concentration of 39.06μg/L. Four typical machine learning algorithms were selected to construct the prediction model of THMs in the pipe network, and the interpretable gradient boosting tree (GBDT) algorithm was able to effectively avoid model overfitting, and the R² of the four THMs prediction accuracies reached 0.839, 0.906, 0.836, and 0.935, respectively. The further application of Shapley's additional explanation (SHAP) to the global analysis of the GBDT model revealed that the water temperature, UV₂₅₄, DOC, and the distance of the water supply were positively correlated with the generation of THMs, while the residual chlorine showed a significant negative correlation with the THMs. The local analysis of SHAP showed that residual chlorine concentration in the water supply network lower than 0.45, 0.55 and 0.55mg/L can significantly reduce the influence weights of residual chlorine on TCM, BDCM and DBCM. Based on the data-driven model constructed in this study, the generation concentration of THMs can be efficiently predicted by environmental factors, and the residual chlorine dosage can be controlled in real time to prevent the over-generation of THMs in summer or at the end of the pipe network.

This paper reviewed current pollution situation of used and waste textile. the global trade of used and waste textiles was analyzed based on the United Nations Comtrade Database. The problems faced in China in this field were analyzed by tracking the management of used and waste textiles in the international community and typical countries, and in combination with China's used and waste textile policies and recycling practices. China didn't effectively distinguish between "waste" and "used" textiles, lacked authoritative data on the generation, encountered numerous obstacles in industrial development, and there were disputes over the export of second-hand clothing. It was suggested that China's used and waste textile management should distinguish between "waste" and "used" textiles from the source, improve the data statistics system to separately count their relevant data, cultivate enterprises with long industrial chains to unblock industrial channels, track international trends and implement export restrictions in a timely manner.

This paper focuses on the problems of landfill gas leakage and the difficulty in controlling malodorous gases during the landfilled waste excavation. A field trial was conducted on a 30m×30m site in a Hainan landfill, equipped with 13injection, 12 extraction, and 16 monitoring wells. An intensive aeration pretreatment experiment was conducted with a gas injection flow rate of 340m³/h and a gas extraction flow rate of 360m³/h to explore the control effects of aerobic intensive aeration on methane and malodorous gases. The results indicate that within 2h of the first intensive aeration, the ambient landfill gas was rapidly displaced, with the oxygen content in the test area exceeding to above 17%, the average methane content decreasing to 1.9%, and the average hydrogen sulfide content decreasing from 21.3mg/m³ to 5.7mg/m³. In contrast, ammonia levels rose sharply to 286.7mg/m³, which is attributed to the stripping of pore leachate by aeration-induced disturbance. Prolonging the aeration duration was found to be crucial for suppressing the rebound of methane and hydrogen sulfide after aeration ceased. After the first 9-day aeration test, methane concentrations at depths of 4.5m and 8.5m were reduced to 0.33% and 0.61%, with hydrogen sulfide inhibition rates of 81.0% and 83.9%, respectively. However, within 8hours of stopping aeration, methane levels rebounded to above 4% and 6%, and inhibition rates for hydrogen sulfide dropped to 65.6% and 74.1%. In contrast, after the second 30-day aeration test, methane concentrations remained below 3%, and hydrogen sulfide inhibition rates were maintained at 81% and 91%, even 48 hours post-aeration. It was estimated that the two trials cumulatively removed approximately 5779.6 mol of ammonia, accounting for 45% of the total ammonia nitrogen in the pore leachate of the test area. The study demonstrates that appropriate short-term, high-intensity aeration pretreatment can effectively inhibit odorous gas emissions during the subsequent excavation of landfill mass.

A combined conditioning system using NaClO as the oxidizing agent was employed to condition sludge. The variations in sludge dewatering performance before and after conditioning were investigated to validate the enhancing effect of ultraviolet irradiation on the advanced oxidation process. Meanwhile, the reasons for the deterioration in dewatering performance were discussed when NaClO was added alone. The effects of dosage ratios (NaClO/FeSO₄), Fe²⁺ dosage, and pH value on sludge dewatering performance were investigated using the capillary suction time (CST) and specific resistance to filtration (SRF) as key evaluation indicators. The results demonstrated that the ultraviolet irradiation activated a higher concentration of strong oxidative free radicals based on the activation of Fe²⁺ towards NaClO, thereby promoting the decomposition of EPS. With the addition of UV irradiation, the CST reduction rate increased from 61.5% to 65.4%, while the SRF reduction rate increased from 71.4% to 79.8%. During the experiment, the TB-EPS of the sludge were converted into the LB-EPS of the sludge. As a result of this conversion, the decomposition and oxidation of protein played a crucial role in enhancing sludge dewaterability. Analysis revealed that the deterioration in dewatering when NaClO was added alone was attributable to the insufficient oxidation capacity within the system and the excessive formation of bubbles during the conditioning process.