A biofilm reactor was designed with flat ceramic substrates to remove Co(II), Ni(II) and Zn(II) from industrial wastewater. The ceramics were made of clay and nano-rubber with high mechanical resistance. The surface of the ceramic substrate was modified with neutral fiber and nano-hydroxyapatite. A uniform and stable biofilm mass of 320 g with 2 mm of thickness was produced on the modified ceramic after 3 d. The micro-organisms were identified in the biofilm by polymerase chain reaction (PCR) method. Functional groups of biofilms were identified with a Fourier transform infrared spectrometer (FT-IR). Experiments were designed by central composite design (CCD) using the responsive surface method (RSM). The biosorption process was optimized at pH = 5.8, temperature = 22 °C, feed flux of heavy metal wastewater = 225 ml, substrate flow = 30 ml, and retention time = 7.825 h. The kinetic data was analyzed by pseudo first-order and pseudo second-order kinetic models. Isotherm models and thermodynamic parameters were applied to describe the biosorption equilibrium data of the metal ions on the biofilm-ceramic. The maximum biosorption efficiency and capacity of heavy metal ions were about 72% and 57.21 mg, respectively.

Plastic film mulching and use of wastewaters for irrigation have been common agricultural practices for over half a century in Tunisia, especially in arid regions, resulting in the undesired creation of a pathway for microplastics (MPs) to enter farmland soil. In order to assess the extent and characteristics of soil contamination by MPs in the Moknine province, an area of intensive agricultural practices, 16 farmland soil samples were collected and characterized. The total concentration of targeted MPs was 50–880 items/kg; among them, the most common MPs type being polypropylene (PP), mainly occurring as white/transparent fibers with small size (cross section <0.3 mm). SEM images of MPs surfaces revealed multiple features related to environmental exposure and degradation. ATR-FTIR spectroscopy and pyrolysis-GC/MS analyses enabled the accurate identification of MPs separated from the embedding soil micro- and macro-aggregates. Finally, contamination of the polymeric microparticles with a broad range of metals was found by ICP-MS analysis, suggesting that MPs can be vectors for transporting heavy metals in the soil and indicators of soil contamination as a result of mismanagement of industrial wastewaters.

Coastal water quality in China has been impacted by direct discharge of industrial wastewater, and various kinds of AOX pollutants have been detected in the seawater and sediment. As the dominant pollution source of Hangzhou Bay, a typical fine chemical industry park “HSEDA” was selected as the study area in this research. The AOX in both wastewater and sludge phases from 22 large-scaled enterprises were simultaneously investigated. The results quantitatively illustrated the AOX flows from engineered wastewater and sludge treatment systems to natural environment. It can be seen that industrial enterprises discharged at least 160 t AOX every year, and about 105.4 t/a AOX eventually entered the natural environment. The dye manufacturing industry, which accounted for more than 60% of the total AOX emission load in HSEDA, was identified as the AOX pollution-intensive sector. The occurrence, characteristic pollutants and fate of AOX in dye wastewater were discussed, on the basis of which the improvements of cleaner production and wastewater treatment technologies have been put forward.

The real-time textile dyes wastewater contains hazardous and recalcitrant chemicals that are difficult to degrade by conventional methods. Such pollutants, when released without proper treatment into the environment, impact water quality and usage. Hence, the textile dye effluent is considered a severe environmental pollutant. It contains mixed contaminants like dyes, sodium bicarbonate, acetic acid. The physico-chemical treatment of these wastewaters produces a large amount of sludge and costly. Acceptance of technology by the industry mandates that it should be efficient, cost-effective and the treated water is safe for reuse. A sequential anaerobic-aerobic plant-microbe system with acclimatized microorganisms and vetiver plants, was evaluated at a pilot-scale on-site. At the end of the sequential process, decolorization and total aromatic amine (TAA) removal were 78.8% and 69.2% respectively. Analysis of the treated water at various stages using Fourier Transform Infrared (FTIR), High Performance Liquid Chromatography (HPLC)) Gas Chromatography-Mass Spectrometry (GC-MS) Liquid Chromatography-Mass Spectrometry (LC-MS) indicated that the dyes were decolourized and the aromatic amine intermediates formed were degraded to give aliphatic compounds. Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM) analysis showed interaction of microbe with the roots of vetiver plants. Toxicity analysis with zebrafish indicated the removal of toxins and teratogens.

Enormous wastewater discharges have significantly impeded the sustainable development. As several economic belt has been formed in China, systematic analysis of multi-regional wastewater metabolic system is required for advancing wastewater mitigation effectively and efficiently. In this study, a distributive environmental input-output model (DEIO) is developed for the Yangtze River Economic Belt (YREB) to provide bases for supporting sustainable development from inter-regional and inter-sectoral perspectives. The discharges and flows of wastewater and related pollutants (i.e., chemical oxygen demand (COD) and ammonia nitrogen (AN)) among sectors and regions are analyzed to providing solid bases for wastewater management within the YREB. The results show that the industrial wastewater mitigation in YREB is desired urgently. The industrial wastewater discharges in Jiangsu and Zhejiang provinces are numerous, while Hunan and Yunnan provinces are more inclined to suffer from serious COD and AN pollution. In addition, the manufacture of food, tobacco, chemical materials, and pharmaceutical are the typical sectors with a large amount of direct wastewater discharge, and the tertiary industry is ranked at the first in indirect wastewater discharge. According to the analysis, the implementation of the “Supply-side Structure Reform” and the “Replace Subsidies with Rewards” policy can benefit the wastewater mitigation in the YREB.

The accidental leakage of industrial wastewater containing heavy metals from enterprises poses great risks to resident health, social instability, and ecological safety. During 2005–2018, heavy metal mixed pollution accidents comprised approximately 33% of the major environmental ones in China. A Bayesian Networks-based probabilistic approach is developed to quantitatively predict ecological and human health risks for heavy metal mixed pollution accidents at the watershed scale. To estimate the probability distributions of joint ecological exposure once a heavy metal mixed pollution accident occurs, a Copula-based joint exposure calculation method, comprised of a hydro-dynamic model, emergent heavy metal pollution transport model, and the Copula functions, is embedded. This approach was applied to the risk assessment of acute Cr⁶⁺-Hg²⁺ mixed pollution accidents at 76 electroplating enterprises in 24 risk sub-watersheds of the Dongjiang River downstream watershed. The results indicated that nine sub-watersheds created high ecological risks, while only five created high human health risks. In addition, the ecological and human health risk levels were highest in the tributary (the Xizhijiang River), while the ecological risk was more critical in the river network, and the human health risk was more serious in the mainstream of the Dongjiang River. The quantitative risk assessment provides a substantial support to incident prevention and control, risk management, as well as regulatory decision making for electroplating enterprises.

The present study is the first comprehensive monitoring of 13 selected endocrine disrupting compounds (EDCs) in untreated urban and industrial wastewater in Serbia to assess their impact on the Danube River basin and associated freshwaters used as sources for drinking water production in the area. Results showed that natural and synthetic estrogens were present in surface and wastewater at concentrations ranging from 0.1 to 64.8 ng L⁻¹. Nevertheless, they were not detected in drinking water. For alkylphenols concentrations ranged from 1.1 to 78.3 ng L⁻¹ in wastewater and from 0.1 to 37.2 ng L⁻¹ in surface water, while in drinking water concentrations varied from 0.4 to 7.9 ng L⁻¹. Bisphenol A (BPA) was the most abundant compound in all water types, with frequencies of detection ranging from 57% in drinking water, to 70% in surface and 84% in wastewater. Potential environmental risks were characterized by calculating the risk quotients (RQs) and the estrogenic activity of EDCs in waste, surface and drinking water samples, as an indicator of their potential detrimental effects. RQ values of estrone (E1) and estradiol (E2) were the highest, exceeding the threshold value of 1 in 60% of wastewater samples, while in surface water E1 displayed potential risks in only two samples. Total estrogenic activity (EEQₜ) surpassed the threshold of 1 ng E2 L⁻¹ in about 67% of wastewater samples, and in 3 surface water samples. In drinking water, EEQₜ was below 1 ng L⁻¹ in all samples.

Tungstate enrichment in aquatic systems may cause negative environmental and health effects. This study addresses tungstate removal from aqueous solution by nanocrystalline iowaite, an iron-bearing layered double hydroxide, which has not been used for treatment of tungstate-rich waters so far. Tungstate sorption experiments were conducted with various contact times, temperatures, initial tungstate concentrations (0.001–2 mM), and solution pH values (2–13), the results indicating that iowaite sorbed aqueous tungstate effectively and quickly, and the sorption maximum can be up to 71.9 mg/g. Moreover, the tungsten sorption capacity keeps nearly constant at a wide pH range from 3 to 11. Duo to its pH buffering effect, the alkaline conditions were generated by the addition of iowaite, which are favorable for the removal of aqueous tungstate because the polymerization of tungstate can be prohibited at alkaline pH values. Zeta potential, XRD and XPS analyses were employed to clarify the sorption mechanisms, and it was concluded that tungstate was sorbed via its exchange with the chloride originally intercalated into iowaite interlayers as well as its stronger inner-sphere complexation with the Fe atoms located in iowaite layers. Nanocrystalline iowaite is suitable for treating both tungstate-bearing natural waters with moderately high tungstate concentrations and industrial wastewaters extremely rich in tungstate.