Full-scale application of heterogeneous photocatalysis for industrial wastewater treatment remains a challenge because of the complex nature of these matrices and the potential to form toxic by-products during treatment. A recent unsuccessful attempt to find adequate conditions for TiO₂/UV treatment of a cotton dyeing textile mill led to this study on the treatability of mixtures of the dyes used in the greatest amounts at the mill and therefore most likely to be present in mill effluent. Four reactive and three vat dyes were mixed in different combinations and treated (10 mg/L of each dye, 0.5 mg/L TiO₂, pH 4) to evaluate the influence of the different dyes on ADMI color, chemical oxygen demand (COD), and acute toxicity. While ADMI color removal was similar in all dye mixtures, COD removal was higher when vat dyes were absent. When treated individually, vat dyes exhibited greater recalcitrance, with no ADMI color removal and COD removals of less than 30%. Toxicity to Daphnia similis was decreased or eliminated from dye mixtures that exhibited the highest COD removals and corresponded to those in which reactive dyes were partially degraded. For raw textile mill effluent, photocatalysis reduced but did not eliminate treated effluent toxicity (EC50 = 26.8%).

The air pollution problem in Xingtai and Handan is the focus of public attention. The seasonal gray model with fractional order accumulation is proposed to predict the quarterly concentrations of PM₂.₅, PM₁₀, NO₂, and CO in Xingtai and Handan. The new model has higher forecasting performance and can describe the characteristics of seasonal fluctuation very well. The forecasting results indicated that except for the PM₁₀ in Xingtai that will increase slowly, the other indicators in the two places will decrease. The changes of the air quality indicator concentration in different quarters are obvious, and in the same quarter tend to be stable. Except for CO and NO₂ in some seasons, other indicators are in the state of exceeding the standard. The effect of air pollution control is not good. The governance needs to be further strengthened.

Soil washing is an effective technology for the remediation of soils contaminated with various metals. However, the bioavailability of residual metals in soils and soil properties can be changed during the washing processes. In this study, we used four amendments to revitalize mixed chelator (MC)–washed soils (WS). These amendments included zeolite, CaCO₃, biochar, and chicken manure. Results showed that inorganic amendments reduced the available Cd and Zn concentrations, while organic amendments, particularly chicken manure, reduced the Pb bioavailability in WS. The combination of 0.2% CaCO₃ and 2% chicken manure amendments reduced the Cd, Pb, and Zn bioavailability by 45.8%, 77.8%, and 15.0% compared with the control treatment, respectively. The inorganic amendments should increase the seed germination rate of Chinese cabbage (Brassica rapa L.). However, the shoot growth decreased significantly. The combination of amendments cannot increase the seed germination but can significantly increase the shoot growth of Chinese cabbage compared with the control. The combination of amendments enhanced the fertility of WS, particularly available P and exchangeable K, which may improve plant growth. These results suggested that the combination of amendments, especially CaCO₃ (0.2%) and chicken manure (2%), can be used to revitalize MC-WS.

An in situ horizontal well (IHW) fan-shaped test tank was constructed in the laboratory. And nitrate removal rates were analyzed under different hydraulic loads. When the initial concentration of groundwater nitrate-N was 25 mg/L and the hydraulic load increased from 0.78 to 3.90 m³/(m² day), the results show that the nitrate-N concentration was less than 1.25 mg/L after the denitrification process stabilized. Additionally, the nitrate-N removal rate was over 95%. The concentration of nitrite-N was still below 1 mg/L, and the level of ammonia-N was between 0.5 and 1.00 mg/L. No increase in nitrite-N and ammonia-N concentration occurred during the test. The hydraulic conductivity of the medium in the horizontal well showed little variation, ranging from 34.09 to 31.64 m/day, indicating that there was no blockage caused by microbial growth in the IHW during the test. In addition, no ethanol was detected in the test tank except for the horizontal well, revealing that ethanol did not diffuse into the surrounding aquifer. Therefore, when the concentration of groundwater nitrate contamination is 25 mg/L, the hydraulic load under the IHW test tank condition is 3.90 m³/(m² day). The IHW test tank had a stable and good biological denitrification effect, and it can provide certain reference significance for in situ remediation of nitrate-contaminated groundwater.

The present work aimed to evaluate the effects of commercial fungicides containing the active compounds from the triazole group—tebuconazole (TBZ) and difenoconazole (DFZ)—and dicarboximide group—procymidone (PRD) and iprodione (IPD) on the mitotic cycle of the plant model Lactuca sativa L. These active compounds have been present in foods sampled at different Brazilian’s states and amounted higher than recommended by law. The bioassay with L. sativa was applied to access the toxicity and better understand the mechanisms of action of these compounds in living beings. The active principles IPD and DFZ presented mitodepressive effect, statistically reducing the MI at all applied concentrations in comparison to the negative control. TBZ was the most cytotoxic active compound tested inhibited in 77% mitotic active in the lowest concentration applied. PRD alter the frequency of mitotic cells only in the concentration above that recommended by the manufacture. C-metaphase and adherent chromosomes were the most frequent cell cycle alteration observed on the treated cells, followed by bridges and lost chromosomes. Therefore, the mechanism of action was mainly aneugenic (70%). For TBZ, the frequency of condensed nucleus was very expressive (313 higher than the negative control).

The ozonation process is efficient in degrading aromatic substances and substances with unsaturated bonds, but cannot effectively destroy small-molecule organic compounds, which accumulate. Likewise, the Fenton process is a classic wastewater treatment method, but requires strict pH control and produces secondary pollution when the concentration of organic substances is high. In this study, we applied a 1stO₃-2ndFenton sequential process to treat diazodinitrophenol (DDNP) industrial wastewater and provide suitable reaction conditions for Fenton process. For the 1stOzone process, organics removal increased as O₃ dosage increased. At optimized operation, the 1stO₃ process provided an acidic effluent (pH = 3) and reduced the organics concentration to a level suitable for the 2ndFenton process. Benzene ring substances as well as nitro group and diazo group compounds were greatly degraded in the 1stO₃ process and were further mineralized in the 2ndFenton process. Additionally, the biodegradability of DDNP industrial wastewater was greatly improved. This is the first reported time that ozonation and the Fenton process have been integrated sequentially to treat an explosive production wastewater. The study provides a feasible chemical oxidation method for treating DDNP industrial wastewater by simply combining two classic treatment processes.

The field experiment of a rice–wheat rotation system was conducted on a coastal reclaimed farmland with different application rates of biogas slurry from a large-scale standardized hoggery. Crop yield, grain quality, and soil properties were examined to determine the appropriate application rate. At the slurry application rates of 480 m³ ha⁻¹ for rice and 9.00–11.25 m³ ha⁻¹ for wheat, grain yields of rice and wheat were 8.9 and 15.7% higher than those under conventional fertilization, respectively. When 840 m³ ha⁻¹ biogas slurry was applied to the rice field, the grain amino acid content was significantly higher than that of conventionally fertilized rice. In the rice–wheat rotation system, under biogas slurry treatments, soil pH and EC did not significantly increase; the contents of soil Pb, Cr, Cu, and Zn were within allowable limits; the contents of soil alkali-hydrolyzable nitrogen were greatly increased and significantly higher than those under conventional fertilization treatment; and the content of soil organic matter had no significant difference with that under no fertilization treatment. Therefore, the recommended application rate of biogas slurry on coastal reclaimed farmland should be 480 and 9.00–11.25 m³ ha⁻¹ for rice and wheat, respectively.

Reverse osmosis (RO) technique plays an important role in the treatment of secondary biochemical effluent. However, the reverse osmosis concentrate (ROC) with high salinity and organic pollutants generated from this process remains a challenge to be tackled. The O₃-assisted UV-Fenton advanced oxidation process (AOP) as a pretreatment for the nanofiltration (NF) was used to treat the ROC of industrial wastewater. The optimal removal rates of COD and UV₂₅₄ were 80.4 and 77.4%, respectively. In the NF process, four types of commercial NF membranes (NF90 (Dow, USA), DK (GE, USA), NT101, and NT103 (NADIR, Germany)) were used to treat the AOP effluent. The effects of operating pressure and feed temperature on ion rejection were investigated. The results show that NF90 and NT103 membranes had better rejections to monovalent ions, while DK and NT101 membranes could effectively separate monovalent and divalent ions and their ion rejections decreased with the increase of feed temperature. With the NF90 membrane, the highest TDS removal rate of 89.65% was obtained at the operating pressure of 1.2 MPa.

Adsorption plays an important role in removing cadmium (Cd²⁺) from water, and magnetic adsorbents are increasingly being used due to their ease of separation and recovery. Magnetic Fe₃O₄–coated hydroxyapatite (HAP) nanoparticles (nHAP-Fe₃O₄) were developed by co-precipitation and then used for the removal of Cd²⁺ from water. The properties of these nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and magnetization curves. Experiments were conducted to investigate the effects of adsorption and mechanisms. Results illustrated that kinetic data were well fitted by a pseudo-second-order model. The adsorption capacity of nHAP-Fe₃O₄ was 62.14 mg/g. The mechanisms for the adsorption of Cd²⁺ on nHAP-Fe₃O₄ included rapid surface adsorption, intraparticle diffusion, and internal particle bonding, with the ion exchange with Ca²⁺ and chemical complexation being the most dominant. The regeneration efficiency and recovery rate of nHAP-Fe₃O₄ eluted by EDTA-Na₂ after the fifth cycle were 63.04% and 40.2%, respectively. Results revealed that the feasibility of nHAP-Fe₃O₄ as an adsorbent of Cd²⁺ and its environmental friendliness make it an ideal focus for future research.

For a long-period comparative analysis of air pollution in coastal and inland cities, we analyzed the continuous Morlet wavelet transform on the time series of a 5274-day air pollution index in Shanghai and Lanzhou during 15 years and studied the multi-scale variation characteristic, main cycle, and impact factor of the air pollution time series. The analysis showed that (1) air pollution in the two cities was non-stationary and nonlinear, had multiple timescales, and exhibited the characteristics of high in winter and spring and low in summer and autumn. (2) The monthly variation in air pollution in Shanghai was not significant, whereas the seasonal variation of air pollution in Lanzhou was obvious. (3) Air pollution in Shanghai showed an ascending tendency, whereas that in Lanzhou presented a descending tendency. Overall, air pollution in Lanzhou was higher than that in Shanghai, but the situation has reversed since 2015. (4) The primary cycles of air pollution in these two cities were close, but the secondary cycles were significantly different. The aforementioned differences were mainly due to the impact of topographical and meteorological factors in Lanzhou, the weather process and the surrounding environment in Shanghai. These conclusions have reference significance for Shanghai and Lanzhou to control air pollution. The multi-timescale variation and local features of the wavelet analysis method used in this study can be applied to varied aspects of air pollution analysis. The identification of cycle characteristics and the monitoring, forecasting, and controlling of air pollution can yield valuable reference.