Water Resources and Industry最新文献

This review evaluates selected advanced oxidation processes (AOPs) - cavitation and photocatalysis - successfully used for wastewater treatment towards degradation of Rhodamine (Rh) dyes. Reactor configuration and impact of process parameters and oxidants addition (hydrogen peroxide, ozone, persulfates) on degradation effectiveness along with degradation mechanisms are discussed. Best technologies provide 100% degradation within 10–30 min. Rhodamine B is effectively degraded in highly acidic conditions (pH 2), while Rhodamine 6G requires basic conditions (pH 10). The most effective oxidants were hydrogen peroxide and ozone. Ecological Structure Activity Relationships (ECOSAR) revealed acute toxicities of the intermediates and by-products of the Rh dye.

Due to the structural similarities, sunflower seed husk (SSH), an agricultural, low-cost, and eco-friendly waste, is employed interchangeably with zeolite to extract Ni (II) ions from model and real industrial wastewater in this work. Batch experiment adsorption was carried out to investigate the possibility of Ni (II) ion removal by adsorbents. Zeolite powder and SSH were used in three different sizes and without any modifications to optimize the effect of adsorbent size. The maximum adsorption rate of 76% for the bulk size of SSH was obtained at pH 6.5, 20 g/L of adsoadsorbent, an initial concentration of ions of 20 mg/L, and 2 h of contact time. Thermodynamic results showed that the process is spontaneous, feasible, and exothermic within the set temperature range (10°C-80 °C). It can be concluded from the results that SSH can be used as a feasible, eco-friendly, and biodegradable organic material for Ni ion adsorption.

Hydrazine has been largely replaced by carbohydrazide (CHZ) as an oxygen scavenger due to safety and health concerns and CHZ is now used in Saline Water Conversion Corporation (SWCC) high pressure boilers. However, the operational problem of phosphate hide-out has become a continuous challenge for the plant operators. Advances in boiler water treatment have shown that effective corrosion control and prevention of scaling can be achieved by using a mixture of film-forming and alkalizing amines and polycarboxylates [Film Forming Amine Product (FFAP)]. With the use of FFAP, carbohydrazide/ammonia treatment of make-up water and phosphate treatment in the drum will not be required. A uniform FFAP formulation was used throughout the test.

The evaluation study was carried out at a boiler of the Yanbu Phase 1 Desalination and Power Plant (Mitsubishi) generating 60 MWh, with make-up water of 15 t h⁻¹ producing 330 t h⁻¹ steam at a pressure of 67 barg and temperature of 480 °C.

The trial provided evidence that FFAP was a good alternative to use of an oxygen scavenger. Changeover from CHZ to FFAP without phosphate addition in the drum was done initially by dosing FFAP from both hydrazine tank and phosphate tank so that pH was maintained to the required values in both feed water and drum water. With the optimal dose rate (0.6 ppm) maintaining FFAP in the range of 0.3–1.0 ppm in feed water, all the key parameters (pH, ammonia and specific conductivity) were within the specified boiler design limits. The average corrosion rates on the water side were low for both CHZ and FFAP treatment (0.009 ± 0.001 mm y⁻¹), however FFAP treated coupons showed much lower corrosion rates compared to CHZ in the steam side (0.0006 ± 0.0003 mm y⁻¹ cf. 0.0075 ± 0.0006 mm y⁻¹).

Semiconductor based photocatalysts have been an efficient technology for water and wastewater remediation, addressing the concepts of green chemistry and sustainable development. Owing to narrow and suitable band structure, BiOBr is a promising candidate for efficient wastewater treatment via photocatalysis. Enhancement of photocatalytic properties can be obtained by various techniques like doping, element rich strategy, facet engineering, and defect control. This review primarily focuses on the band engineering of single BiOBr, its binary, ternary composites and their applications in degradation of hazardous pollutants in wastewater. Moreover, current challenges and future perspectives were discussed along with concluding comments.

Sulfate radical AOPs (SR-AOP) were successfully utilized in degradation of antibiotics in water and wastewater treatment. The review discusses details on SR-AOPs mechanisms and applications for antibiotics degradation. The progress in this field was discussed, highlighting the most promising developments and remaining challenges. The applicability of SR-AOPs was summarized revealing the most susceptible and persistent to oxidation groups of pharmaceuticals. Highest effectiveness was reported for degradation of pharmaceuticals on ppb level. Systems revealed a scavenging effect in case of oxidant dose 0.7 mM of the PS and 2 mM of PMS. Future development demands simple persulfates activation systems for real matrix treatment.

The choice of constructed wetlands substrate is a very important issue, there is still a lack of studies that analyse the effect of different types of substrate on the efficiency of the accumulate and translocate contaminants from landfill leachate. Therefore, the objectives of study were to evaluate the effect of substrate on the potential of Phragmites australis to accumulate and translocate selected contaminants from leachate. The lowest translocation was recorded for Fe and Cu, and the highest for K and Ni. Translocation between root and shoots for most parameters (total Kjeldahl nitrogen, total phosphorus, K and Mn) was high (TF > 1.0). However, for Fe, Cu, Cr and Ni translocation was low in most variants (TF < 1.0). Only for Cr there were statistically significant differences between the substrates. The obtained bioaccumulation factor values for Cu, Cr and Ni show that P.australis does not have a good ability to phytoaccumulate heavy metals from leachate.

Agriculture, industry and municipal water supply compete over scarce freshwater. This study calculated sectoral blue water footprints (WFs) in water scarce Pakistan between 1971 and 2020. Agriculture dominates blue WFs, industry contributed 0.5–1.4%, municipal WFs 0.5–1.7%. Manufacture (cloth and yarn) and electricity production (hydropower) dominated blue industrial WFs. Agricultural crop and livestock production tripled using the same amount of blue water, but industrial and municipal WFs increased with increasing production/population, the blue industrial WF by a factor of 3.3, municipal WFs by a factor of 3.6. Pakistan's water scarcity depends on environmental flow requirement (EFR) definitions. Volumetric government definitions generate low water scarcity allocating almost all water to society. Higher EFR's generate moderate to severe scarcity. Efficient agriculture leaves more water for industry and municipal supply, increasing crop output and decreasing sectoral competition. Policy might support improved water infrastructure. Pakistan's lessons are relevant for other water scarce countries.

An alternative chitosan-based adsorbent modified by impregnation with deep eutectic solvent (DES) choline-chloride:urea at a molar ratio 1:2 proved efficient removal of the anthraquinone dye Acid Blue 80 (AB80) from aqueous solutions, and offered enhanced adsorption capacity compared to the starting materials. The adsorption was mainly affected by initial AB80 concentration, adsorbent dosage, contact time, and slightly influenced by temperature (25–45 °C), and pH (3.5–10). The pseudo-second-order kinetic model fitted the experimental data, and pseudo-first order model fitted as well at the highest AB80 concentration, 250 mg/L. The experimental data agreed with the Langmuir isotherm model, with a maximum adsorption capacity of 61.64 mg/g at 35 °C. The process was exothermic above 100 mg/L of dye and spontaneous up to 200 mg/L (T < 35 °C). The adsorbent could be reused without further treatment at least 5 times providing ≥40% removal, whereas the dye could be efficiently recovered by NaOH desorption. Electrostatic interactions as well as physisorption could explain the adsorption behavior.

Various techniques have been researched and introduced in water treatment plants to optimise treatment and management processes. This paper presents a solution that can help treatment plants to work more effectively and reach their mine water management goals. Using Python 3.7.1 programming language within an Anaconda 4.11.0 platform, neural networks and regression tree algorithms were compared to find the best performing model after the data had undergone robust data pre-processing and exploratory data analysis statistical techniques. The main aim was to use this best performing model to forecast mining influenced water (MIW) parameters. This approach will help the treatment plant operators in knowing the future MIW chemistry, and they can eventually plan ahead of time what chemicals and methods to use to treat and manage polluted MIW. Westrand mine pool water near Randfontein, South Africa is used as a case study, in which historical data (2016–2021) from shaft № 9 is used to train and test the algorithms. These algorithms included the artificial neural network (ANN), deep neural network (DNN), gradient boosting and random forest regression trees, while the multivariate long short-term memory (LSTM) was used to generate new data for the best performing algorithm. Different data pre-processing approaches were explored, including data interpolation and anomaly detection. These processes were carried out to highlight the most important part of completing a machine learning related project, which is data analytics. Finally, the random forest regression tree algorithm showed the overall best performance and was used to forecast Fe and acidity concentrations of MIW for 60 days. It could be shown that artificial intelligence techniques are capable to optimise and forecast mine water treatment plant parameters, and it is imperative to perform robust statistical analysis on the data before attempting to build forecasting models.