Water Resources and Industry最新文献

The converter valve of ultra-high-voltage direct current grid requires a large amount of cooling water for heat dissipation. Considering the generated waste heat, this study proposes a heat pump-driven mechanical vapor compression (HP-MVC) desalination system based on traditional power-driven mechanical vapor compression (MVC). Using the scaling-endoreversible thermodynamic model, the analytical solutions of the structural equation and operating boundary of the proposed HP-MVC system were derived, which is the innovation of this study. The effects of different component parameters on the thermodynamic characteristics and operation boundaries of the HP-MVC were determined. The results revealed that the HP-MVC system alternately exhibited heat-drive dominant and power-drive dominant modes, in which the specific power consumption was lower in the former. When the recovery ratio was 0.3, with an increase in the pressure ratio from 1.15 to 1.50, the heat supplemented by the heat pump decreased by 31.9 %, and the specific power consumption increased by 63.1 %. The analytical solutions of the structural equation provide a theoretical basis for the efficient operation of the system, and the operation boundaries demonstrate the difference between HP-MVC and traditional MVC. The HP-MVC reduces heat dissipation requirements and results in a more energy-efficient desalination system, which is a typical mutually beneficial design and worth promoting.

Pulp and paper mill effluents represent a significant environmental concern due to the presence of various toxic organic and inorganic pollutants, posing risks even at low concentrations. With the paper production process consuming approximately 200 tons of water per ton of paper and generating effluents containing over 250 different chemicals, effective treatment methods are essential to mitigate the environmental impact of the pulp and paper (PP) industry. This study presents a comprehensive evaluation of the efficacy of heterogeneous and homogeneous photocatalytic treatments for PP industry-derived effluents, targeting reductions in major pollutant concentrations below environmental standards. A thorough review of the literature on pollutant removal from PP effluents using photocatalytic treatment, particularly employing UV/TiO₂ and UV/ZnO photocatalysts, reveals significant removal rates. Doped photocatalysts have shown enhanced performance, achieving removal percentages of 98 % for BOD and COD, and 99 % for color and lignin. Additionally, Fenton and photo-Fenton treatment techniques have demonstrated high removal efficiencies for BOD, COD, color, and lignin.

Long term (200 h) continuous operation of a submerged photocatalytic membrane reactor utilizing direct contact membrane distillation (SPMR-DCMD) is presented. Various types of feed contaminated with ketoprofen were treated: brackish water (BW), seawater (SeaW), and secondary wastewater effluent (SE). Ketoprofen decomposition after 24 h exceeded 99.5 %, regardless of feed type. The distillate showed no toxicity to Aliivibrio fischeri. A significant decrease in flux after 100–124 h of BW and SeaW treatment occurred due to scaling, while for SE the flux remained almost constant for 200 h. This indicates that a shorter study would not allow a proper analysis of the process. A scaling layer was formed regardless of feed type, and the formation of CaSO₄⋅2H₂O, CaCO₃ or (Ca,Mg)CO₃ was proved. The porous structure of the deposit during SE treatment prevented significant flux deterioration. The formed TiO₂ layer protected the membrane from damage by the growing salt crystals.

Sugarcane bagasse (SB) was used to produce a new bioadsorbent (STEA), drawing on circular economy concepts. STEA was synthesized using a two-step one-pot reaction, employing epichlorohydrin and triethylamine in the presence of N,N-dimethylformamide, without the use of a petroleum-based catalyst. The structure and surface of STEA were characterized by elemental C, H, N, and Cl analysis, X-ray diffraction, infrared spectroscopy, ¹³C solid-state nuclear magnetic resonance spectroscopy, thermogravimetric analysis, specific surface area and pore size distribution determination, and point of zero charge measurement. Batch adsorption and desorption tests were performed with the model dye Remazol Golden Yellow (RGY) RNL, a reactive anionic azo dye widely used in textile industry, to evaluate the potential reuse and application of STEA in a fixed-bed column for wastewater treatment. For batch adsorption, the best dose and agitation speed were 0.2 g L⁻¹ and 50 rpm, respectively. STEA effectively removed RGY over a wide range of pH (2.00–10.00). The equilibrium time, maximum adsorption capacity (Q_max), and desorption efficiency (E_des) were 720 min, 369 mg g⁻¹ (0.71 mmol g⁻¹), and 49.5 %, respectively. The fixed-bed column fed with a spiked aqueous RGY solution could be operated for 415 min, with Q_max of 422 mg g⁻¹ (0.81 mmol g⁻¹) and E_des of 58.9 %. Batch and continuous experiments using real textile industry wastewater containing reactive azo dyes showed high color removal efficiency by STEA, with no interference of other compounds present in wastewater on adsorption of the reactive azo dyes (overshooting effect). The technology was validated in a relevant environment and achieved technology readiness level 5, showing potential to be upscaled. Therefore, STEA proved to be an efficient bio-based technology for application in tertiary treatment of real textile plant wastewater to remove reactive anionic azo dyes.

Seawater desalination has become an accessible option for augmenting freshwater supplies worldwide. In the countries of the Gulf Cooperation Council (GCC), it has been practiced for decades as the main source for domestic water use. Sustainable desalination requires addressing environmental impacts including damage to ecosystems from the high volumes of brine in the Gulf. This paper examines challenges related to environmental regulation of brine management in the Arab Gulf countries using the example of Qatar. It analyzes the brine challenge through infrastructure planning policies and stakeholders’ perceptions. The brine issue has been identified as a major environmental concern that requires action through discharge infrastructure, brine management technologies, and regulatory approaches based on quality thresholds and monitoring systems. Although there is a high level of agreement on the solvability of the brine issue, there are limitations with regard to the high reliance on desalination rendered through large-scale infrastructure. These limitations necessitate complementary water supply infrastructure for storage or the development of other sources through water reuse and storage. While water security considerations require prioritization of protection and supply continuity through desalination, incremental change through a stepwise dual approach of brine management and regulation is still possible.

Leachate formation is one of the most important factors taken into account during the operation and long-term management of municipal waste landfills. Systematic assessment of groundwater and leachate contamination may be useful in selecting the appropriate method of leachate management or treatment processes. The use of indicators to quantify the contamination potential of leachate and groundwater in the vicinity of MSW could help landfill managers assess their quality. Therefore, the aim of the study was to assess the representativeness of selected indicator methods for analyzing the temporal variability of leachate and groundwater properties in the vicinity of two municipal waste landfills in a Central European country (Poland). The leachate pollution index (LPI), sub-LPI and adjusted leachate pollution index (r-LPI) were used to assess the quality of leachate water, while the landfill water pollution index (LWPI) was used to assess the variability of groundwater quality. The results confirmed that LWPI is an effective method for assessing the quality of groundwater in the vicinity of municipal waste landfills. The obtained results confirm the negative impact of landfills, despite the insulation used. LWPI showed poor quality of groundwater and visible impact of the landfill (landfill W, average LWPI - 2.34) and moderately polluted waters and minor impact of the landfill (landfill S, average LWPI - 1.37). In most cases, it was observed that two parameters, EC and TOC, are the main factors contributing to the deterioration of groundwater quality. The sub-LPI analysis showed that leachates from both landfills have a very low content of heavy metals, so they should not have a negative impact on the biological treatment process. The obtained r-LPI values were in all cases higher than the calculated LPI values. For landfill S, the average r-LPI was 26.3 (Z-1) and 25.7 (Z-2). However, the average LPI was 13.5 (Z-1) and 13.2 (Z-2). For landfill W, the average r-LPI was 14.6 and the average LPI was 11.4. Analysis conducted on multi-year leachate and groundwater data using specific indicators can help managers better understand the impact of MSW on surrounding areas and help avoid potential operational problems in the future.

In this work, the influence of supporting electrolytes (sodium sulfate and sodium chloride) on the electrochemical oxidation of the antihypertensive drug losartan (LOS) was studied under different operating conditions such as current density (4.1–12.5 mA cm⁻²), electrolyte concentration (0.05–0.5 M), initial pollutant concentration (250–1000 μg L⁻¹) and solution pH. The role of cathodes on the removal of LOS has been investigated using five different cathodes with carbonaceous cathodes showing better LOS removal. The effect of matrix composition has been studied using simulated water spiked with various constituents and real water matrices such as bottled water (BW) and wastewater (WW). The removal of LOS was pronounced while using a chloride electrolyte as compared to the sulfate electrolyte. The apparent rate constant increased on adding persulfate (PS) up to concentrations of 150 mg L⁻¹ and decreased in the presence of bicarbonates and organic matter. The transformation products (TPs) formed during the electrochemical oxidation depended on the supporting electrolyte and two common TPs were identified in both electrolytes with a total of 4 TPs identified in the chloride medium and 7 TPs in the sulfate medium. Degradation pathways for LOS in both electrolytes have also been proposed.

Sequencing batch moving bed biofilm reactors have been widely used in commercial wastewater treatment facilities for organic carbon and nitrogen removal. However, these reactors can remove low phosphorus (P) levels. Therefore, this study investigated the potential of SB-MBBRs for maximizing simultaneous nitrification-denitrification and P removal (SNDPR) potential from P-rich municipal wastewater impacted by industrial discharges. A series of experiments were carried out to investigate the effect of external volatile fatty acid (VFA) dosing, airflow rate, and temperature on SNDPR using pilot-scale SBMBBRs. Stable and robust SNDPR was achieved with an optimum acetic acid supply of 150 mg SCOD/L, at 20 ^oC and 2.5 L air/min. A low airflow rate (AFR) and high-temperature conditions affected P release and uptake kinetics. Efficient PHA storage, dissolved oxygen (DO) transfer (outer layer), DO diffusion limitation (inner layer) of biofilm, and conversion of NH₄-N to NO₂-N/NO₃-N enhanced SNDPR in the two pilot SB-MBBRs.