Cleaner Water最新文献

The present work focuses on the optimization of the removal percentage of Chromium (VI) from a real tannery effluent by electrocoagulation process (EC). The influence of high efficiency cathodic materials (titanium and nickel) was also investigated in this work. The tannery effluent is from the town of Maroua in the Far North Region in Cameroon. The effectiveness of the main operational parameters such as current intensity, initial Cr (VI) concentration, initial pH as well as solution conductivity was examined. All experiments were carried out in an electrocoagulation cell with an effective volume of 400 mL using two electrode combinations as anode/cathode (Al/Ti and Al/Ni). It was found that the Al/Ti combination exhibits higher removal efficiency than Al/Ni under the same operational conditions. Cr (VI) removal efficiencies of 90.93 % and 84.30 % were respectively observed for the Al/Ti and Al/Ni electrodes with an optimal initial pH (pH=6). The maximum current intensity, the maximum initial Cr (VI) concentration as well as the NaCl concentration were 0.4 A, 10 mg/L Cr(VI) and 1.5 g/L respectively. Response surface methodology by the mean of central composite design was performed. The influence of current intensity (100–300 mA), electrolysis time (10–30 min) and interelectrode spacing (1–3 cm), the probability and the mathematical model were highly discussed. According to the experimental design results, the removal of Cr (VI) in the real tannery effluent was up to 99.58 %. For the aforementioned efficiency it requires the optimum values of 211.891 mA, 36.8179 min and 1.609 cm for current intensity, time and the interelectrode spacing, respectively. EC has shown to be easy to operate, to be economic by using cheaper electrodes and efficient for the treatment of real tannery effluent.

This research presents a ground-breaking approach to wastewater treatment that leverages hydrodynamic cavitation and ozonation with unprecedented efficiency and environmental benefits by resolving the concern of the ever-present paradox of water scarcity and persistent pollutants in wastewater, and it compels scientists to relentlessly pursue innovative and eco-friendly treatment solutions. This study introduces a pioneering method for treating wastewater employing a sequential approach of hydrodynamic cavitation (HC) coupled with subsequent ozonation (O3). This research examined the process of purifying rainwater collected from the Rankala Lake quarry in Kolhapur, India. The treatment, which lasted for approximately 7 hours each day over a span of three weeks, resulted in notable enhancements in water quality. The initial greenish discoloration and bad odor were notably eradicated within a week, without any chemical additives. The microbial burden decreased significantly from 10⁵ CFU/mL to 10² CFU/mL, indicating a strong level of disinfection. The COD decreased significantly from 110 ppm to less than 10 ppm, while the BOD decreased dramatically to undetectable levels (0 ppm) from 55 ppm. In addition, there was a slight change in the concentration of chloride, water hardness, clarity, and total dissolved solids (TDS). This exemplifies the efficacy of the cavitation process coupled with ozonation for converting polluted, discolored, and malodorous water into purified water appropriate for diverse uses.

Nowadays, the use of natural absorbents to remove pollutants from POME has gained remarkable attention. The main objective of this study is to investigate the suitability and performance of modified peat soil as an adsorbent for the removal of NH₃-N from POME. The chemical activation method was performed using readily available NaOH for the first time to improve the adsorption performance of naturally available low-cost peat soil. The physical properties of raw and modified peat soil were determined using water-holding capacity, moisture content, bulk density, porosity, and BET surface area. The adsorbents were also characterized by SEM and FTIR to investigate surface morphology and chemical composition. To optimize the experimental parameters namely adsorbent dosage, agitation rate, and contact time for removal of NH₃-N from POME, response surface methodology (RSM) was employed in this study with two different activation ratios. Substantial improvement of physical properties was attained after the modification of raw peat soil. The SEM images of modified peat soil showed a more porous space structure with larger voids while the FT-IR demonstrated the distinctive functional groups in the raw and modified peat soil. At optimized conditions of 5.71 g/L adsorbent dosage, 50 rpm agitation rate, and 38.96 min contact time predicted removal efficiency of NH₃-N has been revealed 64.06 and 58.74 % at 1:20 and 1:30 activation ratios, respectively. The experimental investigation using optimized parameters showed 69.12 ± 2.5 and 61.57 ± 4.3 % removal of NH₃-N. The experimental and predicted results showed good agreement. The rapid removal of NH₃-N (69.1 % within 39 min) was achieved by chemically modified peat soil in this study compared to previously reported studies. Nevertheless, the raw and modified peat soil showed good stability up to three cycles of reusability.

Overpopulation, expansion of agricultural practices, misuse of water resources, industrialization, and urbanization are among the major factors that have a big impact on the quantity and quality of water. It has been projected that around 4 billion humans would lack access to pure water by 2025. Thus, for a sustainable lifestyle, it is imperative to improve water quality. Conventional water and wastewater treatment technologies involve various chemical processes such as coagulation and disinfection and physical methods such as filtration and adsorption. For these processes, various chemicals are being used such as alum and lime in coagulation, chlorine and bromine in disinfection, and activated alumina, silica gel and zeolites in adsorption. However, such chemicals have high procurement cost and display negative impacts on environment and human health, due to which plant based coagulants, adsorbents, and disinfectants are now being majorly tested for water and wastewater treatment methods. The objective of this review article is to provide a recent update on plant derived coagulants, adsorbents, and disinfectants for the treatment of water and wastewater. This review article critically examines the various conventional plant based water cleaning methods and discusses their mechanisms. Prior to this study, plant-based coagulants, adsorbents, and disinfectants have been mainly separately reviewed, but a proper combined study is lacking. The present manuscript highlights the procedure of water and wastewater treatment plants first and then discusses all the three plant based water treatment methods sequentially. This study may be useful for the development of an efficient water and wastewater treatment method employing plant based coagulants, adsorbents, and disinfectants. The present study will also be beneficial for the researchers who are actively working on plant derived water cleaning methods.

An accurately pre-trained stacking ensemble machine learning regressor was used to predict sulphate levels in two other Acid Mine Drainage (AMD) treatment plants using Transfer Learning (TL). The model was trained on the large Central Rand (CR) water quality dataset and was used to predict and impute the sulphate levels in the scanty East Rand (ER) and West Rand (WR) datasets which would not have been sufficient to train ML models from scratch. TL was successfully used to overcome this barrier and rapidly predicted sulphate levels in the East Rand and West Rand plants using the pre-trained model and achieved a high level of accuracy (Mean Squared Error:0.00124, Mean Absolute Error:0.0290 and R²:0.963) for the East Rand plant when comparing the predicted and true sulphate values. No true sulphate values existed for the West Rand plant; however, TL was successful in imputing these missing values and rapidly completed the West Rand dataset by providing the historic sulphate levels. This was possible due to the high degree of similarity between all domains (treatment plants) since they had similar geographic locations, the same treatment process, possessed the same important features and had the same relationships between variables. TL was successful in providing three accurate datasets for AMD sulphate levels, an important accomplishment towards having reliable data for use in design of experiments aimed at recovering valuable resources such as elemental sulphur, gypsum and important metals from AMD.

People are exposed to extreme levels of UV radiation from the sun which gives a harmful effect on the skin. A prevention step should be taken such as applying a protective layer that able to protect the skin from UV rays. Hence, the protective layer should contain the antioxidant components that are able to prevent the formation of free radicals. Microalgae and the bioactive components that can be derived from them are thought to be viable raw material replacements in the cosmetics and pharmaceutical industries. In this study, carotenoid compounds with antioxidant characteristics such as neoxanthin and cryptoxanthin were successfully identified in Chlorella sp. by LC‑QTOF and the compounds have been reported to give a shield from skin aging. Meanwhile, the phenolic compounds were successfully identified through LC‑QTOF in Chlorella sp. that also been reported to be an active compound in sunscreen products. Besides, the identification of polysaccharide compounds was done by FTIR analysis, and the presence of the functional group was successfully identified. Polysaccharides have been reported to be an excellent anti-wrinkles characteristic. The alginate compound was analyses from the identification of a functional group based on the peaks formed. The alginate compound has been an excellent free radical scavenging. Therefore, Chlorella sp. can be applicable for cosmetics and skincare products as the antioxidant compounds such as phenolics compound, carotenoids, and polysaccharides have been identified.

The review article explores the state-of-the-art advancements in using bioreactors based on microalgae to detoxify wastewater, with an emphasis on the removal of various environmental contaminants (VECs). Because of their persistence and capacity for bioaccumulation, these pollutants—which include nutrients, heavy metals, organic compounds, microplastics, Polycyclic Aromatic Hydrocarbons (PAHs), and emerging contaminants—pose serious threats to the environment and human health. Innovative solutions are required since traditional wastewater treatment procedures frequently fail to efficiently eradicate VECs. The review carefully looks at how well microalgae can break down and remove VECs from wastewater. It clarifies the numerous processes, including as biosorption, bioaccumulation, and biotransformation, by which microalgae aid in the elimination of pollutants. Contaminants can be ingested by microalgae, which can then metabolise them into less toxic compounds or incorporate them into biomass. This study examines how adding microalgae to traditional treatment methods can improve both overall treatment effectiveness and operational stability. Operational challenges such as maintaining optimal growth conditions for microalgae, scalability of bioreactor systems, and the need for continuous monitoring and control are thoroughly discussed. The analysis highlights several avenues for future research, such as genetically modifying microalgae strains to enhance pollutant degradation, creating more effective bioreactor designs, and incorporating cutting-edge monitoring systems. The analysis indicates that although microalgae-based bioreactors have great potential to remove VECs, further investigation and developments in technology are needed to fully realise this potential in large-scale wastewater treatment applications. Researchers, environmental engineers, and politicians can benefit greatly from this review, which offers a thorough grasp of the present and potential future applications of microalgae-based bioreactor technology for wastewater treatment.

Despite Nigeria's immense wealth in water resources, the country faces a significant water crisis that is exceptionally difficult to resolve, particularly considering the associated public health and security challenges. This review aims to expound on the complex determinants and the outcomes of the water shortage in Nigeria focusing more on its effects on the general livelihood and stability of Nigerians. Using a systematic approach, this paper reviews water scarcity, the causes of pollution– including urban activities, agrochemical run-offs, and mismanagement – and their negative impacts on health and the environment in Nigeria. A total of 305 studies relating to water pollution and crisis in Nigeria were examined in this study. One more point of the evaluation is that the review outlines the existing barriers preventing the all-inclusive availability of clean water, for example, the lack of appropriate infrastructure and inefficient resource management. The review emphasizes improving water treatment facilities, advancing water management strategies that are sustainable, and tightening certain laws.

Livestock production is getting increased attention due to its impact on natural resources, and freshwater is one such limited resource. To reduce the pressure on freshwater use and develop sustainable livestock systems from farm-to-fork we need to study the whole production cycle, and look for hotspots of major freshwater use. Considering this, we chose intensive pork production as our focal livestock system, since it is one the most eaten meats globally. We focused on pork production in Ireland and studied the freshwater use (green and blue) from cradle-to-farm gate using the water footprint (WFP) method. Detailed farm data (e.g. diet composition, production data) were combined with on-farm water meter data to explore variations in water consumption between farms, and potential explanatory variables for differences in consumption between farms. So far, there have been no WFP studies in pork production that explored this, and insight into variation could help to identify options for improvement. We analyzed the direct (on-farm) and indirect (off-farm) green and blue water footprint of 10 Irish pig farms. Our results show that the average total WFP, including the direct and indirect water footprint, was 2537 L/kg pork, which is at the low end of previously published studies. The indirect green water footprint related to the production of purchased feed was responsible for the largest share (99 %) of the total WFP. The direct blue water footprint formed only a minor component of the total WFP (14 L/kg pork), with drinking water playing the major role. We can conclude from this study that variation in WFP between the least and most efficient farms was small (Q3-Q1 = 181 L/kg pork); nevertheless, this indicates that efficiencies of around 7 % could be gained by the least efficient cohort of farms by adjusting on-farm management practices. We also found a weak negative correlation between WFP and farm size, and WFP and meat produced. Overall, this study suggests that to reduce the burden on freshwater resources and reduce the pork WFP, future research should focus on the feed related impacts.

Fluoride (F-) toxicity from contaminated drinking water affects over 200 million people worldwide. While defluoridation with adsorbents such as calcium carbonate, is commonly used, most technologies are unsuitable for resource-constrained areas. Coral sand is readily available in tropical regions but is yet to be investigated as a potential F- adsorbent. The effectiveness of coral sand at removing F- from drinking water was assessed using acid-enhanced lime defluoridation with two beach (Kiribati and Vanuatu) and one commercially available coral sands. Citric acid was selected as it is readily accessible, palatable and safe for human consumption. Mini columns with a 5:1 sand-to-fluid ratio, 0.025 M citric acid and a 4-hour residence time, could be used seven times to reduce F- from 10 mg/L to below the World Health Organization (WHO) guideline value of 1.5 mg/L. Mini columns packed with coarser grained (1.3 mm) Vanuatu sand could be used at least 10 times. Increasing citric acid to 0.050 M reduced removal efficiency. Prototype treatment devices, developed using 1 L polyethylene jerrycans and 1 kg of commercial sand, could only be used a maximum of three times with 0.025 M citric acid. All coral sands contained F- as well as other trace elements of human health concern, including As, B, Cr, Mn, and Ni that were released into the treated water, resulting in exceedances of drinking water standards. Total Cr concentrations in treated water always exceeded the 0.05 mg/L WHO health guideline whereas As exceeded the 0.01 mg/L value in the majority of treated water samples. In addition, B, Na, and Ni concentrations exceeded the WHO guidelines in many water samples treated with Kiribati and Vanuatu sands. Treated water samples were also unpalatable as potable water based on hardness, total dissolved solids and elevated concentrations of Al, Fe, and Mn. It is recommended that drinking water treated with coral sand be analysed for the presence of contaminants of health concern.