Water Treatment Options Research Articles

Wastewater desalination for irrigation in inland regions

ABSTRACT Desalination using membrane processes is increasingly being implemented in coastal regions of the world to meet the water needs of the growing population. The use of this water treatment option to meet the growing water needs in inland regions, however, is impeded by the cost and regulatory challenges associated with responsible disposal of the concentrate brine. For inland regions of Australia, the use of evaporation ponds (EPs) is the only available brine management option. The high cost associated with construction and the high land requirements for EPs necessitates low waste brine volume production. This desktop study investigated the feasibility of achieving very high water recoveries and very low waste brine volumes in the reverse osmosis desalination of municipal wastewater for irrigation of crops near the inland town of Horsham, Victoria, Australia. Interstage lime and soda ash softening was selected as the means of removal of the scalants that prevent the achievement of high water recovery. It is hoped that this study will provide valuable information to aid in the planning of water reclamation operations for agricultural applications in inland areas at a time of increasing demand for water for food production and forecasts of population growth and climate change.

Bridging the Technology Gap for Cost‐Effective and Sustainable Treatment of Per‐ and Polyfluoroalkyl Substances in Surface Water and Stormwater

ABSTRACTThis article addresses the urgent need for cost‐effective and sustainable methods to mitigate per‐ and polyfluoroalkyl substances (PFAS) contamination in surface water and stormwater. Although the majority of PFAS research and development to date has focused on groundwater and soil treatment technologies, in some cases there may be a greater risk posed by the high mobility and potential for direct contact with PFAS in surface water and stormwater. Based on the evolving regulatory landscape and the elevated PFAS concentrations observed in available stormwater data near some fire training facilities, additional attention to this topic is needed to support the development of effective and practical treatment technologies for PFAS in surface water and stormwater. We propose addressing the need to bridge the current technology gap between (1) expensive mechanical and/or construction‐intensive technologies and (2) the development of cost‐effective and sustainable surface water and stormwater PFAS treatment options. We envision a future where nature‐based approaches could be employed for stand‐alone PFAS treatment. Alternatively, nature‐based approaches could be used for initial PFAS mass removal as a pretreatment step within a treatment train followed by engineered adsorbents or other technologies, if needed to achieve low concentration cleanup thresholds. We provide an example of a potential nature‐based treatment train that would rely on the natural propensity of PFAS to accumulate in surface water foams using foam‐enhancing weirs and flumes (FWFs), combined with the demonstrated treatment potential of constructed floating wetlands (CFWs). Additional research into the validation, optimization, and site‐specific design factors of nature‐based treatment trains, such as the FWF+CFW approach, warrants future research and development.

Optimising the effectiveness of osmotic desalination process by using graphene-based nanomaterials

This work examines how graphene-based nanoparticles can be integrated into membranes to improve the effectiveness of water treatment in osmotic desalination processes. This is important since sustainable practices can help address the world's water scarcity. Water treatment, desalination, and resource recovery are areas where osmotic desalination shows great potential. However, membrane performance constraints frequently impede its efficacy. High mechanical strength, superior hydrophilicity, and the ability to lessen internal concentration polarisation are just a few of the remarkable qualities that make graphene-based nanoparticles stand out. In order to increase the membranes' overall functionality, these nanoparticles were created and added to them. Comparing the study to conventional membranes, the main goals were to increase water flux rates and salt ion rejection capacities. It was shown by experimental results that the membranes strengthened with graphene-based nanoparticles performed better. They outperformed conventional membranes in terms of water flow growth and salt ion rejection rates improvement. In order to advance osmotic desalination technologies towards more effective and sustainable water treatment options, this study highlights the revolutionary potential of graphene-based nanoparticles. Graphene-based nanoparticles provide an attractive option for tackling major water issues worldwide by improving membrane characteristics that are essential for osmotic desalination, such as permeability and selectivity. Water management techniques that are environmentally sustainable are supported by their integration into membranes, which also enhances performance metrics. This study opens the door for creative approaches to resource recovery and water treatment by providing important insights into the creation of cutting-edge materials specifically designed for osmotic desalination applications.

Green carbon-based adsorbents for water treatment in Sub-Saharan Africa

Abstract As underlined by the United Nations Sustainable Development Goals (UN SDGs), providing safe and clean potable water remains a significant concern in developing regions of the world, especially Sub-Saharan Africa. Extensive research has been done on this subject in Africa. The concept of sustainable chemistry towards solving another pressing issue in Africa – waste management – led to the decision to investigate green carbon-based materials for water purification on the continent. The conversion of “waste to wealth” is a practical means of achieving proper waste management at a reasonable cost. Low-cost adsorbents such as biochar, activated carbons, graphene and carbon composites, with high surface area, porosity and efficiency have been generated from agricultural waste and biomass, carbon-rich geological materials, carbonaceous polymeric materials, and hydrocarbons/petroleum by-products, using simple thermal and/or green chemical reaction protocols. Several drawbacks have hindered the development and utilization of adsorbents for the treatment of polluted water, including chemical fouling, loss of activity, poor reusability, difficulty associated with sorbent regeneration, production of secondary pollutants, toxicities caused by exposure to sorbent residues, and inability to deal with heavily polluted water. However, the use of adsorbents is still widely acclaimed as an efficient and cleaner method among other existing water treatment options such as extraction, chemical oxidation, bioremediation, and photocatalytic degradation. This paper outlines the research carried out by Sub-Saharan African scientists to proffer solutions to water pollution using green carbon-based adsorbents and discusses the breakthroughs, challenges, and future prospects.

Eco-Friendly Synthesis of Al2O3 Nanoparticles: Comprehensive Characterization Properties, Mechanics, and Photocatalytic Dye Adsorption Study

Metal and metal oxide nanoparticles are gaining traction in inorganic catalysis and photocatalysis, driving the development of eco-friendly methods. This study introduces an eco-friendly and cost-effective approach for synthesizing Al2O3 nanoparticles (NPs) using extracts derived from the leaves of Calligonum comosum L. The primary objective of this investigation is to assess the photocatalytic efficacy of the synthesized catalyst in addressing organic pollutants. The Al2O3 NPs exhibit a spherical morphology with crystalline arrangements, as evidenced by an average crystallite size of 25.1 nm in the XRD analysis. The band gap energy of the Al2O3 NPs is determined to be 2.86 eV. In terms of mechanical properties, the Al2O3 NPs show significant potential in enhancing both flexural and compressive properties, thereby making them a viable choice for improving the mechanical performance of composites. Notably, the Young’s modulus of the hybrid composite (comprising plant material and Al2O3 NPs) exhibits a remarkable increase of 34.4% in flexion and 78.3% in compression compared to the plant material alone. The catalytic performance of the Al2O3 NPs is evaluated using methylene blue (MB) as a cationic dye and Rose Bengal (RB) as an anionic dye. Impressively, the Al2O3 NPs demonstrate degradation efficiencies of 98.2% for MB and 90.5% for RB. The degradation processes occur under solar light irradiation, with a contact time of 120 m, a maintained pH of 7, and a temperature of 25 °C. This study found that Al2O3 nanoparticles are a promising, cost-effective, and environmentally friendly option for water treatment.

SODIS with hydrogen peroxide: an effective household water treatment option under sub-tropical climatic conditions of bangladesh.

Solar disinfection (SODIS) is an affordable and sustainable Household Water Treatment (HWT) method endorsed by WHO. However, its limitations include longer sunlight exposure requirements, incomplete microbial inactivation, and post-SODIS microbial regrowth during monsoon and winter seasons in subtropical climates. To address these limitations, the performance of SODIS with H2O2 for microbial inactivation during the monsoon and winter seasons in Bangladesh was evaluated following the WHO HWT protocols. Moreover, the process was verified using drinking water samples collected from restaurants, households, and slums. All SODIS experiments were conducted using reflective reactors with PET bottles and plastic bags, adding 10 mg/L of H2O2, and exposing them to sunlight for 6 h. The results showed that E. coli was completely inactivated within 2 h in plastic bags and within 3 h in PET bottles during the monsoon season, achieving an LRV of > 5. In winter, both achieved an LRV > 5 within 3 h and plastic bags showed more efficient in microbial inactivation than PET bottles. The microbial inactivation rates were 5 times higher than those of conventional SODIS. No regrowth of microorganisms was observed during the subsequent post-SODIS period of 12 h and 24 h at room temperature. The study findings suggest that SODIS with H2O2 has the potential for complete microorganism inactivation with shorter sunlight exposure in subtropical climates with moderate to low solar irradiation and can be adopted as a reliable disinfection option for rural and urban communities with unsafe drinking water supply.

Insight into the sulfite activation by Fe-rich sludge-derived biochar for efficient organic contaminant degradation: The role of iron species

Sulfate radical-based advanced oxidation processes driven by sulfite [S(IV)] activation offer a sustainable and cost-effective approach for environmental remediation. The utilization of abundant iron oxide species in Fe-rich sludge for S(IV) activation presents a cost-effective and eco-friendly solution, making it an attractive option for Fe-rich sludge disposal and water treatment. Herein, an efficient S(IV) activation system was developed by using Fe-rich sludge-derived biochar (FBC) for the first time. The performance of S(IV) activation by different pyrolyzed FBCs was evaluated in terms of tetracycline (TC) degradation. The highest degradation efficiency of TC was achieved 95.0 % in the S(IV)/FBC700 under the optimum conditions. The reactive radical species responsible for TC degradation in the system were confirmed to be SO4•−. The present work opens up new possibilities for the development of novel advanced oxidation processes utilizing the waste Fe-rich sludge.

Characterization and Performance of Peanut Shells in Caffeine and Triclosan Removal in Batch and Fixed-Bed Column Tests.

Peanut shells' adsorption performance in caffeine and triclosan removal was studied. Peanut shells were analyzed for their chemical composition, morphology, and surface functional groups. Batch adsorption and fixed-bed column experiments were carried out with solutions containing 30 mg/L of caffeine and triclosan. The parameters examined included peanut shell particle size (120-150, 300-600, and 800-2000 µm), adsorbent dose (0.02-60 g/L), contact time (up to 180 min), bed height (4-8 cm), and hydraulic loading rate (2.0 and 4.0 m3/m2-day). After determining the optimal adsorption conditions, kinetics, isotherm, and breakthrough curve models were applied to analyze the experimental data. Peanut shells showed an irregular surface and consisted mainly of polysaccharides (around 70% lignin, cellulose, and hemicellulose), with a specific surface area of 1.7 m2/g and a pore volume of 0.005 cm3/g. The highest removal efficiencies for caffeine (85.6 ± 1.4%) and triclosan (89.3 ± 1.5%) were achieved using the smallest particles and 10.0 and 0.1 g/L doses over 180 and 45 min, respectively. Triclosan showed easier removal compared to caffeine due to its higher lipophilic character. The pseudo-second-order kinetics model provided the best fit with the experimental data, suggesting a chemisorption process between caffeine/triclosan and the adsorbent. Equilibrium data were well-described by the Sips model, with maximum adsorption capacities of 3.3 mg/g and 289.3 mg/g for caffeine and triclosan, respectively. In fixed-bed column adsorption tests, particle size significantly influenced efficiency and hydraulic behavior, with 120-150 µm particles exhibiting the highest adsorption capacity for caffeine (0.72 mg/g) and triclosan (143.44 mg/g), albeit with clogging issues. The experimental data also showed good agreement with the Bohart-Adams, Thomas, and Yoon-Nelson models. Therefore, the findings of this study highlight not only the effective capability of peanut shells to remove caffeine and triclosan but also their versatility as a promising option for water treatment and sanitation applications in different contexts.

Investigation of synergistic effects incorporating esterified lignin and guar gum composite aerogel for sustained oil spill cleanup

The recently developed aerogel demonstrates a high capacity for pollutant absorption, making it an environmentally friendly option for oily water treatment. In an effort to reduce the adverse effects of the black liquor accumulation in the pulp industry, this study focused on utilizing the mentioned abundant bio-resource lignin, which can be applied to various high-value applications such as 3D porous materials for oil spill cleanup. Lignin, precipitated from the black liquor, was esterified using maleic anhydride as the esterifying reagent to enhance the hydrophobicity. Then, the composite aerogel fabricated from esterified lignin and guar gum (GG) was successfully prepared through the facile freeze-drying, using glutaraldehyde (GA) as the cross-linker. The resulting aerogel exhibited high porosity values exceeding 95%, low density (27.4 mg/cm3), and an impressive absorption capacity of 32.5 g/g for sunflower oil. These results demonstrate the potential of black liquor utilization as a bio-waste source of lignin and highlight the cost-effective guar gum-esterified lignin composite aerogel, which exhibits remarkable oil absorption capabilities and environmental sustainability promotion.

Biogenic magnetic nanocomposite of hydroxyapatite and dextran: synthesis, characterization, and enhanced removal of 2,4-D from aqueous environment.

In this study, a biogenic magnetic nanocomposite, HAP@DEX@MNP, using hydroxyapatite from eggshell waste and dextran was developed to efficiently remove 2,4-D from aqueous solutions. The magnetic nano biocomposite underwent rigorous characterization using a comprehensive suite of analytical techniques, including FTIR, XRD, FESEM, EDX, TEM, and VSM. FTIR analysis was used to validate the existence of pivotal functional groups, such as phosphate, carbonyl, hydroxyl, and iron oxide. XRD analysis verified both the crystalline nature of hydroxyapatite and the successful integration of dextran and hematite within the composite structure. FESEM and EDX examinations provided valuable insights into the surface morphology and elemental composition. TEM observations elucidated the existence of nano-sized particles underscoring the unique structural characteristics of the nanocomposite. Batch adsorption experiments were conducted under optimized conditions, highlighting the critical role of pH 2 for efficient 2,4-D removal. The mechanisms driving the binding of 2,4-D to HAP@DEX@MNP were found to encompass diverse interactions, encompassing electrostatic forces, hydrogen bonding, π-π interactions, and van der Waals forces. Adsorption isotherm studies revealed both monolayer and multilayer adsorption, with the Langmuir and Freundlich models fitting well, indicating a maximal adsorption capacity of 217.39µg/g at 25°C. Kinetic investigations supported the pseudo-second-order model for efficient adsorption dynamics, and thermodynamic analysis emphasized the versatility of HAP@DEX@MNP across different temperatures. Importantly, the study highlighted the remarkable regenerative capacity of the nanocomposite using a 0.1M NaOH solution, positioning it as an environmentally friendly option for water treatment. In conclusion, HAP@DEX@MNP holds significant potential for diverse applications in addressing global water treatment and environmental challenges.

Scenario-based assessment of fecal pathogen sources affecting bathing water quality: novel treatment options to reduce norovirus and Campylobacter infection risks.

Wastewater discharge and runoff waters are significant sources of human and animal fecal microbes in surface waters. Human-derived fecal contamination of water is generally estimated to pose a greater risk to human health than animal fecal contamination, but animals may serve as reservoirs of zoonotic pathogens. In this study, quantitative microbial risk assessment (QMRA) tools were used to evaluate the hygienic impact of sewage effluents and runoff water from municipalities and animal farms on surface and bathing waters. The human-specific microbial source tracking (MST) marker HF183 was used to evaluate the dilution of fecal pathogens originating from the sewage effluent discharge to the downstream watershed. As novel risk management options, the efficiency of UV-LED disinfection and wetland treatment as well as biochar filtration was tested on-site for the contamination sources. According to the dilution pattern of the MST marker HF183, microbes from wastewater were diluted (2.3-3.7 log10) in the receiving waters. The scenario-based QMRA revealed, that the health risks posed by exposure to human-specific norovirus GII and zoonotic Campylobacter jejuni during the bathing events were evaluated. The risk for gastroenteritis was found to be elevated during wastewater contamination events, where especially norovirus GII infection risk increased (1-15 cases per day among 50 bathers) compared with the business as usual (BAU) situation (1 case per day). The noted C. jejuni infection risk was associated with animal farm contamination (1 case per day, versus 0.2-0.6 cases during BAU). Tertiary treatment of wastewater with wetland treatment and UV-LED disinfection effectively reduced the waterborne gastroenteritis risks associated with bathing. Based on the experiences from this study, a QMRA-based approach for health risk evaluations at bathing sites can be useful and is recommended for bathing site risk assessments in the future. In case of low pathogen numbers at the exposure sites, the MST marker HF183 could be used as a pathogen dilution coefficient for the watershed under evaluation. The full-scale implementation of novel tertiary treatment options at wastewater treatment plants (WWTPs) as well as on-site runoff water treatment options should be considered for infection risk management at locations where scenario-based QMRA implies elevated infection risks.

Unlocking the potential of lignocellulosic waste: A kinetic modeling approach for bio-coagulants in sewage water treatment

This study explores the potential of lignocellulosic materials, specifically sugarcane bagasse (SB) and coconut fibers (CNW), as coagulants and flocculants for sewage water treatment in combination with alum. The main aim is to evaluate the efficacy of alum:SB and alum:CNW combinations in improving water quality parameters, such as turbidity, EC, pH, TSS, TDS, DO, BOD, and COD, using modified methods (primary and secondary treatment). The results of the water quality parameters show significant reductions in turbidity of 95.32% and 90.94% for sewage waters treated with alum:SB and alum:CNW, respectively, as well as notable reductions in TDS (70.58%, 60.78%), TSS (98.63%, 97.27%), BOD (76.51%, 51.13%), and COD (95.07%, 76.47%). Moreover, bio-coagulants such as alum, SB, CNW, alum:SB, and alum:CNW were characterized by FT-IR. In comparison to other coagulants, the alum:SB treated sewage water was found to be efficient and have excellent coagulation activity (90%). The turbidity removal by both lignomaterials conformed to the WHO and BIS acceptable limits for finished water quality. Therefore, the highest turbidity reduction was achieved in alum:SB>alum:CNW treated sewage water. Statistical analysis also confirmed the effectiveness of alum:SB, highlighting its potential as a feasible option for sewage water treatment through factor and correlation analysis. The MANOVA (p < 0.05) result indicates that both bio-coagulants were significantly different. This study emphasizes the potential and eco-friendly method of using lignocellulosic bio-coagulants for the treatment of municipal sewage water.

Urban Slums Morbidity Spectrum: A Cross Sectional Study on Korogocho Slum, Kenya

Community health outreach is part of community-based health care, an extension of facility-based primary care services used to reach the underserved. Slums population in sub-Sahara Africa has been growing by 9 million persons per year making slum occupancy to form more than 56% of urban settlements. A slum is characterized by inadequate access to safe water, inadequate access to sanitation and infrastructure, poor structural quality of housing, overcrowding, and insecure residential status. People in slums due to their environment are more vulnerable to communicable diseases, respiratory diseases, malnutrition and accidents. The main objective was to identify the 10 top most prevalent diseases in Korogocho slums. A cross-sectional study design was applied. Study period was between January 2021 and December 2021. Data was collected through a series of 12 Community health outreach sessions at Korogocho slums in Nairobi, Kenya. Secondary data was extracted and analyzed using SPSS version 25.A total of 3699 individuals were treated, there were more females (67.96%) than males (32.01%) and at least 1 person was identified as a transgender. Age group of 0 to 59 months (472 patients) had more males than females while 19 to 59 years old (1413 patients) females formed majority of Community health outreach attendants. Modal age group was 19 to 59 years among females and 0 to 59 months among males representing 45.28% of the total patients. An average of 308 patients was seen per session. Respiratory tract infections (44.8%), skin diseases (13.8%), abdominal diseases (13.2%), musculoskeletal disorder (7.86%), eye conditions (4.75%), genitourinary diseases (4.18%), ENT diseases (3.9%), hypertension (3.36%), dental problems (2.1%) and wounds and injuries (2.05%) respectively formed the 10 most prevalent diseases in Korogocho slums. Public health intervention of wearing of medical face mask to prevent allergens and airborne infections is highly recommended, prompt and timely treatment of respiratory diseases will help in reducing respiratory related complications. Cost effective and sustainable water treatment options should be availed to the locals to help in improving water quality so as to reduce infective abdominal-diseases.

Modelling and Prediction of Water Quality Index of Selected Pond Water in Aboh Mbaise Local Government Area, Imo State, Nigeria

The aim of this study is the development of water quality models against water quality parameters from 5 selected ponds in Aboh-Mbaise local government area (LGA) of Imo state.&#x0D; Water quality index (WQI) as dependent variable computed based on water quality parameters which were taken as independent variables and modelled as multiple linear regression. Given that there are over 25 water quality parameters (physiochemical, heavy metals and microbials), it was necessary to adopt factor reduction technique using principal component analysis. In this approach, 3 principal component factors were generated having corresponding factors (independent variables of 5, 6 and 5 respectively). The resulting multiple regression for the 3 principal component factors yielded Goodness of Fit of 92.9, 99.0 and 96.6% as well as root mean square error (RMSE) of 66.673, 0.672 and 51.968 respectively.&#x0D; The model verification was accomplished by plotting the computed WQI against predicted values from the developed models and the best option was the one with 99.0% R2 value with the following independent variables-sulphate, TSS, phosphate, turbidity, total solid and nitrates.&#x0D; The model output is relevant in WQI prediction given the applicable water quality characteristics.&#x0D; This predictive model will find wide application in selecting water treatment options for pond water in the study area.

Utilizing Bentonite as a Natural Material to Enhance the Quality of Community Water Resources in the Urban Area

In this study, the researchers investigated the state of water sources and the potential of bentonite as a water treatment agent. The study encompassed measurements of key water quality parameters for river and well water sources, including pH, TDS, conductivity, and salinity. The findings revealed that while pH levels were generally within the clean water standards, TDS values exceeded the threshold, particularly in river water samples. This suggests contamination due to urban activities and rising sea levels. Furthermore, the study explored using both activated and non-activated bentonite as an adsorption agent to remove contaminants from water sources. The results indicated that bentonite effectively increased pH levels, especially in well water samples, and significantly reduced TDS, conductivity, and salinity values, with non-activated bentonite being a preferred option for river water treatment and activated bentonite for well water treatment. These findings emphasize the potential of bentonite as a valuable water treatment solution. The specific characteristics of the water source should guide the choice between activated and non-activated bentonite. This tailored approach can lead to more effective and sustainable water treatment, contributing to improved water quality and availability for the community in the coastal region.

Efficacy of Peracetic Acid and Chlorine on the Reduction of Shiga Toxin-producing Escherichia coli and a Nonpathogenic E. coli Strain in Preharvest Agricultural Water

Produce-borne outbreaks of Shiga toxin-producing Escherichia coli (STEC) linked to preharvest water emphasize the need for efficacious water treatment options. This study quantified reductions of STEC and generic E. coli in preharvest agricultural water using commercially available sanitizers. Water was collected from two sources in Virginia (pond, river) and inoculated with either a seven-strain STEC panel or environmental generic E. coli strain TVS 353 (∼9 log10 CFU/100 mL). Triplicate inoculated water samples were equilibrated to 12 or 32°C and treated with peracetic acid (PAA) or chlorine (Cl) [low (PAA:6ppm, Cl:2–4 ppm) or high (PAA:10 ppm, Cl:10–12 ppm) residual concentrations] for an allotted contact time (1, 5, or 10 min). Strains were enumerated, and a log-linear model was used to characterize how treatment combinations influenced reductions. All Cl treatment combinations achieved a ≥3 log10 CFU/100 mL reduction, regardless of strain (3.43 ± 0.25 to 7.05 ± 0.00 log10 CFU/100 mL). Approximately 80% (19/24) and 67% (16/24) of PAA treatment combinations achieved a ≥3 log10 CFU/100 mL for STEC and E. coli TVS 353, respectively. The log-linear model showed contact time (10 > 5 > 1 min) and sanitizer type (Cl > PAA) had the greatest impact on STEC and E. coli TVS 353 reductions (p < 0.001). E. coli TVS 353 in water samples was more resistant to sanitizer treatment (p < 0.001) indicating applicability as a good surrogate. Results demonstrated Cl and PAA can be effective agricultural water treatment strategies when sanitizer chemistry is managed. These data will assist with the development of in-field validation studies and may identify suitable candidates for the registration of antimicrobial pesticide products for use against foodborne pathogens in preharvest agricultural water treatment.

Evaluation of Conventional Treated and UV-Ozone Treatment Water Processes for Organic Pollutants from Shendam Dam in Plateau State, Nigeria

The use of contaminated water makes human populations to suffer from water borne diseases. The potential application of ultraviolet-ozone synergy for the removal of organic pollutants in raw water source from Shendam in Plateau state, Nigeria was undertaken. The conventional and uv-ozone treated water samples were extracted with dichloromethane and screened with GC-MS for organic pollutants. GC-MS chromatogram for the conventional treated water yielded 18 different organic pollutants while the uv-ozone treated water yielded 8 different organic compounds. GC-MS of the solvent blank (dichloromethane) used as the control showed similar profile of organic compounds detected as those of uv-ozone treated water. The profile obtained indicated reduction in the number of the organic pollutants because most of the organic compounds detected in the conventional treated water were not detected in the uv-ozone treated water. The results obtained during the evaluation period indicated that the conventional treatment system is highly vulnerable to passing on contaminated treated water to the end user. Uv-ozone treatment system, therefore, can represent an alternative drinking water treatment option. The use of the uv-ozone treatment process could be integrated in a drinking water flow sheet to replace the conventional disinfection processes because it is effective and environmentally friendly.

Water and dialysis fluid purity for contemporary hemodialysis.

The purity of water and dialysis fluids is of utmost importance in ensuring the safe and effective administration of hemodialysis treatment to patients with chronic kidney disease. It is crucial to enforce compliance with international standards for dialysis water and fluids, as this is mandatory in reducing chemical hazards, mitigating the adverse effects of bioincompatibility resulting from contaminated water and ultimately enhancing long-term patient outcomes. Within this comprehensive review, we highlight the presence of water contaminants and thoroughly assess the existing international standards for dialysis water and fluids, spanning from pure to ultrapure. Additionally, we delve into the fundamental components of water purification and present a comprehensive range of water treatment options, encompassing pre-treatment, primary treatment (reverse osmosis), and tertiary water treatment. Furthermore, we outline recommended monitoring and maintenance procedures, ensuring the consistent delivery of high-quality water and dialysis fluids at the point of care. WATER PURIFICATION AND MONITORING SUSTAINABILITY AND FUTURE CHALLENGES: Importantly, we raise concerns regarding the sustainability and conservation of water resources in hemodialysis treatment. It is imperative that these concerns be addressed in the future to avert the potential shortage of this essential resource. In conclusion, the contemporary landscape of hemodialysis conditions has engendered an urgent necessity for advanced water treatment systems and optimized delivery of dialysis fluids. This review serves as a comprehensive update on the latest technological advancements aimed at meeting these critical demands. Dialysis water and fluids must adhere to increasingly stringent purity constraints, encompassing both biochemical and microbiological perspectives.

Introducing hydrothermal carbonization to sewage sludge treatment systems—a way of improving energy recovery and economic performance?

Hydrothermal carbonization (HTC) can mitigate the disposal costs of sewage sludge in a wastewater treatment plant. This study analyzes the impact of integrating HTC with anaerobic digestion (AD) and combustion from a combined energy and economic performance perspective. Net energy balance and investment opportunity are investigated for a number of technical scenarios considering i) different combinations of the technologies: AD + HTC, AD + thermal dryer + combustion, and AD + HTC + combustion, ii) different options for HTC process water treatment: wet oxidation (WO) + AD, and direct return to AD, and iii) different products: heat-only, heat and electricity, hydrochar, and phosphorus.The results show trade-offs between investment cost, self-supplement of heat, and output electricity when WO is used. In AD + HTC, net heat output decreases compared to the reference plant, but avoided disposal costs and hydrochar revenue result in profitable investment when the process water is directly returned to the AD. Although HTC has a lower heat demand than the thermal dryer, replacing the thermal dryer with HTC is only possible when AD, HTC, and combustion are connected, or when WO covers HTC’s heat demand. HTC may impair the electricity production because of the necessity for a high-temperature heat source, whereas the thermal dryer can utilize a low-temperature heat source. In conclusion, energy advantages of HTC in AD + HTC + combustion are insufficient to provide a promising investment opportunity due to high investment costs of HTC. The investment opportunity improves by co-combustion of hydrochar and external sludge.

Combining electrochemistry and ultraviolet radiation for the degradation of per- and poly-fluoroalkyl substances in contaminated groundwater and wastewater

Electrochemical and ultraviolet-based methods are advanced oxidation processes emerging as viable water and wastewater treatment options. In this study, a combination of these two methods (EO-UV) using boron-doped diamond (BDD) electrodes and ultraviolet radiation at both 185 and 254 nm was assessed for the degradation of poly-fluoroalkyl substances (PFAS). Sodium persulfate (Na2S2O8) and sodium sulfate (Na2SO4) were used as electrolytes. The method was investigated on model solutions containing perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS). The method's effectiveness was assessed by comparing PFAS removal efficiencies and energy demands associated with the use of separate and combined treatments. The results showed that the highest removal of PFOA and PFOS was 96 % and 85 % respectively, which was achieved using EO-UV and persulfate electrolytes. Average removal efficiencies were 1.5–2 times higher in EO-UV than in EO and 4–6 times higher than in UV treatment. The degradation of PFAS under EO-UV and persulfate applied to PFAS-contaminated groundwater and wastewater reached 94 % PFOA and 88 % PFOS in groundwater and 51 % and 63 % in wastewater. The removal of the sum of eleven PFAS was 86 % and 66 % in groundwater and wastewater, respectively. The combination of EO, UV and persulfate was the most effective option for PFAS treatment at lower energy consumption.