Denver Water used a variety of water treatment and chemistry approaches to resolve fluctuating pH levels and meet its Lead and Copper Rule variance requirements.

ABSTRACT Decentralized wastewater treatment systems can help mitigate the water crisis. Their successful implementation depends not only on their technological design but also on the level of public support. We aim to assess how a pro-environmental social identity framing in which we present a decentralized wastewater treatment system as an environmentally responsible neighborhood initiative may increase public support of these systems. Two experimental studies examined the impact of pro-environmental social identity framing on public acceptance of decentralized wastewater systems in Groningen (the Netherlands) (n = 92) and Santiago de Compostela (Spain) (n = 208). As expected, pro-environmental social identity framing increased public acceptance in both studies, irrespective of the extent to which people identify with their neighborhood. Specifically, participants in the pro-environmental social identity framing condition displayed more positive attitudes, more positive and less negative emotions, and higher voting intentions toward the decentralized wastewater systems compared to those in the control condition. These results suggest that connecting such systems to shared neighborhood identities can be an effective strategy for overcoming barriers to their implementation. Our study offers valuable insights for policymakers, community leaders, and environmental advocates to craft messages to promote the adoption of decentralized wastewater systems.

ABSTRACT In this study, we utilized direct ultrafiltration (UF) and integrated microflocculation–ultrafiltration (MF–UF) processes to treat raw water from four distinct sources, covering both dry and heavy rainfall periods. We assessed the effectiveness of microflocculation (MF) as a pretreatment to enhance treatment efficiency under complex water conditions, focusing on its role in mitigating membrane fouling. The results demonstrated the superior adaptability of UF membranes when combined with MF pretreatment, particularly in managing high turbidity during heavy rainfall, a challenge for standalone UF processes in meeting regulatory standards. This integrated approach notably improved UV254 removal efficiency from approximately 60–80%. Additionally, excitation–emission matrix spectroscopy revealed that while the MF–UF process is effective in removing dissolved organic matter (DOM), it faces limitations with high DOM concentrations in raw water. Comparative analysis of membrane flux between the two methods showed that MF pretreatment reduces filtration time, enhances flux rates, and significantly decreases membrane fouling. Finally, scanning electron microscopy further provided insights into the structure and morphology of UF membrane surface filter cakes, illustrating how MF pretreatment contributes to the sustained efficiency of membrane flux.

Abstract Background Water temperature and feeding frequency are critical abiotic factors regulating the growth and immune function of aquatic organisms. This study investigated the effects of water temperature and feeding frequency on growth and immune function in Nile tilapia (Oreochromis niloticus) over two months. A total of 360 juvenile fish (average weight: 20.00 ± 1.26 g) were divided into six groups, each with three replicates, based on a combination of three water temperatures (26, 28, and 30 °C) and two feeding frequencies (either 1 or 2 meals per day). Results At 30 ºC and 28 ºC, water electrical conductivity and total dissolved salts increased, while total ammonia nitrogen and dissolved oxygen rose slightly in groups fed twice daily, with a significant interaction between temperature and feeding frequency. The group at 30 ºC with two meals per day showed the highest final body weight (FBW). The interaction between temperature and feeding frequency significantly influenced FBW, total feed intake, and body thickness. Fish at 30 ºC exhibited upregulated hepatic growth hormone receptor 1 and insulin-like growth factor 1, while those at 28 ºC with one meal per day, as well as those at 30 ºC regardless of meal frequency, also showed increased expression of hepatic fatty acid binding protein and intestinal cluster of differentiation 36. Fish at 30 ºC had upregulated leptin levels and downregulated cholecystokinin, while those at 26 ºC displayed the opposite trend, particularly with one meal daily. Higher temperatures significantly boosted serum IgM, superoxide dismutase (SOD), and lysozyme (LYZ) levels, with meal frequency also affecting malondialdehyde, IgM, and SOD levels. Additionally, 30 ºC enhanced the hepatic expression of mucin-like protein (muc), oligo-peptide transporter 1 (pept1), interleukin 1, nf-κB, complement C3, lyz, sod, catalase, and glutathione peroxidase, with twice-daily meals having a more pronounced effect. Conversely, 28 ºC with one meal per day upregulated some of these genes, such as muc, pept1, and sod. Conclusions Overall, 30 ºC with two meals per day significantly improved the growth and health of juvenile Nile tilapia, while 28 ºC with two meals maintained satisfactory performance.

The increasing prevalence of heavy metals and antibiotic-resistant bacteria in wastewater (WW) raises serious environmental and public health concerns. This study investigates the efficiency of the microalgal strain Chlorella vulgaris EV-465 in treating wastewater and evaluates the antibiotic resistance profile of bacterial strains obtained from WW samples. Chlorella vulgaris EV-465 was used to treat four types of wastewater—domestic, municipal, hospital, and industrial wastewater—through 21 days of incubation. The findings demonstrated pH stabilization and significant decreases in nutrients (total nitrogen—TN, total phosphorus—TP), biological oxygen demand (BOD), chemical oxygen demand (COD), heavy metal (HM) concentrations, and bacterial count. Copper (Cu) showed the highest reduction, decreasing by 80% in industrial wastewater within 14 days, while lead (Pb) proved more resistant to removal, with only a 50% decrease by day 21. Additionally, the algae decreased bacterial counts, lowering colony-forming units (Log CFU/mL) from 9.04 to 4.65 in municipal wastewater over the 21-day period. Antibiotic susceptibility tests for isolated bacterial strains revealed high levels of resistance, with seven out of nine bacterial strains exhibiting multidrug resistance. Notably, Enterococcus faecium (PBI08), Acinetobacter baumannii (YBH19), and Pseudomonas aeruginosa (NBH16) displayed resistance to all nine antibiotics tested. Among the tested antibiotics, Ciprofloxacin showed the highest efficacy, with 66% susceptibility of tested bacterial strains. Cluster and phylogenetic analyses showed that the majority of the isolated bacterial strains belonged to the genera Pseudomonas and Escherichia, highlighting their genetic diversity and varied resistance mechanisms.

Cadmium (Cd) contamination in aquatic ecosystems is a serious global environmental issue. Biochar derived from agricultural wastes has recently attracted remarkable attention as it is used as an absorbent in combating heavy metal contamination of water bodies. In the present study, the absorption efficacy of fish bone (FBM) and fishbone-derived biochar prepared at 200 °C, 400 °C, 600 °C, and 800 °C (referred to as B200, B400, B600, and B800, respectively) for the Cd ion (Cd2+) in aqueous solution was investigated. The results showed that high-temperature pyrolysis could optimize the pore structure and specific surface area of FBM, and Cd2+ successfully adsorbed onto FBM and fishbone-derived biochar. High-temperature pyrolysis significantly increased the FBM adsorption capacity for Cd2+ by 49.5–135.1%, with the optimal pyrolysis temperature being 600 °C. Furthermore, the kinetic data of FBM and fishbone-derived biochar for Cd2+ were in better alignment with the pseudo-second-order model, their adsorption isotherms were better in accordance with the Langmuir models, and the thermodynamic analysis showed that the adsorption process was monolayer and favorable adsorption. Moreover, the potential adsorption mechanisms of Cd2+ on FBM and fishbone-derived biochar might be related to pore filling, ion exchange, complexation with oxygen functional groups, and precipitation with the minerals on the biochar surface. Fishbone-derived biochar has significant potential for wastewater treatment and agricultural waste applications.

Wastewater-Based Epidemiology (WBE) has become a powerful tool for assessing disease occurrence in communities. This study investigates the coronavirus disease 2019 (COVID-19) epidemic in the United States during 2023–2024 using wastewater data from 189 wastewater treatment plants in 40 states and the District of Columbia. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and pepper-mild mottle virus normalized SARS-CoV-2 RNA concentration data were compared with COVID-19 hospitalization admission data at both national and state levels. We further investigate temporal features in wastewater viral RNA abundance, with peak timing and cross-correlation lag analyses indicating that wastewater SARS-CoV-2 RNA concentrations precede hospitalization admissions by 2 to 12 days. Lastly, we demonstrate that wastewater treatment plant size has a significant effect on the variability of measured SARS-CoV-2 RNA concentrations. This study highlights the effectiveness of WBE as a non-invasive, timely and resource-efficient disease monitoring strategy, especially in the context of declining COVID-19 clinical reporting.

Aim. The aim of the study was to consider the possibility of using the consortia of chemolithoautotrophic ferrobacteria from Gallionella genus and heterotrophic bacteria from Lepthothrix genus for the biological method of groundwater purification. Methods. The photocolorimetric method to determine the concentrations of ammonium and iron ions, the titrimetric method to determine the hydrocarbon and total alkalinity, the method of determining the permanganate oxidizability using the Kubel method, the potentiometric method to determine the values of рН and Еh, the electronic microscopy using the X-ray spectral analysis of matrix structures of bio-minerals, microbiological and statistical methods. Results. The main technological parameters of the water deironing process were defined as follows: the filtration velocity of the bioreactor – 7–11 m/h, and of the filters – 3.5–5 m/h; the filter-cycle duration – 48 h. It was found that the application of the two-stage technology of biological deironing in the bioreactor and filters provided for the possible removal of Fe2+ compounds up to 5.0 mg/cdm, ammonium nitrogen — up to 1.5 mg/cdm, soluble organic substances by PO – up to 6.0 mg O2/cdm. It was determined that the optimal parameters for the process of biological purification of neutral groundwaters, containing increased concentrations of Fe2+ cations were as follows: рН 7.0–7.2; hydrocarbon alkalinity 2.5–2.2 mmol/cdm; content of soluble oxygen – 1.5–2.0 mg/cdm. The ability of concentrated (Dos 200 mg/cdm) matrix structures of Gallionella and Lepthothrix ferrobacteria to remove Cr6+ ions from natural groundwaters was determined. The study found no considerable differences in the efficiency of applying disinfectants, produced using polyhexamethylene guanidine chloride (PHMGchl) or polyhexamethylene biguanidine chloride (PHMBchl). In concentrations of 0.25–0.5 %, they effectively disinfect pathogenic microorganisms, including Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The same was found true for the bacteria, most common in the systems of technical reverse water supply, the systems of water circulation, plant watering, and fire tanks, including Aeromonas hydrophila, Aeromonas salmonicida, Pseudomonas sp., E. coli, Flavobacterium columnare, Micrococcus lysodeikticus. Conclusions. This was the first study on the possibility of applying the biotechnology of groundwater purification from excessive amounts of iron in conditions of uneven hydraulic burden, notable for the water supply systems of rural areas and most agricultural enterprises in the north-western and northern regions of Ukraine. The specificities and perspectives of PHMGchl application in the systems of water preparation were studied. It was found that from the standpoint of safety and efficiency, the use of the water deironing processes involving iron bacteria was reasonable in the systems of water consumption and technical water supply, and the disinfection of water using PHMG was possible only in the second case, due to some toxicity of the preparation. The optimal parameters for the process of biological purification of neutral groundwaters, containing increased concentrations of Fe2+ cations were determined.

Water scarcity remains a critical global challenge, requiring immediate, sustainable management strategies, particularly in areas with an increasing disparity between water supply and demand. In India, and especially in Delhi, this issue is acute. In response to growing environmental concerns and the urgent need for sustainable water resource management, rainwater harvesting has emerged as a practical and effective solution for water conservation. This study investigates the application of rainwater harvesting to sustainably support water needs for a sports complex located in a salinity affected region. The land, originally intended for agriculture, has been converted into a complex featuring hydro-landscape facilities, including swimming pools, water polo areas, diving pools, toddler pools, and leisure pools. These facilities require an initial water input of 6,754.5 m³ and an annual replenishment of 7,957.28 m³ due to evaporation and seepage. By calculating the total rainwater harvesting potential based on the runoff coefficient, annual rainfall intensity, and the complex's catchment area, the study reveals that 29,693.8 m³ of rainwater can be harvested annually, providing a surplus of 14,981.7 m³ of potable water. This analysis demonstrates the viability of designing sports complexes in saline areas using efficient land use and rainwater harvesting, and presenting a scalable model for sustainable water management in similar regions worldwide.