Water Environment Research最新文献

The waste activated sludge (WAS) generated from sewage treatment accumulates antibiotics including ciprofloxacin (CIP), which may be released into the environments if WAS is not handled properly. Therefore, there is a need to develop technologies aiming at removing CIP from sludge. In this study, electrically activated peroxymonosulfate (E/PMS) was investigated to remove CIP from WAS. The optimal conditions for the degradation of CIP in sludge by E/PMS were determined by response surface methodology (RSM) simulations combined with experimental validation. The highest CIP removal level of 93.8% was achieved in 10 min at a dosage of 250 mg/g dry solid (DS) PMS, and an electrolysis voltage of 23 V. E/PMS facilitated the generation of radicals involved in the elimination of CIP. The contribution of free radicals showed that SO₄ ^•- is more important than HO^• in this process. A degradation pathway for CIP in sludge was proposed based on the detected byproducts and density functional theory (DFT) calculations. The E/PMS process also promoted sludge disintegration, dewatering, heavy metal removal, and morphological transformation. The total content of all six heavy metals decreased, with As and Cr being converted into more stable forms, thereby reducing their leaching rates. The E/PMS process also reduced the toxicity of the sludge filtrate. Finally, the analysis of economic feasibility and energy consumption showed that E/PMS has a significant potential for controlling antibiotics and promoting the harmlessness of sludge. PRACTITIONER POINTS: Effective removal of ciprofloxacin (CIP) from waste activated sludge by electrically activated peroxymonosulfate (E/PMS). Reaction time has little effect on CIP removal from sludge. The degradation sites of CIP in sludge were the piperazine ring, the quinolone fraction, and the cyclopropyl. Promotion of sludge decomposition and dewatering, heavy metal stabilization, and decrease of sludge filtrate toxicity by the E/PMS process.

Microplastics (MPs) are ubiquitous in the marine environment and harmful for biodiversity. This review was based on 311 studies published on various online platforms published between 2006 and 2024 on MP contamination in marine sediment and water in different countries of Asia. The research highlights an increasing trend in MP contamination studies, with China and India. Analytical techniques for sample collection, digestion, flotation, and polymer identification are discussed. Fourier transform infrared spectroscopy (FTIR) emerged as the preferred method for polymer identification. The maximum MP contamination in marine sediments was recorded at Taiwan and Indonesia, while the maximum MP contamination in marine water was recorded in China, Malaysia, and India. The fiber was the most dominant shape. The 1-2 mm and 500 μ-1 mm-sized MPs having blue color were found dominantly. The pollution indices revealed a very high risk of MP contamination in all the Asian countries. PRACTITIONER POINTS: China and India are the leading in publications on MP contamination studies. Common tools used are steel scoop/spatula/shovel for sediment, nets for water. FTIR is the preferred method for polymer identification. Highest MP in sediment of Indonesia and in water of China, Malaysia, and India. Dominant MP shape: fiber; size 1-2 mm and 500 μ-1 mm, blue color.

Per- and polyfluoroalkyl substances (PFAS) are being studied in all environmental matrices because of their ubiquitous presence and adverse human health impacts. This study conducted a surveillance of 27 water resource recovery facilities throughout the United States and Canada to screen the range of PFAS concentrations in pre-stabilized sludge and post-stabilized product. Among the 27 water resource recovery facilities, 82% use anaerobic digestion and the rest use chemical stabilization and/or incineration for sludge stabilization. Forty PFAS compounds were evaluated by US Environmental Protection Agency Method SW846/537.1, and four and nine compounds were reported in the pre-stabilized sludge and post-stabilized product, respectively. Concentrations of reported compounds in pre-stabilized sludge and post-stabilized product varied from 5 to 33 ng/g dry basis and 2 to 220 ng/g dry basis, respectively. 3-Perfluoropentylpropanoic acid (5:3 FTCA) and perfluorooctanesulfonic acid (PFOS) were the most frequently observed compounds, and PFAS concentrations in the post-stabilized products were generally higher than the corresponding pre-stabilized sludge. PRACTITIONER POINTS: Among the 40 target PFAS, four were above reporting limit in the pre-stabilized sludge and nine in the post-stabilized product. Incineration ash (post-stabilized product) samples did not have any reportable PFAS. 5:3 FTCA and PFOS were the two frequently observed compounds; concentrations were higher in the post-stabilized product compared to the pre-stabilized sludge. PFPeA and PFHxA were the only two short chain perfluoroalkyl carboxylic acids reported. PFOA was reported in only one of the 54 samples evaluated.

Understanding crop water requirements is critical for irrigation scheduling and cropping pattern decisions in any environment. Using the CROPWAT model, a study was conducted to estimate the irrigation requirement of major crops cultivated in the humid subtropical climate of Meghalaya from 2001 to 2022 and preparing irrigation scheduling plan for the current scenario. The results showed that the annual ET₀ from 2001 to 2022 at the selected station was 876.7 mm. The lowest monthly ET₀ (46.8 mm) was observed in December and the highest (94 mm) was observed in March. The results also indicated that the seasonal minimum and maximum CWR for rice, maize, ginger, mustard, and potato were 462.5 and 652.2 mm, 314.6 and 455.8 mm, 673.3 and 922.9 mm, 199.8 and 413.4 mm, and 341.5 and 465.3 mm, respectively. The minimum and maximum IR for rice, maize, ginger, mustard, and potato were 152.9 and 378.8 mm, 0 and 30.2 mm, 60.1 and 255.7 mm, 0 and 193 mm, and 0 and 170.8 mm, respectively. The net irrigation requirement (NIR) and gross irrigation requirement (GIR) were calculated using the scheduling option and 70% efficiency for the preparation of the irrigation schedule. For rice (transplant), the effective rainfall partially met its water needs, requiring supplemental irrigation. Maize, Cotton, and Jute relied entirely on effective rainfall, eliminating the need for irrigation. Ginger and Mustard needed both effective rainfall and additional irrigation. These findings delivered a comprehensive understanding of the location-specific water variations for crops in Meghalaya, vital for sustainable water resource management. PRACTITIONER POINTS: CWR are critical for irrigation scheduling and cropping pattern decisions. FAO CROPWAT model was used for crop planning and irrigation scheduling. The net irrigation requirement and gross irrigation requirement for hilly watershed Comprehensive understanding of the location-specific water variations for crops The irrigation needs vary among different crops based on efficiency % and depletion %.

Water browning is the phenomenon of increasing discoloration in lakes and water courses due to the leaching of organic matter from soils. This process has ecological, economic, and social implications, such as affecting light penetration, oxygen levels, nutrient cycling, drinking water quality, and recreational use. This study investigated the potential of wetlands as a natural solution to mitigate water browning by reducing organic matter and iron. Six mesocosms in pilot scale were set up and studied for 3 years for their efficiency to reduce water color, with sampling every 14th day. Parameters measured were the changes in water color, dissolved organic carbon, iron, pH, and conductivity over 3 years, under different hydrological and climatic conditions. The results showed that wetlands can decrease water browning by retaining organic matter and iron, especially in vegetated systems. This study showed that long retention times with vegetated shallow systems were needed to reduce the water color by 47%. The decrease of color was primarily due to reduction of iron that decreased by 66%, while the dissolved organic carbon (DOC) concentration decreased by only 6%. These findings highlight the potential of constructed wetlands as a valuable tool for improving water quality and mitigating the impacts of water browning, though further optimization of wetland design and integration with broader land-use strategies is needed to address this complex issue effectively. PRACTITIONER POINTS: Constructed wetlands can mitigate brownification, especially with long retention times and shallow vegetated wetlands. Iron reduction is more strongly correlated with colour reduction than with DOC reduction. Vegetated constructed wetlands reduced the colour concentration of inflow water by 47% after a 14-day retention time. Wetlands need a long retention time to reduce colour, and should be placed far upstream in the watershed. Vegetated systems may use alternative pathways, like biofilm formation, to reduce humic substances, independent of UV exposure.

This study investigates the efficacy of ginger extract (GE) as a green corrosion inhibitor in the petrochemical industry, specifically targeting microbial corrosion in carbon steel pipes utilized for river water coolant systems. The nutrient-deficient conditions coupled with the presence of nitrate-reducing bacteria (NRB) within these pipelines facilitate microbiologically influenced corrosion, wherein bacteria directly interact with the metal to harvest electrons for metabolic processes. Our findings indicate that GE inhibits microbial corrosion through dual mechanisms: significantly reducing biofilm formation and adsorbing onto the metal surface. Biofilm inhibition was assessed through both qualitative and quantitative assessments, employing light microscopy and confocal laser scanning microscopy (CLSM) to visualize and confirm the suppression of biofilm development by NRB in the presence of GE. Electrochemical techniques, including electrochemical impedance spectroscopy (EIS) and polarization measurements, demonstrated that GE achieved an inhibition efficiency nearing 95%. Further analysis via scanning electron microscopy (SEM) and adsorption studies corroborated the effective adsorption of GE on carbon steel, highlighting the importance of concentration and immersion time in performance outcomes. Notably, elevated concentrations of GE were found to enhance inhibitory effects, with a 7-day exposure period yielding optimal surface coverage. These results establish GE as a promising and environmentally friendly alternative for mitigating microbial corrosion in industrial applications. PRACTITIONER POINTS: The presence of nitrate-reducing bacteria (NRB) and a nutrient-starved environment are commonplace in the coolant pipes carrying water and can cause severe damage to carbon steel pipes. Ginger extract (GE), an inexpensive green corrosion inhibitor, can be a potent microbial corrosion inhibitor in petrochemical industries. The high efficiency (95%), achieved with ginger extract (GE), is due to its dual-acting mechanism: It inhibits the formation of bacterial biofilm on the surface of carbon steel by providing a non-conducive environment for bacterial growth. The components of GE get adsorbed over the surface of carbon steel and hence prevent bacterial attachment. An optimal concentration of 0.5 g/L GE was required to exhibit high efficiency (95%), which can be achieved on 7 days of exposure of carbon steel to GE, in the presence of NRB in a nutrient-starved environment.

The world's most pressing problem is water shortage, which is made worse by fast industrialization and urbanization, especially in places like India where untreated effluent presents serious threats to human health and the environment. In order to treat dairy and municipal wastewater, this study assesses the efficacy of a two-stage hybrid constructed wetland (CW) system. The WWQI is the primary focus of this evaluation over a range of mixing ratios. Before and after treatment, many physicochemical parameters were examined, including pH, total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphorus (TP), ammonia nitrogen ( ${\mathrm{NH}}_3-N$ ), and nitrate nitrogen ( ${\mathrm{NO}}_3-N$ ). The hybrid CWs system dramatically lowers pollutant concentrations, according to the results, with combinations containing higher amounts of MWW showing the best results. The WWQI values, which change from "unfit for any uses" in untreated DWW to "excellent" quality in treated MWW, show these advancements. The results highlight the potential of hybrid CWs as an effective and sustainable wastewater treatment method, especially when it comes to maximizing the proportion of dairy to municipal wastewater. This study adds to our knowledge of efficient wastewater treatment techniques and highlights the significance of incorporating eco-friendly technologies to tackle water scarcity issues. PRACTITIONER POINTS: Hybrid Constructed Wetlands (HCWs) are effective in removing TSS, BOD, COD, TP, ammonia nitrogen, and nitrate nitrogen from dairy and municipal wastewater. On the basis of HCWs performance determine the Wastewater Quality Index (WWQI) for four different ratio proportions of dairy and municipal wastewater. This index is more useful for water quality status determination and treated water reuse for various purposes. This also benefits sustainable treatment technology and contributes to achieving SDGs.

Salinity is a serious concern with groundwater use in irrigation that is very close to a coastal aquifer. The study aims to do a comparative analysis of the physiochemical parameters of groundwater samples obtained from 10 irrigational wells in Guzelyurt. In this study, 10 groundwater samples were collected from irrigational wells in the Guzelyurt aquifer area and were analyzed for important groundwater physiochemical parameters such as pH, EC, Na⁺, Ca²⁺, K⁺, Na⁺, Mg²⁺, HCO₃ ^-, SO₄ ^2-, and Cl^-. The well numbers are 5118 (Cengziköy), 236 (Yesilyurt), 5147 (Döganci), 4548 (Döganci), 2320 (Gunesköy), 881(Guzelyurt), 615 (Aydinköy), 287 (Kalkanli), 2400 (Guzelyurt), and 834 (Guzelyurt). The results obtained from the analysis were compared with the result of groundwater quality data that were taken from these wells in the past 10 years to ascertain the level of contamination of the wells caused by seawater intrusion in the Guzelyurt coastal aquifer. Nine of the wells are affected by seawater intrusion, while one is not affected. Well, 5118 (Cengzıköy), is not affected by the salinity problem. Within the past 11 years, the salinity in wells 615 (Aydinköy) and 834 (Guzelyurt) increased, while wells 881 (Guzelyurt), 287 (Kalkanlı), 2320 (Guneskoy), 236 (Yeşilyurt), 5147 (Dogancı), 4545 (Dogancı), and 2400 (Guzelyurt) show a low salinity. Controlling seawater intrusion and conserving groundwater resources is critical. In conclusion, the study recommends continuous monitoring of the Guzelyurt aquifer, the adoption of desalination plants, and the use of treated wastewater effluent as an option to reduce groundwater withdrawal. PRACTITIONER POINTS: Controlling seawater intrusion and conserving groundwater resources is critical. Groundwater established the significance of the water circle, and it is found in aquifers. The use of polluted groundwater can cause health problems.

Ocean oil spills can severely impact ecosystems and disrupt marine biodiversity and habitats. Microbial remediation is an effective method for removing thin oil slick contamination. In this study, the adsorption and degradation of low-concentration oil spills by Chlorella vulgaris LH-1 immobilized in konjac glucomannan (KGM) aerogel were investigated. The effect of the KGM aerogel-immobilized C. vulgaris on the bacterial community structure in seawater environments was analyzed through bacterial diversity sequencing. In seawater containing 0.01 and 1.00 g/L of crude oil, after 14 days of remediation with the KGM aerogel-immobilized C. vulgaris, crude oil removal rates of 98.73% and 95.13% were achieved, respectively. The FDA hydrolytic enzyme activity curve indicated that the microbial growth activity in the immobilized C. vulgaris group was significantly higher than that in other groups. After remediation, the top three dominant bacterial genera in the seawater were found to be Vitellibacter, Roseitalea, and Methylophaga. Vitellibacter, a genus known for its ability to degrade polycyclic aromatic hydrocarbons (PAHs) in marine environments, showed increased abundance in seawater treated with the KGM aerogel-immobilized C. vulgaris, suggesting enhanced PAH degradation capability in the presence of the immobilized C. vulgaris. Functional prediction using PICRUSt indicated that the oil metabolism capability of bacteria was promoted by the KGM aerogel-immobilized C. vulgaris. PRACTITIONER POINTS: High degradation efficiency across various oil concentrations is exhibited by KGM-immobilized microalgae. KGM aerogels effectively confine C.vulgaris, reducing loss in marine systems. The impact of KGM aerogel-immobilized C. vulgaris on bacterial community structure in marine environments was analyzed. Immobilized C. vulgaris enhanced the growth of polycyclic aromatic hydrocarbon-degrading bacteria, such as Vitellibacter, in seawater.