High Total Dissolved Solids Research Articles

Assessment of water quality and identification of priority areas for intervention in Guanabara Bay basin, Rio de Janeiro, Brazil, using nonparametric and multivariate statistical methods.

The Guanabara Bay hydrographic region (GBHR) has served as a central hub for human settlement and resource utilization throughout Brazil's history. However, the region's high population density and intense industrial activity have come at a cost, leading to a significant decline in water quality. This work aimed to identify homogeneous regions in GBHR according to water quality parameters in dry and rainy periods. The following water quality monitoring variables were monitored at 49 gauge stations: total phosphorus (TP), nitrate (NO3-), dissolved oxygen (DO), hydrogenionic potential (pH), turbidity (Turb), thermotolerant coliforms (TCol), total dissolved solids (TDS), biochemical oxygen demand (BOD), water temperature (Tw), and air temperature (Ta). The statistical analysis consisted of determining principal components, cluster analysis, seasonal differences, and Spearman's correlation. The water quality parameter correlations were not expressively influenced by seasonality, but there are differences in the concentrations of these parameters in the dry and rainy periods. In the dry period, urban pressure on water quality is mainly due to fecal coliforms. The resulting clusters delimited areas under urban, agricultural, and forestry influence. Clusters located in areas with high demographic density showed high concentrations of TCol and TP, while clusters influenced by forestry and agriculture had better water quality. In the rainy season, clusters with urban influence showed problems with TCol and TP, in addition to some characteristics in each group, such as high TDS, NO3-, and BOD. Forested areas showed high DO, and clusters under agricultural influence had higher concentrations of TCol, BOD, and NO3- concerning forested regions. The troubling state of sanitation in GBHR occurs in metropolitan regions due to lack of a formal sanitation system.

Strontium Isotopic Composition as Tracers for Identifying Groundwater Recharge Sources in the Choushui River Alluvial Plain, Western Taiwan

Groundwater is a vital resource in the Chuoshui River alluvial plain (CSAP), a key agricultural area in Taiwan. Understanding groundwater recharge is crucial for sustainable water management amidst changing climatic conditions and increasing water demand. This study investigates the major ion composition, solute Sr concentrations, and 87Sr/86Sr ratios in groundwater and stream water from the Choushui River (CSR) to trace groundwater recharge sources. The Piper diagram reveals that most groundwater samples are of the freshwater Ca–HCO3 type, aligning with the total dissolved solids (TDS) classification. TDS and major ion compositions indicate that groundwater near Baguashan Terrace (BGT) and Douliu Hill (DLH) primarily derives from stream water and rainwater. Na+ and Cl− enrichment in some aquifers of BGT and DLH is attributed to the dissolution of paleo-sea salt and mixing with paleo-seawater from sedimentary porewater. Elevated dissolved Sr concentrations and lower 87Sr/86Sr ratios in these aquifers further support the intrusion of paleo-seawater. Groundwater in the proximal fan shows high TDS due to intensive weathering, complicating the use of TDS as a tracer. Sr isotopic compositions and solute Sr2+ concentrations effectively distinguish recharge sources, revealing that the CSR mainstream primarily recharges the proximal fan and BGT region, while CSR tributaries and rainwater mainly recharge the DLH region. This study concludes that Sr isotopic compositions and solute Sr2+ concentrations are more reliable than TDS and major ion compositions in identifying groundwater recharge sources, enhancing our understanding of groundwater origins and the processes affecting water quality.

Groundwater and Dissolved Gases Geochemistry in the Pesaro-Urbino Province (Northern Marche, Central Italy) as a Tool for Seismic Surveillance and Sustainability

The Pesaro-Urbino province (PUP) (northern Marche, central Italy) is one of the most seismically active areas in Italy, with the most recent earthquakes (5.2 and 5.5 Mw) having occurred on 9 November 2022 with an epicenter located in the Adriatic Sea. A detailed geochemical and isotopic characterization of 87 groundwaters (and dissolved gases) circulating in the PUP was carried out to (i) unravel the geochemical processes controlling the water circulation, (ii) investigate the interplay between deep originated fluids and shallow aquifers, (iii) evaluate the reliability of specific geochemical parameters as tracers for seismic activity, and (iv) select the most suitable sampling sites to deploy a monitoring network to highlight possible compositional changes related to the regional and local tectonic activity. The geochemical dataset includes waters showing five different hydrochemical compositional facies: (i) calcium bicarbonate with low Total Dissolved Solids (TDS); (ii) calcium bicarbonate with relatively high concentrations of sulfate (>200 mg/L); (iii) sodium bicarbonate with pH > 8.8; (iv) calcium sulfate; (v) sodium chlorine. Two distinct groups of dissolved gases can be recognized: (a) N2-dominated gases with N2/Ar ratios similar to those of Air-Saturated Water (ASW); (b) CO2- and CH4-rich gases associated with high TDS and springs rich in S-bearing reduced species. The isotopic values of δ13C-CO2 and δ13C-CH4 suggest a predominant biogenic origin for both species with a negligible contribution from deep-seated fluids. The Ca-HCO3(SO4), Ca(Na)-SO4(Cl), and Na-HCO3 waters, being likely related to deep hydrological pathways, are the best candidates to be included in the monitoring network in the Pesaro-Urbino province. This will be of paramount importance in addressing the challenge of unravelling fluid geochemical precursors of earthquakes, thus increasing and improving seismic surveillance practices and hazard mitigation.

Assessment of tube well water quality in selected residential areas in Khulna

Clean water is vital for sustainable development, fostering socio-economic growth, ecological stability, and human survival. The study aimed to evaluate the quality of tube well water in specific residential areas of Khulna for drinking purposes, comparing it with the standards of World Health Organization (WHO) and Bangladesh (BD). Twenty tube well water samples were collected from residential areas at depths of 700-1500 ft. The samples were tasted with about 20 parameters, including physical: color, taste, odor, total dissolved solids (TDS) and total suspended solids (TSS); chemical: acidity/alkalinity (pH), arsenic (As), electrical conductivity (EC), dissolved oxygen (DO), bicarbonate (HCO3–), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), chloride (Cl–), iron (Fe), phosphate (PO43–), sulfate (SO42–), potassium (K+); and bacteriological parameters: total coliforms and E. coli bacteria. Most of the samples were found to have higher TDS (avg. 1380 mg/L), TSS (avg. 620 mg/L), Fe (avg. 20.2 mg/L), K+ (avg. 194.1 mg/L), and Na+ (avg. 439 mg/L) concentrations compared to the WHO and BD Standards. 90 to 95% of samples exhibited acceptable levels of EC, pH, DO, Mg2+, Ca2+, Cl–, and SO43–. The salinity levels in most of the samples were excessive to be used for drinking, and the levels were especially very high in samples S-01(Na+ 820 and Cl- 3195 mg/L) and S-04 (Na+ 660 and Cl- 2946 mg/L). The arsenic levels were found to be higher than acceptable limit in S-01 (0.086 mg/L) and S-04 (0.091 mg/L) as well. E. coli and other bacteria in a few samples (S-01, 04, 13, 16, 17, 19) were detected.

PHYSICO-CHEMICAL ANALYSIS OF SOIL IN PERSPECTIVE OF SUSTAINABLE AGRICULTURE FROM SUBDIVISION ROUNDU, DISTRICT SKARDU PAKISTAN

The study conducted in Sub Division Roundu assessed various soil characteristics, including conductivity, pH, organicmatter, total dissolved solids (TDS), salinity, and nutrient content, with a focus on their suitability for plant growth. Soilsamples were collected from different locations for analysis. The conductivity values of the soil ranged from 22.3 to78.3, with Bilamik having the highest conductivity and Bagardo showing the least electrical conductivity. The areas withthe highest conductivity were Tormik, Bilamik, Harpo, and Gunji. The pH values of the 20 soil samples ranged from 5.1to 7.4, indicating that the soil pH was suitable for plant growth. Harpo had the highest pH value, while Shout had alower pH value. Surprisingly, the soil samples from Sub Division Roundu exhibited a medium level of organic matter,ranging from 48% to 76%, which is uncommon for Pakistani soil. Tormik and Gunji had the highest organic mattercontent, while Bagardo had the lowest. Total dissolved solids (TDS), representing inorganic salts in the soil, rangedfrom 9.8 to 32 in the samples. Bagardo had the lowest TDS value, whereas Bilamik showed a high TDS value. Thesalinity levels in the soil were generally low, except for minor salinity in soils from Dassu, Dambodas, Khumrah, andHarbot. However, the study revealed widespread deficiencies in nitrogen and phosphorus content in the soil, with onlymarginal amounts of potassium present in some regions like Tormik, Harpo, Gunji, and Bilamik. Around 85% of the soilsamples lacked sufficient nitrogen and phosphorus, while 15% had marginal concentrations. In contrast, potassium wassufficient in 79.8% of the samples, with 20.2% showing marginal amounts.

Efficient integration of electrocoagulation treatment with the spray-pyrolyzed activated carbon coating on stainless steel electrodes for textile effluent-bath reuse with ease.

In this study, the electrocoagulation (EC) treatment was used to minimize and separate pollutants from textile industrial wastewater (TIWW), including high colour, chemical oxygen demand (COD), total organic carbon (TOC), and total dissolved solids (TDS). To enhance the EC treatment efficiency, a novel strategy has been followed in the study that involves thin-film coating on 316 stainless steel (SS) electrodes with banana peel-derived activated carbon (BPAC) by dip coating, spin coating, or spray coating. Among the different types of coating, thickness and contact angle measurements have elucidated that the spray coating of BPAC on SS electrode is the best tool with minimum thickness and contact angle. In this study, a bare SS electrode was used as the anode and a thin-film spray-coated BPAC on the SS electrode was used as the cathode. Moreover, optimization plays a key role in EC treatment process, where operating conditions such as a current density of 10 mA/cm2 , contact time of 15 min, and a pH of 7 were fixed. As a result, the findings indicate comparatively high colour removal of 98%, COD removal of 91%, TOC removal of 89.6%, and TDS removal of 68 % are achieved with ease. Accordingly, in comparison to plain SS electrodes or dip or spin-coated BPAC on SS electrodes, spray-coated BPAC on SS electrodes in EC treatment outperforms in removing high colour, TOC, COD, and TDS. Overall, the study highlights the potential of EC treatment integrated with adsorption procedures for TIWW treatment. Particularly, the use of thin-film spray-coated BPAC on SS electrodes in the EC treatment process led to an effective and sustainable tool for treating and reuse of TIWW. It is due to its low operation and maintenance cost and studied in a short interval of time. Finally, the ultimate goal was firmly achieved in pilot scale studies by the safe discharge into the environment or reuse of treated textile wastewater. Thus, it is a promising alternative with an environmentally friendly footprint that could be easily implemented in any textile industry premises.

Temporal Accumulation of Geosmin, Oxalic Acid, and Total Dissolved Solids in Table Beet

Consumers perceive flavor as a critically important attribute of vegetable crops. Gas chromatography-mass spectrometry (GC-MS), spectrophotometry, and refractometry of tissue samples collected during multiple years from table beet (Beta vulgaris) at various stages of maturity were performed to characterize the endogenous production of geosmin, oxalic acid, and total dissolved solids within the root. The geosmin concentration was primarily influenced by the cultivar and peaked early during the growing season, with root concentrations at 6 weeks after planting that were 312% higher, on average, than those found in harvest stage roots at 15 weeks after planting. The highest average concentration of geosmin in harvest stage roots was detected in tissue from the cultivar Bull’s Blood (16.08 μg⋅kg−1). The oxalic acid concentration showed a strong cultivar influence and statistically significant variability across the growing season. Hybrid beet cultivar Boro had the lowest soluble oxalic acid concentration (95.73 mg⋅100 g−1 fresh tissue) at all locations and during all years. The oxalic acid concentration peaked 12 weeks after planting, and it was lower at the postharvest sampling date 18 weeks after planting. Total dissolved solids (TDS) concentrations were strongly influenced by year and growing environment and displayed crossover interactions for environment × week. TDS measurements had a moderate negative correlation with root mass. ‘Chioggia Guardsmark’ consistently had the highest TDS during all years and at all locations at 12.01 °Brix. The TDS varied significantly according to time, and diurnal sampling revealed fluctuations as large as 4 °Brix over the course of a 12-hour period. The TDS concentrations increased throughout the growing season, although the rate at which they increased changed according to plant age. The results from this study suggest that interactions between cultivar, time, and environment are important determinants of oxalic acid and TDS concentrations, but they have less influence on geosmin. This information may influence the methods that plant breeders use to collect phenotypic data of important flavor compounds in beets.

A model for the observed secondary-maximum in backwash-effluent-TDS-data obtained during backwash of spiral-wound RO membranes

Observation of a “secondary maximum” in the effluent Total Dissolved Solids (TDS) concentration data, during back-washing of micro-scale spiral-wound Reverse Osmosis (RO) membranes, has been reported (Varma and Chatterjee, 2023). This observation is of interest because a “wash-out” process for any system, may be expected to produce effluent water, which shows an exponential decline in the contaminant, from its initial peak concentration, to that of the water used for washing. Hence the observation of a “secondary maximum” in the back-wash effluent TDS data is interesting and has been examined experimentally in (Varma and Chatterjee, 2023). In this work, we present a mathematical model, which can explain the above observations. This model shows that high TDS water is trapped in the RO membrane element, when the RO system is shut-off. A complete wash-out of this high TDS water, which is held close to the membrane surface requires RO permeate osmotic backwash of a “critical” volume. This “critical” RO permeate volume, can be estimated from the method used in this study. The model is based on coupled-unsteady-state material balances for the salt held in different pseudo-compartments within the RO membrane module.

Study on the Leaching Conditions of the Shihongtan Uranium Deposit

CO2 + O2 is a relatively mature, neutral, in situ leaching process that has been widely used. However, the decrease in uranium concentration in the leaching solution during production has become a serious problem in the western section of the south ore belt of the Shihongtan deposit in Xinjiang, China. In order to solve this problem, mineralogy and batch tests were carried out to explore the reason for the low uranium resource leaching efficiency and determine better leaching process parameters. A total of 16 tests were carried out under different conditions of CO2/O2 ratios and HCO3− concentrations. The results show that: (1) The uranium minerals in the ore were mainly pitchblende and titanium-bearing uranium mineral. Part of the uranium resources were mixed in quartz, which were difficult to activate and recover. The high content of calcium carbonate and clay minerals in ore and the high TDS (total dissolved solid) content in groundwater would cause a reduction in porosity. (2) According to the uranium concentration and uranium leaching rate, a better leaching efficiency was obtained when the pH was lower than 6.6, and the HCO3− concentration was 800 mg/L. This result could serve as a reference for production in other similar mines.

Effect of Water TDS, on the Growth of Plant (Phaseolus vulgaris)

Water is the major constituent of life for the growth of animals and flora species. Water is available around the world with different Total Dissolved Solids (TDS) levels and minerals. On the basis of TDS, the hardness and softness of water are determined. (Underground water and oceanic water are found to have higher TDS than fresh water).
 Aim: To understand the effect of TDS on the growth of plant.
 Objectives: A study was conducted on the basis of the TDS of water to observe the effect of TDS on the growth of phaseolus vulgaris (kidney bean) plants and to check whether the water TDS is responsible for the growth of the plants or not.
 Methods: Water of different TDS levels was collected from Gwalior district (Gwalior, Gwalior fresh water Takenpur, and distilled water). Water has different TDS levels ranging from 95ppm (Parts Per Million), 750ppm, 2000ppm, distilled water with 0ppm TDS, and acidic distilled water (pH 3.5–4, by adding HCl acid). The kidney beans (phaseolus vulgaris) were purchased from a local mart and sowed into the washed sand with a neutral pH of 7, and the growth was observed under sunlight. (Each pot containing 7 beans).
 Results: The result of the experiment was positive as required, as the water TDS level affects the growth of plants. It has been observed that distilled water with a TDS of 0 ppm shows almost no growth, but a TDS of 750 ppm shows the maximum growth. Therefore, it has been concluded that TDS is also responsible for the growth of plants, and this practice can be done on a large scale also for the best result of growth.

Optimum chain desalination process design for treatment of high TDS brine: A case assessment for future treatment of extracted brine from Shenhua CO2storage site

AbstractCarbon dioxide‐enhanced water recovery (CO2‐EWR) is a promising strategy for managing reservoir pressure build‐up and mitigating the risk of fault activation resulting from CO2injection in deep saline aquifers. CO2‐EWR can also be employed for supplying the required water for different applications after a treatment stage for the produced saline water. In this study, a brief review on CO2‐EWR technology and its necessities are first carried out. After that, the feasibilities, advantages, and challenges of various available treatment technologies that can potentially be used to treat high total dissolved solids (TDS) brine are comprehensively assessed. Based on comprehensive evaluation on technologies, a chain desalination process, consisting of pretreatment, main treatment, and post treatment, is proposed as a strategic path for the treatment of high TDS brine extracted from the Shenhua CCS site. It is concluded that coagulation‐flocculation and gravity filtration are needed as primary stages to remove suspended particles, while membrane distillation (MD) is selected as a suitable main treatment technology for high TDS Shenhua brine. Then, MD treatment is comprehensively discussed for a small‐scale treatment of extracted Shenhua brine assuming that the pretreated brine is free of suspended solids. After presenting the heat and mass transfer equations for direct contact membrane distillation (DCMD), a mathematical thermodynamic model is programmed in EES (Engineering Equation Solver) software to briefly analyze the performance parameters of DCMD. The results indicate that the designed DCMD, in the absence of auxiliary systems and considering the inherent temperature of extracted brine from different formations, has the capability of producing 15.1 kg m−2hr of freshwater from the extracted brine of the Shihezi formation layer. In the case of employing the auxiliary system of flat‐plate collector (FPC) combined with heat exchanger (HX) to heat up the extracted Shenhua brine to the desired temperature of 80°C, the amounts of produced flux are enhanced by 133%, 72%, and 45% for the brine extracted from Liujiagou, Shiqianfeng, and Shihezi formations, respectively. Using the yearly solar radiation model in TRNSYS software, the maximum solar radiation on the tilted surface at the location of Shenhua project in Inner Mongolia Autonomous Region of China reaches 3800 kJ m−2hr at 1 PM on April 1. Considering maximum solar radiation on the tilted surface, it is proved that a small‐surface FPC can supply the required energy to heat up the extracted brine from its inherent temperature to the desired temperature of 80°C. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

In-Depth Laboratory Proppant Transport Study Using HVFRs for Marcellus High TDS Environments

Summary Excellent proppant transport can be accomplished by introducing high-viscosity friction reducer (HVFR) fracture fluids. However, HVFRs face several challenges that prevent these fluids from providing good proppant transport performance, including the presence of total dissolved solids (TDS) in the produced water. TDS can negatively impact the viscous and elastic properties of HVFR. This study evaluated the rheological and proppant transport performance using HVFRs at extreme salinity conditions using water samples from the Marcellus Basin. The anionic and cationic HVFRs with a concentration of 4 gpt were used. Experimental evaluation work, including the rheology, static proppant settling measurements, and dynamic proppant transport, was conducted using three Marcellus TDS concentrations (68,000; 137,000; and 229,000 ppm). All the experiments were performed at a high-temperature condition that mimics the Marcellus reservoir temperature of 65.5°C (150°F). The results show that the existence of TDS was largely impacted by both types of HVFRs, but the cationic HVFR exhibited better resistance to the Marcellus TDS compared to the anionic HVFR in terms of transporting proppant. The viscosity of the anionic HVFR was reduced more than that of the cationic HVFR, as TDS concentrations increased to 229,000 ppm. However, the elasticity of both HVFRs was weak, as a switch was made from using low TDS to high TDS. This could imply that HVFR viscosity provides the main contribution to proppant transport in high TDS environments. Therefore, it is crucial to evaluate the impact of TDS on the effectiveness of HVFR by investigating HVFR rheology, static proppant settling, and dynamic proppant transport in the TDS environment.

Study of the Effect of Physical Parameters on Commercial Hydroponics Based on Internet of Things (IoT): A Case Study of Bok Coy Plants (Brassica rapa) and Water Spinach (Ipomoea Aquatica)

Population growth causes the demand for food to increase. One solution that can be applied is agriculture with hydroponic technology. To increase production efficiency, one must know the physical parameters that most influence the production process. This research used an IoT system to gather accurate and precise measurement data of physical parameters to be used as a dataset for machine learning. The dataset consisted of light intensity, humidity, air temperature, and total dissolved solids (TDS). Plant growth was measured by leaf area of the plant, number of leaves, and plant stem length every 3 to 4 days. The models used in the machine learning process were linear regression, polynomial regression, and random forest regression. The machine learning results showed that the best model for predicting plant growth was random forest regression with an MAE of 8.3% and an R2 of 0.93, for both bok coy and water spinach. The variables that influence growth the most are TDS and light intensity. According to the relationship between TDS gradient and plant growth gradient, the most optimal growth can be achieved by raising the TDS gradient or by maintaining a high TDS, which can be achieved by adding nutrient solution to the tank regularly.

Seasonal Variations in Groundwater Quality under Different Impacts Using Statistical Approaches

The objective of this study was to evaluate seasonal fluctuations in groundwater quality, determine the effects of different stressors on this resource, and recognize the potential pollution sources in a coastal region of southern Vietnam. Eleven samples collected in Ben Tre province during the dry and wet seasons were then analyzed for sixteen parameters, including pH, total dissolved solids (TDS), salinity, total hardness (TH), ammonium (NH₄⁺-N), nitrite (NO₂ˉ-N), nitrate (NO₃ˉ-N), sulfate (SO₄²ˉ), chloride (Clˉ), iron (Fe), manganese (Mn), lead (Pb), mercury (Hg), arsenic (As), coliforms, and Escherichia coli (E. coli). Pearson correlation analysis, principal component analysis (PCA), and cluster analysis (CA) were employed. The results indicated that total dissolved solids, salinity, total hardness, Clˉ, E. coli and coliform were detected as contaminants in groundwater samples. The trend of fluctuations in the parameters was mostly higher in the dry season. Which Mn and coliform significantly fluctuated between the dry and wet seasons. Activities in industrial-craft areas, landfills and seawater-intruded areas negatively impacted groundwater quality, typically TDS in industrial-craft areas, coliform and E.coliat the landfill area. Six principal components obtained from PCA could explain 93.6% of the variance, and all parameters are responsible for variations in groundwater quality. Geology, discharged wastewater, landfill leachate, agricultural activities, and saltwater intrusion can be considered representative factors. CA grouped the collected samples into four clusters based on the similarity in water properties. The analysis results showed that the locations in each cluster have outstanding water quality characteristics, clusters I and III have high TDS characteristics, cluster II has coliforms, and cluster IV sets of locations with high salinity. This study is promised to partially fill the gap in comprehensive information on groundwater quality in the coastal province so that policymakers can develop sustainable water management strategies in the future. Doi: 10.28991/CEJ-2023-09-03-01 Full Text: PDF

Assessment of Groundwater Suitability for Irrigation and Livestock Purposes in Sayed Al-Shuhadaa Agricultural City, Karbala, Central Iraq

The study investigates the anion and cation concentrations and their distribution in the Dammam aquifer to assess the groundwater suitability for irrigation and livestock in Sayed Al-Shuhadaa, Karbala, central Iraq. It lies between longitudes 43º 29' 00'' – 43º 40' 00'' E and latitudes (32º 17' 00'' – 32º22' 00'') N. The physicochemical properties, cations and anions were measured in 14 active wells distributed in the study area. The assessment was conducted based on the sodium adsorption rate (SAR), sodium percentage (Na%), electrical conductivity (EC), total dissolved solids (TDS), and Hydrogen number (pH). Groundwater in the study area is very good for livestock and characterised by no damage, as the rate of sodium adsorption was good. The percentage of sodium and pH values are within the permissible values for irrigation, except for some wells that have high TDS and EC, which leads to an increase in salinity.

Performance of Copolymerized Organo-Selenium RO Feed Spacers during Fouling

Fouling of reverse osmosis (RO) systems to produce clean drinking water is a major problem. Organo-selenium inhibition is an attractive solution for this application because biofilm prevention has been shown in medical devices, water filtration systems, and plastics. This study examined whether selenium-coated polymers would have positive effects in controlling RO fouling. This study included an analysis of modified feed spacers’ performance on reduction of total biomass concentration, average biofilm thickness on the surface of RO membranes versus real wastewater sources, the impact of selenium catalytic activity on the reduction of RO membrane chemical scaling, and the performance of fouling and biofilm formation. A 1.5% organo-selenium was copolymerized into spacer elements used in an RO system. These systems were then tested with both city and industrial wastewater with different total dissolved solids (TDS) concentrations for effects on (1) flux, (2) biofilm formation, and (3) inorganic binding. The comparison of an organo-selenium spacer with a control spacer yielded the following for RO membranes: (1) lower calcium and magnesium binding; (2) better flux at high TDS concentrations in both city and industrial water; (3) lower biofilm thickness and volume; and (4) a decrease in both dead and viable bacteria. Testing of varying solids concentrations resulted in greater log inhibition of fouling as a result of operating the RO system with selenium copolymerized feed spacer. The impact of selenium catalytic activity versus divalent foulants (magnesium and calcium) is important because of their ability to create bridges between biological cells and membrane surface, leading to increased possibility of biofouling.

Origin and Enrichment Mechanisms of Salinity and Fluoride in Sedimentary Aquifers of Datong Basin, Northern China.

The exposure of inhabitants to high fluoride and saline groundwater is the main health issue in Datong Basin, Northern China. This study aims to elucidate the spatial distribution and the mechanisms of high fluoride and salinity occurrence in the shallow sedimentary aquifers of the Datong Basin. Groundwater salinity and fluoride content, and their association with measured hydrochemical parameters, were conducted using multivariate statistical analyses. The analytical results revealed that the concentrations of fluoride and total dissolved solids (TDS) show dramatic variations within the study area. Around 41.4% of groundwater samples contained high-level fluoride concentration (F- > 1.5 mg/L), whereas 32.8% contained elevated-level TDS (TDS > 1000 mg/L). Both fluoride and TDS concentrations had elevated trends towards the central part of the basin. Shallow groundwater was seriously affected by evaporation and evapotranspiration, which can be the critical factors responsible for rather high TDS and F- concentrations in shallow aquifers. Water-rock reactions including silicate hydrolysis, dissolution-precipitation of carbonates and evaporates, adsorption, and ion exchange processes, as well as evapotranspiration, are the main governing factors for salinity and fluoride enrichment in groundwater. Solubility control of F-bearing and carbonate minerals is the dominant mechanism affecting F- levels. Prevailing conditions of alkaline pH, moderate TDS and Na+, high HCO3-, and lower Ca2+ content facilitate the enrichment of fluoride in the study area. Excessive evapotranspiration can be also the most influencing factor responsible for high fluoride and TDS content, due to the extended residence time of groundwater and the arid climate of the central part of the Datong Basin.

Water Footprint Calculation, Effluent Characteristics and Pollution Impact Assessment of Leather Industry in Bangladesh

Leather processing industries consume high volumes of water and chemicals and release effluents into the environment that pollute the surface water and may cause harm to human health. Leather processing involves different wet processing stages such as soaking, liming, chrome tanning, rechroming, neutralization, fatliqouring and dyeing. The pollution generated from the leather processing stages varies in volume, nature and concentrations. Qualitative and quantitative assessments of effluents generated from different stages of leather processing can be useful to understand the stagewise and overall water pollution of leather wet processing and to design and plan pollution abatement initiatives. Water footprints (WF) can help in understanding the total water consumption and water pollution caused by the leather sector. The objectives of this research are to assess the characteristics of effluents generated from different stages of leather processing, calculate the water footprint (WF) and analyze the pollution load of the Bangladesh leather sector. To perform experimental analyses, effluent samples were collected from the following leather processing stages: soaking, liming, deliming and bating, pickling and tanning, wet back, rechroming, neutralization, retanning, dyeing and fatliqouring from four leather processing factories. The key pollution indicating parameters, such as pH, chemical oxygen demand (COD), biological oxygen demand (BOD), total dissolved solid (TDS) and total suspended solid (TSS) of the effluent samples were analyzed. The experimental study showed that almost 52% effluents generate from beam house and tan yard operations, and about 48% effluents generate from post tanning operations. Due to the presence of high amounts of salt, insecticides and bactericides, the effluent generated from the soaking stage contains high BOD and TDS. On the other hand, effluent generated from liming contains the highest amounts of BOD, COD, TDS, and TSS. The reduction or segregation of soaking and liming effluents will be effective in improving the environmental performance of the wet processing of leather. To assess the total water footprint of the leather sector, the water footprint of feed crops and raw hides were calculated, along with the water footprint of the leather processing stages. The water footprints of bovine and ovine crust leather were found to be 34,000 m3/ton and 17,300 m3/ton, respectively. The blue water footprint is higher in soaking, liming and finishing. The green water footprint of leather is mainly contributed by feed crops of farming animals. The grey water footprint was found higher in the soaking, liming, fatliqouring and dyeing stages. About 97% of the water footprints of tanneries are contributed by the wet processing stages. The grey water footprint is the most significant part of the total water footprint of the leather sector, which indicates the impact of high water pollution by the leather processing stages. This study can help to understand the overall scenario of water consumption and water pollution caused by the leather sector in Bangladesh. This study can also be useful in designing sustainable leather products by reducing the total water footprint per unit of leather goods. The systematic approach of this study could be useful for other countries in leather processing.

Physical Properties of Orange Peels Eco-enzyme: One way to Reduce and Recycle Waste and Environmental Problem

A high quantity of organic waste without proper waste management can endanger public health and environmental sustainability. To reduce the risk that can be caused by organic waste pollution, then there should be a solution. One of them is to make eco-enzyme. Eco-enzyme is a fermented solution from organic waste that can be used as floor cleaner, plant disinfectant, hand sanitiser, plant fertilizer, etc. A good eco-enzyme solution has special properties. One of them is the low-value power of Hydrogen (pH). In this study, other physical properties of eco-enzyme are analyzed. Eco-enzyme was produced from organic waste. Here, Sunkist orange peel and various mixtures of orange peel were used as the main materials of eco-enzyme. The eco-enzyme solutions were carried out for 33 days, accompanied by routine monitoring by reviewing physical parameters such as pH, Total Dissolved Solid (TDS), and Electrical Conductivity (EC) values. The results showed the characteristics of the eco-enzyme product by physical properties are the eco-enzyme has an acidic with a low pH value (<3.6) accompanied by high values of TDS (>1000 ppm) and EC (>1500mS/cm). The finding is TDS and EC have high value whereas usually high EC and TDS are owned by polluted liquids.

Optimizing the desalination rate in a photoelectrocatalytic desalination cell (PEDC) by altering operational conditions

Abstract Desalination of seawater is a promising response to solving the lack of drinkable water. The separation of cations and anions is carried out by inserting a desalination cell in the middle of a novel design of photoelectrocatalytic desalination cell (PEDC). Different parameters were evaluated and optimized for increasing the capability of system to desalt hypersaline water. Ultraviolet illumination (UV) was used as the driving force, exciting coated titanium nanotubes on the anode electrode, producing electron/hole pairs that degraded organic matter. Methylene blue degradation by UV irradiation was performed, owing to a high salt concentration level, and desalinated to produce electrical current. Performance of PEDCs was investigated by salt content, pH, and ion-exchange resin. The results indicated that higher total dissolved solid (TDS) removal occurred in acidic environments in anode chamber whereas the maximum produced electrical current occurred in alkaline environments in the cathode chamber. Also, the higher amount of salt content in the middle chamber resulted in the high TDS removal until the amount of electrical conductivity in the middle chamber reached 190 mS/cm. The TDS removal rates with and without using resins in the middle of the desalination cell after 10 days were 70.69% and 51.37%, respectively.