Total Dissolved Solids Concentration Research Articles

Novel electro-oxidation unit for electro-disinfection of E. coli and some waterborne pathogens during wastewater treatment: batch and continuous experiments

The prime objective of the current investigation is to evaluate a promising alternative method for disinfection wastewater using a novel electro-oxidation unit. The study focused on determining the best-operating conditions from a techno-economic point of view to be applied to continuous flow simulating actual disinfection modules. The treatment unit consisted of a Plexiglas container with a 3 L volume containing nine cylindrical shape electrodes (6 graphite as anode and 3 stainless steel as a cathode) connected to a variable DC power supply. Determination of the best operating parameters was investigated in batch mode on synthetic wastewater by studying the effect of contact time, current density (CD), total dissolved solids concentration (TDS), and bacterial density. Moreover, the continuous mode experiment was considered on real wastewater from an agricultural drain and the secondary wastewater treatment plant effluent before chlorination. The batch mode results revealed that the best applicable operational conditions that achieved the complete removal of E. coli were at a contact time of less than 5 min, TDS of 2000 mg/L, and CD of 4 mA/cm2. Application of these conditions on the continuous mode experiment indicated the complete removal of all bacterial indicators after 5 min in the drainage wastewater and after 3 min in the secondary treated wastewater. Physico-chemical characterization also suggested that no chlorine by-products displaying the hydroxide ion formed due to water electrolysis is the main reason for prohibiting the growth of pathogenic microbes. The electrical consumption was calculated in the continuous mode and found to be 0.5 kWh/m3 with an operational cost of about 0.06 $/m3, including the cost of adding chemicals to increase the TDS. The results proved that this novel electro-oxidation unit is a robust and affordable disinfection method for complete bacterial removal from wastewater and is more environmentally benign than other conventional disinfection methods.

Seasonal Variability of Phytoplanktons in the Non-Point Source Polluted River Nggada, Maiduguri – Borno State, Nigeria

Borno State is the epicenter of Boko Haram crisis which displaced millions of individuals. Maiduguri metropolis which became the principal refuge centre, has witnessed a rapid demographic change, land use and economic activities resulting into intense irrigational practice along the bank of river Nggada. This may result into changes in the physico – chemical parameters of the aquatic ecosystem and the dynamism may disrupt phytoplantonic community. The study was aimed at assessing the seasonal variability of phytoplanktons in non-point source polluted river Nggada of Maiduguri. Water samples for physico -chemical analysis were collected bi-weekly for a period of 11 months at three sampling stations. Physico-chemical parameters, including Dissolve Oxygen (DO), Dissolved Nitrate concentration, Dissolved Phosphorus Concentration, Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Surface Water Temperature (SWT) and potential Hydrogen (pH) were determined using standard procedures. Results indicated that all physico – chemical parameters except temperature, DO and pH of the river during both irrigational and non-irrigational regimes were slightly above the National Environmental Standards and Regulations Enforcement Agency’s (NESREA) permissible limits. A total of 7 classes (Cyanophyceae Chlorophyceae, Cryptophyceace, Euglenophyceae, Bacillariophyceae, Crysophyceace and Rhodophyceae) and 16 genera of phytoplanktons were identified. The results further revealed that the irrigation activities (dry season) have impacted on the physico – chemical parameters (pH, DO, TDS, nitrate and phosphate concentrations) of the study area. Remarkably, the changes in the physico – chemical parameters during the irrigational regime (dry season) have not impacted on the abundance and distribution of phytoplanktons. Hence, the non-point pollutants influenced the physico – chemical parameters of the river butalgal abundance and distribution were not influenced by the changes in the physico – chemical parameters of the river. The study thus, recommends the continuous monitoring and systematic effort to conserve the bio-resources and water quality of the river

Laboratory Comparative Study of Anionic and Cationic High-Viscosity Friction Reducers in Moderate to Extremely High Total Dissolved Solids Environments

Summary High-viscosity friction reducers (HVFRs) have been recently gaining more attention and increasing in use, not only as friction-reducing agents but also as proppant carriers. Reusing produced water has also been driven by both environmental and economic benefits. Currently, most friction reducers on the market are anionic friction reducers, which are fully compatible with most produced water with low to medium level of total dissolved solids (TDS) but show a significant drop at high TDS conditions in terms of their friction reduction performance in most cases. On the contrary, cationic friction reducers are believed to have better TDS tolerance and friction reduction performance under high TDS conditions. However, concerns remain about performance of using anionic and cationic HVFRs with produced water to transport proppant. The ultimate objective of this experimental study is to comparably analyze the proppant transport capabilities of anionic and cationic HVFRs in high TDS and reservoir temperature environments. An anionic HVFR and a cationic HVFR, both at 4 gallons per thousand gallons (GPT), were selected and analyzed. The rheology measurements of these anionic and cationic HVFRs were conducted in deionized (DI) water and high TDS water conditions. Static and dynamic proppant settling tests were conducted at various TDS conditions at reservoir temperature. Wall retardation and particle hindering on the performance of both anionic and cationic HVFRs were also observed and investigated using the particle image velocimetry (PIV) method. The results showed that the anionic HVFR had higher viscosity than the cationic HVFR due to larger molecular weight and had much higher elasticity. Increase in TDS concentration would decrease the viscous and elastic profiles of both anionic and cationic HVFRs. In particular, the elastic profile became negligible for both HVFRs. Besides, the “critical salinity” phenomenon was observed. Above this salinity, the viscosity of HVFRs was no longer affected by increasing TDS level. The “critical salinity” for both of the 4-GPT anionic and cationic HVFRs was in the range of 30 000 to 200 000 mg/L. Moreover, the cationic HVFR had lower “critical salinity” than the anionic HVFR. Finally, the correlation between rheology and proppant transport capabilities of HVFRs is discussed in this paper, and a simplified decision-making process of selecting fracturing fluids is proposed.

Coupled modeling and process optimization in a genetic-algorithm paradigm for reverse osmosis dialysate production plant

The integrity of dialysis procedure is dependent on multivariate factors of which the production of ultrapure dialysate is considered a vital criterion in the spate of the growing rate of renal-related hospitalization. Hence the need to maintain equilibrium between process conditions and configuration of operational factors is attributed to ensuring dialysate purity under a reverse osmosis technique is an identified focus for research. This study is designed to model and optimize osmotic pressure, specific energy, and permeate water quality in a reverse osmosis (RO) plant intended to improve dialysate quality by utilizing established computational resources. The simulation of feed pressure, feed temperature, concentrate recycle and membrane type, on recovery percentage, permeate total dissolved solids concentration (TDS), cost of operation, and energy consumption, is implemented using Water Application Value Engine (WAVE) Software. The optimization efficiencies are analyzed via an artificial neural network (ANN) type generic algorithm (GA) scheme in the water purification model on the architecture of Neural Power Software. The ANN model R2 for the three outputs, permeate recovery, permeate total dissolved solids concentration (TDS) and specific energy, is 1, 0.99997 and 0.99999 respectively, while RMSE for ANN is estimated as 0.0213, 0.0248, and 0.0085 respectively. The optimum design shows a net energy saving of 2.4% can be achieved, accompanied by a 24% reduction in operating cost, a 14% reduction in permeate TDS, and a 20% increase in permeate recovery. The study achieves energy minimization, cost-effectiveness, and process integrity under a modified process design for RO-mediated ultrapure dialysate production suitable for highly sensitive applications such as clinical hemodialysis systems.

Linking remote sensing analysis and reservoir operation optimization for improving water quality management of reservoirs

The present study proposes and evaluates an integrated framework in which water quality distribution model of the lake and reservoir operation optimization are linked for improving the environmental management of the reservoir. Coupled remote sensing data processing- machine learning model was utilized to simulate water quality distribution in the reservoir in which one machine-learning model was used for converting the spectral images to the total dissolved solids (TDS) distribution in the reservoir. Then, another machine-learning model was developed based on the generated data by the first model for predicting water quality distribution map for unseens reservoir inflow/outflow scenarios. This machine-learning model was applied in the structure of reservoir operation optimization. Particle swarm optimization was utilized in the optimization process. Based on the results in the case study, the proposed method is able to minimize environmental impacts in the reservoir while the benefits from the reservoir such as water supply are maximized. However, its performance is not perfect that seems logical. In fact, the proposed model is able to balance the environmental requirements and losses of the reservoir. According to the generated water quality distribution map in a critical month of the simulated period, TDS concentration alters in range of 258 mg/L to 1091 mg/L in the lake that demonstrates using water quality distribution model in the optimal reservoir operation is necessary. The proposed method highlights the importance of using the remote sensing-based models in the structure of water resources optimization systems.

Heavy metal pollution in leachates and its impacts on the quality of groundwater resources around Iringa municipal solid waste dumpsite.

Heavy metal pollution in groundwater due to leachates leaking from the Iringa municipal dumpsite was investigated. The pollution was studied by analyzing pH, electrical conductivity (EC), total dissolved solids (TDS), and heavy metals (Fe, Pb, Cr, Cd, Cu, Ni, Mn, and Zn) in leachates collected within the dumpsite and groundwater samples from residential wells close to the dumpsite. The pH of the leachate samples varied from 7.40 to 9.10, implying alkaline behavior and the methanogenic phase of solid waste deposits. The levels of EC, TDS, and heavy metals (Fe, Pb, Cr, Cu, Ni, Mn, and Zn) in leachates were above the national and/or international standards. On other hand, groundwater samples presented pH values ranging from 7.15 to 7.60 which were within the World Health Organization acceptable limit. The concentrations of EC, TDS, Fe, Pb, Ni, Mn, and Zn in most groundwater samples exceeded the national and/or international permissible limits for drinking water. In addition, the water quality indices (WQI) of groundwater samples ranged between 8.30 and 17.90, which implied the excellent quality of groundwater sources. However, the presence of high levels of heavy metals above the permissible limits in both leachate and groundwater samples signified potential risks to the environment and public health. Therefore, the present study calls for proper management of municipal solid waste to reduce the potential risks of further contamination on the groundwater resources and environment around the Iringa municipal dumpsite.

Optimization of the biological salt removal process from artificial industrial wastewater with high TDS by Spirulina microalga using the response surface method.

This study aimed to examine the direct applicability of Spirulina maxima as a new conceptual method for removing total dissolved solids (TDS) from artificial industrial wastewater (AIW). In this study, live microalgal cells were used in a photobioreactor for TDS removal. The effects of TDS levels, pH, light intensity, and light retention time on microalgal growth and TDS removal were investigated, and optimal conditions were determined using the response surface method and Box-Behnken Design (RSM-BBD). The calculated values of coefficient of determination (R2), adjusted R2, and predicted R2 were 0.9754, 0.9508, and 0.636, respectively, which are close to the R2 values and validated the proposed statistical model. A second-order model could optimally determine the interactions between the studied variables according to the one-way analysis of variance (ANOVA). The results showed that increasing TDS levels reduced microalgal growth and TDS removal efficiency in AIW. S. maxima reduced TDS by 76% and 47% at TDS concentrations of 2,000-4,000 mg/L, respectively, when used in AIW. Maximum biomass efficiency (1.8 g/L) was obtained at a TDS concentration of 2,000 mg/L with other parameters optimized.

Source water vulnerability to elevated total dissolved solids within a mixed-use Appalachian River basin

The upper Monongahela River basin in West Virginia represents a watershed wherein historic land use activities, including coal mining, conventional oil and gas development, and residential and urban development have contributed to elevated total dissolved solids (TDS) concentrations within surface and source waters with widespread exceedance of the 500 mg/L secondary drinking water standard for TDS. Our research was designed to characterize spatial variability in and sources of elevated and assess vulnerability of surface and source waters to additional TDS sources and loading. We compiled 3439 unique water quality sampling records throughout the study area over a ten-year period and applied boosted regression tree (BRT) analysis to model log[x]-transformed TDS as a function of landscape attributes across the 885 sampled NHD catchments. We predicted (i.e., elevated TDS and reduced dilution capacity) and observed (i.e., increased variability in TDS and temporary exceedances of 500 mg/L) elevated vulnerability of source waters, with vulnerability being largely driven by a few dominant contributors of TDS throughout the stream network. Notably, seven 12-digit hydrologic unit code (HUC) inflows to the Monongahela River and its vulnerable tributaries were predicted to require a combined 6,664,879 m3 of water (i.e., chemical footprint) to dilute TDS concentrations below 500 mg/L from July through September. Our results provide insights into how the mixed land uses containing extractive industries can impact water quality and demonstrates the importance of both spatial and temporal processes in controlling vulnerability of source waters to water pollution.

Geochemical analysis and quality assessment of geothermal water in Gujarat, India

Geothermal water can have a wide range of direct applications, including drinking, domestic use, irrigation and industrial use. This study analyses geothermal water from Dholera, Diu, Gandhar, Kutch, Porbandar, Tulsishyam, and Unai regions located in Gujarat, India, to determine the hydrochemistry for establishing the water's suitability for drinking and irrigation purposes. From each region, three different water samples were collected. For drinking purpose, total eleven water quality parameters such as pH, electrical conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, chloride, sulphate, carbonate and bicarbonate were evaluated. Piper and Durov plots were used to understand the ionic composition and evolution of water. Whereas for irrigation, the parameters such as total dissolved solids, sodium absorption ration, electrical conductivity, and potential salinity were used for water quality check. Wilcox Plot was plotted to understand the sodium and salinity hazard of water. Water quality index and irrigation water quality index were used to assess the water quality for making the analytical procedure easy. The findings indicate that the water samples from the Dholera and Diu areas had extremely high values for both the water quality index and total dissolved solids content. Water in these places may be appropriate for making salt. All the other samples show adequacy for utilization in irrigation purpose.

Boron removal from synthetic brines and oilfield produced waters using aluminum electrocoagulation

High boron (B) levels in oil and gas produced waters prevent its beneficial reuse as irrigation water without proper treatment. Aluminum (Al) electrocoagulation (EC) is a promising technology for B removal, but further research and development is needed to optimize EC for use in removing B from produced waters. To this end, B removal by adsorption onto insoluble aluminum hydroxide solids, generated by EC in simulated brines (up to 50,000 mg/L NaCl) and real oilfield produced waters, was studied. B removal during EC was greater than when aluminum hydroxide solids formed by EC were subsequently exposed to B containing solutions. Working parameters affecting B removal during the EC process, including current, total dissolved solid (TDS), temperature, pH, scale-forming cations and organic matter, were investigated to explore ways to achieve higher B removal. Boron removal increased with increased current loading and time, and with the concomitant increased Al solids concentration. However, too high a current loading limited B removal because of a change in the structure of the aluminum hydroxide solids. Higher TDS decreased B removal slightly, but lower TDS concentrations limited the use of higher current loadings. Temperature increased during EC treatment, particularly at higher current loadings, and this inhibited B removal due to an accelerated aggregation of amorphous Al solids into larger, denser, and presumably more crystalline particles. The best B removal occurred at pH 8, corresponding to a slightly positive zeta potential for aluminum hydroxide and a small but significant fraction of negatively charged B species. Scale-forming cations such as Ba2+ and Sr2+ had no obvious effect on the EC process. The presence of high concentrations of Mg2+ and Ca2+ resulted in low bulk pH values during the EC process and greater formation of solid products, but B removal did not decrease during a pH-controlled (pH = 8) EC process with these divalent cations present. Two produced water samples collected from oilfields in Kansas, US were treated using EC for 1 h, resulting in up to ~70 % B removal from solution with a current loading of 6.67 A/L, and up to 78 % with 13.33 A/L.

GALDIT Modification for Seasonal Seawater Intrusion Mapping Using Multi Criteria Decision Making Methods

Recently, coastal aquifers have been found to be increasingly exposed to seawater intrusion (SWI) due to climate change and anthropogenic activities. Various method exists for coastal aquifer vulnerability mapping and the one most commonly used is GALDIT because of its simplicity. The present study modified the original GALDIT ratings and weights using Shannon’s entropy theory to study the seasonal vulnerability of coastal aquifer in the coastal region of Benin, West Africa. Thus, the monthly GALDIT index for the study region was computed using 5 years of (2015–2019) average data of GALDIT dynamic input parameters. The original and modified GALDIT approaches were validated using total dissolved solid (TDS) concentration. Pearson’s correlation and Spearman coefficient correlations were calculated, and generally the modification of the GALDIT parameters’ relative weight using entropy has improved the method as this gave a better correlation with TDS concentration (0.739). From the calculated monthly GALDIT index, the most vulnerable period was identified using TOPSIS method. Based on TOPSIS results, the coastal aquifer of Benin is more vulnerable to seawater intrusion in February due to the decrease of groundwater level in that period and less vulnerable in July. The performed sensitivity analysis showed that height of groundwater level above the mean sea level, distance from shore, and thickness of the saturated aquifer have the most influence in vulnerability to SWI assessment in the study area.

Dilution and Pollution: Assessing the Impacts of Water Reuse and Flow Reduction on Water Quality in the Los Angeles River Basin

Los Angeles (LA), California, USA is one of many population-dense, arid cities whose treated wastewater discharge comprises most of the river flow (up to 70% in the LA River). Like other arid cities, LA plans to improve water supply by reusing treated wastewater and diverting nonstorm stormdrain flows. This study quantifies the impact of these management actions on pollutant loads and concentrations in the LA River. Daily pollutant loads and concentrations for total suspended solids (TSS), total dissolved solids (TDS), copper, zinc, and lead were predicted using EPA SWMM across nine wastewater reuse and nonstorm stormdrain diversion scenarios. Reduced flows generally decreased daily loads for all pollutants, but the impact on daily concentrations varied. Concentrations of TDS, TSS, copper, and lead increased with wastewater reuse, while zinc concentrations increased with the reduction of nonstorm stormdrain flows. Copper, zinc, and TDS water quality objectives were met less frequently with increasing flow reduction. These results elucidate the potential impacts of flow reductions on water quality and will help inform management decisions in effluent-dominated rivers.

Effects of return flows on stream water quality and availability in the Upper Colorado, Delaware, and Illinois River Basins

Understanding effects of human water use and subsequent return flows on the availability and suitability of water for downstream uses is critical to efficient and effective watershed management. We compared spatially detailed estimates of stream chemistry within three watersheds in diverse settings to available standards to isolate effects of wastewater and irrigation return flows on the suitability of downstream waters for maintaining healthy aquatic ecosystems and for selected human uses. Mean-annual flow-weighted total and source-specific concentrations of nitrogen and phosphorus in individual stream reaches within the Upper Colorado, Delaware, and Illinois River Basins and of total dissolved solids within stream reaches of the Upper Colorado River Basin were estimated from previously calibrated regional watershed models. Estimated concentrations of both nitrogen and phosphorus in most stream reaches in all three watersheds (at least 78%, by length) exceed recommended standards for the protection of aquatic ecosystems, although concentrations in relatively few streams exceed such standards due to contributions from wastewater return flows, alone. Consequently, efforts to reduce wastewater nutrient effluent may provide important local downstream benefits but would likely have minimal impact on regional ecological conditions. Similarly, estimated mean-annual flow-weighted total dissolved solids concentrations in the Upper Colorado River Basin exceed standards for agricultural water use and (or) the secondary maximum contaminant level (SMCL) for drinking water in 52% of streams (by length), but rarely due to effects of irrigation return flows, alone. Dissolved solids in most tributaries of the Upper Colorado River are attributable primarily to natural sources.

Climate change impacts on the flow regime and water quality indicators using an artificial neural network (ANN): a case study in Saskatchewan, Canada

AbstractIn this study, the artificial neural network (ANN) method was applied to investigate the impacts of climate change on the water quantity and quality of the Qu'Appelle River in Saskatchewan, Canada. First, the second-generation Canadian earth system model (CanESM2) was adopted to predict future climate conditions. The Statistical DownScaling Model (SDSM) was then applied to downscale the generated data. To analyze the water quality of the river, concentrations of dissolved oxygen (DO) and total dissolved solids (TDSs) from the river were collected. Using the collected climate and hydrometric data, the ANNs were trained to simulate (i) the ratio of snowfall-to-total precipitation based on the temperature, (ii) the river flow rate based on the temperature and precipitation; and (iii) DO and TDS concentrations based on the river flow and temperature. Finally, the generated climate change data were used as inputs to the ANN model to investigate the climate change impacts on the river flow as well as DO and TDS concentrations within the selected region. Hydrologic alteration of the river was evaluated via the Range of Variability Approach (RVA) under historical and climate change scenarios. The results under climate change scenarios were compared with those under historical scenarios and indicated that climate change would lead to a heterogeneous change in precipitation and temperature patterns. These changes would have serious degrading impacts on the river discharge as well as DO and TDS concentration levels, causing deterioration in the sustainability of the river system and ecological health of the region.

Piezoelectric atomizer in aeroponic systems: A study of some fluid properties and optimization of operational parameters

The piezoelectric method to atomize fluids in aeroponic systems is known as a new application. In the current study, the effects of four independent variables on the misting rate were investigated. These variables were Dosage of Chemical Fertilizer (DCF), the Height of Solution above Piezoelectric Ceramic (HSPC), Piezoelectric Location at the Bottom of the Container (PLBC), and the Container Geometry (CG). Physical properties such as fluid density, viscosity, surface tension, Total Dissolved Solids (TDS), and Electrical Conductivity (EC) of the solutions were measured. Moreover, optimization was performed to determine suitable ranges of independent variables to get the optimum value of the misting rate. Results showed that the HSPC, PLBC, and CG significantly affect the total misting rate (P < 1%). Besides, the DCF, HSPC, and CG have significant effects on surface evaporation at a probability level of 1%. At the temperature of 25 ℃ and for different concentrations of fertilizer, the density, viscosity, surface tension, TDS, and EC varied between 1 002–1 006.5 kg/m3, 1.009–1.395 mPa·s, 0.071 82–0.072 98 N/m, 253–3 397 mg/L, 502–6 795 µS/cm, respectively. Total misting rate ranged between 0.499 and 5.720 g/min. In the outlet of the mist generation container, mass flow rate was in the range of 59.895 to 65.116 g/min. Also, theoretically calculated mist average droplet size was in the range of 2.90 to 2.92 µm for different fertilizer doses. The present study is the first research on the factors affecting the ultrasonic mist production rate in an aeroponic system. For future developments, effect of voltage, frequency, and using horn should be investigated. Besides, similar research should be done in the field of gas-phase bioreactors (mist bioreactors).

Applying Saudi clay deposits for treatment of household water at the point-of-use

This research aims to beneficiate the clay deposits abundant in the Al Baha district to produce ceramic filters for “point-of-use” household water treatment technology to remove dissolved solids from water that is no longer valid for drinking purposes to meet the needs of the community through a safe household and industrial water supply after further treatment purposes. In addition, it helps to reduce the expenses of citizens earmarked to buy drinking water. A sample of laterite, clay, and kaolin from Al Baha district was thermally treated at 800 °C, acid treated with HCl, analyzed by XRD, FTIR, and SEM, and tested for treatment of household water. The temperature, pH, electrical conductivity (EC), and total dissolved solids (TDS) were measured. In the application step for point-of-use water treatment of household water, the treated materials were introduced in calcined kaolin filters and commercial polypropylene filters. Based on the results of household water treatment with raw and treated clay materials, the raw clay materials, has poor adsorption capacity. The thermal treatment of clay samples dehydrates the clay minerals into sintered aluminosilicates and enhances the conversion of poorly crystallized iron oxide to α-Fe2O3 without improving the adsorption capacity of clay materials. However, the acid treatment of the clay samples removes iron-bearing minerals leaving behind amorphous aluminosilicate matter characterized with improved adsorption capacity. It was concluded that the acid treatment of clay material by concentrated HCl acid completely leaches iron oxide phases and broke down and disintegrated the clay minerals into the amorphous matter with enhanced the adsorption capacity. The combination of selected acid-treated laterite, clay, and charcoal for the household water treatment filter at the point of use in the calcined kaolin filter and the polypropylene filter reduced the TDS content by 40–42%.

Cultivation Innovations of Growth Promoting Bacteria and the Characteristics of Several Vegetables

Reducing the use of chemicals in vegetable cultivation is an environmentally friendly cultivation technology that is expected to reduce negative impacts on the environment. One of the efforts to reduce chemicals in cultivation is to use bacteria that live in plant roots as plant growth promoters or biopesticides. This study aims to determine the number of endophytic bacteria from bamboo and leguminosae roots that have the potential as plant growth promoting agents. The making of plant growth-promoting rhizobacteria (PGPR) starter which was carried out in this study used the roots of bamboo, lemongrass and Mimosa Pudica Linn. Furthermore, it is applied to vegetable cultivation (Chinese cabbage, tomato, carrot and green mustard/caisim) to determine the physical characteristics of vegetables from the result of PGPR application compared to results from conventional farmers. This study used a factorial randomized block design with 2 factors. The first factor is the plant roots used, while the second factor is the length of the plant roots soaking in water, namely 72, 96, 120 hours. The data from the PGPR starter analysis results are made into a table, then a descriptive discussion is carried out. For vegetable data from the cultivation results using PGPR compared to vegetable from conventional farmer results. Based on laboratory analysis, obtained the total microbes in samples from bamboo roots with a soaking time of 72 hours were higher than the other samples, namely 8.49 x 106 cfu ml-1; pH in samples of PGPR from the roots of Mimosa Pudica Linn, bamboo, lemongrass, commercial PGPR (from Central Java farmers) ranged from 3.0 to 6.7; while the total dissolved solids content ranged from 0.2 to 2.6%. Based on the graph of plant growth in the PGPR treatment and with no treatment, there is a slight difference, not much increase or decrease. In tomatoes with PGPR treatment, plant growth was higher than without the use of PGPR, while for Chinese cabbage and caisim the growth was almost the same between PGPR treatment and without PGPR. For carrots, it was seen that with PGPR treatment, plant growth was lower than without PGPR. The results of the analysis of texture, brightness level and total dissolved solids in Chinese cabbage, caisim, tomatoes and carrots with PGPR application, the characteristics are almost the same as the results of conventional farmers. By looking at these results, it is hoped that in the future cultivation innovation by utilizing bacteria around the roots, is one of the environmentally friendly cultivation applications and begins to reduce the use of chemicals in cultivation.

Characterization of Solid Waste Leachateand Its Impact on Surface Water Quality: A Case Study at Rajbandh, Khulna, Bangladesh

The present study was carried out to characterize leachate from waste dumping site and its impact on surrounding surface water quality at Rajbandh in Khulna. For this purpose, surface water samples (10) and leachate samples (5) were taken from the site during two season the monsoon season and post monsoon respectively. The samples were taken during the daytime from 9 a.m. to 1 p.m because at midday the temperature rises and the physico-chemical parameters of the water are modified. Some physico-chemical parameters such as pH, Electrical conductivity (EC), Total dissolved Solids (TDS), Dissolve Oxygen (DO), Chloride (Cl-), Magnesium (Mg2+), Calcium (Ca2+), Sodium (Na+), Potassium (K+), Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Iron (Fe2+), Phosphate (PO43-), Sulfate (SO42-), Nitrate (NO32-) were analyzed in the laboratory in accordance with standard laboratory procedure. As well as some heavy metals such as Cadmium, Chromium, Lead, Manganese, Iron and Zinc were also analyzed in the laboratory. It is observed that, the physicochemical characteristics of surface water and leachate samples vary among the parameters in two seasons throughout the study period. The concentration of TDS and EC were found to be high in leachate compare to surface water samples that might be caused due to the existence of high-level various anions and soluble salts with other inorganic components. In monsoon the TDS values ranged from 3227 ± 2357 for leachate and 737 ± 498 for surface water samples whereas in post-monsoon the variation followed by 4640 ± 1790 and 803 ± 232 for surface water and leachate respectively. In case of EC for leachate it varied from 3630 ± 1397 and 4900 ± 1734 for monsoon and post-monsoon seasons correspondingly but varied from 1473 ± 498 in monsoon and 1627 ± 473 in post-monsoon for surface water samples. The high concentration of BOD (3.91 ± 1.54 in monsoon and 6.25 ± 3.27 in post- monsoon) and COD (117.80 ± 58.31 in monsoon and 229.39 ± 166.55 in post-monsoon) value were found in surface water samples compared to leachate samples. In case of Cr for leachate it varied from 0.081 ± 0.029 and 0.070 ± 0.026 for monsoon and post-monsoon seasons correspondingly. As well as the concentration of Cd (0.023± 0.006 in monsoon and 0.087±0.068 in post monsoon) and Pb (0.35±0.109 in monsoon and 0.025±0.013 in post monsoon) varied greatly during both season. The concentration of heavy metals such as Pb, Zn, Cr and Mn in surface water samples was also greater than 0.001mg/l. Further for leachate COD was very strongly correlated with TDS and cadmium. Magnesium was significantly correlated with potassium. For surface water sample TDS was significantly correlated with EC and pH. Chloride was significantly correlated with Cd and pb was correlated with calcium. This study recommended that the authority should take proper steps for the management of waste as well as give emphasis on the leachate collection.

Effects of simulated surface freshwater environment on in situ microorganisms and their methanogenesis after tectonic uplift of a deep coal seam

Secondary biogenic coalbed gas (CBG) is the gas generated by the microbial degradation of coal or wet gas components after freshwater recharge events. However, in situ microorganisms in deep coalbed water with high total dissolved solids (TDS) content may be overlooked. The evolution of the community structure and gene function of in situ microorganisms and their contributions to secondary biogenic CBG are poorly understood. The coalbed water TDS content in the Miquan region of southern Junggar Basin is unusually high (up to 45,000 mg/L), CBG is biogenic, and microorganisms have been detected in coalbed water. This study collected coal and high-TDS coalbed water samples in the Miquan region. Gas production experiments in a simulated freshwater environment (carrying nutrients) were conducted. Microbial community structure and gene function were analyzed using metagenomic sequencing. The gas production capacity of microorganisms in high-TDS coalbed water was significantly enhanced (up to 220.81%) under subculture with deionized water and nutrients. Microbial community analysis indicated that the hydrolytic bacterial group changed from a single genus to a state of synergistic degradation by multiple genera. The abundances of acidogenic bacteria, hydrogen-producing acetogenic bacteria, and methanogens gradually increased. Overall, the relationships between microorganisms were significantly optimized. Gene function analysis showed that most of the functional types were related to metabolism. Low-TDS culture enhanced the metabolic capacity of the microorganisms, thereby improving the fermentation performance. Finally, through combining the succession of the microbial communities, gene function changes, and gas production results, the geological methane-producing process of the in situ microorganisms in deep high-TDS coalbed water against the background of tectonic uplift was recreated.

Influence of permafrost and hydrogeology on seasonal and spatial variations in water chemistry of an alpine river in the northeastern Qinghai-Tibet Plateau, China

Known as the third pole of the world, the Qinghai-Tibet Plateau has been experiencing rapid permafrost warming and thawing over the last few decades. However, the impact of permafrost distribution and hydrogeology on river hydrochemistry in alpine areas remains unclear. This study conducted four sampling campaigns to reveal the temporal and spatial variations in and factors driving river hydrochemistry in the upper reaches of the Heihe River, the northeastern Qinghai-Tibet Plateau. We found that the concentrations of major ions and total dissolved solids (TDS) in river water showed substantial seasonal variations; the concentrations were generally lower during the initial thawing and thawed periods than during the initial freezing period. However, solute fluxes during the thawed period were much higher than those during the frozen period. The concentrations of major ions and TDS gradually decreased to a minimum from the permafrost meander (PM) section to the seasonal frost meander (SFM) section and then increased the seasonal frost canyon section. Using the revised forward model, we found that river solutes were contributed by carbonate weathering (mean 38.9%) > sulfide oxidation (22.9%) > evaporite dissolution (20.2%) > atmospheric precipitation (8.7%) > silicate weathering (5.0%) > glacial meltwater (4.3%). The higher TDS, Na+, Cl−, Ca2+, Mg2+, and SO42− concentrations in the PM section reflected the influence of freeze-out fractionation. The concentrations of major ions and TDS were lowest in the SFM section, indicating that the riparian porous aquifer was essential in regulating river hydrochemistry, thus reducing its spatiotemporal variations in the alpine area. In the mountain glacier–hillslope–riparian porous aquifer–river system, the river was mainly recharged by groundwater with insufficient water–rock interactions due to the rapid flow owing to the high elevation difference and high permeability of the riparian quaternary porous aquifers. Our findings provide insights into the construction of hydrogeochemical models in alpine areas and are practically important for the scientific management of water resources in the Qinghai-Tibet Plateau.