Product Water Quality Research Articles

Formation and Fate of Carbonyls in Potable Water Reuse Systems.

Low molecular weight, uncharged compounds have been the subject of considerable study at advanced treatment plants employed for potable water reuse. However, previously identified compounds only account for a small fraction of the total dissolved organic carbon remaining after reverse osmosis treatment. Uncharged carbonyl compounds (e.g., aldehydes and ketones) formed during oxidation have rarely been monitored in potable water reuse systems. To determine the relative importance of these compounds to final product water quality, samples were collected from six potable water reuse facilities and one conventional drinking water treatment plant. Saturated carbonyl compounds (e.g., formaldehyde, acetone) and α,β-unsaturated aldehydes (e.g., acrolein, crotonaldehyde) were quantified with a sensitive new analytical method. Relatively high concentrations of carbonyls (i.e., above 7 μM) were observed after ozonation of wastewater effluent. Biological filtration reduced concentrations of carbonyls by over 90%. Rejection of the carbonyls during reverse osmosis was correlated with molecular weight, with concentrations decreasing by 33% to 58%. Transformation of carbonyls resulted in decreases in concentration of 10% to 90% during advanced oxidation, with observed decreases consistent with rate constants for reactions of the compounds with hydroxyl radicals. Overall, carbonyl compounds accounted for 19% to 38% of the dissolved organic carbon in reverse osmosis-treated water.

Ultrafiltration pretreatment enhances membrane distillation flux, resilience and permeate quality during water recovery from concentrated blackwater (urine/faeces)

In this study, the pretreatment of concentrated blackwater using ultrafiltration (UF) was shown to improve the permeability, selectivity and robustness of membrane distillation (MD) for application to wastewater treatment. Concentrated blackwater comprises urine and faeces, with minimal flushwater added. The faecal contribution increased the soluble organic fraction and introduced coarse and colloidal particles into the urine, which increased resistance to filtration during dead-end UF. Ultrafiltration removed the particulate and colloidal fractions (MW > 500 kDa) from the blackwater, which permitted similar permeability and robustness for MD to that observed with urine (29.9 vs 25.9 kg m−2h−1), which comprises a lower colloidal organic concentration. Without UF pretreatment, a higher density organic layer formed on the MD surface (197 vs 70 gCODm−2) which reduced mass transfer, and transformed the contact angle from hydrophobic to hydrophilic (144.9°to49.8°), leading to pore wetting and a dissipation in product water quality due to breakthrough. In comparison, with UF pretreatment, MD delivered permeate water quality to standards satisfactory for discharge or reuse. This is particularly timely as the ISO standard for non-sewered sanitation has been adopted by several countries at a national level, and to date there are relatively few technologies to achieve the treatment standard. Membrane distillation provides a robust means for concentrated blackwater treatment, and since the energy required for separation is primarily heat, this advanced treatment can be delivered into areas with more fragile power networks.

Water Quality Index of Suceava River in Suceava City Metropolitan Area

The water quality of rivers worldwide is of persistent interest due to its impact on human life. Five streamwater quality parameters of Suceava River were monitored in 2019 upstream and downstream of Suceava city, Romania: dissolved oxygen, specific conductivity, pH, oxidation-reduction potential, and temperature. Data was recorded at a high temporal frequency, every hour, and produced Water Quality Index (WQI) time series of similar resolution. Our additive WQI has variants with particular advantages. Water quality of Suceava city exhibits a diurnal cycle. Upstream, WQI values indicate a quasi-permanent good water quality; downstream, the water quality oscillates around the average WQI value because of the various sources of water contaminants, especially the wastewaters from the wastewater treatment plant. Parameters from this point source of pollution are taken into account to explain the decaying streamwater quality towards the end of 2019. WQI is useful for detecting time intervals when water self-purification events have a high chance of occurrence.

Ultrafast Ion Sieving from Honeycomb-like Polyamide Membranes Formed Using Porous Protein Assemblies.

Despite the commercial success of thin film composite polyamide membranes, further improvements to the water permeation of polyamide membranes without degradation in product water quality remain a great challenge. Herein, we report the fabrication of an interfacially polymerized polyamide nanofiltration membrane with a novel 3D honeycomb-like spatial structure, which is formed from a tobacco mosaic virus (TMV) porous protein nanosheet-coated microfiltration membrane support. TMV nanosheets with uniform pores and appropriate hydrophilicity deposited inside the support membrane pores facilitate the construction of a localized water-oil reaction interface with evenly distributed monomers and guide the formation of a defect-free polyamide layer with a spatial structure that copies the geometry of the membrane cavities. Such a 3D morphology possesses ultrahigh specific surface area, leading to unprecedented membrane water permeance as high as 84 L m-2 h-1 bar-1, high MgSO4 rejection of 98%, and monovalent/divalent ion sieving selectivity up to 89.

Zero Liquid Discharge of Ultrahigh-Salinity Brines with Temperature Swing Solvent Extraction.

Zero liquid discharge (ZLD) of hypersaline brines is technically and energetically challenging. This study demonstrates ZLD of ultrahigh-salinity brines using temperature swing solvent extraction (TSSE), a membrane-less and nonevaporative desalination technology. TSSE utilizes a low-polarity solvent to extract water from brine and then releases the water as a product with the application of low-temperature heat. Complete extraction of water from a hypersaline feed, simulated by 5.0 M NaCl solution (≈292 g/L TDS), was achieved using diisopropylamine solvent. Practically all of the salt is precipitated as mineral solid waste and the product water contains <5% of NaCl relative to the hypersaline feed brine. Consistent ZLD performance of high salt removals and product water quality was maintained in three repeated semibatch TSSE cycles, highlighting recyclability of the solvent. The practical applicability of the technique for actual field samples was demonstrated by ZLD of an irrigation drainage water concentrate. This study establishes the potential of TSSE as a more sustainable alternative to current thermal evaporation methods for zero liquid discharge of ultrahigh-salinity brines.

Performance Improvement and Biofouling Mitigation in Osmotic Microbial Fuel Cells via In Situ Formation of Silver Nanoparticles on Forward Osmosis Membrane.

An osmotic microbial fuel cell (OsMFC) using a forward osmosis (FO) membrane to replace the proton exchange membrane in a typical MFC achieves superior electricity production and better effluent water quality during municipal wastewater treatment. However, inevitable FO membrane fouling, especially biofouling, has a significantly adverse impact on water flux and thus hinders the stable operation of the OsMFC. Here, we proposed a method for biofouling mitigation of the FO membrane and further improvement in current generation of the OsMFC by applying a silver nanoparticle (AgNP) modified FO membrane. The characteristic tests revealed that the AgNP modified thin film composite (TFC) polyamide FO membrane showed advanced hydrophilicity, more negative zeta potential and better antibacterial property. The biofouling of the FO membrane in OsMFC was effectively alleviated by using the AgNP modified membrane. This phenomenon could be attributed to the changes of TFC–FO membrane properties and the antibacterial property of AgNPs on the membrane surface. An increased hydrophilicity and a more negative zeta potential of the modified membrane enhanced the repulsion between foulants and membrane surface. In addition, AgNPs directly disturbed the functions of microorganisms deposited on the membrane surface. Owing to the biofouling mitigation of the AgNP modified membrane, the water flux and electricity generation of OsMFC were correspondingly improved.

Effect of produced water treatment technologies on irrigation-induced metal and salt accumulation in wheat (Triticum aestivum) and sunflower (Helianthus annuus)

Produced water (PW), a wastewater resulting from hydraulic fracturing and oil and gas production, has been utilized in arid regions for irrigation purposes and potentially presents a new water source for crop irrigation in areas of increasing water scarcity. However, there is a potential for both synthetic and geogenic contaminants in these waters to accumulate in irrigated food crops. This study assessed how water treatment technologies targeted at removal of salinity (i.e., total dissolved solids) and organic chemical content (i.e., dissolved organic carbon) from PW to achieve agricultural irrigation standards altered the impact of inorganic contaminants and nutrient uptake on two salt-tolerant food crops, sunflower (Helianthus annuus) and wheat (Triticum aestivum). The impacts of the treatment technologies on inorganic contaminant loadings in the irrigated soils were also assessed. Treatment technologies to improve PW quality decreased the adverse impacts on plant health; however, plant health was more affected by dilutions of PW than by the treatment technologies employed. Phenotypically, plants irrigated with 90% dilution (low) treatment groups, regardless of treatment technology, were comparable to controls; however, plants watered with high proportions (50%) of raw or treated PW displayed stunted growth, with reduced height and leaf area, and sunflower seed saw 100% yield loss. Although phenotypically similar, plants of the low treatment groups exhibited changes in the ionome, illustrating the influence of PW on plant uptake, translocation, and accumulation of metals, salts, and micronutrients. In addition, bioavailability of metals and nutrients was impacted by the unique and complex PW matrix: bioconcentration factors traditionally used to evaluate risk may therefore over or underestimate accumulation.

Application of environmental probiotic on rearing snakehead fish (Channa striata)

This study aims to evaluate the application of environmental probiotic on production performance (survival rate, absolute weight and length, biomass weight and specific growth rate and blood condition level in snakehead fish (Channa striatus) rearing. The research was conducted at the Cibalagung Environmental Research and Toxicology Installation, Bogor, Indonesia. The experiment was conducted in a completely randomized design with three treatments, including RIFA probiotic, commercial probiotic, and without probiotic application repeated three times each experiment. Fish (weight: 6.5-6.9 ± 0.04 g) were reared in 300 L tanks with density of about 30 fish/tank. Fish were fed with commercial feed (31% protein content) about 5% biomass per day. The parameters observed were production performance, hematology, and water quality. All data were analyzed using ANOVA and continued by the Duncan test. Water quality parameters were analyzed descriptively. The results showed that RIFA probiotic treated on snakehead fish produced the best production performance compared to commercial probiotic and without probiotic applications. These results were supported by much better water quality parameters and hematology performance of the fish.

A statistical assessment of micropollutants occurrence, time trend, fate and human health risk using left-censored water quality data

In recent years, the presence of micropollutants in drinking water has become an issue of growing global concern. Due to their low concentrations, monitoring databases are usually rich in censored data (e.g. samples with concentrations reported below the limit of quantification, LOQ) which are typically eliminated or replaced with a value arbitrarily chosen between 0 and LOQ. These conventional methods have some limitations and can lead to erroneous conclusions on: presence of micropollutants in the source water, treatment efficiencies, produced water quality and associated human health risk. In this work, an advanced approach, based on Maximum Likelihood Estimation method for left-censored data (MLELC), was applied on monitoring data of 19 contaminants (metals, volatile organic compounds, pesticides and perfluorinated compounds) in 5362 groundwater (GW) and 12,344 drinking water (DW) samples, collected from 2012 to 2017 in 28 drinking water treatment plants in an urbanized area. This study demonstrates the benefits of MLELC method, especially for high percentages of censored data. Data are used to build statistical distributions which can be effectively used for several applications, such as the time trend evaluation of GW micropollutant concentrations and the estimation of treatment removal efficiency, highlighting the adequacy or the need for an upgrade. Moreover, the MLELC method has been applied to assess the human health risk associated with micropollutants, indicating the high discrepancy in the estimations obtained with conventional methods, whose results do not follow precautionary or sustainability criteria.

The effects of artificial substrate and stocking density on Pacific white shrimp (Litopenaeus vannamei) performance and water quality dynamics in high tunnel-based biofloc systems

The use of artificial substrates in shrimp aquaculture may allow for production of shrimp at increased densities while providing a growth medium for microbes that assist with water quality processes and provide supplemental nutrition for shrimp. Greenhouse-based shrimp production systems can extend the shrimp production season in temperate climates while conserving water and energy. For this study, we evaluated the effects of providing extra substrate and shrimp density on water quality and shrimp production in greenhouse-based biofloc systems. Four 11-m3, wood framed, and rubber-lined tanks were constructed in each of four high tunnel greenhouses (for a total of 16 tanks). Four treatments were evaluated: high-density stocking with substrate (HDS), high-density stocking with no substrate (HDNS), low-density stocking with substrate (LDS), and low-density stocking with no substrate (LDNS). Each treatment was randomly assigned to one tank in each tunnel to block for location. No artificial heat was used, and shrimp were grown for 120 days. High-density systems were stocked at 200 shrimp/m³ while low-density tanks had 100 shrimp/m³. Adding substrate increased total in-tank surface area by 13.4%. The addition of substrate had no significant effect on any shrimp production or standard water quality parameters. Shrimp had significantly greater final weight, faster growth rate, and lower feed conversion rate in low-density treatments (P ≤ 0.02 for all). Total shrimp biomass production was significantly higher in high-density treatments (HD: 4.0 kg/m3; LD: 2.3 kg/m3; P < 0.05). There were no significant differences in survival between densities (HD: 91.3%; LD: 94.5%; P = 0.43). Peak and overall mean nitrite levels were significantly higher in high-density treatments compared to low-density treatments. Dissolved oxygen levels and pH over the course of the study were significantly lower in high-density treatments, likely due to increased respiration rates in the water column. This project shows the feasibility of shrimp production in temperate climates with no artificial heat using high tunnel greenhouses, few impacts of added substrate on shrimp production, and increased shrimp density can result in much larger harvests with few negative impacts on production metrics.

A new technique to purify biologically treated wastewater by reverse osmosis: utilization of concentrate

Introduction. Possibilities to purify municipal wastewater using reverse osmosis membrane techniques are investigated aimed at production of quality water for industrial use or meeting regulations for surface water sources discharge. A new eveloped tools to utilize concentrate effluents by reducing its flow by a value that does not exceed 0.5–1.0 per cent of initial feed water flow and it’s withdrawal of all rejected impurities together with dewatered sludge as a sludge moisture. Objectives: development of reverse osmosis techniques to purify wastewater after biological treatment; evaluation of possibilities to radically reduce concentrate flow to withdraw it together with activated sludge as it’s moisture. &#x0D; Materials and methods. Experimental research is conducted to develop membrane operational modes during wastewater treatment. Experimental procedure is developed and described to evaluate reduction of membrane rejection of dissolved impurities and product flow decrease during experimental wastewater treatment and concentrate utilization test run. &#x0D; Results. The basic equations are derived that enable us to determine: the required concentrate flow value that corresponds to concentration values of COD and suspended solids values in the feed water; the required values of membrane recoveries that correspond to ammonia concentration in the feed water to meet required regulation values in the product water. The tools to evaluate membrane area and a number of membrane modules are developed and described. Optimum values of the working pressure are evaluated as well as other economic parameters are presented to compare the developed techniques with biological treatment.&#x0D; Conclusions. To reach the required ammonia concentration in product water, double stage treatment of feed water with low-pressure reverse osmosis membranes is required. Influence of dissolved organics defined as COD, on membrane performance. The optimum value of working pressure is determined which is 7.5–8 Bars.

Design of Low Energy Integrated Membranes Units for Production of Highly Purified Water

Some industries like medical, pharmaceuticals, cosmetics, chemical manufacturing need a special quality of treated water which is called Purified water. Integrated membrane system was designed and developed to produce Purified water grades to serve these industries. A simple engineering design for water filtration through membrane systems was scanned; beginning from carbon filters, followed by different kinds of membranes like microfiltration, ultrafiltration, nanofiltration and reverse osmosis membrane. These units were developed according to membranes type and the produced water quality before and after each unit. The Produced water and its quality control tests were compared with the World Health Organization water quality standard. The produced water from the integrated membrane system has TDS reached 0.95 mg/L, which matched with the World Health Organization water quality standard.

Optimization of Cipageran water treatment plant, Cimahi, West Java, Indonesia

The Cipageran Water Treatment Plant (WTP) is one of water treatment plants managed by PDAM Tirta Raharja, Bandung Regency, which supply drinking water for Cimahi District and Central Cimahi Subdistricts with an average production capacity of 169 L/sec. This research aims to evaluate the performance of the operating unit and process in Cipageran WTP and provide optimization recommendations based on evaluation results. The steps in this research include evaluated the existing conditions of Cipageran WTP, providing recommendations on the results of evaluations and analyzing the quality of the production of Cipageran WTP. From the results of Cipageran WTP evaluation, there were several parameters that did not fulfil the design criteria which were Gtd on coagulation, NFr values on sedimentation and backwash rate on filtration. The evaluation result of maximum discharge in intake was 400 L/second, coagulation of 210 L/second, flocculation of 210 L/second, sedimentation of 270 L/second and filtration of 250 L/second, with the result the optimum discharge can operated in Cipageran WTP is 210 L/second. The quality water production has met the quality standard according to the Minister of Health Regulation No. 492 of 2010 concerning drinking water quality requirement, that turbidity limit is 5 NTU with very high removal efficiency, which was more than 90%. From the result, it can be said that Cipageran water treatment plant in this study had met the drinking water quality standard to be applied as drinking water treatment plant.

An environmentally sustainable approach for online chemical cleaning of MBR with activated peroxymonosulfate

Online chemical cleaning of membrane bioreactor (MBR) has been widely applied as a promising alternative to alleviate membrane fouling, while sustaining the permeability of MBR. However, the conventional chlorine-based chemical cleaning of MBR has been receiving increasing concerns on product water quality, environmental sustainability and human health due to the generation of harmful halogenated by-products. Therefore, in this study, peroxymonosulfate (PMS), a chlorine-free and thermodynamically strong oxidant, was explored as an environmentally friendly agent for online chemical cleaning of MBRs. Results show that the cleaning efficiency of fouled membrane by PMS was comparable with that by NaClO at the same dosages. Moreover, Fe2+-activated PMS could significantly improve the cleaning efficiency of the membrane, leading to a 75% reduction in chemical dosage against NaClO. It was also found that Fe2+-activated PMS was more effective than PMS in removing organic foulants from the cake layer and supressing cell survivability, ultimately leading to significantly reduced adhesion force of foulants to membrane surfaces. More importantly, as a chlorine-free chemical cleaning agent, Fe2+-activated PMS had a lower tendency of forming halogenated by-products during chemical cleaning. Consequently, this study indicates that Fe2+-activated PMS offers a promising alternative to commonly used NaClO for online chemical cleaning of MBR, not only for more effective cleaning at lower dosages but also the lack of toxic by-products.

ОПРЕДЕЛЕНИЕ ОСНОВНЫХ ПАРАМЕТРОВ РАБОТЫ УСТАНОВОК ОБРАТНОГО ОСМОСА ПРИ ОЧИСТКЕ ФИЛЬТРАТОВ ПОЛИГОНОВ ТБО

Results of investigations are presented that were aimed at production of quality water that meets regulations for surface water sources discharge. All impurities rejected by reverse osmosis membranes that are contained in concentrate stream can be withdrawn together with the dewatered sludge. Experimental research is conducted to develop membrane operational modes during leachate treatment. Experimental procedure is described to evaluate reduction of membrane flux and rejection during leachate treatment and recovery increase. Results of investigations are presented that enable us to determine main characteristics of membrane process such as: membrane flux, ammonia rejection, membrane types required, number of stages, recovery values. Experimental relationships are developed to determine the required membrane recovery values that correspond to ammonia concentration in the feed water to meet required regulation values in the product water. Tools to evaluate the required membrane area and required amount of membrane modules are developed and described. Influence of organics defined as COD (chemical oxygen demand) on membrane performance is investigated. Optimum values of working pressure are evaluated as well as economical parameters of membrane process are determined. Main tools to handle concentrate streams of membrane facilities and to withdraw it with dewatered sludge as well as methods to utilize sludge and concentrate are discussed.

Seawater Desalination by Using Nanofiltration (NF) and Brackish Water Reverse Osmosis (BWRO) Membranes in Sequential Mode of Operation

In this study, the applicability of nanofiltration (NF) membranes as a pretreatment prior to reverse osmosis (RO) in seawater desalination was investigated. The membranes used wereNF270 and NF90 as the NF membranes, while the brackish water (BW) RO membrane BW30 was used as the RO membrane. In desalination tests, permeates of the NF membraneswere collected and used as the feed to the BW30 membrane. The calculated permeate fluxes were 6.7 L/h.m2, 11.3 L/h.m2, 24.3 L/h.m2, and 36.6 L/h.m2 for single BW30-35 bar,NF270-30 bar + BW30-35 bar, NF90-30 bar + BW30-25 bar and NF90-30 BW30-35 bar, respectively. The calculated water recovery and rejected salt values were 51.6%, 41.4%,24.8%, 15.4% and 98.2%, 98.2%, 96.0%, 91.0% for NF90-30 bar + BW30-35 bar, NF90-30 bar + BW30-25 bar, NF270-30 bar + BW30-35 bar and single BW30-35 bar, respectively.The qualities of the product waters of integrated systems (NF+BWRO) and the single BWRO system were also investigated. Boron rejection was fairly well with average boronrejections of 59.3% and 60.2% by NF90-30 bar + BW30-25 bar and NF90-30 bar + BW30-35 bar combinations, respectively while single BW30-35 bar gave an average rejection of49.6%. The results obtained showed that the quality of product water obtained using single BWRO did not comply with the irrigation standards, while the integrated systems providedtotal compliance to irrigation standards with the exception of boron.

Quality of product water by three full-scale seawater reverse osmosis desalination in China

Quality of product water by three full-scale seawater reverse osmosis desalination in China

How to Use Wind Power Efficiently for Seawater Reverse Osmosis Desalination

Due to water scarcity and the global trends in climate change, winning drinking water through desalination is increasingly becoming an option, especially using reverse osmosis (RO) membrane technology. Operating a reverse osmosis desalination plant is associated with several expenses and energy consumption that take a very large share. Several studies have shown that wind power incurs lower energy costs compared to other renewable energy sources, therefore, should be the first choice to be coupled to an RO desalination system to clean water using sustainable energy. Therefore, in this paper, we investigate the feasibility of driving an RO desalination system using wind power with and without pressure vessel energy storage and small scale energy recovery using Clark pump based on simulation models. The performance of both variants was compared with several scenarios of wind patterns. As expected buffering and energy recovery delivered higher water production and better water quality demonstrating the importance of an energy storage/recovery system for a wind-power-supplied desalination plant.

Long-term performance and economic evaluation of full-scale MF and RO process – A case study of the changi NEWater Project Phase 2 in Singapore

The Changi NEWater Project Phase 2 purifies the secondary effluent of an urban sewage treatment plant using a two-stage microfiltration membrane (MF) and reverse osmosis (RO) process to produce NEWater for industrial use and to supplement drinking water sources. The total recovery rate of the system was 73.5%. The turbidity removal rate of the MF unit was 93.4% and the silt density index (SDI) value of MF product water was stable below 3. The performance of the pretreatment unit met the design standards. After reverse osmosis treatment, the total organic carbon removal rate was 99.4% and the desalination rate was greater than 99%. The quality of the NEWater was superior to the drinking-water standards of Singapore and the World Health Organization. Because of its advanced automatic control system, the Changi NEWater Project Phase 2 required a staff of only 15 operation and management personnel. The total operational cost was between 0.08 and 0.15 $/m³, of which energy consumption, chemical consumption, maintenance costs, and labor costs accounted for 62.9%, 20.2%, 7.3% and 9.6%, respectively. The energy consumption was between 0.6 and 0.8 ​kWh/m³. The Changi NEWater Project Phase 2 represents a milestone in water cycle engineering practice because of its excellent process design, superior product water quality, high degree of automatic control, and low operational energy consumption.

The Situation Of Water Treatment Plant In Mosul City

The present paper dealt with the evalution of quantiy and qualtiy of water treatmetn plants WTPs withen Mosul city. According to the total productivity of WTPs the per capita share of water was 785 L/d, and after subtracting the losses and violation upon the water supply network that reaches upto 50% the per capita portion of water becomes 392 L/d. For the quality of water; the study revealed that there are a segnificant effect of the WTPs processes upon the water quality parameters of the product water comparing with the raw water, and the quality of product water is withen the Iraqi dirnking water spicifications regarding to the parameters taken into account withen the study. This study concentric to the turbidity removal by WTPs because these plants are designed to reduce the turbidity of water to acceptable levels withen the Iraqi specification. turbidity of water is out of the specification in 13% of the samplise with different portions through the WTPs, but the highst was at aldanadan and alsaheroon plants. Duncn test revealed that there are a significant different betweent the average of the residual turbidity and between the average of percentage removal of turbidity between WTPs and the worest plant from the residual turbidity are alsaheroon, alghzlani and aldanadan. And the woreste plant from the percent turbidity removal are alaiser aljadeed and alaiser altawsie.