Reuse rate of treated wastewater in water reuse system

A water quality model for water reuse was made by mathematics induction. The relationship among the reuse rate of treated wastewater（R）, pollutant concentration of reused water（ Cs ）, pollutant concentration of influent（ C0）, removal efficiency of pollutant in wastewater（ E）, and the standard of reuse water were discussed in this study. According to the experiment result of a toilet wastewater treatment and reuse with membrane bioreactors, R would be set at less than 40%, on which all the concerned parameters could meet with the reuse water standards. To raise R of reuse water in the toilet, an important way was to improve color removal of the wastewater.

Renovated water reuse for rapid infiltration system

The renovated water in the rapid infiltration system (RI) as area for fish and duck farming is feasible. The flesh of fish and duck is edible. The farming of fish for 5 months and duck for 120 - 130 days can be accepted. It is beneficial to environment and economy, especially in developing countries. The production of fish and duck can make up for the cost of wastewater treatment.

Implications of de Facto Reuse on Future Regulatory Developments for Beaufort-Jasper Water & Sewer Authority in Okatie, South Carolina, USA

A significant portion of the national water supply can be attributed to de facto or unplanned potable reuse, though the extent of its contribution is difficult to estimate. Fortunately, the contribution of Water Resource Recovery Facility (WRRF) effluent to waters that supply drinking water treatment plants has been documented by some communities. In the United States (US), among the top 25 most impacted drinking water treatment plants by upstream WRRF, 16% of the influent flow to the drinking water treatment plant under average streamflow and up to 100% under low-flow conditions is WRRF effluent. Currently, the full extent of de facto reuse in the US may be much higher because of population growth. The scenario is no different for Beaufort-Jasper Water and Sewer Authority (BJWSA) in South Carolina, US, with contributions to the Savannah River originating from numerous WRRF and other upstream dischargers. South Carolina coastal utilities such as BJSWA are considering direct and indirect potable reuse options, driven by disposal limitations and challenges. Currently, South Carolina does not have a framework, guidelines, or regulations for reuse, but discussions have started among the regulated community. In addition to understanding the extent of de facto reuse, the state will need to develop standards and best practices to enable future adoption of planned potable reuse solutions to water resources challenges. Such guidance should address human health risk management and technical considerations regarding treatment in addition to other factors, including source control, storage, fail-safe operation, monitoring, non-cost factors, and public acceptance. This study conducted a mapping assessment specific to BJWSA, sampled at four locations on Savannah River, and observed that de facto reuse is approximately 4.6% to 5.9% during low-flow months and is within the range generally observed nationwide. When coupled with evidence that planned potable reuse can improve human health and environmental risks, this practice is a meaningful option in the water supply portfolio for many utilities.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

Effects of land use change and water reuse options on urban water cycle

The aim of this article was to study the effects of land use change and water reuse options on an urban water cycle. A water cycle analysis was performed on the Goonja drainage basin, located in metropolitan Seoul, using the Aquacycle model. The chronological effects of urbanization were first assessed for the land uses of the Goonja drainage basin from 1975 to 2005, where the ratio of impervious areas ranged from 43% to 84%. Progressive urbanization was identified as leading to a decrease in evapotranspiration （29%）, an increase in surface runoff （41%） and a decrease in groundwater recharge （74%）, indicating a serious distortion of the water cycle. From a subsequent analysis of the water reuse options, such as rainwater use and wastewater reuse, it is concluded that wastewater reuse seemed to have an advantage over rainwater use for providing a consistent water supply throughout the year for a country like Korea. where the rainy season is concentrated during the summer monsoon.

Three industries and water consumption of Beijing

Beijing has been experiencing a severe shortage of water. At present serious wastes of water resources result from the unreasonable structure of water uses in various industries sectors. The current conditions of the municipal water use structure and its changes in the industrial sectors were analysed and discussed in terms of the indicators, such as direct water use coefficient, complete water use coefficient, water use multiplier and water reuse rate, by taking a year of 1990s as the base year. Some response strategies for water conservation have been studied and the corresponding recommendations were put forward. All of these have provided a basis for coordinating the relationship between aquatic environment and economic growth in this city, establishing a system for rational utilization of water resources, and promoting the implementation of a strategy for sustainable development.

Water conservation in the Arab region: a must for survival

The Arab region covers an area over 13 million square kilometers in size, with almost 90% of its area classified as arid or ex- tremely arid with very little precipitation, extremely high evaporation and almost no vegetation cover. The region is classified in many international reports as the poorest region in the world in the context of renewable water resources and critical water scarcity which hinders the socio-economfic development of many countries in this region. The rapidly increasing population has reduced the per capita share of renewable water to less than the poverty line of 1,000 m3/（capita＇a） and, in some Arab countries, to less than the extreme poverty line of 500 m3/（capita＇a）. This has led to over-exploitation of non-renewable groundwater and desalination of salty water in many countries with considerable costs and contamination of many renewable sources. Atmospheric processes re- sponsible for aridity in the Arab region are projected to intensify due to climate change, resulting in an alarming decrease in pre- cipitation and increase in evaporation rates. Many concerned entities in the region consider water security as a key element for food security and ultimately political stability. Hence, various efforts have been exerted to identify key problems and suggested solutions. The Arab Water Ministers Council of the Arab League, as well as Reports of the Arab Forum for the Environment and Development （AFED） and the recommendations of the 13th Regional Meeting of the Arab National Committees of the Interna- tional Hydrological Programme of UNESCO （niP）, have all made similar recommendations on the need to address the issues of water scarcity in the Arab region which will be further discussed in this paper. However, none of these reports focused on ＂Water Conservation＂ as an equally important action for coping with water scarcity in the region. There are many definitions for ＂Water Conservation＂ in the scientific literature, including huge water savings from irrigation, industrial use, and domestic use as well as methods and approaches for augmenting water supply through non-conventional practices such as water harvesting and waste water reuse. In this paper, a review is provided for definitions, methods and impacts of water conservation and its role in alleviat- ing water scarcity in the Arab region.

Latent dimensions between water use and socio-economic development: A global exploratory statistical analysis

Water use and socio-economic development are interconnected in complex ways.Causalities are not easy to identify but it is evident that a nexus between water use and socio-economic development does exist.Considering the diversity of national situations relating to these interrelated phenomena,its study should be considered from a global perspective.This article critically reviews the literature and information from official sources on the relevance of water use and circular economy in order to create a global picture,linking water with socio-economic development.Data from 195 countries were analyzed statistically.A factor analysis defined five essential latent dimensions on the nexus between water use and socio-economic development:development and basic services,population and resources,economic volume,health and well-being,and population density.Based on the identified factors,countries were classified into six groups:Global South in difficulty,global semi-periphery,advanced economy,Middle East and other Global South developing economy,global weight,and small highly developed economy.The clustering results clarify connections between water use conditions and socioeconomic development.Understanding the variety of national profiles is helpful to reveal the magnitude and urgency of dealing with the nexus between water use and socio-economic development for many countries.

Reverse Osmosis Performance in MBR-RO Process with Recirculation of RO Concentrate to MBR for Water Reclamation

An integrated membrane system, membrane bioreactor-reverse osmosis (MBR-RO), has become highly efficient in producing high-quality water for municipal wastewater reclamation. However, disposal of a highly concentrated waste stream (RO concentrate or RO retentate) generated in this combination is an important issue. This work investigated RO behaviour in an integrated pilot scale MBR-RO system for municipal wastewater reuse with the continuous recycling of RO retentate to the MBR influent. RO membrane retention and the fouling propensity were studied. RO concentrate, produced by the RO process at a fixed concentration factor (CF) of 3, was recycled continuously to the MBR, leading to water recovery of the entire process around 92%. Osmotic pressure model, saturation index method, high performance liquid chromatography equipped with size exclusion column (HPLC-SEC) and specific filtration test were used to analyse the fouling potential of the RO membrane. The results obtained showed that even though RO concentrate recycling changed remarkably, the compositions of both MBR permeate and RO concentrate, the quality of RO permeate remained almost constant in terms of organic matters, conductivity, and ionic salts. However, these high concentrations of organic or inorganic substances in RO concentrate were major factors leading to the RO membrane fouling. Before RO concentrate recycling, a decline of approximately 30% of the initial RO permeate flux was observed in the period when the CF was increasing to 3, mainly due to the osmotic pressure effect of retained ions and the deposits of organic matters at the RO membrane surface. After RO concentrate addition to the MBR, due to the continuous accumulation of ionic salts on the RO membrane surface, a gradual reduction in RO permeate flux (additional 19%) was also mainly attributed to the osmotic pressure effect of the retained ions. These observations showed that the continuous addition of RO concentrate to the MBR was successful in a combined MBR and RO process in terms of the excellent quality of RO permeate.

Five Years of Rice Cultivation in Paddy Fields for Treated Water from Humus Bioreactor-Type Rural Wastewater Treatment Plants

The treated sewage has a color as well as odor and is difficult to reuse.Physical methods to reduce color with odor are costly and more difficult to reuse.Since the color and odor were reduced by pellet-type bioreactor sewage treatment using humus,rice was cultivated for 3 years.Industrially,3 years is sufficient to investigate the stability of treatment facilities,but when biological treatment is applied,5 to 10 years of investigation is required.In addition,in rice cultivation,a similar 5 to 10 years survey is required to investigate the accumulation of low-concentration pollutants.This report is a five-year report and is the result of paddy rice cultivation in a stable wastewater treatment facility.The cultivated rice fully satisfied the edible standards and was able to obtain safe rice,and the effect of reducing fertilizer applied was obtained by using nitrogen and phosphorus from the treated water.In addition,the yield was able to be within the range of the standard yield of 500 kg to 550 kg/1,000 m^(2).

Gray Water Measurement and Feasibility of Retrieval Using Innovative Technology and Application in Water Resources Management in Isfahan-Iran

Reuse of wastewater for agriculture and green spaces purposes is significant.A mean yearly precipitation in Esfahan is 150 mm.The drinking water and agriculture usually used underground resources in the city.Gray water recycling is known as a suitable option today.Delivering all the water requirements of a home from refined water rises the cost of water.Whereas the essential water quality for garden,toilet and irrigation is less than drinking water.Therefore,the aim of this study is to analyze the evaluation of gray water and estimate the amount of recycle gray water which can use for drinking water with innovation method in Esfahan region in Iran.Previous studies did not measure the value of recycling gray water with new method of waste water treatment that can use for drinking purpose.In this study,gray water in Esfahan city is measured and technical aspects of its recycling is examined.Because of the lack of referable guidelines and official technical reports,studies from other similar countries applied in this study and on the basis of which the amount of recoverable gray water was calculated.Evaluations indicates that the overall recovery of gray water in Esfahan saves nine million cubic meters of water.The price of the rial of this value established on water is 190 billion Rials.Given the lack of water sources in Esfahan,the recycle of gray water seems to be a good option,however more research is required to select a recovery strategy.

One-Step Reverse Osmosis Based on Riverbank Filtration for Future Drinking Water Purification

The presence of newly emerging pollutants in the aquatic environment poses great challenges for drink-ing water treatment plants.Due to their low concentrations and unknown characteristics,emerging pol-lutants cannot be efficiently removed by conventional water treatment processes,making technically,economically,and environmentally friendly water purification technologies increasingly important.This article introduces a one-step reverse osmosis(OSRO)concept consisting of riverbank filtration(RBF)and reverse osmosis(RO)for drinking water treatment.The OSRO concept combines the relatively low-cost natural pretreatment of river water with an advanced engineered purification system.RBF pro-vides a continuous natural source of water with stable water quality and a robust barrier for contami-nants.With the pre-removal of particles,organic matter,organic micro-pollutants(OMPs),and microbes,RBF becomes an ideal source for a purification system based on RO membranes,in comparison with the direct intake of surface water.OSRO treatment removes almost 99.9%of the particles,pathogens,viruses,and OMPs,as well as the vast majority of nutrients,and thus meets the requirements for the chlorine-free delivery of drinking water with high biostability.The OSRO treatment is cost effective com-pared with the standard conventional series of purification steps involving sprinkling filters,softening,and activated carbon.Artificial bank filtration(ABF),which functions as an artificial recharge in combi-nation with a sand filtration system,is proposed as an alternative for RBF in the OSRO concept to supply drinking water from locally available resources.It is also suggested that the OSRO concept be imple-mented with wind power as an alternative energy source in order to be more sustainable and renewable.An OSRO-based decentralized water system is proposed for water reclaiming and reuse.It is suggested that future water treatment focus on the combination of natural and engineered systems to provide drinking water through technically efficient,financially feasible,resource reusable,and environmentally relevant means.

Coking wastewater treatment for industrial reuse purpose: Combining biological processes with ultrafiltration, nanofiltration and reverse osmosis

A full-scale plant using anaerobic, anoxic and oxic processes （A1/A2/O）, along with a pilot-scale membrane bioreactor （MBR）, nanofiltration （NF） and reverse osmosis （RO） integrated system developed by Shanghai Baosteel Chemical Co. Ltd., was investigated to treat coking wastewater for industrial reuse over a period of one year. The removals reached 82.5% （COD）, 89.6% （BOD）, 99.8% （ammonium nitrogen）, 99.9% （phenol）, 44.6% （total cyanide （T-CN））, 99.7% （thiocyanide （SCN-）） and 8.9% （fluoride）, during the A1/A2/O biological treatment stage, and all parameters were further reduced by over 96.0%, except for fluoride （86.4%）, in the final discharge effluent from the currently operating plant. The pilot-scale MBR process reduced the turbidity to less than 0.65 NTU, and most of the toxic organic compounds were degraded or intercepted by the A1/A2/O followed MBR processes. In addition, parameters including COD, T-CN, total nitrogen, fluoride, chloride ion, hardness and conductivity were significantly reduced by the NF-RO system to a level suitable for industrial reuse, with a total water production ratio of 70.7%. However, the concentrates from the NF and RO units were highly polluted and should be disposed of properly or further treated before being discharged.

Wastewater reclamation and reuse in China:Opportunities and challenges

The growing water stress both in terms of water scarcity and quality deterioration promotes the development of reclaimed water as a new water resource use. This paper reviewed wastewater reuse practices in China, and the opportunities and challenges of expanding reclaimed water use were analyzed. Rapid urbanization with the increasing of water demand and wastewater discharge provides an opportunity for wastewater reuse. The vast amount of wastewater discharge and low reclaimed water production mean that wastewater reuse still has a great potential in China. Many environmental and economic benefits and successful reclamation technologies also provide opportunities for wastewater reuse. In addition, the overall strategy in China is also encouraging for wastewater reuse. In the beginning stage of wastewater reclamation and reuse, there are many significant challenges to expand wastewater reuse in China including slow pace in adopting urban wastewater reuse programs, the establishment of integrated water resources management framework and guidelines for wastewater reuse programs, incoherent water quality requirements, the limited commercial development of reclaimed water and the strengthening of public awareness and cooperation among stakeholders.

Salinity exchange between seawater/brackish water and domestic wastewater through electrodialysis for potable water

Two-thirds of the world’s population has limited access to potable water.As we continue to use up our freshwater resources,new and improved techniques for potable water production are warranted.Here,we present a general concept called“salinity exchange”that transfers salts from seawater or brackish water to treated wastewater until their salinity values approximately switch,thus producing wastewater with an increased salinity for discharge and desalinated seawater as the potable water source.We have demonstrated this process using electrodialysis.Salinity exchange has been successfully achieved between influents of different salinities under various operating conditions.Laboratory-scale salinity exchange electrodialysis(SEE)systems can produce high-quality desalinated water at~1 mL/min with an energy consumption less than 1 kWh/m3.SEE has also been operated using real water,and the challenges of its implementation at a larger scale are evaluated.

Treatment of Reused Comprehensive Wastewater in Iron and Steel Industry With Electrosorption Technology

Electrosorption technology was used to treat the reused comprehensive wastewater from iron and steel industry. A problem of relatively high conductivity of wastewater which greatly affects the reuse was examined, and industrial test was conducted for the reused water advanced deionization and purification in a comprehensive wastewater treatment plant o{ WISCO [Wuhan Iron and Steel （Group） Corporation]. The results of the on-site in- dustrial test showed a satisfactory treatment performance for the reused water even at a flow rate of 1 000 L/h in a standard 500 L/h unit. The average conductivity decreased by about 70%, from 580--780 μS/cm to 100--350 μS/cm. The average removal efficiency of CI and Ca2＋ was about 75% and 68%, respectively, and CODcr of the treated wa- ter was also reduced in some degree while the pH value was almost unchanged. The energy consumption was as low as 0.6 kWh/t, which was remarkably superior to the conventional technologies. Therefore, it is entirely feasible that the novel eleetrosorption technology can be used in enhanced desalination and purification treatment of reused com- prehensive wastewater in iron and steel industry.

Scenario analysis for reduction of pollutant load discharged from a watershed by recycling of treated water for irrigation

A model in which a river model was layered on a distributed model （double-layered model） was developed to analyse the transport of water and pollutants （nitrogen, phosphorus, and BOD as organic matter） in watersheds and rivers. The model was applied to the watershed of Abragafuchi Lake, Japan, where serious water pollution has occurred over three decades, and the applicability of the model was demonstrated. Scenarios of recycling of sewage treated-water into agriculture to reduce pollutant load discharged into the lake were analysed. The results showed that irrigating paddy fields with the sewage-treated water could contribute to conserving water and reducing pollutant load, with reduction rate in BOD, nitrogen, and phosphorus ranging from 6%-36%, 16%-46%, and 18%-51%, respectively. Particularly, the results indicated that, irrigating paddy fields with the treated water during non-cropping periods and the accompanying reduction in withdrawn water from the river were more effective in reducing pollutant loads discharged into the lake. Further study is required on the effect of recycled water on crop cultivation and soil conditions for safe implementation.

Role of water chemistry on estrone removal by nanofiltration with the presence of hydrophobic acids

Hydrophobic acid organic matter （HpoA） extracted from treated effluent has been known to improve the rejection of steroid hormone estrone by reverse osmosis （RO） and nanofiltration （NF） membranes. In this study, the effects of solution chemistry （solution pH and ionic strength） on the estrone rejection by NF membrane with the presence of HpoA were systematically investigated. Crossflow nanofiltration experiments show that the presence of HpoA significantly improved estrone rejection at all pH and ionic strength levels investigated. It is consistently shown that the ＂enhancement effect＂ of HpoA on estrone rejection at neutral and alkaline pH is attributed to the binding of estrone by HpoA macromolecules via hydrogen bonding between phenolic functional groups in feed solutions, which leads to an increase in molecular weight and appearance of negative charge. The membrane exhibited the best performance in terms ofestrone rejection at pH 10.4 （compared to pH 4 and pH 7） as a result of strengthening the electrostatic repulsion between estrone and membrane with the presence of HpoA. At neutral pH level, the ability of HpoA macromolecules to promote estrone rejection became stronger with increasing ionic strength due to their more extended conformation, which created more chances for the association between estrone and HpoA. The important conclusion of this study is that increasing solution pH and salinity can greatly intensify the ＂enhancement effect＂ of HpoA. These results can be important for NF application in direct/indirect potable water reuse.

Aerosol exposure assessment during reclaimed water utilization in China and risk evaluation in case of Legionella

Reclaimed water utilization provides an effective way to alleviate water shortage.However,the residual pathogens in the recycled water like Legionella,could be spread into the air as aerosols through water-to-air transmission process.Inhaling the aerosols by the people nearby increases their susceptibility to diseases.For estimating the health risks associated with the potential exposure of airborne Legionella emitted from the urban use of reclaimed water in China,nationwide questionnaire was designed to investigate the exposure habits of Chinese population in different scenarios.Quantitative microbial risk assessment(QMRA)served as the suitable explanatory tool to estimate the risk.The results indicated that annual infection probability of populations exposed to Legionella for three scenarios,0.0764(95%CI:0.0032−0.6880)for road cleaning,1.0000(95%CI:0.1883−1.0000)for greenfield irrigation,0.9981(95%CI:0.0784−1.0000)for landscape fountain,were markedly higher than the threshold recommended by WHO(10^(−4) per person per year(pppy))according to the concentration distribution of Legionella in the reclaimed water.An age-,educational background-,region-and gender-specific data in annual infection probability also showed different tendencies for some subpopulations.This study provides some detailed information on the health risks from the water reuse in China and will be useful to promote the safe application of reclaimed water in water-deficient areas.

A review of crosslinked fracturing fluids prepared with produced water

The rapidly increasing implementations of oilfield technologies such as horizontal wells and multistage hydraulic fracturing,particularly in unconventional formations,have expanded the need for fresh water in many oilfield locations.In the meantime,it is costly for services companies and operators to properly dispose large volumes of produced water,generated annually at about 21 billion barrels in the United States alone.The high operating costs in obtaining fresh water and dealing with produced water have motivated scientists and engineers,especially in recent years,to use produced water in place of fresh water to formulate well treatment fluids.The objective of this brief review is to provide a summary of the up-to-date technologies of reusing oilfield produced water in preparations of a series of crosslinked fluids implemented mainly in hydraulic fracturing operations.The crosslinked fluids formulated with produced water include borate-and metalcrosslinked guar and derivatized guar fluids,as well as other types of crosslinked fluid systems such as crosslinked synthetic polymer fluids and crosslinked derivatized cellulose fluids.The boratecrosslinked guar fluids have been successfully formulated with produced water and used in oilfield operations with bottomhole temperatures up to about 250
F.The produced water sources involved showed total dissolved solids(TDS)up to about 115,000 mg/L and hardness up to about 11,000 mg/L.The metal-crosslinked guar fluids prepared with produced water were successfully used in wells at bottomhole temperatures up to about 250
F,with produced water TDS up to about 300,000 mg/L and hardness up to about 44,000 mg/L.The Zr-crosslinked carboxymethyl hydroxypropyl guar(CMHPG)fluids have been successfully made with produced water and implemented in operations with bottomhole temperatures at about 250t
F,with produced water TDS up to about 280,000 mg/L and hardness up to about 91,000 mg/L.In most of the cases investigated,the produced water involved was either untreated,or the treatments were minimum such as simple filtration without significantly changing the concentrations of monovalent and divalent ions in the water.Due to the compositional similarity(high salinity and hardness)between produced water and seawater,crosslinked fluids formulated with seawater for offshore and onshore jobs were also included.The crosslinked guar and derivatized guar fluids have been successfully formulated with seawater for operations at bottomhole temperatures up to about 300
F.Operating costs have been significantly reduced when produced water or seawater is used to formulate fracturing fluids in place of fresh water.With various challenges and limitations still existing,the paper emphasizes the needs for new developments and further expansion of produced water reuse in oilfield operations.