Chemical and membrane desalination of natural water with high content of iron-organic compounds

Under the conditions of modernization of Russian thermal power plants (TPP), water treatment plants based on imported membrane technologies are often put into operation without consideration of the quality of the source (natural) water and variable-performance operating modes. At the same time long-running water treatment plants and their capabilities are not considered. In this regard, the cost of additional water is three or more times higher, and the average output is respectively lower than at traditional water treatment plants. Often, one doesn’t take the advantages of reverse osmosis installations based on the rejection of the use of aggressive reagents such as sulfuric acid, etc. The aim of the study is to increase the efficiency of desalinated water production. It is especially important to conduct studies of natural waters with high content of iron-organic compounds characteristic of the regions of the center and north of Russia. The authors have carried out laboratory studies of various, primarily new filter materials, regents, and devices, both at the stages of pre-purification of water i.e., clarification, and at the stages of demineralization of clarified water. Water treatment plants of Ivanovo combined-cycle plant (CCP) and Cherepovets state district power station (GRES) are considered as the subject of the research. It is found out that if one applies ion-exchange and membrane water treatment technologies to treat water with high content of iron-organic compounds, high-quality desalinated water can be obtained. The properties of water are the following: specific electrical conductivity of no more than 0,2 mcm/cm and permanganate oxidizability of no more than 1 MgO/l. Results of studies at the Ivanovo CCP and Cherepovets GRES have shown practicability to coagulate water with aluminum sulfate using an anionactive flocculant, for example, during the flood period. Application of coagulation and ultrafiltration units before reverse osmosis installation ensures removing organic impurities from the water. Based on the obtained research results, recommendations are given for the implementation of the results at Ivanovo water treatment plants.

Dubai will draw in investment through share offerings

Significance On the same day, its new USD450mn desalination project, publicised as the most sustainable in the region, was reported to be on track for completion. DEWA, the emirate’s principal provider of power and desalinated water, is seeking to attract investors as it gears up to launch the first in a run of new major initial public offerings (IPOs) in Dubai. Impacts The reliance of companies targeted for IPOs on service charges levied on Dubai’s majority-expatriate population may deter some investors. Dubai will showcase future deals to advertise its claim that it is still the most attractive investment location in the Gulf. The IPO push will be personally driven by Dubai’s deputy ruler, Maktoum bin Mohammed bin Rashid Al Maktoum.

Financial Evaluation of the Use of Reclaimed Water in Agriculture in Southeastern Spain, A Mediterranean Region

In a global context where agriculture is the major consumer of water, there is a pressing need to look for alternative water resources. In light of there being a lack of studies that compare the use of diverse water alternatives in different crops, the overall objective of this research is to evaluate the impact generated by the use of tertiary water from an economic and financial perspective and compare it with groundwater and desalinated water. To reach this objective, a detailed study of the cost structure of greenhouse investment has been developed. Furthermore, the most traditional indicators for investment profitability have been calculated for the three different water alternatives: tertiary water, groundwater and desalinated water. The cost analyses demonstrate the relative short reach that the price of water has in an area of greenhouse agriculture exploitation, which provides a margin of increasing water costs while still allowing for economic profit. Taking into account the three water resources considered, evidence shows that the use of tertiary water is not only financially and economically viable but is also the best alternative water resource above desalinated water in terms of profitability and sustainability.

Impacts of Desalinated and Recycled Water in the Abu Dhabi Surficial Aquifer

In Abu Dhabi, one of the most arid regions in the world, in recent decades, desalinated water has been identified as a prime solution in solving the water demand issues. In this study, a three-dimensional coupled density-dependent flow and solute transport model was set up in order to study the effect of the artificial recharge using desalinated water and the influence of nonconventional water with a salt concentration in the range 0.1–2 g/L The results confirm that this region demands the adoption of a more rational use of irrigation water or additional usage of desalinated water and recycled water together with optimizing groundwater pumping at locations that are vulnerable to further quality degradation and depletion. The long-term storage of desalinated freshwater with a maximum radial distance of 653 m in the dune surface is ensured with the formation of the transition zone, and change in the groundwater head up to 5 km. The maximum recovery obtained by immediate recovery is 70%. The study expresses the long-term feasibility of desalinated freshwater storage and the need for further management practices in quantifying the contribution of desalinated and recycled water for agriculture activities which might have improved groundwater quality and increased hydraulic head at some locations.

Managing Water Scarcity Futures: Identifying Factors Influencing Water Quality, Risk Perception and Daily Practices in Urban Environments after the Introduction of Desalination

During the last two decades on a global scale, there has been a significant development of desalination as a strategy to ensure the urban water supply in arid and semi-arid areas. Beyond issues related to the higher economic costs, one of the main barriers that may limit this water source’s development is its supposed negative water quality perception. This research aims to understand better which factors are behind water quality perception in Antofagasta (Chile), where desalinated water was introduced in 2003. Since then, this urban water supply system has increasingly incorporated desalination, creating three parallel areas according to the water sources used in each of them (desalinated water, freshwater and a mix of both). To do so, more than 800 questionnaires to test water quality perception and water consumption habits were conducted in households. Up to six logistic regression models have been implemented to identify which variables better explain water quality satisfaction, risk perception and daily water practices considering the water supply area. It is worth noting that most of this type of research has been carried out in study cases with homogeneous urban water supply systems with conventional water resources. Results indicate that, among other factors, organoleptic water characteristics, such as taste, and socioeconomic status are some of the main factors that explain the perception of water quality and daily practices. In addition, a lower water quality perception and greater risk perception have been identified where desalinated water has been introduced, which makes some households develop averting behaviors to improve water quality, such as boil water.

Assessing the Impact of Water Efficiency Policies on Qatar’s Electricity and Water Sectors

Water and electricity have a unique relationship in the modern world as one requires the other in a complex system of networks to supply the utility to the customers. This energy–water interaction is especially peculiar in the Gulf Cooperation Council, where there are limited water resources, but extremely high use rates. Qatar provides a unique case in terms of extreme water scarcity and excessive water use. To understand the intricate network, this paper establishes an updated and comprehensive qualitative model of the water system in the country with the help of a water balance and system dynamics (causal loop diagram) methodology. Regression estimates are then used to estimate future water and energy consumption in addition to carbon dioxide emissions until the year 2050. Finally, system dynamics (stock and flow diagram) is used to determine the supply impacts of efficiency policies including limiting of groundwater abstraction to only 50 million m3, reduction of water consumption in the household, commercial and industrial sector by 10%, and gradual increase in the share of reverse osmosis (RO)-produced desalinated water to 50% in order to assess the supply volume, electricity consumption and CO2 emissions. The efficient use of water in different sectors of the economy results in a combined saving of 1222 GWh (8.1%) or 594,000 tons CO2. Furthermore, by moving to membrane-based desalination technology energy consumption and carbon dioxide emissions can be reduced by 3672 GWh (24.3%) and 1.8 million tons CO2, respectively. Further results suggest that while replacing groundwater with desalinated water can increase the energy consumption significantly, reuse of treated wastewater has almost the same footprint as groundwater, but can increase the resilience of the system considerably as groundwater abstraction levels are lowered to their renewal rates.

Modification in energy and productivity of high temperature variable pressure humidification compression

One of the important approaches in the thermal desalination processes is consumed energy reduction. To achieve this aim, three arrangements of humidification-compression (HC) processes are designed. Two single-stage and one double-stage HC processes are designed and their performances are compared based on desalinated water production, gained output ratio (GOR) and power consumption. Attempt is made to reduce the power consumption and improve the system performance. All three processes are simulated to examine the effect of operation parameters on HC performance. To validate these simulations, the theoretical results are compared with an experimental rig with a humidifier column of 1.5 m height. The results indicate that the simulation values conform the experimental data. The effect of minimum approach temperature (ΔTmin) on system performance is investigated for three processes subject to constant operating conditions (feed temperature, water mass flow, air mass flow, and pressure ratio). For this purpose, four values of ΔTmin are considered (7.5, 10, 12.5 and 15 °C) for heat exchanger operations. The results indicate that an increase in ΔTmin in all three cases, increases desalinated water volume and GOR. Also, double-stage HC system, has higher water production rate (66.08 kg/h) and higher GOR (17.19) compared to its counterparts.