Membrane-based Desalination System Research Articles

Practicality and Economic Assessment on Using the Solar Organic Rankine Cycle as a Power Source for a Specific Membrane-based Desalination System

Practicality and Economic Assessment on Using the Solar Organic Rankine Cycle as a Power Source for a Specific Membrane-based Desalination System

Environmental performance of a photovoltaic brackish water reverse osmosis for a cleaner desalination process: A case study

Reverse osmosis (RO) membrane-based desalination system with various configurations has emerged as a critical option for reclaiming brackish water. This study aims to evaluate the environmental performance of the combination of photovoltaic-reverse osmosis (PVRO) membrane treatment system via life cycle assessment (LCA). The LCA was calculated using SimaPro v9 software with ReCiPe 2016 methodology and EcoInvent 3.8 database following the ISO 14040/44 series. The findings identified the chemical and electricity consumption at both the midpoint and endpoint level across all impact categories with terrestrial ecotoxicity (27.59 kg 1,4-DCB), human non-carcinogenic toxicity potential (8.06 kg 1,4-DCB) and GWP (4.33 kg CO2 eq) as the highest impacts for the PVRO treatment. As for the endpoint level, the desalination system affected human health, ecosystems and resources at 1.39 × 10−5 DALY, 1.49 × 10−7 species·year and 0.25 USD2013 respectively. The construction phase for the overall PVRO treatment plant was also assessed and impacted less significantly compared to the operational phase. Three different scenarios (i.e. S1: Grid input (Baseline); S2: Photovoltaic (PV)/Battery; S3: PV/Grid) based on different sources of electricity used were also compared as electricity consumption is one of the significant impacts in the operational phase. The study found that S2 had the lowest environmental impact, while S1 contributed the highest when both midpoint and endpoint approaches are considered.

Performance improvement of thermal-driven membrane-based solar desalination systems using nanofluid in the feed stream

Different techniques have been proposed so far to improve the performance of thermal-driven membrane modules applied in solar desalination systems. These techniques have increased the freshwater productivity of the system but at the cost of its increased overall specific energy requirement. Due to this major drawback, the main objective of this study is to implement nanofluid in the feed stream of a heat pipe solar membrane-based desalination system, which not only aims to improve the freshwater productivity of the system, but also has the capability of decreasing its specific energy requirement. Synthetic seawater (with the salinity of 3.5%) was generated by dissolving appropriate amount of Sodium Chloride (NaCl) salt in normal tap water and used as the base fluid. Then, Aluminium oxide (Al2O3) nanoparticles were applied to fabricate the nanofluid. The performance of the system in terms of freshwater productivity, quality of treated water, specific thermal and electrical energy consumptions, gained output ratio, and overall efficiency was experimentally studied and compared under hot and cold climatic conditions of Perth in Australia. The results indicated that the application of nanofluid increased the freshwater productivity in hot and cold seasons by 18% and 22%, respectively. It also decreased the specific thermal energy consumption as this parameter was 17.5% and 14% lower in hot and cold seasons compared to the system without nanofluid. Moreover, using nanofluid improved the gained output ratio of the system by 9% and 18% under hot and cold climatic conditions, respectively. The overall efficiency of the system was also proved to be enhanced upon the application of nanofluid where the results showed 17.4% and 18% increase in hot and cold seasons, respectively.

Optimal Design of a UF-RO Treatment System for Shale Gas Fracturing Flowback Wastewater

A membrane-based desalination system under consideration for shale gas fracturing flowback wastewater treatment involves ultrafiltration (UF), reverse osmosis (RO), and storage tanks. The membrane unit (UF, RO) consists of online washing, operation, and offline chemical washing sub-units. These sub-units operate in semi-continuous mode and have the similar characteristics as batch water-using processes. Based on their semi-continuous behaviors, the models of UF and RO sub-units are developed. The objective is to maximize the total water production ratio and profit while minimizing storage tank capacity. Three nonlinear programming optimization models are developed for an optimal design of the UF-RO treatment system for shale gas fracturing flowback wastewater. Two scenarios, fixed schedule and fixed operating period, for UF/RO treatment sub-units are investigated. Results show that with the increasing of the operation duration of treatment sub-units, the water production ratio and profit will increase. The schedule of treatment sub-units has significant impact on the water storage profiles, without adversely affecting the water production ratio. The proposed approach can guide the design of the UF-RO desalination system.

A novel solar-driven direct contact membrane-based water desalination system

This study proposes a novel integrated solar membrane-based desalination system. The system includes vacuum glass tubes to increase absorbed solar energy and to decrease heat loss, heat pipes to transfer the absorbed energy efficiently, and a tubular direct contact membrane distillation module to use the absorbed energy more effectively. To improve the freshwater production rate and overall efficiency of the proposed system, a cooling unit was also added to the permeate loop of the desalination unit. The performance of the system was experimentally investigated without (Case I) and with (Case II) the cooling unit in summer and without the cooling unit in winter (Case III) under climatic conditions of Perth, Western Australia. The experimental results indicated that except a few minutes in the morning, the heat pipe solar system was able to provide all the required thermal energy for the desalination system. The maximum thermal efficiency of the solar system in summer reached ~78% and its exergy efficiency fluctuated between 4 and 5% for a noticeable amount of time from 10:30 AM to 3 PM. Moreover, the maximum freshwater production rate were 2.78, 3.81, and 2.1 L/m2h in Cases I, II, and III, respectively. The overall efficiency of the system improved from 46.6% in Case I to 61.8% in Case II showing the technical effectiveness of implementing the cooling unit in the permeate flow loop of the system. In addition, the daily averaged specific energy consumption in Cases I, II, and III were 407, 377, and 450 kWh/m3, respectively.

Conducting a Water Safety Plan (WSP) Relied on WHO Recommendations for the Assessment of Qom Desalinated Water Supply System

This work aimed to apply the water safety plan (WSP), a plan suggested by the World Health Organization (WHO), to evaluate desalinated water supply system in Qom province of Iran, assisting a systematic prevention approach based on risk assessment. Major portion of Qom drinking water is supplied by an integrated membrane-based desalination system through a private water network. WSP includes 12 phases comprising chapters like "System Description", "Hazard Identification", and "Risk Assessment". The abovementioned phases were conducted according to filled checklists which finally served as the input data for WSP software, namely WSP QA Tool. The processed information by the software attributed to each step was presented finally as appropriate tables and histograms. Total score obtained for Qom desalinated water supply system via WSP was 302 whereas, the full obtainable score considered in WSP was 440. Accordingly, 68.6% of the total WSP obtainable scores was acquired. The scores achieved in steps "catchment", "treatment", "distribution", and "point of use" were 67%, 67%, 64%, and 65%, respectively. The minimum obtained score was 25% assigned to the step "Improvement Plan". The maximum scores were 100% and 97% attributed to "Identification of Stakeholders" and "Hazard Identification and Risk Assessment", respectively. The score of 68.6% from WSP was achieved by Qom desalinated water supply system. The step "Improvement Plan" should be performed simultaneously with the entire WSP to improve the coordination for better enforcement of the plan. To enhance the current condition, the funding demands assigned to each uncontrolled risk which is attributed to each improvement program must be supplied, ranked, and enforced.

Energy and economic analysis of a hollow fiber membrane-based desalination system driven by solar energy

A novel solar energy driven and membrane-based air humidification-dehumidification desalination (MHDD) system is designed and constructed. To realize a water-salt separation, a hollow fiber membrane module is employed as the humidifier to humidify air with solar energy heated saline water. The humidified air is then cooled and condensed to obtain distilled water. A detailed theoretical model is developed and validated to evaluate the performance of the proposed MHDD system. The whole model includes submodels for the solar collector, the water tank, the membrane humidifier, and the vapor condenser. At a specified membrane area, the effects of the water tank volume and solar collector area on the system performance such as the electric energy consumption for water production (SEC), the coefficient of performance (COP), etc., are analyzed. The optimal water tank volume and the optimal solar collector area for the desalination system are evaluated. In addition, an economic analysis on the whole system reveals that the system needs a low maintenance cost to make the water production competitive. Generally it provides an attractive alternative to small-scale, stand-alone desalination systems that could provide high purity drinkable water.

Integrated Membrane Desalination Systems with Membrane Crystallization Units for Resource Recovery: A New Approach for Mining from the Sea

The mining industry is facing problems of clean production in terms of mineral processing, pollution, water consumption, and renewable energy. An interesting outlook can be to combine the mining industry with membrane-based desalination in the logic of mining from the sea. In fact, several of the drawbacks found in both mining and desalination can be minimized or overcome, which includes hindering mineral depletion, water production instead of water consumption, smart usage of brine instead of disposal, and low energy consumption, etc. Recently, membrane crystallization (MCr) has been developed to recover minerals from highly concentrated solutions. This study suggests MCr for the treatment of nanofiltration (NF) retentate and reverse osmosis (RO) brine leaving membrane-based desalination system. Thermodynamic modeling has been carried out to predict at which water recovery factor and which amount of minerals can be recovered. Theoretical results deviate only 2.09% from experimental results. Multivalent components such as barium, strontium, and magnesium are easier to recover from NF retentate with respect to RO brine. KCl and NiCl2 might be recovered from both NF retentate and RO brine, whereas lithium can only be recovered from RO brine. Moreover, copper and manganese compounds might also be recovered from desalination brine in perspectives.