Energy management of a Reverse Osmosis desalination process powered by renewable energy sources

A brackish water Reverse Osmosis (BWRO) desalination unit is studied in this paper. This unit is designed to be fed by a renewable energy based on hybrid source (wind and photovoltaic: hybrid system) with/without storage battery. The energy will be directly transmitted to the motos-pump of the BWRO process. An appropriate energy management starts from the understanding of the BWRO desalination process with its energy consumption. To optimize the energy transfer towards the load, it is useful to study the mechanical and the hydraulic system behaviour. Experimental characterizations of the motos-pumps and hydraulic load are elaborated from which significant results are drawn.

Jordan was late in adopting seawater and brackish water desalination as a source until the late 1990s and early 2000s. However, ongoing studies are still discussing the technical, economic, and socio-political aspects of brackish water reverse osmosis (BWRO) desalination plants. In this study, the water–energy nexus was considered, in order to highlight the main challenges facing BWRO desalination. We discuss the use of photovoltaic (PV) technology, together with BWRO desalination, as an approach to compensate for ecological, financial, and social challenges in Jordan. For this purpose, the performance of nine existing BWRO desalination plants in the agricultural, domestic, and industrial sectors is assessed. The water performance is assessed based on water consumption, safe yield extraction, plant recovery rate (R, %), and compliance to local and international water quality standards; the Specific Energy Consumption (SEC, kWh/m3) is taken as the main evaluation criterion to assess the energy performance of the BWRO desalination plants; and economic performance is assessed based on the overall cost of water produced per cubic meter (USD/m3). The main environmental component is the brine disposal management practice utilized by each plant. Based on this assessment, the main challenges in BWRO desalination are the unsustainable patterns of water production, mismanaged energy performance, low recovery rates, and improper brine disposal. The challenges in domestic and industrial BWRO desalination, which are completely dependent on the electricity grid, are associated with critical energy and costs losses, as reflected by the high SEC values (in the range of 2.7–5.6 kWh/m3) and high water costs per cubic meter (0.60–1.18 USD/m3). As such, the use of PV solar panels is suggested, in order to reduce the electricity consumption of the assessed BWRO plants. The installation of PV panels resulted in significantly reduced energy costs (by 69–74%) and total costs (by 50–54%), compared with energy costs from the electricity grid, over the lifetime of the assessed BWRO desalination plants.

Long-term intermittent operation of a full-scale BWRO desalination plant

Long-term performance decline in a brackish water reverse osmosis desalination plant. Predictive model for the water permeability coefficient

80,000 h operational experience and performance analysis of a brackish water reverse osmosis desalination plant. Assessment of membrane replacement cost

Performance analysis of a medium-sized industrial reverse osmosis brackish water desalination plant

Capital cost estimation of RO plants: GCC countries versus southern Europe

Evaluation and minimisation of energy consumption in a medium-scale reverse osmosis brackish water desalination plant

A theoretical analysis on upgrading desalination plants with low-salt-rejection reverse osmosis

Renewable energy sources are abundant and environmentally friendly and therefore present a promising alternative to power desalination units. This is why the Water-Energy nexus is a crucial step towards sustainable development. Thus, the integration of renewable energy sources (RES) in water desalination processes is very important. The main objective of this paper is to analyse a Brackish Water Reverse Osmosis (BWRO) desalination system powered by a microgrid system without the use of electro-chemical storage devices. Considering the intermittent nature of the renewable energy source and their sensitivity to the Water-Energy nexus, this work proposes to identify the various constraints and operating limits through an experimental BWRO desalination unit with all the elements of water-energy measurement, control and management. The control and management are based on a new technique of "Electrical Power Sharing" through the pressurization systems while using a specific Power Field Oriented Control (PFOC) while respecting the Safe Operating Window (SOW) of the desalination unit.

Design and experimental performance of brackish water reverse osmosis desalination unit powered by 2 kW photovoltaic system

Brackish water reverse osmosis (BWRO) desalination of groundwater is believed to be a sustainable method of providing municipal utilities with a high-quality supply in regions where freshwater sources are stressed and not sustainable. A key aspect of water management is the ability to evaluate an aquifer containing brackish water to ascertain future pumping-induced water quality changes and their impacts on the facility operation and economics. The city of Hialeah, Florida, has operated a BWRO facility for the last 9 years. The facility has a maximum design capacity of about 88,000 m3/d but is currently operating at about 33,000 m3/d. The facility was designed to treat water with a TDS of up to 10,000 mg/L. A detailed hydrogeologic investigation, including groundwater solute-transport modeling, suggested that the salinity of the source water would remain under 10,000 mg/L of TDS during the 30-year life expectancy of the facility. However, after 9 years of operation, it was found that the rate of salinity increase was much higher than predicted (27.5%), at the low rate of 33,000 m3/d. If the faculty was operated at the maximum capacity, the ability of the plant to treat the source water might be between 5 and 10 years. The conceptual model used to guide the solute transport modeling was not accurate for this site because it did not incorporate the apparent enhanced leakance through the basal confining unit below the aquifer. The greater leakance was likely caused by undetected, irregularly distributed fracturing of the underlying confining dolostones. The facility will require a major redesign to upgrade the process to be able to treat seawater at a TDS significantly above 10,000 mg/L in the future, should that occur. While the change will be costly, with a high capital cost to change the process, increased energy consumption, and overall higher water treatment cost, it is still more sustainable and has less environmental impact compared to other alternatives (e.g., treating tidal sources of seawater). The use of electricity from nuclear or solar generation could mitigate the environmental impacts of higher power consumption.

In this paper, the authors investigate a systemic modeling of a small-scale Brackish Water Reverse Osmosis (BWRO) desalination unit. This unit is powered by hybrid renewable energy system (photovoltaic-wind) without battery storage. The RO desalination process includes several disciplinary fields such as mechanical, hydraulic, chemical and thermal domains. Therefore, a multidisciplinary approach is proposed in this work. The bond graph is a modeling technique well known for dynamic modeling of such a multi-physical system. An experimental characterization of a BWRO test bench is performed in order to assess the established bond graph model of the studied desalination process. The simulation results drawn from a dedicated software tool reveal significant results when compared to experimental results.

Innovative system for BWRO desalination powered by PV and pumped hydro storage – Economic and GHG emissions analysis

Estimation of the maximum conversion level in reverse osmosis brackish water desalination plants