Optimization of Osmotic Desalination Plants for Water Supply Networks

Abstract

Water scarcity and the poor quality of water resources are leading to a wider diffusion of desalination plants using the Reverse Osmosis (RO) process. Unfortunately, the cost of a cubic meter of fresh water produced by an RO plants is still high and many efforts are in progress to increase the efficiency of the membranes used in osmotic plants and to limit the energy required by the process. A further reduction of the energy cost could be obtained by an optimal operation of the desalination plant so reducing the hourly energy cost, or by coupling the RO plant with an energy production plant based on direct osmosis (Pressure Retarded Osmosis PRO). The economic viability of the desalination process has been analyzed until now without accounting for the integration of the RO plant with the existing water network. This analysis is developed in the present paper with reference to a hypothetical change of water supply in a real network, where a desalination plant is used to satisfy the fresh water demand. Several scenarios will be analyzed to assess the minimum cost of fresh water production and water supply to the network, including the use of energy recovery systems, such as an integrated use of RO and PRO processes, or the regulation of pressure at the network intake by a micro hydro power plant.

Reducing the Energy Dependency of Water Networks in Irrigation, Public Drinking Water, and Process Industry: REDAWN Project

“…A residual hydraulic head can be converted at different points of the network in order to grant optimal pressure values to end users. A PAT is the most advanced solution to replace pressure reducing valves, reducing the energy footprint connected to water transportation and the amount of water lost in leakage [1,2].…”

Energy Transfer from the Freshwater to the Wastewater Network Using a PAT-Equipped Turbopump

“…Therefore, a turbine could be located at the tank inflow in order to both reduce pressure and produce energy to supply the pump. Furthermore, in order to reduce equipment costs, a pump as turbine (PAT) [31] could be employed instead of a classic turbine, with acceptable efficiency [32][33][34][35], obtaining a PAT-pump turbocharger (P&P). The operating principle, the performance, and the advantages of a P&P plant in a water supply system have been stressed by [21].…”

Optimal Pump Scheduling for Urban Drainage under Variable Flow Conditions

“…Nowadays, the issue of management efficiency is of great concern in the context of water infrastructures. Focus is usually given to the reduction of cost of production [1], energy recovery [2], reduction of water losses [3], reduction of pipe breaks and maintenance operations [4]. Cost of production especially includes cost of the energy used for pumping, which, according to recent reports [5,6], constitutes 4% of the entire amount of national electricity consumed in U.S. [4,7] and 7% of the electrical energy worldwide [8,9].…”