Osmotic Membrane Water Recovery for Cooling Tower Makeup
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Solution Overview
Problem
Current reverse osmosis (RO) and forward osmosis (FO) processes face inefficiencies in water extraction and recovery, leading to high operational costs, waste production, and limited utilization of inferior water sources, particularly in cooling tower applications, due to energy-intensive methods and membrane fouling, which are not economically viable without significant chemical treatment and water wastage.
Innovation Solution
Combining RO and FO processes with specific pre-treatment steps and the WCTI methods to reduce water consumption, chemical usage, and waste disposal costs, allowing for the use of inferior water sources in cooling tower applications by achieving synergistic efficiencies that conserve fresh water and reduce environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If RO reject is used as cooling tower makeup with traditional scale and corrosion control treatment methods, then cooling tower water can be supplied, but significant increased chemical treatment cost and increased cooling tower discharge of dissolved mineral concentrates are required to avoid scale and corrosion performance consequences
Solution Approach 1:
The patent changes the chemical parameters of cooling tower water by introducing silicates and phosphates that fundamentally alter scale and corrosion inhibition mechanisms. Instead of relying on traditional chemical treatments that require significant discharge, the patent uses silicate-phosphate combinations that form protective films on metal surfaces and prevent mineral precipitation, thereby reducing the need for chemical treatment and blowdown discharge.
Solution Approach 2:
The patent converts the harmful effect of dissolved mineral concentrates in RO reject water into a beneficial outcome. By using silicate-phosphate chemistry, the previously problematic mineral content is transformed into protective scales on heat transfer surfaces, which actually improve cooling efficiency while preventing corrosion. This eliminates the need to discharge these minerals as waste.
2Productivity
If RO operators use the best quality feed water available to reduce RO reject waste volume and RO operating costs, then RO operating efficiency is improved, but the scarcer and more limited supply of city potable water and other broadly useful fresh water sources is consumed
Solution Approach 1:
The patent changes the operational parameters of RO systems by enabling them to process lower quality feed water with higher total dissolved solids (TDS) content. The silicate-phosphate treatment allows RO membranes to operate effectively with feed water quality that previously would have caused fouling and reduced efficiency, thereby expanding the range of usable water sources from inferior sources such as brackish water or recycled water.
Solution Approach 2:
The patent converts the previously harmful effect of high TDS and poor quality feed water into a beneficial outcome. The silicate-phosphate chemistry protects the RO membranes from fouling and allows the system to efficiently process water sources that were previously unsuitable, thereby converting waste or inferior water sources into valuable cooling tower makeup water without consuming fresh potable water.
3Quantity of substance
If FO processes are applied to produce cooling tower makeup from brackish water sources with traditional scale and corrosion control treatment methods, then water extraction is achieved, but substantial evaporative system water discharge and/or osmotic agent recovery is required to avoid scale and corrosion performance consequences
Solution Approach 1:
The patent changes the chemical parameters of FO processes by introducing silicate-phosphate treatments that fundamentally alter the behavior of dissolved minerals during evaporation. Instead of forming problematic scales that require discharge, the silicates and phosphates form protective films that prevent corrosion and scale formation, allowing the evaporative cooling system to retain and reuse water that would otherwise be discharged.
Solution Approach 2:
The patent converts the harmful effect of brackish water minerals and FO process concentrates into a beneficial outcome. The silicate-phosphate chemistry causes minerals to precipitate as protective rather than harmful deposits, and the osmotic agents are retained and reused in the closed-loop system. This eliminates the need for substantial water discharge and osmotic agent recovery that previously limited FO process viability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The combined processes significantly reduce water consumption, chemical usage, and waste disposal costs, enabling the use of a broader range of inferior water sources while maintaining water quality suitable for cooling tower applications, thereby enhancing operational efficiencies and reducing environmental impact.
Implementation Method 1
Water produced via the application of an osmotic membrane, and in particular the reject waste produced from reverse osmosis or process water extraction produced from forward osmosis
Data Source
AI summary
Synergies in recovery of reverse osmosis (RO) membrane process reject waste and forward osmosis (FO) membrane process water extraction, using such osmotic process byproducts in applications for makeup to evaporative cooling towers, concurrent with use of specific corrosion and scale inhibition methods that permit tower water discharge reduction to approach zero blowdown. Such synergies are derived from methods for application of subsequent RO feed water and reject wastewater with pre-treatment steps, and FO process optimization steps to permit water quality and economic performance efficiencies when used as makeup to evaporative cooling systems.