Semi-Closed Salinity Gradient Loop for Wastewater Energy Recovery

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Solution Overview

Problem

Industrial systems, such as natural gas refining plants, generate wastewater streams that are typically discharged and mixed, resulting in energy wastage due to salt concentration differences, and current treatment methods require significant energy and do not effectively reuse wastewater.

Innovation Solution

A semi-closed loop salinity gradient energy harvesting system is introduced, which involves drawing low and high salinity water streams through separate pumps into a salinity energy harvesting system, generating energy through mixing, and using this energy to power a separator system that treats and recycles the wastewater.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If wastewater streams are mixed in a water pond, then wastewater collection is simplified, but energy is wasted due to salt concentration differences

Engineering Contradiction:

Improvewastewater collection systemVSAvoidenergy of mixing

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent converts the harmful energy loss from salt concentration mixing into a beneficial energy source by implementing a salinity gradient energy harvesting system. The mixed wastewater streams with different salinities are directed through energy harvesting devices that generate electricity from the salinity difference, transforming the previously wasted energy into a useful resource that can power the treatment process.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If traditional wastewater treatment methods are used, then wastewater can be treated, but significant energy is required and wastewater is not effectively reused

Engineering Contradiction:

Improvewastewater treatment effectivenessVSAvoidenergy for wastewater treatment

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements a self-service system where the wastewater treatment process is powered by the wastewater itself. The salinity gradient energy harvesting system uses the salinity difference present in the wastewater streams to generate the electricity needed for treatment, making the system energy-self-sufficient and eliminating the need for external energy inputs.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent recovers energy that would otherwise be discarded when wastewater streams mix. By capturing the energy from salinity gradient mixing and using it to power treatment processes, the system transforms a waste stream into a resource, enabling sustainable wastewater treatment and reuse.

Inventive Principle:

Principle #34Discarding and recovering

3Ease of manufacture

If all wastewater streams are discharged to ponds, then treatment requirements are reduced, but water reuse in industrial processes is lost

Engineering Contradiction:

Improvewastewater disposal simplicityVSAvoidwater reuse capability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent implements a feedback loop where treated wastewater is recycled back to upstream industrial processes. The system continuously monitors and treats wastewater streams, then feeds the treated water back into the production process, creating a closed-loop system that maintains water quality and enables sustained industrial water reuse.

Inventive Principle:

Principle #23Feedback

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 system effectively harvests energy from salinity gradients, reduces energy requirements for wastewater treatment, and recycles treated wastewater back into upstream processes, promoting sustainable energy production and water reuse.

Implementation Method 1

A semi-closed loop salinity gradient energy harvesting system, including a first water stream drawn through a low salinity feed line by a first pump upstream of a salinity energy harvesting system and a second water stream drawn through a high salinity feed line by a second pump upstream of the salinity energy harvesting system

Methodology Applied

Scientific EffectSalinity gradient energy harvesting: Osmosis

Implementation Method 2

a separator system, configured to receive the mixed water exit stream and separate dissolved salts from the mixed water exit stream to produce a high salinity water exit stream and a pure water stream

Methodology Applied

Scientific EffectSeparation of dissolved salts: Reverse Osmosis

Data Source

PatentUS20250187950A1Semi-closed-loop salinity gradient energy harvesting system for sustainable power generation and water treatment

Publication Date: 2025.06.12 SAUDI ARABIAN OIL CO

AI summary

Systems and methods for treating and recycling wastewater using a semi-closed loop salinity gradient energy harvesting system. The system includes a low salinity water stream and a high salinity water stream pumped through a salinity energy harvesting system, which produces a mixed water exit stream pumped through a separator system, producing a high salinity water exit stream and a pure water stream. The method includes pumping a low salinity water stream and a high salinity water stream to a salinity energy harvesting system, operating the salinity energy harvesting system to produce a mixed water exit stream and a produced energy, pumping the mixed water exit stream to a separator system, separating dissolved salts from the mixed water exit stream, and producing a high salinity water exit stream and a pure water stream. The separator system operates using the produced energy from the salinity energy harvesting system.