Grey Water Purification via Mechanical Foam Separation

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Solution Overview

Problem

Current methods for purifying grey water from laundry wash and rinse processes often require harmful chemicals and are inefficient in removing high concentrations of surfactants, leading to low recovery rates of purified water.

Innovation Solution

A device and process that uses aeration to generate and break foam using a rotating disc with a patterned rough surface, allowing for the removal of surfactants and recovery of over 90% of grey water as purified water without chemical additives, with the foam being channeled and collapsed outside the container to eliminate surfactants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical coagulants and flocculants are used for grey water purification, then purification effectiveness is improved, but environmental harm increases

Engineering Contradiction:

Improvepurification effectivenessVSAvoidenvironmental harm

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical coagulation and flocculation processes with a mechanical foam separation system. Grey water is aerated to generate foam containing surfactants and particulates, which is then mechanically separated using a rotating drum with hydrophobic surfaces that selectively retain foam while allowing purified water to pass through, eliminating the need for harmful chemicals.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the phase transition of water from liquid to foam through aeration. By introducing air into grey water, surfactants and suspended particles are transformed into a foam phase that can be easily separated from the liquid phase using the mechanical foam separation system, achieving purification without chemical additives.

Inventive Principle:

Principle #36Phase transitions

2Productivity

If high disc speed is used in foam breaking, then foam removal efficiency is improved, but liquid carryover increases

Engineering Contradiction:

Improvefoam removal efficiencyVSAvoidliquid carryover

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent applies local quality by creating different surface properties in different locations of the foam separation system. The rotating drum has hydrophobic surfaces that selectively attract and retain foam while hydrophilic surfaces allow purified water to pass through, enabling efficient foam removal without liquid carryover by treating different areas with different surface characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs a dynamic rotating drum system where the drum rotation speed and position are optimized to control foam breaking and separation. The rotating motion creates varying forces that efficiently break foam while the controlled rotation speed prevents excessive liquid carryover, balancing productivity and substance retention.

Inventive Principle:

Principle #15Dynamics

3Reliability

If foam is channeled outside the container for breaking, then surfactant removal is improved, but device complexity increases

Engineering Contradiction:

Improvesurfactant removalVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated foam separation device. The rotating drum combines foam retention, foam breaking, and liquid separation functions in one component, while the aeration system and drum rotation work together to achieve surfactant removal without requiring separate complex subsystems for each function.

Inventive Principle:

Principle #5Merging (Combining)

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 solution achieves a significant reduction in surfactant levels from 0.1% to less than 1 ppm, enabling the recovery of more than 90% of grey water as purified water, which can be further filtered for enhanced purity.

Implementation Method 1

aeration of grey water for generating foam

Methodology Applied

Scientific EffectFoam generation through aeration: Foam

Implementation Method 2

mechanical foam breaking by the shearing action of a high speed rotating disc

Methodology Applied

Scientific EffectMechanical foam breaking by shearing action:

Implementation Method 3

remove foam from the grey water by only channelling the foam while substantially preventing the liquid from getting channelled

Methodology Applied

Scientific EffectFoam channelling with liquid prevention:

Data Source

PatentUS10710904B2Device and a process for purification of grey water

Publication Date: 2020.07.14 CONOPCO INC

AI summary

The present invention relates to a device and a process for purification of grey water. In particular the invention relates to in-home purification of grey water generated from laundry wash and/or rinse liquor for water saving by re-use. Surprisingly it has been found that it is possible to design a device and a process where, by continuous aeration, foam breaking and separation, the laundry wash and rinse water can be made substantially free of surfactants. This water is then preferably filtered to recover fresh water which can be reused for multiple applications.