Electrokinetic Biosolids Dewatering with Chlorine Dioxide

Solution Overview

Problem

Conventional mechanical dewatering methods for municipal biosolids are inefficient due to low conductivity of the material, requiring high polymer doses and being unsuitable for continuous operation, while traditional electrokinetic dewatering is not well-suited for municipal biosolids due to low conductivity and low throughput.

Innovation Solution

The method involves treating biosolids with chlorine dioxide to enhance conductivity and facilitate electro-osmosis, using an electrokinetic dewatering device with graphite electrodes and a filter material to separate water from pretreated biosolids, allowing for continuous thickening or dewatering without polymer addition and achieving high total solids content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional mechanical dewatering methods are used, then water removal is achieved, but the process requires high polymer doses and is inefficient due to low conductivity of biosolids

Engineering Contradiction:

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent replaces conventional mechanical dewatering methods with an electrokinetic dewatering system that uses electrical fields to drive water removal through electro-osmosis. This substitution eliminates the need for chemical polymers and mechanical compression, directly addressing the contradiction by improving water removal efficiency while eliminating polymer consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the electrical conductivity parameter of biosolids by adding electrolytes, transforming the material from low-conductivity (unsuitable for electrokinetic treatment) to high-conductivity (suitable for efficient electro-osmotic water removal). This parameter change enables the electrokinetic process to work effectively without requiring mechanical polymers.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If traditional electrokinetic dewatering is applied, then water separation is possible, but the throughput is low and it is not well-suited for municipal biosolids

Engineering Contradiction:

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent divides the treatment process into two distinct stages: (1) electrokinetic dewatering to remove free water and achieve initial concentration, and (2) mechanical filtration through the filter press to remove remaining water. This segmentation allows each method to operate in its optimal range, significantly increasing overall throughput while maintaining effective water separation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary electrokinetic treatment to remove free water and concentrate biosolids before applying mechanical filtration. This preliminary action prepares the material for more efficient mechanical processing, increasing the overall productivity of the system by optimizing the sequence of operations.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If high polymer doses are used in mechanical dewatering, then dewatering efficiency improves, but operational costs increase

Engineering Contradiction:

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent replaces chemical polymer addition with electrical field application for dewatering. This substitution eliminates ongoing chemical costs while maintaining dewatering efficiency, directly addressing the contradiction by improving operational efficiency without increasing operational costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Quantity of substance

If conventional dewatering methods are used, then water removal is achieved, but continuous operation is not suitable

Engineering Contradiction:

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

The patent designs a system where electrokinetic treatment operates continuously to remove free water from incoming biosolids, and the filter press operates in a continuous cycle of filtration and discharge. This continuous operation capability eliminates idle time between batches and maintains constant water removal, directly addressing the contradiction by enabling continuous operation while achieving effective water removal.

Inventive Principle:

Principle #20Continuity of useful action

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

This approach significantly increases the efficiency of water removal, reduces operational costs, and maintains organic material and BTU value, achieving Class B pathogen reduction standards with reduced odor and energy consumption, overcoming limitations of traditional methods.

Implementation Method 1

treating a sludge or biosolids with chlorine dioxide to form a pretreated biosolids

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

subjecting the pretreated biosolids to electro-osmosis to separate water from the pretreated biosolids

Methodology Applied

Scientific EffectElectro-osmosis: Electro-Osmosis

Data Source

PatentUS10766006B2Electrokinetic thickening and dewatering method and system

Publication Date: 2020.09.08

AI summary

A method and device for using electrokinetic forces for thickening or dewatering municipal biosolids is provided. The method uses chlorine dioxide to accelerate and improve the efficiency of electrokinetic dewatering.