Open Mixer for Excavated Sludge Dewatering

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Solution Overview

Problem

Current methods for treating excavated materials, particularly sludge with low dryness or non-shovelable waste, face challenges such as large footprint requirements, inability to handle high volumes, and environmental impact, especially in urban contexts, due to the need for significant space and energy consumption.

Innovation Solution

The use of an open mixer, such as an arm rotomixer, within a transportable container to mix a dehydrating agent with excavated sludge, allowing for homogeneous treatment and storage directly in the container, reducing the need for additional processing steps and minimizing environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If dewatering units (filter press/centrifuge) are used to treat excavated sludge, then the sludge can be dewatered and handled, but significant land area is required and additional transport steps are needed

Engineering Contradiction:
Improvesludge handling capabilityVSAvoidland footprint
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent combines the dewatering function and mixing function into a single integrated device (the open mixer with desiccant addition capability). Instead of using separate dewatering units like filter presses or centrifuges that require significant land area, the invention integrates these functions into one compact unit that can be positioned directly in the excavation pit, eliminating the need for additional transport steps and reducing land footprint.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The open mixer device performs multiple functions: it mixes excavated material with desiccant, enables dewatering through desiccant action, and facilitates handling of treated sludge. This multi-functional approach replaces the need for separate specialized equipment (dewatering units, mixing equipment, transport vehicles), thereby reducing overall land requirement and operational complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If traditional dewatering units are used, then sludge treatment is achieved, but energy consumption is high and environmental impact increases

Engineering Contradiction:
Improvesludge treatment capabilityVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The system uses desiccant materials that passively absorb water from the sludge through capillary action and adsorption, eliminating the need for energy-intensive mechanical dewatering processes. The desiccant performs the dewatering function autonomously without requiring external energy input, thereby significantly reducing energy consumption and environmental impact compared to traditional filter presses or centrifuges.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If excavated sludge with low dryness is stored directly, then storage is simple, but it violates environmental regulations and cannot be stored in waste facilities

Engineering Contradiction:
Improvestorage simplicityVSAvoidregulatory compliance
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary dewatering treatment by adding desiccant to the excavated sludge before storage. This pre-treatment increases the dry matter content of the sludge to meet regulatory requirements (above 30% dry matter), enabling lawful storage in waste facilities without requiring complex subsequent treatment processes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The addition of desiccant fundamentally changes the moisture content parameter of the excavated sludge, transforming it from a liquid/pasty state with low dryness to a more solid state with sufficient dry matter content. This parameter change enables the material to comply with environmental regulations and be stored in approved waste facilities.

Inventive Principle:
Principle #35Parameter changes

4Area of stationary object

If open mixer with desiccant is used, then treatment of large volumes is achieved with minimal footprint, but homogeneous mixing must be ensured

Engineering Contradiction:
Improveland footprintVSAvoidmixing homogeneity
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The open mixer employs dynamic mixing elements (rotating arms, paddles, or augers) that actively circulate and blend the excavated sludge with desiccant material. This dynamic mixing action ensures homogeneous distribution of the desiccant throughout the sludge volume, achieving consistent dewatering performance across the entire batch while maintaining a compact device footprint.

Inventive Principle:
Principle #15Dynamics

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 method enables efficient treatment of large volumes of excavated materials with varying dryness and particle sizes, reducing energy consumption and environmental impact while allowing for direct storage and transport in a minimal footprint, making it suitable for urban environments.

Implementation Method 1

adding a desiccant to said materials

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

adding a desiccant to said materials in said container

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

mixing said materials and said desiccant in the container, the mixing being carried out with an open mixer, in particular of the rotomixer type with arm

Methodology Applied
Scientific EffectMechanical mixing: Stirring

Data Source

PatentEP3712333A1Method for the treatment of excavation materials
Publication Date: 2020.09.23 SUEZ GRP SAS
  • EP3712333A1 patent drawingFigure 1~2
  • EP3712333A1 patent drawingFigure 3~4
  • EP3712333A1 patent drawingFigure 5~6

AI summary

The invention relates to a method for treating liquid or pasty materials from excavations, comprising a step of storing said materials in an open container, a step of adding a desiccant to said materials in said container, and a step of mixing said materials and said desiccant in the container. The invention also relates to an installation for treating liquid or pasty materials from excavations, comprising a container suitable for holding liquid or pasty materials, an addition means suitable for adding a desiccant to said container, and an open mixing means suitable for mixing the desiccant with the liquid or pasty materials in the container.