Bentonite Clay Cover Composition for Landfill Waste Piles

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Solution Overview

Problem

Existing cover materials for bulk waste piles face challenges such as high volume requirements, poor adhesion to surfaces like plastic, inconsistent quality, and non-uniform coverage, particularly due to the scarcity and cost of mineral binders like cement kiln dust, and the limitations of fiber-based materials which tend to slide off and lose integrity with rain and wind.

Innovation Solution

A bulk material cover composition comprising at least 50 weight percent liquid, 3 to 18 weight percent bentonite clay, and synthetic fibers, with optional additives like Portland cement, pregelatinized wheat starch, and latex paint, which can be sprayed onto waste piles to form a durable and adherent cover.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If fiber-based cover materials are used, then the cover can be applied with minimal equipment, but the material tends to slide off surfaces and lose integrity under rain and wind

Engineering Contradiction:
Improveapplication simplicityVSAvoidcover integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent combines organic fibers (providing structural framework and ease of application) with clay binder (providing adhesion and cohesion) to create a composite cover material that maintains integrity under environmental stress while remaining easy to apply. The fiber-clay composite structure allows the cover to adhere to surfaces and resist displacement by rain and wind.

Inventive Principle:
Principle #40Composite materials

2Reliability

If mineral binders like cement kiln dust are used, then good adhesion and opacity are achieved, but the supply is reduced and cost increases

Engineering Contradiction:
Improveadhesion qualityVSAvoidmaterial availability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive, scarce mineral binders (cement kiln dust, Portland cement) with inexpensive, readily available clay and organic fiber materials. This substitution maintains adequate adhesion and cover functionality while dramatically improving material availability and reducing cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical composition parameters of the cover material from mineral-based binders to clay-based binders, altering the material properties to achieve comparable adhesion performance using abundant, low-cost natural materials.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If large volumes of dirt are used to cover waste piles, then adequate coverage and protection are provided, but the available volume for waste is significantly reduced

Engineering Contradiction:
Improvecoverage effectivenessVSAvoidwaste storage volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent employs a thin, flexible sprayable cover composition that forms an effective protective layer over waste piles. This thin-film approach provides adequate coverage and protection while minimizing the volume consumed by cover material, thereby maximizing waste storage capacity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses a spray application method (hydraulic/pneumatic delivery) to apply the cover material as a thin, uniform layer. This spray technique achieves effective coverage with minimal material volume compared to traditional thick dirt layers.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Ease of manufacture

If substitute mineral binders like Portland cement or coal fly ash are used, then mineral binder availability is improved, but the cost increases and quality consistency deteriorates

Engineering Contradiction:
Improvebinder availabilityVSAvoidquality consistency
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent changes the binder type from inconsistent substitute mineral binders to consistent, naturally variable clay materials. While clay composition varies by source, this variability is actually advantageous as it provides flexibility in material selection while maintaining consistent performance characteristics through the fiber-clay composite structure.

Inventive Principle:
Principle #35Parameter changes

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 provides improved adhesion and durability, reducing the need for large volumes of cover material, maintaining integrity under rain and wind, and ensuring uniform coverage with minimal maintenance, while being cost-effective and readily available.

Implementation Method 1

A bulk material cover composition including at least 50 weight percent liquid, about 3 to about 18 weight percent bentonite clay

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

spraying the slurry onto the bulk material pile

Methodology Applied
Scientific EffectSpray deposition: Spray

Data Source

PatentUS8029616B2Bulk material cover composition
Publication Date: 2011.10.04 LSC ENVIRONMENTAL PRODS

AI summary

A cover composition that can be applied to a bulk material pile, such as landfill refuse, to protect the pile from wind, precipitation, and access by animals and insects is provided. The cover composition is a mixture of a liquid, typically, water; bentonite clay; and synthetic fibers. The composition may be enhanced by the addition of one or more of the following additives: Portland cement, pregelatinized wheat starch, synthetic polymers, soda ash, and latex paint. Unlike prior art cover compositions, the disclosed composition adheres well to waste material, most notably plastics, whereby the composition is easy to apply and provides a substantially uniform, durable protective cover to landfill refuse piles and other bulk materials. Methods of applying the composition to bulk material piles are also disclosed.