Sewer Sludge HDPE Composite Structural Members
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Solution Overview
Problem
Current methods for recycling non-biodegradable and toxic waste, such as incinerator ash, are inefficient and generate secondary waste streams, while existing composite materials using recycled plastics have limited mechanical properties due to high proportions of non-plastic components, compromising environmental benefits and structural integrity.
Innovation Solution
A composite formulation combining dried sewer sludge, a byproduct of incinerator burning, with recycled high density polyethylene (HDPE) and/or polypropylene plastics, creating a feedstock that can be processed into structural and non-structural building materials, railroad ties, and other products through continuous batching or compression molding, without the need for cement or fibrous materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high proportions of non-plastic components (such as incinerator ash) are used in composite materials, then environmental benefits are improved by utilizing waste materials, but mechanical properties deteriorate compromising structural integrity
Solution Approach 1:
The patent changes the physical and chemical parameters of the composite material by controlling the ratio of plastic to non-plastic components, using specific types of plastics (HDPE, PP), and adjusting processing parameters (temperature, pressure, mixing time) to optimize mechanical properties while maintaining high recycled content
Solution Approach 2:
The patent creates a composite material system combining recycled plastics with incinerator ash and other non-plastic waste components, where the synergistic interaction between materials produces a composite with both environmental benefits and acceptable mechanical properties for structural applications
2Ease of manufacture
If chemical compounds (such as formaldehyde in polymeric binders) are used to improve composite material properties, then manufacturing processability is improved, but long term stability deteriorates due to flammability and noxious fumes
Solution Approach 1:
The patent extracts and eliminates harmful chemical compounds (formaldehyde, organic binders) from the composite material formulation, relying instead on the physical properties of recycled plastics and inorganic components to achieve processability and long term stability without flammability or noxious fumes
Solution Approach 2:
The patent replaces expensive and harmful chemical binders with inexpensive, non-harmful inorganic materials and recycled plastic components that provide sufficient binding and structural properties without the negative environmental and safety characteristics of chemical compounds
3Strength
If ceramic binders are used in composite materials, then structural strength is improved, but cost increases due to high weight ratios required
Solution Approach 1:
The patent replaces expensive ceramic binders with inexpensive recycled plastics and inorganic waste materials that provide adequate structural strength at much lower costs, eliminating the need for high weight ratios of costly ceramic components
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 method produces strong, cost-effective structural members and products with improved mechanical properties, utilizing large quantities of recycled materials and reducing the need for landfill space, while eliminating the use of petroleum products and generating revenue from waste materials.
Implementation Method 1
mixing dried sewer sludge with heated recycled plastic resin to obtain a fluidized mixture
Data Source
AI summary
A composite formulation consisting of agglomerated industrial/residential sewer sludge and recycled high density polyethylene (HDPE) and/or polypropylene (PP) materials. The recycled plastic materials act as a binder for the pozzolan industrial/residential sewer sludge. The composite formulation can be produced in a batching process wherein the sieved dried sewer sludge and the recycled plastic in appropriate small cut pieces is fed into a large plastic extruder, heated and extruded into specific structures. The formulation can also be compounded using a compression mold wherein sieved dry sewer sludge are added to heated chopped recycled plastics and heat mixed to produce pellets or directed into a compression mold to create a structural member of predetermined shape.