Solid Waste Treatment Process for Anaerobic Digestion
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Solution Overview
Problem
Solid waste contains contaminants such as heavy and light non-organic materials that are detrimental to anaerobic digestion processes, leading to equipment damage and reduced efficiency.
Innovation Solution
A two-stage separation process involving a light fraction separator and a grit removal system, using a hydrocyclone, to remove light and heavy contaminants, respectively, and dilute the organic waste to facilitate anaerobic digestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If solid waste is directly fed into anaerobic digester, then processing is simple, but contaminants damage equipment and reduce efficiency
Solution Approach 1:
The patent applies preliminary action by implementing a separation process before anaerobic digestion to remove light contaminants (plastics, foam) and heavy contaminants (grit, glass) from solid waste. This pre-treatment prepares the organic fraction in advance, preventing equipment damage and efficiency reduction in the downstream digester while maintaining overall process reliability
2Manufacturing precision
If liquid is added to dilute organic waste, then separation of light contaminants improves, but solids content decreases
Solution Approach 1:
The patent applies parameter changes by adjusting the solids content of organic waste to an optimal range (10-12% dried solids) through controlled liquid addition. This parameter optimization improves the separation precision of light contaminants in the vertical mill while maintaining adequate solids concentration for effective anaerobic digestion, resolving the trade-off between separation quality and substrate concentration
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 process effectively separates contaminants, reducing damage to downstream equipment and enhancing the efficiency of the anaerobic digestion process by producing a digestible slurry with controlled solid content, thereby improving biogas production and digestate quality.
Implementation Method 1
the slurry passes through a grit removal system optionally including a hydrocyclone. This system removes heavy and/or settleable material
Implementation Method 2
the waste is processed through a separator, for example a vertical mill or depackaging machine, which removes light contaminants
Implementation Method 3
The cleaned organic fraction is subsequently processed by anaerobic digestion, which converts volatile solids to biogas among other things
Data Source
AI summary
In an apparatus and process described, an organic fraction of solid waste is separated from light contaminants such as plastics and heavy contaminants such as grit. The organic fraction is subsequently processed by anaerobic digestion, which converts volatile solids to gas. In a first stage of the process, the waste is processed through a separator such as a vertical mill, which removes light fraction contamination, reduces organics particle size and dilutes the waste to thereby produce a slurry. In a second stage of the process, the slurry passes through a grit removal system, which removes heavy and settleable material, for example by way of a hydrocyclone. The light and heavy fraction contaminants are not carried through to the digestion process. The particle size of the organics is also reduced to facilitate digestion and the slurry has a dry solids concentration suitable for anaerobic digestion.