Sludge Dehydration via Particle Size Control
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Solution Overview
Problem
Advanced anaerobic digestion sludge poses challenges due to its small particle size and high usage of inorganic conditioning agents, leading to high dehydration costs and unfavorable sludge cake properties.
Innovation Solution
A method for conditioning advanced anaerobic digestion sludge through deep dehydration based on particle size control, involving the use of cationic organic flocculants, aggregates, and inorganic agents to achieve specific floc particle sizes and surface hydrophobicity, facilitating effective dehydration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional compound conditioning with inorganic conditioning agents and organic flocculants is used, then dehydration efficiency is improved, but conditioning agent dosage increases and dehydration cost increases
Solution Approach 1:
The patent changes the particle size parameter of sludge flocs from the original small size (median about 14 μm) to a controlled larger size distribution (D10: 70-150 μm, D50: 200-400 μm, D90: >500 μm) through multi-stage flocculation. This parameter change improves dehydration efficiency while reducing conditioning agent dosage by creating a particle size distribution optimal for mechanical dehydration.
Solution Approach 2:
The patent uses a composite conditioning approach combining organic flocculants (first and second cationic organic flocculants) with inorganic conditioning agents in a multi-stage process. This composite material strategy achieves effective dehydration with reduced overall dosage compared to traditional single-stage compound conditioning.
2Productivity
If traditional compound conditioning with inorganic conditioning agents is used, then dehydration efficiency is improved, but sludge cake EC value increases
Solution Approach 1:
The patent performs preliminary flocculation with organic flocculants before adding inorganic conditioning agents. This preliminary action creates a particle size-controlled floc structure that reduces the subsequent need for inorganic agents, thereby achieving dehydration efficiency while limiting EC value increase in the final sludge cake.
Solution Approach 2:
By controlling particle size parameters through organic flocculation first, the patent changes the physical structure of sludge flocs to a state that requires less inorganic conditioning agent for effective dehydration, thus reducing the harmful effect of high EC value in the dehydrated cake.
3Productivity
If high dosage of inorganic conditioning agents is used, then dehydration efficiency is improved, but dehydration cost increases
Solution Approach 1:
The patent applies preliminary flocculation with organic flocculants to create particle size-controlled flocs before adding inorganic conditioning agents. This preliminary action prepares the sludge structure to require smaller doses of inorganic agents, maintaining dehydration efficiency while reducing cost.
Solution Approach 2:
The patent changes the particle size distribution parameter of sludge flocs through organic flocculation to optimize the subsequent inorganic conditioning step, reducing the dosage required while maintaining effective dehydration performance.
4Use of energy by moving object
If thermal hydrolysis treatment is applied, then biogas recovery is improved, but floc particle size is reduced and dehydration becomes difficult
Solution Approach 1:
The patent applies preliminary multi-stage flocculation with organic and inorganic conditioning agents after thermal hydrolysis treatment. This preliminary action restores and controls particle size (D10: 70-150 μm, D50: 200-400 μm, D90: >500 μm) of the thermally treated sludge, making it suitable for mechanical dehydration while preserving the biogas recovery benefits of thermal hydrolysis.
Solution Approach 2:
The patent changes the particle size parameters of sludge flocs that were reduced by thermal hydrolysis treatment. Through controlled flocculation, the particle size is increased and optimized for dehydration, resolving the contradiction between biogas recovery and subsequent dehydration efficiency.
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 reduces the usage of inorganic agents, lowers the conductivity of the sludge cake, and decreases dehydration costs, making the process more efficient and cost-effective while improving the handling and disposal of dehydrated sludge.
Implementation Method 1
uniformly mixing the advanced anaerobic digestion sludge with first cationic organic flocculant to obtain non-hard muddy flocculated particles
Implementation Method 2
uniformly mixing mixture obtained in step (2) with inorganic agent to improve a particle surface hydrophobicity
Implementation Method 3
performing plate and frame dehydration on substance obtained in step (4) to reduce moisture content of the sludge to 60% or less
Data Source
AI summary
A method for conditioning advanced anaerobic digestion sludge by deep dehydration based on particle size control, the use thereof and a floc particle. The method for conditioning advanced anaerobic digestion sludge by deep dehydration comprises: (1) uniformly mixing advanced anaerobic digestion sludge with a first cationic organic flocculant to obtain non-hard muddy flocculated particles; (2) uniformly mixing the muddy flocculated particles with aggregate; (3) uniformly mixing the resulting mixture with inorganic agent; (4) adjusting the particle size of the floc particles using second organic flocculant; and (5) performing plate-frame dehydration so as to reduce the moisture content to 60% or less. In the method, by means of the combination of organic flocculation nucleation with a particle size skeleton, the use amount of the inorganic agent is effectively reduced, such that the conductivity of the mud cake is reduced, facilitating the landscaping utilization, incineration disposal etc., of the dehydrated mud cake.