Depuration Sludge Treatment via Acid-Alkaline Hydrolysis
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Solution Overview
Problem
The treatment and disposal of wastewater depuration sludges pose significant environmental and economic challenges due to their variable composition and high content of pollutants, requiring efficient methods to reduce suspended solids and chemical reagent consumption in existing processes.
Innovation Solution
A process involving acid and alkaline oxidizing hydrolysis steps, followed by separation to obtain an acid liquid phase for neutralization and a solid phase for further treatment, significantly reduces the volume and reagent consumption, allowing for complete oxidation and neutralization of organic matter, and heat recovery for energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional treatment processes are used for depuration sludges, then the sludges can be treated and disposed of, but the volume of sludges and consumption of chemical reagents remain high
Solution Approach 1:
The treatment process is divided into distinct sequential stages: acid hydrolysis followed by alkaline hydrolysis. This segmentation allows each stage to target specific components of the sludge, achieving progressive degradation and volume reduction while maintaining treatment effectiveness.
Solution Approach 2:
The acid hydrolysis step is performed as a preliminary action before alkaline hydrolysis. This preliminary treatment breaks down complex organic structures and prepares the sludge for more efficient subsequent treatment, enabling better overall volume reduction and reagent utilization.
2Object-generated harmful factors
If chemical reagents are used in conventional treatment processes, then organic matter can be oxidized, but reagent consumption is high
Solution Approach 1:
The process utilizes parameter changes by sequentially adjusting pH conditions - first acidic then alkaline. This parameter variation enables different chemical mechanisms to act on the organic matter at optimal conditions, achieving complete oxidation while reducing overall reagent consumption compared to single-condition treatments.
Solution Approach 2:
The dual hydrolysis process provides continuous useful action through sequential acid and alkaline treatments. Each stage builds upon the previous one, ensuring complete organic matter degradation without requiring excessive reagent doses, as the second stage completes the oxidation initiated in the first stage.
3Ease of manufacture
If depuration sludges are disposed of in landfills or incinerated, then disposal is achieved, but environmental risks and operational costs increase
Solution Approach 1:
The process converts the harmful organic pollutants in sludge into beneficial products through controlled hydrolysis. The organic matter is transformed into soluble compounds and gases, while the remaining solid residue becomes a safe soil improver, thereby converting waste into a useful resource and eliminating environmental hazards.
Solution Approach 2:
The process discards harmful organic pollutants through oxidation while recovering valuable components. The solid residue after treatment is recovered and can be reused as soil improver, and heat recovery systems capture energy from the exothermic reactions, thereby reducing overall environmental impact and operational costs.
4Power
If heat is generated during treatment processes, then organic matter oxidation is enhanced, but energy balance optimization is needed
Solution Approach 1:
The process incorporates feedback through heat recovery systems that capture thermal energy from exothermic oxidation reactions. This recovered heat is fed back into the system to preheat incoming sludge or sustain reaction temperatures, thereby optimizing energy balance and reducing external energy requirements while maintaining high oxidation intensity.
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 process effectively reduces the volume and pollutant content of depuration sludges, minimizing reagent use and operational costs, while enabling the safe disposal and potential reuse of treated residues as soil improvers, and optimizing energy balance through heat recovery.
Implementation Method 1
performing an acid oxidizing hydrolysis of an incoming waste charge
Implementation Method 2
performing an acid oxidizing hydrolysis of an incoming waste charge
Implementation Method 3
performing an alkaline oxidizing hydrolysis of the outgoing charge from the acid oxidizing hydrolysis step
Implementation Method 4
performing an alkaline oxidizing hydrolysis of the outgoing charge from the acid oxidizing hydrolysis step
Implementation Method 5
separating the undissolved residue, if any
Implementation Method 6
neutralizing the outgoing charge from the alkaline oxidizing hydrolysis step
Implementation Method 7
heat recovery for energy efficiency
Data Source
Figure 1
AI summary
Process for the treatment of waste products, in particular depuration sludges, comprising: performing an acid oxidizing hydrolysis of an incoming waste charge; performing an alkaline oxidizing hydrolysis of the outgoing charge from the acid oxidizing hydrolysis step; neutralizing the outgoing charge from the alkaline oxidizing hydrolysis step; separating a solid residue, if any, remaining after the neutralization step. The outgoing charge from the acid oxidizing hydrolysis step is subjected to a separation step so as to obtain an acid liquid phase which is sent to the neutralization step of the outgoing charge from the alkaline oxidizing hydrolysis step, and a solid phase which is sent as charge to the alkaline oxidizing hydrolysis step. In this way, it is possible to considerably reduce the volume of the ingoing charge to the alkaline oxidizing hydrolysis step, and therefore the consumption of the alkaline reagent necessary for bringing the pH of the charge to the desired value. At the same time, sending the acid liquid phase to the neutralization step allows to drastically reduce the consumption of acid reagent necessary for the neutralization of the outgoing charge from the alkaline oxidizing hydrolysis step.