Fluidized Sludge Bed Clarifier with Recycled PAC
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current water treatment processes are inefficient in removing dissolved organic matter and micropollutants, particularly due to the need for separate unit treatments and high investment costs associated with granular activated carbon filtration, which limits the elimination of refractory Total Organic Carbon (TOC) and micropollutants like pesticides.
Innovation Solution
A process combining clarification and adsorption on powdered activated carbon in a fluidized sludge bed decanter with a mixture of metal hydroxides and powdered activated carbon, where the powdered activated carbon is recycled to maintain high concentrations within the bed, allowing for simultaneous elimination of suspended matter, dissolved organic matter, and micropollutants in a single treatment step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate unit treatments (clarification followed by granular activated carbon filtration) are used, then treatment effectiveness is improved, but device complexity and investment costs increase
Solution Approach 1:
The patent combines clarification and adsorption treatments into a single integrated unit. The fluidized bed contains both coagulant flocs for clarification and powdered activated carbon for adsorption, allowing simultaneous removal of suspended matter and dissolved organic matter in one treatment stage, thereby reducing device complexity while maintaining treatment effectiveness
Solution Approach 2:
The fluidized bed system performs multiple functions simultaneously: it acts as a clarification unit through coagulation-flocculation, an adsorption unit through powdered activated carbon, and a separation unit through the fluidized bed structure. This multi-functionality eliminates the need for separate treatment trains, reducing both device complexity and investment costs
2Reliability
If granular activated carbon filtration is used, then removal of refractory TOC and micropollutants is improved, but investment costs and space requirements increase
Solution Approach 1:
The patent uses powdered activated carbon instead of expensive granular activated carbon. PAC is more cost-effective, easier to dose and recycle, and can be maintained in the fluidized bed at lower costs. The powdered form allows for more flexible dosing and integration into the fluidized bed system, reducing investment costs while maintaining adsorption effectiveness
Solution Approach 2:
The patent changes the physical state of activated carbon from granular to powdered form, and incorporates it into a fluidized bed system. This parameter change enables better mixing, more uniform distribution, and easier recycling of the adsorbent, thereby reducing investment costs and operational complexity while maintaining or improving removal efficiency for refractory TOC and micropollutants
3Reliability
If coagulant dosages are increased to enhance adsorption, then removal of dissolved organic matter is improved, but cost of chemical reagents increases
Solution Approach 1:
The fluidized bed system allows the activated carbon to be recycled and reused continuously. The PAC is not consumed but rather circulated through the bed, allowing it to perform adsorption multiple times. This self-service approach eliminates the need for continuous addition of fresh PAC and coagulants, significantly reducing chemical reagent costs while maintaining effective removal of dissolved organic matter
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 approach effectively reduces turbidity, suspended matter, and organic pollutants, achieving comparable or superior results to traditional methods while reducing costs and footprint by integrating clarification and adsorption in a single stage, maintaining high adsorption performance and reducing residual TOC and micropollutant levels.
Implementation Method 1
adsorption on powdered activated carbon in a mixed sludge bed decanter consisting of a mixture of powdered activated carbon and metal hydroxide sludge, aimed at removing suspended matter, dissolved organic matter and organic micropollutants from aqueous fluids
Implementation Method 2
combining clarification and refining by adsorption on powdered activated carbon in a mixed sludge bed decanter
Implementation Method 3
fluidized sludge bed decanter with a mixture of metal hydroxides and powdered activated carbon
Implementation Method 4
recycling of at least one fraction of powdered activated carbon separated from the mixed sludge which is extracted from the decanter
Data Source
Figure 1~2
Figure 3
AI summary
A process for treating an aqueous fluid, in particular water, by clarification and adsorption on powdered activated carbon in a continuously fed, upward-flow fluidized sludge bed clarifier, characterized in that said fluidized sludge bed is a fluidized bed of mixed sludge of metal hydroxides and powdered activated carbon in which the concentration of mixed sludge within the bed is at least 1 g/L, said powdered activated carbon representing at least 33% by weight of the mixed sludge and said powdered activated carbon having an average diameter of less than 30 µm, and in which the proportion of powdered activated carbon within the bed is maintained by recycling at least a fraction of the powdered activated carbon separated from the mixed sludge, advantageously by means of at least one hydrocyclone.The present invention also relates to an aqueous fluid treatment installation, comprising a fluidized sludge bed clarifier, suitable for implementing the process.