Wastewater Clarifier Integrating Biosorption and Sedimentation
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Solution Overview
Problem
Current wastewater treatment methods require separate processes for physical and biological separation of organic solids, leading to inefficiencies in resource usage, infrastructure, and energy consumption, as well as variable performance due to external factors affecting biosorption/bioflocculation processes.
Innovation Solution
Integrating biosorption or bioflocculation steps within primary clarifiers or chemically enhanced primary treatment (CEPT) processes, utilizing alternating clarifier cycles with feed, withdrawal, aeration, and settling phases to maximize organic suspension removal and subsequent thickening, while minimizing resource use and equipment needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate processes are used for physical and biological separation of organic solids, then each process can be optimized independently, but resource usage, infrastructure, and energy consumption increase
Solution Approach 1:
The patent combines physical separation (sedimentation) and biological separation (biosorption/bioflocculation) into a single integrated process within one clarifier unit. The clarifier simultaneously performs settling of particulate solids and biosorption of colloidal solids through activated sludge, eliminating the need for separate physical and biological treatment processes while maintaining optimization of both functions
Solution Approach 2:
The clarifier is designed to perform multiple functions simultaneously: it acts as both a sedimentation tank for physical separation and a biosorption reactor for biological separation. The activated sludge serves dual purposes as both the settling medium and the biosorptive agent, making the single unit universally capable of handling both separation mechanisms
2Loss of substance
If biosorption/bioflocculation processes are used for organic suspension removal, then chemical usage is reduced, but process performance becomes variable due to external factors
Solution Approach 1:
The patent implements a recycle stream where a portion of the activated sludge is continuously returned to the clarifier inlet. This feedback mechanism maintains a consistent concentration of biosorptive biomass in the clarifier, stabilizing the biosorption process performance and making it less sensitive to variations in influent characteristics or environmental conditions
Solution Approach 2:
The patent controls the solids residence time (SRT) and hydraulic retention time (HRT) parameters to optimize biosorption performance. By maintaining specific ranges for these parameters and using aggressive wasting of concentrated solids, the process achieves reliable and consistent organic matter removal without depending on variable external factors
3Productivity
If traditional primary clarifiers are used for solids removal, then settleable material is efficiently removed, but colloidal non-settleable suspensions remain in the effluent
Solution Approach 1:
The patent introduces activated sludge as an intermediary substance that mediates the removal of colloidal suspensions. The activated sludge flocs act as collectors that adsorb and aggregate fine colloidal particles through biosorption and bioflocculation, making them settleable and removable in the clarifier effluent, thereby addressing the limitation of traditional clarifiers that cannot remove non-settleable colloids
4Quantity of substance
If chemically enhanced primary treatment (CEPT) is used to remove finer colloidal suspensions, then solids removal efficiency increases, but significant chemical sludge is generated for downstream processing
Solution Approach 1:
The patent uses activated sludge, a biological material with short residence time, as a substitute for expensive and persistent chemical coagulants. The activated sludge performs the flocculation function temporarily and is then wasted or recycled, avoiding the generation of harmful chemical sludge while achieving comparable or superior solids removal efficiency for colloidal suspensions
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 integrated approach enhances the efficiency of organic suspension removal and thickening, reducing energy and equipment requirements, and achieving higher solids concentrations with improved process control and reduced footprint, infrastructure, and energy consumption.
Implementation Method 1
The clarifier is operated to maximize settlement and concentration of these solids to downstream processes
Implementation Method 2
This biosorption 'A' step is achieved in a separate reactor/clarifier combination that is maintained at very short solids and hydraulic residence times
Implementation Method 3
This biosorption process occurs through a bioflocculation process described to occur using bacterial extracellular polymeric substances (EPS), as the bacteria in sludge change physiological states to form aggreagates
Data Source
AI summary
A method for clarification of wastewater that operates at least two alternating and equal process cycles in two or more clarifiers (1a, 1b), each process cycle consisting of a feed period with concurrent feeding and discharging and a reset period in which excess sludge is removed into a thickener (2a, 2b) and the remaining sludge blanket gets homogenized and pre-settled, wherein at each point of time in at least one clarifier (1a, 1b) the feed period is performed.