Dissolved Air Flotation Unit for High Solids Wastewater Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wastewater treatment systems face inefficiencies in handling high solids content wastewater, particularly in reducing biological oxygen demand and managing waste sludge, which increases operational and capital costs.
Innovation Solution
The integration of a dissolved air flotation (DAF) unit between a contact tank and biological treatment unit, recycling solids back to the contact tank to reduce biological oxygen demand and utilizing an anaerobic digester for biogas production, thereby reducing aeration needs and sludge production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wastewater treatment systems are used to handle high solids content wastewater, then the treatment process can proceed, but the biological oxygen demand reduction efficiency decreases and waste sludge management costs increase
Solution Approach 1:
The patent extracts and removes a portion of the solids from the mixed liquor in the contact tank before it enters the biological treatment unit. This is achieved by taking out suspended solids through the DAF unit, thereby reducing the solids content and biological oxygen demand that would otherwise burden the biological treatment system and increase sludge production.
Solution Approach 2:
The patent performs preliminary solids removal in the contact tank using the DAF unit before the mixed liquor enters the biological treatment unit. This preliminary action reduces the solids content and biological oxygen demand in advance, allowing the biological treatment unit to operate more efficiently with reduced sludge production.
2Productivity
If solids are removed from the contact tank and recycled back, then biological oxygen demand is reduced, but the system complexity increases
Solution Approach 1:
The contact tank serves multiple functions: it acts as a mixing tank for the activated sludge process, a thickening tank for solids concentration, and a DAF unit for dissolved air flotation. This multi-functionality reduces the need for separate equipment and simplifies the overall system configuration while achieving effective solids removal and biological oxygen demand reduction.
3Use of energy by moving object
If the biological treatment unit size is reduced, then energy consumption decreases, but the treatment capacity may be compromised
Solution Approach 1:
By extracting and removing a portion of the solids from the mixed liquor in the contact tank before biological treatment, the patent reduces the biological oxygen demand that needs to be processed. This allows for a smaller biological treatment unit with lower energy consumption while maintaining adequate treatment capacity for the reduced load.
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 configuration enhances the efficiency of wastewater treatment by reducing the size and energy consumption of biological treatment units, increasing biogas production, and minimizing waste sludge, while allowing for the reuse of recycled solids to enhance treatment processes.
Implementation Method 1
The dissolved air flotation unit may be configured to treat the second mixed liquor with the gas to form the floated solids and the effluent
Implementation Method 2
The aeration unit may be configured to aerate the wastewater with the oxygen to form a first mixed liquor
Implementation Method 3
utilizing an anaerobic digester for biogas production
Data Source
AI summary
A wastewater treatment system including an aeration unit, a contact tank, a dissolved air flotation unit, and a biological treatment unit is disclosed. A method of retrofitting a wastewater treatment system by providing an aeration unit and fluidly connecting the aeration unit to the wastewater treatment system is also disclosed. A method of treating wastewater including aerating wastewater with oxygen, combining the aerated wastewater with activated sludge, floating biosolids from the activated wastewater, and biologically treating the effluent is also disclosed. The method optionally includes combining the floated biosolids with the aerated wastewater and/or activated wastewater. A method of facilitating treatment of high solids content wastewater is also disclosed.