Wastewater Biological Selector Using ORP-Controlled Aeration
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Solution Overview
Problem
Current aeration systems in wastewater treatment plants face challenges in optimizing bacterial concentrations, particularly in reducing dedicated anaerobic and aerobic bacteria while increasing facultative anaerobic bacteria, which are more efficient in nutrient reduction. Additionally, these systems incur high operational energy costs due to constant air supply.
Innovation Solution
A diffused aeration system with process control that uses an array of air diffusers positioned at the bottom of a vessel to distribute air into wastewater, monitored by an ORP probe and controller. The system controls the air blower's operation based on ORP readings, cycling the blower on and off to optimize bacterial populations and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If constant air supply is used to maintain aerobic environment, then dissolved oxygen concentration is improved, but energy consumption increases and dedicated anaerobic bacteria are not eliminated
Solution Approach 1:
The air blower operates in cyclic intervals rather than continuously, providing periodic aeration that maintains dissolved oxygen levels while allowing anaerobic bacteria to settle and be removed from the system during off-periods, thereby reducing energy consumption
Solution Approach 2:
The system uses ORP (oxidation-reduction potential) monitoring to detect the chemical state of the wastewater and automatically adjusts blower operation accordingly, creating a closed-loop control system that optimizes oxygen supply based on real-time conditions
2Quantity of substance
If constant aeration is applied, then aerobic bacteria concentration is increased, but dedicated anaerobic bacteria persist and produce harmful gases
Solution Approach 1:
By alternating between aeration on and off periods, the system creates periodic aerobic and anaerobic conditions that selectively promote facultative anaerobes while eliminating dedicated anaerobes through gravitational settling during off-periods, preventing harmful gas production
Solution Approach 2:
The system changes the ORP parameter dynamically through periodic aeration cycles, creating fluctuating oxidation-reduction conditions that favor facultative anaerobic bacteria over dedicated anaerobes, thereby eliminating harmful gas production
3Quantity of substance
If high concentration of dedicated aerobes is produced through over-aeration, then oxygen supply is improved, but biomass becomes buoyant and settling is compromised
Solution Approach 1:
The periodic interruption of aeration allows buoyant aerobic biomass to settle during off-periods, restoring good settling characteristics while maintaining adequate oxygen supply during on-periods through controlled cyclic aeration
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
The system effectively increases the concentration of facultative anaerobic bacteria, improving nutrient reduction efficiency while reducing operational energy costs by optimizing blower run times. This leads to a more optimized aerobic environment, reducing undesirable bacteria and minimizing odorous gas production.
Implementation Method 1
supplemental air must be introduced into the system to promote the dissolution of gaseous oxygen into the liquid phase
Implementation Method 2
monitoring a state of the wastewater process fluid with an oxygen reduction potential (ORP) probe
Implementation Method 3
controlling a rate of the air supply to the wastewater process fluid by cycling of an air blower on and off
Data Source
AI summary
A method for treating a wastewater process fluid includes: distributing air into a vessel having wastewater process fluid with an external air supply through an array of air diffusers; monitoring a state of the wastewater process fluid with an oxygen reduction potential (ORP) probe and a controller in operable communication with the ORP probe; and controlling a rate of the air supply to the wastewater process fluid by cycling of an air blower on and off. The time periods for operating the air blower are based on ORP readings. A biological selector system is also included.