Wastewater Nitrate Control via Dynamic Aeration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wastewater treatment systems face challenges in controlling denitrification treatment and nitrogen removal rates due to fluctuations in organic and ammonia loadings, leading to inadequate oxygen supply and inefficient nitrogen removal.
Innovation Solution
A method and program that dynamically control the gas supply amount to the reaction tank based on nitrogen loading, using a nitrate meter to monitor and adjust the gas supply, ensuring appropriate oxygen levels and optimizing denitrification and nitrification reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If influent proportional control is used to supply air in proportion to influent amount, then the control is simple, but excess or shortage of air occurs inevitably due to fluctuations in organic loading and ammonia loading
Solution Approach 1:
The patent uses a nitrate meter to measure nitrate nitrogen concentration in the reaction tank and feeds this information back to the control device. The control device then adjusts the air supply amount based on this feedback, creating a closed-loop control system that adapts to fluctuations in organic and ammonia loading, thereby resolving the contradiction between simple control and accurate air supply.
Solution Approach 2:
The patent replaces the mechanical/proportional control method with an instrument-based control system using a nitrate meter and control device. This substitution enables precise measurement and control of air supply based on actual nitrogen content, improving air supply accuracy while maintaining operational simplicity through automated control.
2Reliability
If DO control is used to maintain dissolved oxygen concentration, then oxygen levels are controlled, but air supply becomes excessive when loading decreases or insufficient when loading increases
Solution Approach 1:
The patent changes the control parameter from dissolved oxygen concentration to nitrate nitrogen concentration. By measuring nitrate nitrogen levels and controlling air supply based on this parameter, the system directly targets nitrogen removal efficiency rather than merely maintaining oxygen levels, resolving the contradiction between oxygen control and nitrogen removal productivity.
3Reliability
If ammonia control is used to supply air according to ammonia loading, then appropriate air supply is achieved, but denitrification treatment in the previous stage cannot be controlled
Solution Approach 1:
The patent makes the control system universal by using nitrate nitrogen concentration as the control parameter, which reflects the overall nitrogen removal process including both nitrification and denitrification stages. This single control parameter enables the system to control both ammonia oxidation and denitrification treatments, resolving the limitation of ammonia control that could only address one stage.
4Ease of operation
If fixed air supply amount is used in the reaction tank, then the system is simple to operate, but nitrogen removal rate is insufficient when loading increases
Solution Approach 1:
The patent transforms the static fixed air supply system into a dynamic system that automatically adjusts air supply amount based on real-time nitrate nitrogen concentration measurements. The control device modifies the air supply rate in response to changing loading conditions, maintaining operational simplicity while significantly improving nitrogen removal rate through adaptive control.
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 improves the nitrogen removal rate and water quality by providing optimal oxygen levels and controlling denitrification treatment, addressing the inefficiencies in previous systems.
Implementation Method 1
a nitrate meter (7) that measures a nitrate concentration
Implementation Method 2
air diffuser units (6a to 6d) that perform air diffusion into the respective aerobic tanks
Implementation Method 3
organic matter contained in the sewage in the reaction tank is decomposed by an action of the aerobic microorganisms
Implementation Method 4
aeration treatment is performed to supply oxygen to various kinds of aerobic microorganisms present in a reaction tank
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Biological treatment is performed with respect to water to be treated flowing in a plurality of aerobic tanks 2a to 2d that constitute a reaction tank 2. Air is supplied to the reaction tank 2 from air diffuser units 6a to 6d respectively provided in the respective aerobic tanks 2a to 2d, to aerate the water to be treated. A nitrate meter 7 is provided on an inflow side of the aerobic tank 2c, which is a desired position along the flow of the water to be treated in the reaction tank 2, to measure a nitrate concentration. The nitrate meter 7 supplies a measurement value of the nitrate concentration to the control unit 9. The control unit 9 supplies a control signal to gas supply-amount control units 10a to 10d so that the nitrate concentration falls within a predetermined range of the nitrate concentration to be controlled, and controls a gas supply amount from the air diffuser units 6a to 6d to the water to be treated for each of the air diffuser units 6a to 6d or collectively in the air diffuser units 6a to 6d.