Biological Wastewater Treatment Using Gas-Phase VOC Feedback
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Solution Overview
Problem
Existing methods for determining the optimal additive amount of nutrient substances in biological wastewater treatment face instability due to clogging and measurement inaccuracies in on-line TOC concentration meters, leading to inefficient nutrient addition and increased volatile organic compound emissions.
Innovation Solution
A method for measuring the efficacy of concentration of volatile organic compounds in the gas phase during biological treatment, combined with carbon dioxide concentration and flow rate measurements, to control the additive amount of nutrient substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If on-line TOC concentration meter is used to measure organic matter concentration, then nutrient substance addition can be controlled, but clogging occurs inside piping due to accumulation of suspended solids and oil contents
Solution Approach 1:
The invention extracts the measurement function from the water phase to the gas phase. Instead of measuring TOC directly in the wastewater stream (which causes clogging), the system measures volatile organic compound concentrations in the gas phase above the water surface, thereby avoiding contact with suspended solids and oil contents that cause piping clogging.
Solution Approach 2:
The invention introduces gas phase volatile organic compounds as an intermediary medium. Rather than directly measuring the problematic water parameters, the system uses VOC concentrations in the gas phase as a proxy indicator for organic matter content, allowing indirect measurement without physical contact with clogging substances.
2Productivity
If aerobic treatment is performed with carriers to increase BOD volume loading, then treatment capacity increases, but the amount of surplus sludge generated increases
Solution Approach 1:
The invention implements a feedback control system where VOC concentrations in the gas phase are continuously monitored and used to adjust nutrient substance addition rates. This feedback mechanism allows optimization of microbial activity and organic matter decomposition efficiency, thereby reducing excess sludge production while maintaining high treatment capacity.
Solution Approach 2:
The system changes the control parameter from direct TOC measurement in water to VOC concentration measurement in gas phase. This parameter change enables more precise control of nutrient addition based on actual organic matter degradation status, optimizing the balance between treatment productivity and sludge generation.
3Productivity
If volatile organic compounds are transferred to gas phase by aeration, then biological treatment proceeds, but volatile organic compound emissions into atmosphere increase
Solution Approach 1:
The system uses VOC concentration measurements in the gas phase as feedback to control nutrient substance addition rates. By monitoring VOC emissions in real-time and adjusting nutrient supply accordingly, the system optimizes biological degradation efficiency while minimizing excessive VOC generation and emissions to the atmosphere.
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
Stable determination of optimal nutrient substance addition, reducing volatile organic compound emissions and minimizing surplus sludge generation.
Implementation Method 1
the volatile organic compound in the water may be transferred to the gas phase by aeration or the like depending on the biological treatment conditions
Implementation Method 2
a concentration measurement step to measure concentration of at least a volatile organic compound in gas released from water in the reaction tank
Data Source
AI summary
A wastewater treatment apparatus included: a reaction tank which performs biological treatment of raw water, which is organic wastewater; an adding device that adds a nutrient substance to the raw water; a meter that measures the concentration of at least a volatile organic compound in gas released from water in the reaction tank; and a control device for controlling an additive amount of the nutrient substance by the adding device based on a measured value of the concentration obtained by the meter.