Molybdenum-Enhanced Nitrification for High Nitrogen Wastewater
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Solution Overview
Problem
Current biological water treatment methods for ammonium nitrogen in wastewater are limited by the slow growth rate of nitrifying bacteria, which affects the nitrification step and results in reduced nitrogen removal efficiency, especially at high nitrogen concentrations, and are sensitive to temperature changes.
Innovation Solution
Incorporating a molybdenum compound into the treatment process to achieve a concentration of at least 0.025 mgMo/gN, enhancing the sludge nitrification rate to at least 0.11 kgN/(kgVSS·day) and controlling the hydrogen donor variation in the denitrification step to stabilize the treatment process even at high nitrogen concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrifying bacteria are used in microbial activated sludge for biological treatment, then nitrogen removal function is achieved, but treatment rate is limited due to extremely slow growth rate of autotrophic bacteria
Solution Approach 1:
The patent changes the chemical composition parameter by adding specific metal elements (Fe, Mn, Zn, Cu, Mo, Co, Ni) to the wastewater. This supplementation of trace elements stimulates the metabolic activity of nitrifying bacteria, enabling them to achieve higher treatment rates (0.05-0.2 kgN/kgVSS/day) while maintaining their slow growth characteristics, thus resolving the contradiction between reliability and productivity
2Productivity
If sludge treatment rate is increased to improve productivity, then treatment rate increases, but nitrification activity deteriorates due to sensitivity to operational conditions
Solution Approach 1:
The patent modifies the chemical environment by introducing metal element supplements, which enhance the robustness of nitrifying bacteria to operational variations. This allows the system to maintain stable nitrification activity even at higher sludge treatment rates, as the supplemented metals act as cofactors that stabilize enzyme functions under varying operational conditions
3Adaptability or versatility
If water temperature decreases to operate in colder conditions, then adaptability improves, but nitrification activity significantly deteriorates due to temperature sensitivity
Solution Approach 1:
The patent compensates for temperature effects by supplementing metal elements that are essential cofactors for nitrification enzymes. These metal supplements help maintain enzyme activity and bacterial metabolism at lower temperatures, allowing the system to adapt to colder conditions while preserving nitrification activity through enhanced metabolic efficiency
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 significantly improves the metabolic activity of nitrifying and denitrifying bacteria, allowing for stable and high-rate nitrogen removal from wastewater with high nitrogen concentrations, maintaining treatment efficiency despite temperature variations.
Implementation Method 1
a nitrification step of oxidizing the ammonium nitrogen under aerobic conditions to obtain nitrite or nitrate nitrogen
Implementation Method 2
a denitrification step of reducing the nitrite or nitrate nitrogen to nitrogen gas under anoxic conditions
Data Source
AI summary
Provided are a water treatment method and a water treatment device wherein in a biological treatment of ammonium nitrogen-containing water to be treated, the water to be treated can be treated stably at a high treatment speed even when the nitrogen concentration of the water to be treated is high. This water treatment device biologically treats ammonium nitrogen-containing water to be treated. The water treatment device (water treatment method) is provided with: a nitrification device (nitrification step) for oxidizing ammonium nitrogen to nitrite or nitrate nitrogen using nitrifying bacteria including autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria contained in microbial activated sludge; and a nitrification rate control means which maintains a molybdenum compound in the nitrification device in such a manner as to control the molybdenum concentration of the water to be treated to 0.025 mg Mo/gN or more, and controls the nitrification rate for the sludge to 0.11 [kgN/(kgVSS·day)].