Urea Wastewater Treatment via Dynamic Aerobic Anaerobic Control

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Solution Overview

Problem

Existing wastewater treatment plants face challenges in optimally regulating the conversion of urea in wastewater, particularly with high urea concentrations, to achieve complete treatment with minimal energy consumption, as existing processes often require separate aerobic and anaerobic steps and struggle to control substance conversions effectively.

Innovation Solution

A wastewater treatment plant with a first treatment tank equipped with an oxygen supply device and a control system that allows for aerobic or anaerobic operation based on ammonium or ammonia concentration, enabling flexible switching between these states to optimize energy use and substance conversion, along with additional tanks for nitrification and denitrification processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate aerobic and anaerobic process steps are used to treat urea-containing wastewater, then complete treatment can be achieved, but the system complexity and difficulty of regulation increase

Engineering Contradiction:
Improvetreatment completenessVSAvoidprocess regulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple treatment processes (aerobic nitrification and anaerobic denitrification) into a single bioreactor system. The bioreactor is equipped with both an aeration device for oxygen supply and a recirculation system that creates anaerobic zones, allowing both aerobic and anaerobic processes to occur simultaneously in different regions of the same reactor, thereby reducing system complexity while maintaining treatment effectiveness

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system employs dynamic control through a recirculation pump that can adjust flow rates to create varying oxygen conditions within the bioreactor. By controlling the recirculation rate, the system dynamically switches between aerobic and anaerobic conditions in different zones, enabling flexible regulation of nitrification and denitrification processes without requiring separate fixed reactors

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If multiple separate treatment tanks are used for nitrification and denitrification, then process control is simplified, but the plant requires more space and equipment

Engineering Contradiction:
Improveprocess control easeVSAvoidplant footprint
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent merges nitrification and denitrification tanks into a single integrated bioreactor. The reactor design includes internal zoning where aerobic conditions occur in the aeration zone and anaerobic conditions occur in the recirculation zone, eliminating the need for separate physical tanks while maintaining distinct process zones for both nitrogen transformation processes

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If conventional multi-step treatment processes are used, then thorough wastewater treatment is achieved, but energy consumption increases

Engineering Contradiction:
Improvewastewater treatment qualityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system maintains continuous simultaneous nitrification and denitrification processes within the bioreactor through continuous aeration and recirculation. This eliminates the need for sequential batch processing and allows both aerobic and anaerobic zones to operate continuously, improving energy efficiency by eliminating idle periods and reducing the total volume of aeration required compared to conventional separate-tank systems

Inventive Principle:
Principle #20Continuity of useful action

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 allows for flexible and efficient wastewater treatment by controlling oxygen supply and circulation, reducing energy consumption and maintaining optimal ammonium and ammonia levels, while supporting simultaneous process steps in the same tank, thereby enhancing treatment efficiency and adaptability.

Implementation Method 1

urea being converted into ammonia and carbon dioxide by way of ammonification

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

This is preferably done by urease or urease enzymes, which are preferably formed by bacteria

Methodology Applied
Scientific EffectEnzyme catalysis: Enzyme

Implementation Method 3

the at least one first processing tank is designed in such a way that it has an oxygen supply device, via which oxygen can be supplied to the contents of the processing tank

Methodology Applied
Scientific EffectAeration: Aeration

Implementation Method 4

ammonium ions are formed in the water, which in a second step can be oxidized to nitrite and then to nitrate by adding oxygen

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 5

the nitrate is converted into nitrogen by means of denitrification in the absence of oxygen

Methodology Applied
Scientific EffectAnaerobic digestion: Anaerobic Digestion

Data Source

PatentEP3067330B1Water treatment plant and process for the treatment of urea containing water
Publication Date: 2019.07.24 GRUNDFOS HLDG
  • EP3067330B1 patent drawingFigure 1

AI summary

The invention relates to a wastewater treatment plant for treating urea-containing wastewater, comprising at least one first treatment tank (2) which has a wastewater inlet (8) through which urea-containing wastewater is introduced into the first treatment tank, wherein, during operation of the wastewater treatment plant, urea is converted into ammonia in the first treatment tank (2), preferably by urease enzymes, wherein an oxygen supply device (14, 16), in particular in the form of an aeration device (16), is arranged in the first treatment tank (2), and the wastewater treatment plant has a control device (46) by which the oxygen supply device (14, 16) can be switched on and off in such a way that the conversion of urea into ammonia can be carried out selectively aerobically or anaerobically, as well as a corresponding wastewater treatment process.