Equalization Basin Reactor for Wet Weather Wastewater Treatment
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Solution Overview
Problem
Sewage treatment plants face challenges in processing variable wastewater flow rates and volumes, especially during wet weather conditions, leading to solids breakthroughs and reduced pollutant removal efficiency due to increased hydraulic detention times and loading rates, which existing methods attempt to mitigate through equalization basins but result in odor issues and carbon source reduction.
Innovation Solution
The implementation of a Storm Surge Flow Equalization (EQ) Reactor, which serves as an equalization basin reactor capable of handling wet weather inflow rates and volumes, performing first, second, and third-stage wastewater treatment, including activated sludge treatment and nitrogen removal, while maintaining aerobic conditions without aeration, thus preventing protection mode operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If equalization basins are used to store wet weather sewage influent flow surges, then peak throughput sewage flow rates are reduced, but odors occur and carbon source is reduced
Solution Approach 1:
The patent combines the equalization basin function with biological treatment functions by integrating multiple treatment stages (nitrification, denitrification, phosphorus removal) into the equalization structure. This merging allows the equalization basin to perform both flow equalization and wastewater treatment simultaneously, eliminating odors through aerobic conditions and preserving carbon sources for downstream processes.
Solution Approach 2:
The equalization basin is designed to perform multiple functions: flow equalization, biological nutrient removal (nitrogen and phosphorus), and carbon source preservation. By making the equalization basin multi-functional, the patent avoids the need for separate treatment units that would generate odors and consume carbon sources, thereby resolving the contradiction between flow rate reduction and harmful factor generation.
2Productivity
If equalization basins are used to store wet weather sewage influent flow surges, then peak throughput sewage flow rates are reduced, but carbon source is reduced
Solution Approach 1:
The patent merges flow equalization with biological treatment processes, allowing carbon sources to be utilized for nutrient removal rather than being lost. The integrated design enables carbon sources to serve dual purposes: maintaining aerobic conditions for odor prevention and providing substrates for nitrification and denitrification processes.
Solution Approach 2:
The patent changes the operational parameters of the equalization basin by maintaining aerobic conditions through controlled aeration and integrating biological treatment stages. This parameter change allows the system to preserve carbon sources for downstream processes while still achieving flow equalization, resolving the contradiction between flow rate reduction and carbon source loss.
3Reliability
If mixing and aeration equipment is shut off during wet weather inflow conditions, then activated sludge solids settle out in reactors, but total nitrogen and total phosphorus removal efficiency decrease
Solution Approach 1:
The patent applies preliminary action by pre-treating the wastewater in the equalization basin before it enters the biological treatment reactors. The equalization basin performs initial nutrient removal and carbon source preservation, reducing the burden on downstream processes and maintaining pollutant removal efficiency even when aeration is reduced during wet weather events.
Solution Approach 2:
The patent segments the treatment process into distinct functional zones: equalization basin for flow equalization and initial treatment, nitrification zone for nitrogen removal, denitrification zone for nitrate removal, and phosphorus removal zone. This segmentation allows each zone to operate optimally independently, maintaining overall pollutant removal efficiency while allowing flexible operation during wet weather conditions.
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 method allows for continuous wastewater treatment under wet weather conditions, maintaining pollutant removal efficiency and avoiding protection mode operations, while reducing odors and preserving carbon sources for downstream processes.
Implementation Method 1
equalization basins (EQs) to store wet weather sewage influent flow surges and reduce peak throughput sewage flow rates
Implementation Method 2
first stage of wastewater treatment may be an activated sludge treatment with significant removal of BOD and removal of nitrogen from nitrates
Implementation Method 3
removal of nitrogen from nitrates
Implementation Method 4
nitrogen removal by biological denitrification
Implementation Method 5
activated sludge is precipitated, thereby obtaining treated water from the substantially treated wastewater
Implementation Method 6
equalization basins are used to store, blend and equalize variable wastewater influent flows and loads upstream of the BNR treatment process units. Storing raw wastewater and stormwater inflow in an equalization basin (FEB) can produce odors unless the FEB is operated with aeration to transfer oxygen into the wastewater in order to maintain aerobic conditions
Data Source
AI summary
Method for treating wastewater, in particular municipal wastewater, in which the wastewater is initially received in an equalization basin reactor for performing an infiltration and inflow equalization process. The equalization basin reactor has sufficient capacity for the increased inflow of wastewater received under wet weather conditions. However, the increased inflow is not merely stored in the equalization basin reactor for later processing, but the wastewater treatment process continues throughout the wet weather period with the first stage wastewater treatment being performed in the equalization basin reactor, which further provides a substantially constant outflow of partially treated wastewater for subsequent treatment stages.