Granular Sludge Selection in Continuous-Flow Nutrient Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wastewater treatment systems face challenges in efficiently selecting and concentrating granular biomass for effective nitrogen and phosphorus removal, particularly in continuous flow granular/flocculent sludge processes, where control of granule size and concentration is suboptimal, leading to inefficient nutrient and solids removal.
Innovation Solution
A wastewater treatment system with a series of biological process zones and a downstream clarifier, incorporating a sidestream separator and a multi-stage anaerobic zone, to enhance granular biomass growth and separation, including a sidestream separator for granule/floc separation and a clarifier with a special separator to concentrate granules, and a multi-stage anaerobic zone for intimate food contact and high soluble BOD loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous flow granular/flocculent sludge process is used for nutrient removal, then nitrogen and phosphorus removal capability is improved, but control of granule size and concentration becomes suboptimal leading to inefficient solids removal
Solution Approach 1:
The system divides the sludge treatment into separate functional zones: a granular sludge treatment zone and a flocculent sludge treatment zone. The granular sludge classifier separates granular biomass from flocculent biomass, allowing independent optimization of each stream. This segmentation enables precise control over granule size and concentration in the granular stream while maintaining effective nutrient removal overall.
Solution Approach 2:
The invention extracts and removes flocculent sludge from the granular sludge stream using a granular sludge classifier. By taking out the flocculent portion, the system concentrates the granular biomass for enhanced settling and nutrient removal, while the flocculent sludge is separately treated in a dedicated zone. This extraction enables independent optimization of granule characteristics.
2Speed
If granular sludge is concentrated in the clarifier, then settling speed is improved, but separation efficiency of granules from floc decreases
Solution Approach 1:
The system performs preliminary separation of granular and flocculent sludge in the granular sludge classifier before the sludge reaches the clarifier. This preliminary action concentrates the granular biomass in a controlled manner, preparing it for efficient settling in the clarifier while preventing mixed granular-flocculent sludge from compromising separation efficiency.
Solution Approach 2:
The granular sludge classifier acts as an intermediary device between the aeration tank and the clarifier. It mediates the transition by separating granular biomass from flocculent biomass, allowing the clarifier to receive a optimized granular sludge stream that settles efficiently without interference from lighter flocculent sludge.
3Quantity of substance
If flocculent sludge is recycled to the aerobic zone, then biomass concentration is improved, but granule size control becomes difficult
Solution Approach 1:
The system segments the sludge recycle streams into separate granular and flocculent recycle lines. The granular sludge classifier provides a separate recycle path for granular biomass to the anaerobic zone, while flocculent sludge is recycled separately to the aerobic zone. This segmentation allows independent control of granule size in the anaerobic zone while maintaining adequate biomass concentration through flocculent sludge recycle.
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
Enhances granular sludge concentration and settling, allowing for quicker sludge settlement and higher granular sludge concentration at the bottom of the clarifier, improving nutrient removal efficiency and optimizing granule size and concentration for better separation and treatment performance.
Implementation Method 1
a sidestream separator and a clarifier with a special separator to concentrate granules
Implementation Method 2
a multi-stage anaerobic zone for intimate food contact and high soluble BOD loading
Implementation Method 3
The granule-rich sludge goes to a clarifier, which may include a second separator within the clarifier, for further concentration of granules
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A continuous flow granular/flocculent sludge wastewater process selects for granule biomass capable of nitrogen and phosphorus removal and controls granule size and concentration of granular and flocculent sludge for optimal nutrient, organic, and solids removal in a smaller footprint. A series of biological process zones lead to a secondary clarifier. Mixed liquor sludge, preferably from an aerobic zone, goes through a classifier or separator processing flow from the aerobic zone, to the secondary clarifier. In a sidestream process that can be included a portion of sludge preferably from an aerobic zone goes through a classifier or separator to selectively produce a granular-rich effluent, and the clarifier may also have a separator to further concentrate granular biomass, most of which is cycled back to an initial multi-stage anaerobic process zone. The anaerobic zone is structured and operated to encourage growth of granules in subsequent process zones.