Granular Sludge Classifier for Wastewater Nutrient Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wastewater treatment systems using granular activated sludge struggle to maintain low effluent concentrations of total suspended solids (TSS) and nutrients, such as nitrogen and phosphorus, due to inefficiencies in granular biomass growth and separation from flocculent biomass, leading to higher treatment footprints and operational complexities.
Innovation Solution
A continuous flow combined granular and flocculent activated sludge process that controls granular sludge size and relative concentrations through an anaerobic first reactor with high soluble BOD loading and a granular sludge classifier, allowing for efficient recycling and wasting of sludges to optimize nutrient removal and reduce treatment footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional flocculent activated sludge process is used, then effluent TSS can be kept low, but treatment footprint and system complexity increase
Solution Approach 1:
The patent changes the physical state and size parameters of the biomass from flocculent (0.05-0.30 mm) to granular (0.5-4.0 mm), which fundamentally alters settling behavior and allows for higher biomass concentrations in smaller volumes, reducing treatment footprint while maintaining low effluent TSS
Solution Approach 2:
The patent uses a granular sludge classifier that copies and separates granular biomass from flocculent biomass, allowing the system to leverage the superior settling characteristics of granules while maintaining the nutrient removal capabilities of flocculent sludge
2Productivity
If granular activated sludge is used, then treatment capacity and biomass concentration increase, but effluent TSS control becomes difficult
Solution Approach 1:
The patent segments the biomass into two distinct populations (granular and flocculent) and uses a classifier to separate them, allowing each type to perform its specialized function - granules for high-rate treatment and flocculent for effluent clarification
Solution Approach 2:
The granular sludge classifier acts as an intermediary device between the reaction zone and the effluent stream, selectively removing granular biomass while allowing flocculent biomass to continue providing TSS removal in the effluent
3Productivity
If separate granular and flocculent sludge streams are maintained, then treatment efficiency improves, but operational complexity increases
Solution Approach 1:
The patent merges the management of granular and flocculent sludge into a single continuous flow system with a integrated classifier, allowing both biomass types to coexist and be controlled through unified hydraulic and operational parameters rather than separate systems
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 enables efficient removal of organics, particulates, nitrogen, and phosphorus to low effluent concentrations, achieving higher biomass concentrations and treatment capacity with a smaller footprint, while maintaining effective nutrient removal capabilities.
Implementation Method 1
Gravity settling of solids in a clarifier is the most common liquid-solids separation method
Implementation Method 2
The activated sludge process has been used since the early 1900s for the treatment of domestic and industrial wastewater by microorganisms
Implementation Method 3
Biomass growth in aerobic activated sludge processes is the result of assimilation and oxidation of influent organic substrate with a suitable electron acceptor such as oxygen
Implementation Method 4
These suspended biofilms are self-aggregating, do not require a carrier media and are referred to as granular activated sludge
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
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. It includes anaerobic, anoxic, and aerobic process zones, a high soluble biodegradable COD loaded first reactor in anaerobic or anoxic zones, a granular sludge classifier with recycle of underflow granular sludge to the first reactor, a secondary clarifier to settle flocculent sludge and particulates and recycle of flocculent sludge from the secondary clarifier underflow to an aerobic process zone. Wasting of sludge from the two separate recycle lines controls the bioprocess flocculent and granular sludge concentrations and CRTs. Bypass around and recycle flow to the classifier to maintain desired flow under various influent flow conditions aid control of granule size. On/off mixer operation of anaerobic and anoxic reactors may be used.