Granular Activated Sludge Membrane Reactor for Clogging Prevention
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Solution Overview
Problem
Conventional sewage/wastewater treatment systems using membrane bio-reactors face challenges with membrane clogging due to sticky activated sludge, requiring frequent cleaning and additional facilities, which increases installation and operating costs and reduces treatment efficiency.
Innovation Solution
A sewage/wastewater treatment system utilizing granular activated sludge and a membrane bio-reactor with movable membranes located on the upper portion of a granulation tank, where the sludge is agitated to prevent attachment and accelerate granulation, reducing clogging and the need for additional facilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membranes are submerged in the aerobic tank to replace the clarifier, then solid-liquid separation is improved, but membrane clogging occurs due to broken activated sludge
Solution Approach 1:
The system divides the treatment process into distinct functional zones: an aeration tank for biological degradation and a separate granulation tank for solid-liquid separation using granular activated sludge. This segmentation prevents broken sludge from reaching the membranes while maintaining effective separation.
Solution Approach 2:
Granular activated sludge acts as an intermediary medium between the aeration tank and the membrane filtration system. It provides the necessary solid-liquid separation function without directly contacting the membranes, thereby preventing clogging while maintaining separation efficiency.
2Productivity
If activated sludge is aerated to maintain biological activity, then organic matter oxidation is improved, but sludge breakdown occurs causing membrane clogging
Solution Approach 1:
The system separates the aeration function (organic matter oxidation) from the granulation function (sludge stabilization). By maintaining distinct functional zones, the aeration process can proceed efficiently without causing excessive sludge breakdown that would harm the membrane system.
Solution Approach 2:
The system converts the potentially harmful effect of aeration-induced sludge breakdown into a beneficial granulation process. By controlling the granulation conditions, the broken sludge is transformed into useful granular activated sludge that performs separation functions without clogging membranes.
3Loss of time
If granular activated sludge is used to prevent membrane clogging, then membrane cleaning frequency is reduced, but granulation process complexity increases
Solution Approach 1:
The granulation process utilizes the self-granulating characteristics of activated sludge microorganisms. By providing appropriate hydrodynamic conditions and contact time, the system achieves automatic granulation without requiring complex external media or sophisticated control mechanisms, thus minimizing added complexity.
Solution Approach 2:
The system transitions from a two-dimensional surface aeration approach to a three-dimensional granulation process. By inducing vertical mixing and vortex formation in the granulation tank, the system achieves effective granulation through hydrodynamic forces rather than complex mechanical structures.
4Reliability
If membranes are cleaned frequently to maintain performance, then treatment efficiency is maintained, but operating costs increase
Solution Approach 1:
The system performs preliminary granulation of activated sludge before the sludge reaches the membrane filtration stage. This preliminary action prevents broken sludge particles from forming and clogging membranes in the first place, eliminating the need for frequent cleaning operations and reducing operating costs.
Solution Approach 2:
The system converts the potentially harmful effect of sludge breakdown into a beneficial granulation process that protects membranes. By controlling the granulation conditions, the system prevents membrane clogging without requiring frequent cleaning, thereby reducing operating costs while maintaining treatment 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 configuration minimizes installation area, extends membrane cleaning periods, reduces operating costs, and enhances pollutant removal efficiency for organic matters, nitrogen, and phosphate, while maintaining advanced water treatment standards.
Implementation Method 1
an indirect aeration tank adapted to supply air thereto to allow dissolved oxygen contained in raw water to reach a saturation concentration
Implementation Method 2
the contacts between the activated sludge are generated by means of the bridge reaction of the activated sludge to allow the activated sludge to bind with each other, so that the activated sludge becomes granulated through self-granulation thereof
Implementation Method 3
filtering supernatant liquid except the granulated sludge in the granulation step through movable membranes
Implementation Method 4
the granulation is accelerated through a first hydrodynamic force caused by the treated water conveyed from the indirect aeration tank and a second hydrodynamic force caused by the agitation means of the granulation tank
Data Source
AI summary
The present disclosure relates to a sewage/wastewater treatment system using granular activated sludge and a membrane bio-reactor and a sewage/wastewater treatment method using the same that are configured to effectively remove pollutants contained in raw water through a granulation tank in which the granular activated sludge is contained and to allow the raw water to be filtered through movable membranes located on the upper portion of the granulation tank. The system includes: an indirect aeration tank adapted to supply air thereto to allow dissolved oxygen contained in raw water to reach a saturation concentration; a granulation tank adapted to allow floating microorganisms contained in the treated water passing through the indirect aeration tank to be granulated and having a sludge blanket formed thereon; and movable membranes located on the upper portion of the granulation tank in such a manner as to be movable in the granulation tank.