Membrane Bioreactor Coagulant-Polymer Blend for Phosphorus Removal and Flux
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Membrane bioreactors face issues with membrane fouling and high energy demand for aeration, limiting their widespread adoption in wastewater treatment due to increased costs and efficiency drawbacks.
Innovation Solution
A blend product comprising inorganic coagulants, such as iron and aluminum compounds, combined with organic anionic polymers like acrylamide and acrylic acid, is added to the wastewater to enhance phosphorus removal and permeate flux in membrane bioreactors, addressing membrane fouling and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If inorganic coagulant is added to improve phosphorous removal, then phosphorous removal efficiency is improved, but membrane flux is not improved and fouling occurs
Solution Approach 1:
The patent combines inorganic coagulant (such as aluminum sulfate or ferric chloride) with organic water-soluble polymer (such as polyacrylamide) to form a composite chemical system. This composite approach leverages the phosphorous precipitation capability of inorganic coagulants while the organic polymer provides anti-fouling properties and maintains membrane flux, resolving the contradiction between phosphorous removal and flux maintenance.
Solution Approach 2:
The invention merges two separate chemical functions into a single treatment process: phosphorous removal via inorganic coagulant and membrane fouling prevention via organic polymer. By combining these functions in one system, the patent achieves both phosphorous removal efficiency and sustained membrane flux without requiring separate treatment steps.
2Productivity
If air sparging and backwashing are performed to prevent membrane fouling, then membrane flux is maintained, but energy consumption and process costs increase
Solution Approach 1:
The organic water-soluble polymer acts as an intermediary substance that modifies the interaction between suspended solids and the membrane surface. By introducing this chemical mediator, the patent reduces the need for mechanical interventions like air sparging and backwashing, thereby lowering energy consumption while maintaining flux.
Solution Approach 2:
The patent replaces mechanical fouling control methods (air sparging, backwashing) with a chemical approach using organic polymer additives. This substitution reduces reliance on energy-intensive mechanical processes while achieving the same fouling prevention objective.
3Reliability
If chemical cleaning is performed to address membrane fouling, then membrane performance is restored, but membrane downtime and process costs increase
Solution Approach 1:
The organic polymer is added in advance to prevent fouling from occurring in the first place, rather than cleaning the membrane after fouling has set in. This preliminary protective action maintains membrane performance continuously without requiring periodic shutdowns for cleaning.
Solution Approach 2:
The organic polymer provides continuous self-service protection against fouling by maintaining a protective layer on the membrane surface throughout operation. This eliminates the need for external chemical cleaning interventions and associated downtime.
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
The combination significantly improves phosphorus removal and membrane flux, achieving a 112% increase in permeate flux while maintaining effective nitrogen removal, outperforming traditional methods with reduced chemical usage.
Implementation Method 1
improves phosphorous precipitation
Implementation Method 2
organic water soluble polymer seems not to affect phosphorous and nitrogen removal to a large extent and mainly affects permeability of the membrane
Data Source
Figure 1
AI summary
The present invention relates to a composition for treatment of wastewaters in a membrane bioreactor comprising a mixture of inorganic coagulants and organic water soluble polymer(s), wherein the inorganic coagulants are selected from iron and/or aluminium containing compounds and the organic water soluble polymers are selected from the group consisting of anionic, cationic,nonionic polymers,polysaccharides and polyphenolic compounds and any combination thereof. The present invention further relates to a method for treating of wastewaters in a membrane bioreactor, and uses thereof.