Membrane Filtration Waste Treatment Using Sludge Adsorption
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Solution Overview
Problem
Membrane filtration techniques in water treatment, such as reverse osmosis and nanofiltration, produce significant amounts of phosphonate-laden concentrates that are difficult to dispose of, leading to environmental concerns and increased operating costs, particularly in drinking water production units.
Innovation Solution
A method that incorporates a coagulation-flocculation step followed by a settling step, preceded by an adsorption phase using sludge from settling stages to reduce phosphonate levels in membrane filtration rejects, leveraging the adsorption capacity of clays and metal hydroxides present in the sludge to minimize phosphonate discharge and coagulant usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane filtration techniques (reverse osmosis or nanofiltration) are used to treat water, then water quality is improved and organic micro-pollutants are removed, but phosphonate concentrates are produced representing 10 to 60% of initial flow that are difficult to dispose of
Solution Approach 1:
The patent converts the harmful phosphonate concentrates into a beneficial resource by using them as adsorbent material. The phosphonate-rich rejects from membrane filtration are utilized to adsorb and remove phosphonates from water, transforming the waste product into an effective treatment medium that eliminates phosphonate discharge while maintaining water quality improvement benefits
Solution Approach 2:
Instead of discarding the phosphonate concentrates as waste, the patent recovers and reuses them as adsorbent material in the treatment process. The phosphonate-rich rejects are recovered, concentrated, and applied to adsorb phosphonates from water, creating a circular process that eliminates disposal problems while maintaining treatment effectiveness
2Object-generated harmful factors
If coagulation-flocculation treatment is carried out to remove phosphonates, then phosphonate elimination is achieved, but coagulant dosages are high (two to three times higher than optimized processes)
Solution Approach 1:
The patent applies self-service by using the phosphonate concentrates themselves as the adsorbent material that performs the phosphonate removal function. The waste product serves its own purpose by adsorbing phosphonates, eliminating the need for external coagulant additives and reducing coagulant dosages to optimized levels
Solution Approach 2:
The phosphonate-rich concentrates act as an intermediary substance that mediates phosphonate removal. Instead of using chemical coagulants as intermediaries, the patent uses the phosphonate concentrates as the mediating adsorbent material, which selectively binds and removes phosphonates from water, achieving effective elimination with minimal additional chemical substances
3Object-generated harmful factors
If phosphonates are completely stopped by membrane filters, then phosphonate removal is achieved, but phosphonates are concentrated approximately 2 to 7 times in membrane discharges
Solution Approach 1:
The patent applies preliminary action by treating the phosphonate concentrates immediately after membrane filtration before they can be discharged. The concentrated phosphonates are captured, concentrated further, and used as adsorbent material in a subsequent treatment stage, preventing their discharge while utilizing their concentrated form for effective phosphonate removal
Solution Approach 2:
The patent changes the parameter of phosphonate concentration by utilizing the concentrated phosphonate form as the active adsorbent material. The 2 to 7 times concentration achieved during membrane filtration is not treated as a problem but as an advantage, as the concentrated phosphonates provide higher adsorption capacity and more effective phosphonate removal
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 effectively reduces phosphonate concentrations, lowers coagulant dosages, and recycles sludge for agricultural use, enhancing soil fertilization while minimizing environmental impact and operational costs.
Implementation Method 1
said coagulation-flocculation step being preceded by at least one adsorption step on said sludge from the first and/or second settling step, said step adsorption aimed at reducing the phosphonates contained in said waters resulting from said membrane filtration step
Implementation Method 2
said treatment phase including at least one coagulation-flocculation step
Implementation Method 3
said treatment phase including at least one coagulation-flocculation step
Implementation Method 4
followed by a second settling step producing sludge
Data Source
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AI summary
The invention relates to a water treatment process comprising a first pre-treatment step which produces pretreated water and sludge, wherein said pretreated water undergoes at least one filtration step, at least one of which is a membrane filtration step, and wherein said filtration step produces waste, characterized in that said waste derived from said membrane filtration step undergoes a treatment phase which includes at least one coagulation-flocculation step followed by a second decanting step which produces sludge, wherein said coagulation-flocculation step is preceded by at least one step of adsorption onto said sludge derived from the pretreatment or the decanting step, wherein said adsorption step is aimed at removing the phosphonates contained in said water derived from said membrane filtration step.