Greywater Clarification via Composite Flocculation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current water purification processes for greywater are inefficient in removing suspended solids and surfactants, leading to slow clarification and resource-intensive methods, particularly when reusing greywater for household purposes.
Innovation Solution
A water purification composition comprising an inorganic flocculant, a surfactant scavenging system with a water-soluble divalent sulfate salt and quaternary ammonium cationic surfactant, and a non-ionic or anionic polymeric flocculant with a molecular weight over 100 kDa, which enhances the precipitation of anionic surfactants and Al(OH)3 or Fe(OH)3 sweep flocs, improving both sweep flocculation and surfactant removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sweep flocculation is used to clarify greywater, then suspended solids are removed, but the clarification process is slow and the flocs are difficult to separate
Solution Approach 1:
The patent combines sweep flocculation and bridging flocculation into a single integrated composition. The inorganic flocculant (Al-based or Fe-based salt) performs sweep flocculation to remove suspended solids, while the polymeric flocculant simultaneously performs bridging flocculation to form larger, faster-settling flocs. This merging of two separate processes into one composition resolves the contradiction by achieving both solid removal and fast separation without requiring sequential treatment steps.
Solution Approach 2:
The patent uses a composite flocculation system comprising both inorganic flocculants (Al2(SO4)3·18H2O, Fe2(SO4)3·9H2O) and organic polymeric flocculants (polyacrylamide, polyacrylic acid). This composite material approach allows the system to leverage the advantages of both flocculation mechanisms - the sweep action of inorganic salts and the bridging action of polymers - to achieve rapid clarification and easy separation simultaneously.
2Speed
If polymer flocculant is added for bridging flocculation, then settling velocity increases, but the process becomes more complex and resource-intensive
Solution Approach 1:
The patent merges sweep flocculation and bridging flocculation into a single integrated composition that can be added in one step. The inorganic flocculant and polymeric flocculant work synergistically to achieve both suspended solid removal and rapid settling, eliminating the need for separate treatment stages and reducing process complexity while maintaining high settling velocity.
Solution Approach 2:
The integrated flocculation composition performs multiple functions simultaneously: it removes suspended solids through sweep flocculation, accelerates settling through bridging flocculation, and removes surfactants through the cationic surfactant component. This multi-functionality reduces process complexity by consolidating what would otherwise require multiple separate treatment steps.
3Manufacturing precision
If traditional water purification processes are used for greywater, then surfactants are removed, but the processes are time-consuming and resource-intensive
Solution Approach 1:
The patent combines surfactant removal with the flocculation process in a single integrated system. The cationic surfactant (quaternary ammonium compound) in the composition scavenges anionic surfactants from greywater through electrostatic interaction, while the flocculants simultaneously remove suspended solids and accelerate settling. This merging of surfactant removal with particulate removal into one process achieves both goals rapidly without requiring separate treatment steps.
Solution Approach 2:
The patent uses a composite formulation containing inorganic flocculants, polymeric flocculants, and cationic surfactants that work synergistically. This composite material approach enables simultaneous removal of multiple contaminants (suspended solids, surfactants) through different mechanisms, achieving efficient purification in a single time-consuming step rather than multiple sequential steps.
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 composition achieves faster clarification of greywater, reducing turbidity and surfactant levels significantly, allowing for quicker reuse of treated water with reduced resource consumption.
Implementation Method 1
electrolyte flocculants, such as Al-based salts or Fe-based salts, are added in a sufficient amount so that they form amorphous Al(OH)3 or Fe(OH)3 particles. These amorphous particles entrap suspended solids leading to clarification of water.
Implementation Method 2
addition of a polymer flocculant with a molecular weight of at least 100 kDa. These polymers are thought to adsorb on the sweep flocs and thereby bring the sweep flocs together to form bigger and stronger flocs.
Implementation Method 3
a surfactant scavenging system comprising a water-soluble divalent sulfate salt and a quaternary ammonium cationic surfactant, which enhances the precipitation of anionic surfactants
Data Source
AI summary
The present invention relates to a water purification composition and to the use of the water purification composition for clarifying greywater, preferably for clarifying greywater produced by laundry washing. The water purification composition comprises an inorganic flocculant, a surfactant scavenging system and a non-ionic and/or anionic polymeric flocculant having a molecular weight of more than 100 kDa. Wherein the surfactant scavenging system comprises a water-soluble divalent sulfate salt and a quaternary ammonium cationic surfactant. The invention further relates to a process for clarifying greywater.