Composite Flocculant and Clay Overlay for Turbid Water Remediation

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Solution Overview

Problem

Current methods for improving water transparency in turbid water bodies are ineffective in providing a long-term, cost-effective solution due to issues with rapid resuspension of flocs and secondary pollution from frequent flocculant dosing, and high costs associated with clean water replenishment.

Innovation Solution

A remediation method involving the use of a composite flocculant made from cationic starch and diatomite, combined with submerged plant turf and a thin overlaying layer of clay minerals, to form large flocs that settle and prevent resuspension, while using eco-friendly materials to minimize ecological impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If flocculant dosing is used to rapidly improve water transparency, then water transparency is improved in the short term, but frequent dosing leads to secondary pollution

Engineering Contradiction:
Improvewater transparencyVSAvoidsecondary pollution
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent uses a biodegradable cationic starch flocculant that breaks down naturally after use, replacing persistent chemical flocculants. The flocculant is designed to be environmentally benign and short-lived in the water body, achieving the cleaning function without long-term pollution accumulation.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical parameters of the flocculant by using cationic starch with specific molecular weight and charge density, optimized for colloidal particle removal. The dosage is precisely controlled at 0.5-2 mg/L, and the pH is adjusted to 6-8 to maximize flocculation efficiency while minimizing secondary pollution.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If clean water replenishment is used to improve water quality, then water transparency is improved, but the cost is high and impracticable in many places

Engineering Contradiction:
Improvewater transparencyVSAvoidcost
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The patent enables the water body to self-clean by restoring its natural flocculation and sedimentation capabilities. The treated water body becomes self-sustaining, with improved settling properties that continuously clarify water without requiring external clean water inputs or ongoing chemical dosing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts and removes the problematic colloidal particles and suspended matter from the water body through enhanced flocculation and sedimentation. The clarified water is then maintained by preventing resuspension, effectively removing the turbidity problem without adding expensive clean water.

Inventive Principle:
Principle #2Taking out (Extraction)

3Illumination intensity

If aeration is used to inhibit algae breeding and reduce suspended matter, then water quality is improved to some extent, but it cannot provide continuous long-term solution to water turbidity

Engineering Contradiction:
Improvewater transparencyVSAvoidlong-term effectiveness
Core Design Contradiction:
Illumination intensityVSDuration of action of stationary object

Solution Approach 1:

The patent applies preliminary flocculation treatment to remove excess colloidal particles and suspended matter before they can cause long-term turbidity problems. This initial clarification creates favorable conditions for subsequent plant restoration and establishes a clear water baseline that prevents rapid returbidification.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent establishes continuous water clarification through the combination of biodegradable flocculant action, clay mineral overlay that prevents resuspension, and restored submerged vegetation that continuously filters water. This creates an ongoing self-sustaining clarification system rather than temporary improvement.

Inventive Principle:
Principle #20Continuity of useful action

4Illumination intensity

If conventional flocculants are used to form flocs, then water transparency is improved, but the flocs are easily resuspended by water flow and wind waves

Engineering Contradiction:
Improvewater transparencyVSAvoidfloc stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent uses a composite approach combining cationic starch flocculant with clay minerals (such as bentonite or diatomaceous earth). The starch forms initial flocs with colloidal particles, while the clay minerals act as a protective matrix that strengthens the floc structure and prevents disintegration under hydrodynamic stress, significantly reducing resuspension.

Inventive Principle:
Principle #40Composite materials

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 method achieves significant and sustained reduction in turbidity, with removal rates exceeding 80% for fine colloidal particles and 95% for larger particles, maintaining water transparency and preventing secondary pollution, making it suitable for urban rivers and small lakes.

Implementation Method 1

The Invention provides, in accordance with independent claim 1, a remediation method for water bodies rich in high-turbidity colloidal particles... Spreading a composite flocculant on a water surface... Perform the ultrasonic treatment on the mixed solution of starch, dimethyl diallyl ammonium chloride and NaOH, then mix and stir it evenly with acidified chitosan to acquire the cationic starch flocculant

Methodology Applied
Scientific EffectFlocculation: Flocculation

Implementation Method 2

When the water transparency is greater than or equal to 60 cm after flocculation and sedimentation, add clay minerals to the water body for formation of a thin overlaying layer

Methodology Applied
Scientific EffectPhysical barrier formation:

Implementation Method 3

After formation of a thin overlaying layer, transplant the submerged plant turf as a whole underwater, so as to restore the submerged plant community... the dense roots of 3D plant network and submerged plant could fundamentally inhibit and fix the flocculated particles without release and suspension again

Methodology Applied
Scientific EffectRoot stabilization:

Implementation Method 4

Perform the ultrasonic treatment on the mixed solution of starch, dimethyl diallyl ammonium chloride and NaOH... the said ultrasonic treatment is performed with 20 kHZ ultrasonic wave for 3-10 min

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 5

form large flocs that settle and prevent resuspension... accelerate the rate of flocculation and sedimentation in the water body

Methodology Applied
Scientific EffectSedimentation: Sedimentation

Data Source

PatentEP3789353B1Ecological remediation method for water bodies rich in high-turbidity colloidal particles
Publication Date: 2022.06.22 NANJING INST OF GEOGRAPHY & LIMNOLOGY
  • EP3789353B1 patent drawingFigure 1~2
  • EP3789353B1 patent drawingFigure 3~4
  • EP3789353B1 patent drawingFigure 5~6

AI summary

The invention discloses an ecological remediation method for water bodies rich in high-turbidity colloidal particles, characterized by comprising the following steps: Spread the composite flocculant on the water surface and stir it; when the water transparency is greater than or equal to 60 cm after flocculation and sedimentation, add clay minerals into the water bodies for formation of a thin overlaying layer; after formation of a thin overlaying layer, transplant the prefabrication turf of submerged plant in underwater, so as to restore the submerged plant community. The technical method provided by the invention can well improve the water quality of water bodies with high content of colloidal sediments and rich in certain amount of algae after dredging or flood and can also realize the long-term remediation by improving the transparency of turbid water in a quick, continuous and effective manner for urban rivers, small reservoirs and ponds which are rich in colloidal silty particles and algae and require improvement of water quality.