Wastewater Sludge Decantation Mode Switching

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Solution Overview

Problem

Sludge bed reactors face challenges in transitioning from 'reagent-free' to 'reagent' operation during high flow events, leading to potential contamination and increased operational and investment costs due to the need for forced sludge evacuation and prolonged startup times.

Innovation Solution

A method that involves packaging single decantation sludge with reagents at the onset of high flows, using a three-mode operation system: 'reagent-free', 'unreacted', and 'reagent' modes, where sludge is recirculated and conditioned with coagulants and flocculants to ensure efficient decantation, allowing for seamless transition without prolonged evacuation processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If sludge bed reactors operate in reagent-free mode during high flow events, then operational costs are reduced and organic material supply is increased, but sludge decantation efficiency deteriorates and contamination risk increases

Engineering Contradiction:
Improvereagent consumptionVSAvoidsludge decantation efficiency
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The system performs preliminary action by detecting high flow events in advance and automatically switching to reagent mode before the event fully impacts the treatment process. This proactive approach ensures sludge is properly conditioned and decanted before high flow conditions compromise efficiency, preventing contamination while avoiding unnecessary reagent use during normal operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback control by continuously monitoring flow rate and automatically adjusting reagent injection based on detected conditions. When high flow is detected, the system feedback-triggered switching to reagent mode, ensuring optimal sludge decantation efficiency is maintained while minimizing reagent consumption during normal flow conditions

Inventive Principle:
Principle #23Feedback

2Reliability

If forced extraction of unpackaged primary sludge is performed before switching to reagent operation, then sludge decantation efficiency is improved, but operational time is increased and treatment capacity is reduced

Engineering Contradiction:
Improvesludge decantation efficiencyVSAvoidstartup time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary conditioning of sludge with reagents during the transition phase, preparing the sludge for efficient decantation before high flow events begin. This preliminary reagent injection allows the system to maintain decantation efficiency without requiring time-consuming forced extraction and evacuation procedures

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts its operation mode based on real-time flow conditions, seamlessly transitioning between reagent-free and reagent modes. This dynamic approach eliminates the need for static, time-consuming sludge evacuation procedures by adapting the treatment process to current operational conditions

Inventive Principle:
Principle #15Dynamics

3Productivity

If sludge is recirculated during high flow events without reagent conditioning, then treatment capacity is maintained, but water quality deteriorates due to insufficient flocculation

Engineering Contradiction:
Improvetreatment capacityVSAvoidwater treatment quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system uses feedback control to monitor flow rate and automatically adjusts reagent injection levels based on detected conditions. When high flow is detected, the system increases reagent dosing to ensure proper flocculation and water quality while maintaining treatment capacity, eliminating the need to choose between productivity and quality

Inventive Principle:
Principle #23Feedback

4Object-affected harmful factors

If prolonged forced evacuation of sludge is performed before reagent operation, then contamination risk is reduced, but operational costs and investment requirements increase

Engineering Contradiction:
Improvecontamination riskVSAvoidsystem complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system performs preliminary reagent conditioning of sludge during the transition phase, preparing it for efficient decantation before high flow events begin. This preliminary action eliminates the need for complex forced extraction and prolonged evacuation systems, reducing both contamination risk and system complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses reagents as an intermediary substance to condition sludge during the transition phase, enabling smooth switching between operation modes without requiring complex mechanical evacuation systems. This chemical intermediary approach simplifies the overall system while effectively preventing contamination

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables efficient and cost-effective operation during high flow events by ensuring optimal sludge decantation and water treatment quality, reducing the risk of contamination and minimizing startup times, thus enhancing the reliability and economic viability of wastewater treatment.

Implementation Method 1

coagulation, in particular by adding metal salts (usually iron or aluminum), eliminates intercolloidal repulsions

Methodology Applied
Scientific EffectCoagulation: Coagulation

Implementation Method 2

coagulation-flocculation physico-chemical treatment of water purification that promotes sedimentation of colloids

Methodology Applied
Scientific EffectFlocculation: Flocculation

Implementation Method 3

promotes sedimentation of colloids

Methodology Applied
Scientific EffectSedimentation: Sedimentation

Implementation Method 4

suspended materials are separated from the water only by gravity

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP3374319B1Primary treatment of wastewater with switching from reagent-free operation to operation with reagent
Publication Date: 2021.04.21 SUEZ INTERNATIONAL
  • EP3374319B1 patent drawingFigure 1
  • EP3374319B1 patent drawingFigure 1
  • EP3374319B1 patent drawingFigure 1

AI summary

A method for treating municipal or industrial wastewater, in particular a method for the primary treatment of the water, the method comprising a first operating mode P1 of the treatment system referred to as reagent-free mode, a second operating mode P2 transitioning from the first reagent-free mode P1 to a third mode P3, said third operating mode P3 of the treatment system being referred to as mode with reagents, the shift from the first mode P1 to the second mode P2, from the second mode P2 to the third mode P3 and from the third mode P3 to mode P1 taking place respectively after verification of a set of conditions C1, C2 and C3.