Water Treatment Using Coagulant-Dosed Backwash Recirculation
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Solution Overview
Problem
Existing water treatment methods consume large quantities of reagents and consumables, such as coagulant and flocculating reagents, due to varying pollutant concentrations, and require expensive sensors for concentration measurements, increasing operational costs.
Innovation Solution
A method and installation where coagulant product is distributed in recirculating backwash water with higher pollutant concentrations, rather than in the incoming water, enhancing efficiency and reducing the need for reagents and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coagulant reagents are applied to the whole amount of water to be treated, then pollutant removal efficiency is maintained, but reagent consumption increases significantly
Solution Approach 1:
The treatment process is segmented into two distinct stages: a first treatment stage handling a portion of the polluted water, and a second treatment stage handling the remaining portion. This segmentation allows different reagent dosages to be applied to different water volumes based on their respective pollutant concentrations, optimizing overall reagent usage while maintaining removal efficiency.
Solution Approach 2:
Different reagent dosages are applied locally to different portions of the water flow. The first portion receives a first dosage of coagulant reagent, while the second portion receives a second dosage that is lower than the first dosage. This local quality differentiation optimizes reagent consumption by matching reagent application to the actual pollutant load in each portion.
2Quantity of substance
If sensors are installed to measure pollutant concentration, then reagent distribution can be optimized, but installation and operational costs increase
Solution Approach 1:
The system utilizes the backwash water itself to provide information about pollutant concentration. By analyzing the turbidity or other properties of the backwash water, the system self-regulates the dosing of coagulant reagents without requiring external sensors or complex measurement equipment. This self-service approach optimizes reagent usage while avoiding additional installation costs.
3Reliability
If coagulant reagents are used for highly loaded backwash water, then reagent efficiency increases, but reagent consumption decreases
Solution Approach 1:
The backwash water, which contains concentrated pollutants from the filtration process, is recirculated to the input of the treatment system before being treated. This preliminary action of recirculating the highly loaded water allows it to be treated in the first treatment stage where a higher dosage of coagulant reagent is applied, maximizing reagent efficiency. The fact that reagent consumption decreases suggests that the system is optimizing overall reagent usage by treating concentrated pollutants more effectively.
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
Reduces reagent consumption and operational costs while maintaining pollutant reduction efficiency by targeting higher pollutant concentrations with coagulant product, utilizing recirculating backwash water in the treatment process.
Implementation Method 1
Coagulating reagents are materials having a positive charge which allows them to associate with suspended or dissolved materials which have a negative charge. The positive charge of the coagulant reagents neutralizes the negative charge of the suspended or dissolved materials, coagulates are formed which have a density higher than that of water.
Implementation Method 2
Flocculating reagents can be used in previously coagulated water for increasing the size and density of the coagulates obtained during the prior coagulation step. The flocs thus obtained further improve the efficiency of subsequent separation steps.
Implementation Method 3
filtering said partially treated water by using said filtration means, and obtaining a treated water
Implementation Method 4
backwashing said filtration means with a portion of said treated water and obtaining a backwash water containing pollutants
Data Source
Figure 1~2
Figure 3
AI summary
A method for treating water containing pollutants comprising bringing, through a primary pipe (1), said water containing pollutants to separation means (2), separating a portion of the pollutants contained in said water by using said separation means (2), and obtaining a partially treated water, bringing said partially treated water to filtration means (4) through a secondary pipe (3), filtering said partially treated water by using said filtration means (4), and obtaining a treated water, backwashing said filtration means (4) with a portion of said treated water and obtaining a backwash water containing pollutants, evacuating said treated water from the installation through an evacuating pipe (5), recirculating, through a recirculation pipe (7), said backwash water containing pollutants to said separation means (2) or said primary pipe (1), said method being characterized in that it comprises distributing at least one coagulant product in said recirculating means.