Colorimetric Test Kit for On-Site Water COD Estimation
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Solution Overview
Problem
Conventional methods for estimating chemical oxygen demand (COD) in water samples are time-consuming and cannot be performed on-site, requiring laboratory procedures that take over three hours.
Innovation Solution
A color chart and test kit that includes specific color components and reagents, such as PANTONE colors and potassium dichromate, ammonium iron(II) sulfate, and a ferrion indicator, allowing for on-site estimation of COD by matching the color of the treated water sample with the chart.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laboratory methods are used for COD estimation, then measurement precision is maintained, but testing time increases significantly (over three hours)
Solution Approach 1:
The patent extracts the essential measurement function from the complex laboratory procedure by using a portable test kit that performs COD estimation through a simplified colorimetric method, separating the core measurement capability from the time-consuming laboratory infrastructure
Solution Approach 2:
The patent replaces the mechanical/chemical laboratory procedures (heating, reflux, titration) with an optical detection system that measures color intensity to determine COD levels, eliminating the need for complex mechanical operations and extended processing time
2Measurement precision
If conventional laboratory procedures are used, then accurate COD results are obtained, but on-site testing capability is lost
Solution Approach 1:
The test kit is designed to be self-contained and self-sufficient, containing all necessary reagents, standards, and detection components in a single portable unit that can be operated independently without laboratory infrastructure
Solution Approach 2:
The portable test kit combines multiple functions (sample preparation, reagent storage, color development, and measurement) into a single device that can be used in various locations, making the testing system both portable and adaptable to different field conditions
3Productivity
If rapid testing methods are implemented, then testing time is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent incorporates pre-prepared reagents and standardized protocols in the test kit that have been optimized in advance to ensure accurate results are achieved quickly without requiring complex real-time adjustments or extended processing
Solution Approach 2:
The patent changes the measurement parameter from traditional titration-based chemical analysis to optical density measurement, which provides rapid results while maintaining precision through calibrated colorimetric detection
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
Enables rapid and on-site estimation of COD, providing instant results within a short time frame, suitable for various water samples including wastewater and river water.
Implementation Method 1
Chemical oxygen demand (COD) is defined as the required oxygen equivalents to oxidize reducing substances in each liter of water sample
Implementation Method 2
adding a reductant to the water sample; adding an indicator to the water sample, such that the water sample develops a color
Data Source
AI summary
The present disclosure provides a color chart and a test kit for estimating chemical oxygen demand of water. The color chart includes a blue component, an indigo component, an umber component, and an orange component. The test kit includes an oxidant, a reductant, an indicator, and the color chart. The present disclosure also provides a method for estimating chemical oxygen demand of water. The method includes providing a water sample; adding an oxidant to the water sample; heating the water sample; adding a reductant to the water sample; adding an indicator to the water sample, such that the water sample develops a color; and matching the color of the water sample with the color components of the color chart to estimate the chemical oxygen demand of the water sample.