Correlating Wastewater Quality with Live Process Data

Situation

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A chemical company in the Netherlands that produces corrugated cardboard wanted to review the correlation between various processes and wastewater parameters. The company especially was interested in learning about how the influence of organic acids, particularly n-butyric acid, affects wastewater quality.

Problem

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To ensure the wastewater meets acceptable quality, the company must monitor the concentration of unwanted substances. Because online concentration measurements can be expensive, difficult, or even impossible, the company relied on lab analysis. This approach is time consuming and can lead to a delay of several days before process experts can see the results. By the time they receive the lab analysis, it could be too late to improve operational performance.

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Solution

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• Create tags in TrendMiner using the lab data
• Identify correlations between wastewater quality and live process parameters, especially n-butyric acids
• Determine if a correlation exists between different wastewater quality parameters and the redox value

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Challenges

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Wastewater quality lab results were not available in the company’s historian.

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Approach

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• Add the lab data into TrendMiner and create tags to compare it to live data
• Use the influence factor functionality in TrendMiner to find influences for the organic acid concentrations
• Use the time shift function to search for optimal correlation
• Determine if the company can use the redox value to measure the acid concentration in the wastewater

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Results

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• Process experts easily could see that there was a correlation between the redox value and the n-butyric acid concentration five days later
• They also found a strong correlation between the redox value and other organic acids
• In the future, the redox value can be used to conclude the acid concentration and thus intervene in the process in time

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