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Aug 04, 2023Aug 04, 2023

In this case study, a wastewater treatment plant in a large dairy facility was looking for ways to reduce chemical coagulant costs and labor to monitor and operate the dissolved air flotation (DAF) unit.

Like many dairy processing facilities, this one uses a DAF to remove protein, fats, oils, grease and suspended solids from the wastewater stream. DAF operations use chemical coagulant and flocculant to increase solid particle size. Micro-bubbles attach to the particles, causing the suspended solids to float to the surface where they are skimmed off. This process clarifies the process water before it is discharged to the city utility.

This dairy facility processes 600,000 gallons per day at their on-site wastewater pre-treatment plant (WWTP). Before installing a Real-Time Control System, the WWTP operator working the overnight shift made manual adjustments — based on visual observations and readings from a sensor to manage effluent total suspended solids (TSS).

One challenge is that the pH levels have to be within their wastewater discharge permit. This presents a challenge because the chemicals that help control TSS also reduce pH levels. Their sewer bill is tied to the flow, BOD and TSS levels of the effluent they discharge, so treating and balancing these parameters more efficiently could have a real impact on the bottom line.

To help ensure proper TSS and pH levels while reducing operator workloads, the facility looked for a solution that decreased grab sample testing and manual analysis. In conjunction with their chemical supplier, a Hach Real-Time Control (RTC) solution was recommended.

After an onsite trial, during which Hach engineers made adjustment to meet performance requirements, the facility was able to validate a reduction in coagulant dosing and decided to install the Hach Real-Time Control for Sludge Thickening (RTC-ST) permanently.

After just a few months of operation, Hach RTC-ST helped this facility control its chemical costs and help them reassign some of their utility’s mechanics’ and operators’ time to more productive tasks.

The maintenance manager comments, “I would think anybody running a DAF type system would benefit from it.”