Tapered vs. Uniform Baffle Configuration

Introduction

The vertical flow hydraulic flocculator has been used to test tapered and uniform baffle configurations during previous semesters, but the two configurations have never been compared with similar raw water conditions. For this reason the Fall 2008 Pilot Plant team plans to repeat testing with the two configurations. We plan to develop [turbidity profiles|] that are comparable for both configurations. This data will enable us to determine whether or not tapered flocculation is more efficient than uniform flocculation as has been suspected in past semesters.

Methods

Flow through the flocculator measured with a digital flow meter. The flocculator has been dosed with 20 mg/L alum. This dosage will be changed if deemed appropriate. Alum dosing and turbidity readings are controlled by process controller.

This method will be repeated with the uniform and tapered configurations.

Results

Several tests have been run with the uniform baffle configuration. The initial results were inaccurate due to a clog in the inlet valve of the raw water sampling line. A turbidity profile taken after this clog was fixed is shown below.

The accuracy of this result is questionable. The tank had to be cleaned before the measurement could be taken. Cleaning may have increased turbidity in the last section of the flocculator.