...
The team has been able to run three base case experiments. One with PACl dosages of 0, 5-10 mg/L (increments of 1 mg/L) and two with PACl dosages according to the power law: PACl dosage = coefficient x base^maxreps (where coefficient = .25, base = 1.25, and maxreps = 10)
Preliminary results from the base case described above suggest that a PACl dose of 2 mg/L is sufficient in achieving the desired mean residual turbidity because all PACl PACl doses above 2 mg/L yield similar results for residual turbidity of around .8 NTU for the effluent1 NTU (+/- .5 NTU) for the effluent.
Using this dosage range, we conducted another base case with dosages of 0, .8, and 1.8 mg/L of PACl. We then began one clamp tests, where we placed one clamp in the middle of the tubing arrangement. The purpose of the clamp is to breakup flocs by increasing the energy dissipation rate where the clamp is located. Clamp sizes of 4 and 5 mm were tested. These two sizes were chosen from the results of the summer research, where they found 4 and 5 mm clamps showed significant floc breakup.
The results of our one clamp testing has shown that a 4 mm clamp increases residual turbidity and a 5 mm clamp decreases the residual turbidity, as compared with the base case, where no clamp was used. Our results suggest that perhaps a 4 mm clamp breaks up flocs too much, to a point where they cannot fully recover and collect more colloids.
Our progress has been greatly hindered by challenges with malfunctioning equipment and software errors. The pump for the synthetic raw water was replaced, the code in Mathcad was edited, and various changes have been made in Process Controller. Our current setup should run smoothly and help us progress further in our base case testing and our experiments.