...

Tube Settlers are used to mimic sedimentation before the turbidity of water in the flocculator is measured. They can be moved to different locations along the flocculator in order to examine effluent turbidity at various stages of flocculation.

Data Collection and Analysis

Data is collected using process controller. It is stored in process controller and then analyzed.

Results

Results

The team had difficulty finding the correct alum dose at low temperatures and incoming turbidity this semester. The team determined a relationship between the WFP's PAC (polyaluminum chloride) dosage and the alum dose at the plant. The composition of PAC is a trade secret and its chemical formula is unknown. The relationship was determined between the percent active ingredients in PAC and alum. At the plant 48.8% of 11.1 lb/gal alum is active and 33% of 10.84 lb/gal of PAC is active. Therefore 1 ppm of PAC should have the same effects on flocculation as 0.182 mg/L alum.

...

Figure 2: Uniform vs. Tapered Configuration. (12/14/08)

...

Conclusions

The alum dose set based on plant PAC dosage gave the best results for an incoming turbidity of 2.3 NTU. If this relationship is confirmed to work at a broad range of incoming turbidities, it can hopefully be used by future semesters. The plant operators obviously have much more experience determining alum dosing and this relationship can help us take advantage of their expertise.

...