AWWA ACE95250

Due to recent trihalomethane (THM) limitations proposed by the Enhanced Surface Water Treatment Rule, the Squaw Peak Water Treatment Plant has recently undergone an extensive upgrade project including modifications to presedimentation, flocculation and filtration systems as well as converting the overall treatment technique to a low pH, enhanced coagulation treatment system. This expansion presented the opportunity to modify two off-line flocculation basins in an effort to determine the effect of: adding baffles, and baffle configuration at simulated total plant flows from 64 MGD to Plant Two's ultimate future capacity of 160 MGD and respective flocculation detention times of 152 and 25 minutes. This plant scale study was warranted partly due to the fact that this 25 minute detention time is less than the recommended minimum detention time of 30 minutes. Additional concerns were short circuiting problems observed during tracer test studies, perceived flocculation deficiencies, flow dependant performance variances, as well as the general desire to increase the efficiency of both the flocculation and sedimentation basins and improve finished water quality. Historically, flocculation basin performance has often been assessed solely on turbidity which, depending on particle size and count, can yield faulty conclusions as documented countless times throughout research literature. In an effort to eliminate the potential for such erroneous conclusions, the primary measuring device used during the analysis phase of this study was a laser particle counter, with both turbidimeter and visual observations serving as secondary indicators of baffle performance.

Product Details

Published:

01/01/1995

ISBN(s):

089867834X

Number of Pages:

12

File Size:

1 file , 550 KB