As a design-build contractor, Globaltech conducted a conditional assessment report for Filter No. 1 at the City of Boynton Beach East Water Treatment Plant (WTP). As part of the analysis the existing filter media was replaced and minor repair work was conducted on the filter.
The City of Boynton Beach’s East Water Treatment Plant uses rapid sand filtration to polish water prior to distribution. The filter media had been in service for approximately 20 years and had degraded from its original design parameters.
Globaltech was hired to assess the performance of the existing filters. Filter 1 was chosen as a representative filter for further investigation in which the existing filter media was removed to evaluate the media condition and to perform an assessment of the underdrain tiles. Following the removal of the filter media, the filter basin was cleaned and a visual inspection of the underdrain tiles was performed. All of the underdrain holes were re-drilled to remove mineralization and to establish uniform flow patterns. A small diameter endoscope was then installed in approximately 25% of the underdrain holes to inspect for blockages. A remote camera was also used to inspect the backwash supply line. A conditional assessment report was then prepared recommending minimal repairs to the filter basin including leveling intake weirs, minor crack repairs and the replacement of 16-inch butterfly valve.
After the filter media was replaced and the filter placed back into service, Filter 1 was subjected to a filter test at a loading rate of 3 gpm/ft2. The test revealed that the time between backwashing cycles increased from about 40 hours with the old media to over 200 hours with the new media. The increase in filter run time will significantly increase the filtration efficiency and reduce the timing constraints on the operators.
City of Boynton Beach