Specifications include, but are not limited to: 1. Base Bid: a. Removal of existing filter-media support gravel and filter media from Filters 5, 7,10, and 12. b. Cleaning of floor of filter and underdrain after removal of existing filter-media support gravel and filter media. c. Video inspection of: 1) Filter underdrain laterals in Filters 5 and 7. 2) Filter underdrain plenum in Filters 10 and 12. 3) Filter effluent/backwash supply manifold at the end of the inspected 4-inch diameter underdrain in Filters 5 and 7. d. Storing and handling replacement filter media-support gravel and filter media. e. Placing new silica filter-media support gravel and silica filter media in accordance with the Contract Documents. 2. Alternate Bid 1: Substitute placement of high-density support gravel (garnet) in lieu of silica gravel for top layer of filter-media support gravel system.
