Subcontractors

R: No change will be made to the documents.28. Q: 28(WT) SECTION 44 42 24.03 - SECONDARY CLARIFIER MECHANISM2.12 SCUM SKIMMING SYSTEMG. Please add the following to the end of this section, "Spray nozzles thatare attached to the walkway and act to direct the scum to the ports at theperimeter of the flocculation well will also be acceptable."R: Revised per Addendum No. 8.29. Q: 29(SA) Section 44 45 16.02 - Page 3 - We recommend replacing Items G, Hand I with the following:G Design and furnish the membrane disc aeration system to transfer thefollowing lbs. of oxygen per day in tap water at 14.7 PSIA, 20oC, zero dissolvedoxygen and a diffuser submergence of 19.7 feet.Zone 1 Zone 2 Zone 3 TotalMinimumStandard Oxygen Transfer 40,593 24,259 23,394 88,246Rate (lb 0 2 /day)Air (scfm) 4 .00 21600 2,600 9,200Pressure at Top of Dropleg 9.0 9.0 9.1(psi)AverageStandard Oxygen Transfer 88,124 24,259 23,394 135,77Rate (lb O02day) 7Air (scfm) 9,400 2,600 2,600 14,600Pressure at Top of Dropleg 9.2 9.0 9.1(psi)Max MonthStandard Oxygen Transfer 109,85 26,773 23,394 160,02Rate (lb 0 2 /day) 6 3Air (scfmn) 12,000 2,900 2,600 17,500Pressure at Top of Dropleg 9.3 9.0 9.1(psi)PeakStandard Oxygen Transfer 166,65 42,178 32,133 240,96Rate (lb O 2 1day) 8 9Air (scfm) 19,000 4,800 3,700 27,500Pressure at Top of Dropleg 9.7 9.2 9.3(psi)H. Furnish the following minimum quantity of 9" diameter membrane discdiffuser units in each tank arranged as follows:Zone Minimum Quantity ofDiffusersZone 1 1,950Zone 2 840Zone 3 700Total Per Tank 3,490Total In 3 Tanks 10,47005/16/08 02001-158A OR 5-4