Specifications include, but are not limited to: Contractor shall provide annual aeration membrane diffuser testing with their specialized test equipment to evaluate the oxygen transferring efficiency of the membrane under process conditions. The testing will be performed on membrane diffusers from two locations, 23rd Avenue and 91st Avenue Wastewater Treatment Plants. The City will provide to the Contractor a sample of aeration membrane diffusers for testing by shipping the sample to the Contractor's facility. The City tests approximately 8 diffusers 6 times per year. After testing is complete, Contractor shall provide a detailed testing report of their finding to the Process Control Specialist and the Water Facilities Supervisor in PDF format. Testing - Contractor will, at a minimum, perform the following testing methods on the aeration membrane diffuser. Testing will be done on the membrane in the as-received condition, followed by the manual cleaning condition. Dynamic Wet Pressure - to quantify diffuser head loss in a submerged condition with a range of different air flux rates. Membrane Activity Measurement - to determine the percent of active perforated surface area per total perforated surface area. Oxygen Transfer Efficiency - to determine the oxygen content of off-gas after it has diffused through the aeration membrane. Physical Measurement and Material Testing -material property testing in accordance with the American Society for Testing and Materials (ASTM), to include elongation, weight, specific gravity, shore A durometer hardness, dimensions, thickness, diameter and length. The City will review each report submitted to ensure that all testing was completed and recorded. If the report is unsatisfactory or the testing is incomplete, the City will notify the Contractor of the deficiencies. The Contractor will correct all deficiencies within 30 days to the satisfaction of the City. Plant staff will review the detailed report and make the final decision whether or not to replace with new diffusers.
