Field Flow Testing of Four Large Primary Influent Meters -- Twin Cities Metro Waste Treatment Plant

Abstract

The St. Anthony Falls Hydraulic Laboratory performed field flow measurement tests for four large meters (M001A, M001D, M001E, M001W) owned and operated by the Metropolitan Waste Control Commission (MWCC) at their large Metro Waste Treatment Plant. The MWCC oversees the collection and treatment of sanitary wastewater in the Twin Cities metropolitan area of Minnesota. The tests were completed as a subcontract to James M. Montgomery Consulting Engineers, Inc., of Wayzata, Minnesota, with whom the MWCC had contracted to conduct an overall evaluation of the meters. The meters tested included two 72-inch magnetic flow meters, designated M001A and M001D, and two 60-inch venturi meters, designated M001E and M001W. Both meters M001A and M001D were tested using two different methods simultaneously. The first method was the dye dilution technique for which dye was injected just downstream of gate 454. Continuous monitoring of the effluent and withdrawal of discrete samples was done at the location of the metering tunnel discharge into the east primary influent channel. Meters M001E and M001W were tested using the dye dilution technique only. Throughout the testing process all dye dilution samples were analyzed separately using fluorometers operated by both SAFHL and the research and development staff at the MWCC. The second method involved the area-velocity integration method utilizing a March-McBirney Model 511 insertion magmeter. The meter was installed on a traversing mechanism just downstream of gate 454 at the plan influent diversion structure (see Fig.1 for location).