Friday, June 3, 2011

Self-Priming 18NHFL's installed in Brussels South ...

Six (6) 18NHFL-RP-F24K: Assembled and Installed


There are two major waste water treatment plants in Brussels: Brussels North and Brussels South. Six (6) Cornell 18NHFL's have been installed during the end of 2010 in the waste water treatment plant of Brussels South. The plant has been online since February of 2011.

Before the installation of this new process, the sludge circulation to the decantation basins were producing foam and the particles were floating at the waters surface. Too much air was being trapped with the sludge particles and the particles were not settling to the bottom of the decantation tanks. It was then decided that another step needed to be added to the process: pumping sludge from the lower tank to the upper tank with CORNELL SELF-PRIMING PUMPS. The SELF-PRIMING PUMPS help remove the excess air from the sludge before it is pumped into the upper tanks and comes into contact with the surface mixers. See here a picture of the tests, taking samples before and after the addition of the CORNELL SELF-PRIMING PUMPS.

Because of Cornell's SELF-PRIMING capacities, HYDRO+ could install the pumps at ground level in a new building. Each of the CORNELL SELF-PRIMING PUMPS connected to the suctions of the three lower tanks, which in turn, pumped to the upper tanks. The civil works was therefore minimized (The corps' Civil Works program involves flood control, water supply, hydroelectric power generation, navigation, recreation, and environmental regulation. The boundaries for the Civil Works program often follow watersheds or parts of watersheds).

Cornell's SELF-PRIMING PUMPS also aided in the removal of air bubbles that were trapped in the water (which at times can be heavily loaded with air). From time to time but mostly during slow pumping periods, one could actually hear the vacuum pumps extracting the air that had already been separated from the water by turbulence. That means that without the SELF-PRIMING PUMPS, the main pumps would lose their prime because of the excess air. These pumps now have two functions within the HYDRO+ application: The initial priming at start-up and extracting the excess air during the pumping process.

These pumps are driven by 90kW electric motors and are controlled by variable frequency drives that operate between 400rpm and 600rpm at the pump shaft. The maximum hydraulic efficiency of the pumps are 87.3%!

Thank you to Nicolas Lefèvr of HYDRO+ for providing the information for this article.