This slide presentation outlines information on maintaining disinfectant residuals in distribution storage tanks. Topics covered include: development of poor water quality in distribution tanks; methods to prevent it; tools including CFD modeling results; 3DLIF modeling results; empirical formulas; types of water storage; short-circuiting; mixing equation and mixing time comparison; velocity vectors - isothermal and negative buoyancy; CFD Model; maximum rise of negatively buoyant jet; terminal rise height of vertical jet; water quality problems and their causes; identifying dead zones by monitoring; temperature and Cl<sub>2</sub> residual data; maintaing water quality in reservoirs; guidelines on water turnover rate; basic principal for optimizing water quality within a storage reservoir; inlet configurations to avoid; inlet/outlet separation; typical duckbill manifold configuration for circular ground level reservoirs; and, hydraulic comparison duckbill to equivalent pipe diameter. Several case studies are outlined that include: Eugene Water and Electric Board, (2) 1mg reservoirs; Mashpee Water District, Massachusetts, 1mg composite elevated tank; Town of Narragansett, Rhode Island, 750,000 gallon fluted hydropillar; Shortsville, New York, 250,000 gallon standpipe; and, Lakeshore Reservoir. Information is also outlined on the 2002 AwwaRF unsolicited research proposal titled, "Physical and Numerical Modeling of Mixing in Water Storage Tanks". The AwwaRF research summary results include: multiple inlets reduce mixing times up to
35% (same momentum);
with negative buoyancy, multiple inlets
can mix a tank when a single inlet will not;
low momentum and buoyant jets (+ or -)
may never mix the tank; and,
simultaneous fill & draw tanks take longer
to mix.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 9.6 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 61 |
| Published : | 09/29/2004 |
