SU0002246 SSNL - Laserfiche WebLink

Home Browse Search

Technical Description F = Flow in gpd h = Hours of detention Hl = Hours per day (24) C = Capacity of aeration chamber(to level of weir) ]Vitrification addition: Given: Maximum NH., expected: 27.5 Desired: 27.5 to 26.5 = 94.5%removed so 26.5 x 4.2 02 = 11 1.3 mg/L(lbs)of 02 is required for conversion. CLARIFIER SIZING Sedimentation is based upon detention capacity design. Since the entire volume of mixed liquor in aeration standby (batch) is physically transferred into the clarifier, settling time may be ad- justed to allow even the smallest particle to settle. Unlike a conventional flowthrough clarifier, where the surface area must be Iarge enough to al- low particles to settle downward in a constantly moving stream, the batch clarifier provides parti- cle settling under completely static, quiescent conditions. This method is more efficient and eco- nomical than meeting the need in flowthrough systems for greater surface_areas with increasing flow rates at larger capacities. With the batch process, the static clarifier does not require this larger surface area; therefore, in design, the batch clarifier volume capacity is equal to the mixed-liquor volume, or batch, to be transferred. Surface Settling Rate (SSR) does apply, however, but only on a batch-by-batch basis. SSR are based upon flow in static conditions and are thus accurate for the 24-hour period flow. The Nitro- Raptor.batch process is unique in that longer retention times are not required to do the accurate sludge volume results obtained in the standard SSV-30 and SSV-60 tests.By staying within those basic design parameters of SSR per batch,the static condition of the batch clarification process is directly comparable to settleometer readings. Complete control of the entire process can be based upon the SSV-30 and -60 tests. When the sludge flocculates well and settles rapidly, the 7-H TC2K Computerized Monitoring and Control System through process monitoring probes will allow for automatic sequencing of the batch cycle based upon current biomass conditions within the treatmentplant. This change can increase or decrease aeration detention and the subsequent clarifier cycle surface settling rate. The clarifier has a dual-weir system for removal and return of floatables to aeration. The weir system is sized using hydraulic return/surface area(square feet). One hundred percent of all weir wastewater is returned to aeration and thus is contained within the internal detention time of the treatment process. Provisions are made to ensure that any residual floatable scum is not trans- ferred into any downstream process by SNT pump elevation control. FLOW EQUAL17ATION Widely fluctuating influent flow rates are typical at nearly all wastewater treatment plants. This fluctuation can result in a loss of treatment efficiency. With higher degrees of treatment con- stantly being required, some method of flow equalization is a design necessity. - 14- 7-H Technical Services Group,Inc. I