Optimizing the DAF Process Utilizing Two Phase 3D CFD Modeling

摘要

The paper describes the development of Computation Fluid Dynamics (CFD) models toimprove the performance of the dissolved air flotation (DAF) clarifier designed for theproposed 405-mgd (1,533 Ml/d) Walnut Hill full filtration option for the City of Bostonand environs.The CFD models were constructed in three dimensions to improve the relative accuracyof the representation. Fluid regimes used were single phase (water) and two phase (waterand air).The DAF clarifier design was improved by varying key parameters such as inlet andoutlet arrangement,recycle water injection and baffle wall configuration. The CFDprogram’s graphical output was utilized to determine whether an even flow distributionwas achieved within the basin. The design was optimized to statistically minimize carryover of air micro-bubbles into the clarifier outlet for all modeled arrangements and flows.