title: Tracer experiment and RTD analysis of DAF separator with bar-type baffles.
abstract: This paper describes the development of a new dissolved air flotation (DAF) separator with a flow streamlining baffle to improve solid separation efficiency. The analysis of the RTD (residence time distribution) curves indicated that the parameter θ(10) (dimensionless time at which 10% of tracer has discharged) increased from 0.38 for control reactor to 0.54 for the test reactor, suggesting significant reduction in short circuit flow. The RTD curves were also used to develop a compartment model for white water (rich in micro-bubbles and water flow is turbulent) and clear water (little or no air content and water flow is quiescent) zones in the reactor using a series of CSTR (continuous stirred tank reactors) and plug flow regime respectively. The proportion of the volume occupied by the white water zone was different in control and test configurations. In the test reactor, the fraction of the clear water zone was found to increase from 6 to 37%, resulting in improvement of the suspended solid (SS) removal efficiency from 97 to 99%.
authors: Kurita Water Industries Ltd, Nogimachi, Shimotsugagun, Tochigi, Japan. mitsuharu.terashima@kurita.co.jp
authors: M
authors: M
authors: Terashima
authors: M
authors: M
authors: Iwasaki
authors: H
authors: H
authors: Yasui
authors: R
authors: R
authors: Goel
authors: K
authors: K
authors: Suto
authors: C
authors: C
authors: Inoue
mesh_terms: D004867:Equipment Design; D008962:Models, Theoretical; D062065:Wastewater; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D062065:Wastewater