Foaming Characteristics of the Food-Industry Biological Wastewater Treatment Plant

Abstract

Intensive foaming observed during aeration of the aerobic food industry wastewater treatment plant is presented. This
study was conducted to establish the foaming characteristics using a pilot three-phase fluidized bed bioreactor (TPFBB).
A fluidization column (0.2 m i.d. and 6 m high) was used. The TPFBB was loaded with variable masses of novel biomass
support particles (BSP). Wastewater samples collected from a plant processing both vegetable oil (VOPWW) and soap
(SPWW) were immediately introduced in the TPFBB for aeration. The characteristics studied include: variation of foam
volume with time, foam multiplicity, foaming and foam collapse rates. The SPWW produced excessive foam volumes at a
higher rate and higher foam multiplicity compared to VOPWW. Dilution, increasing aeration rate or BSP loading led to
higher foaming rate, which decreased with time. Spraying wastewater at the top of the liquid surface minimized foaming
rate.