Biological waste gas treatment with a modified rotating biological contactor. Ι. Control of biofilm growth and long-term performance

Abstract

In this work, we introduce a modified rotating biological contactor (RBC) system and demonstrate its feasibility by applying the newly devised process to the biological treatment of artificial waste gas. In the proposed system, the waste gas is introduced to the bioreactor in the spacings between the rotating discs through a hollow shaft, thus allowing for intimate gas-liquid contact. A 91-l modified RBC containing 20 biofilm support discs 40 cm in diameter was used in the experiments. Toluene was used as the model pollutant, and the system was operated under standard operating conditions for more than one year in order to investigate its long-term performance and assess its ability to control the growth of the biofilm. It was demonstrated that the proposed system allows to efficiently control the growth of the biofilm, thus overcoming the clogging problem inherent in most conventional methods for the biological treatment of waste gas. Moreover, the system was shown to exhibit stationary long-term performance for a period of more than one year, hence indicating its feasibility for industrial application.

Bioprocesses for air pollution control

“…123 A modified RBC was later used in which the air was fed through the hollow shaft on which the discs were mounted. 124 Under such condition, the polluted air flew in a radial direction with respect to the discs (Fig. 8).…”

Biological waste gas treatment with a modified rotating biological contactor. ΙΙ. Effect of operating parameters on process performance and mathematical modeling

“…It was demonstrated that the modified RBC process is feasible for the biological treatment of waste gas [1]. Not only has it been possible to successfully suppress the unlimited growth of the biofilm, but it has also been proved that the system is able to match the industrial demand of stable long-term operation at minimum maintenance requirements.…”

“…

In the first part of this paper, we introduced a modified rotating biological contactor (RBC) for the biological treatment of waste gas, and demonstrated its feasibility by applying the process to the biodegradation of toluene in a 91-liter reactor containing 20 biofilm support discs with a diameter of 40 cm [1]. We showed that the proposed system allows the unlimited growth of the biofilm to be suppressed, hence eliminating the risk of clogging associated with other biological waste gas treatment systems.

…”

Novel membrane bioreactor: Able to cope with fluctuating loads, poorly water soluble VOCs, and biomass accumulation

“…The superficial velocity of the culture liquid over the biofilm, and with that the flow rate, was chosen based on a preceding study in our lab in which the influence of shear forces on biofilm thickness was analyzed in a rotating biological contactor modified for waste-gas treatment (Vinage and von Rohr, 2003). The tip speed of the disks in the steady-state operating condition in which the reactor did not clog reached 0.12 m s…”

“…Two bacterial strains were used for inoculating the reactor, Pseudomonas putida F1 and Rhodococcus globerulus PWD1 (Vinage and von Rohr, 2003).…”