Bioscrubbers

A typical bioscrubber consists of two units, as illustrated in Fig. 3.5. The first part is an absorption tower where pollutants are absorbed in a liquid-phase followed by biodegradation in a bioreactor. This bioreactor contains suspended activated sludge which is sufficiently aerated and much larger than the absorber. The effluent of this bioreactor is then recirculated over the absorption tower in a co-or counter-current mode to the flow of waste-gas. Microbial activity is enhanced by adding sufficient nutrients in the reactor. This makes them flexible to handle fluctuating loads of waste-gas streams (van Groenestijn and Hesselink 1993 ; van Groenestijn 2001; Kennes et al. 2009a). The main advantages of this technique are (i) better removal of reaction products by washing out (ii) no clogging problem and (iii) low occurrence of toxic metabolites in water phase.

Typical volatile compounds that have been removed in this system include; phenol, NH3; methanol, isopropyl alcohol, acetone, heptane and H2 S (Whaley et al. 1998; van Groenestijn 2001). However, this technique is only effective for pollutants having partition coefficient values less than 0.01 (Kok 1992). The mass transfer

Treated air

Treated air

Scrubber unit

Polluted air

Bioreactor unit

Scrubber unit

Pump

Polluted air

Bioreactor unit

For aeration

0 0

Post a comment