Biodegradation of Phenol by Immobilized in Peo-Cryogel Bacillus Laterosporus BT-271 in Sequencing Batch Biofilter

ABSTRACT

A long (20 days) model process of phenol biodegradation was performed in biofilters in sequencing batch regime and with active biological system—polyethylene oxide cryogels (PEO-cryogel) with immobilized bacteria Bacillus laterosporus BT-271. The model waste water, containing mineral medium and phenol as the only source of carbon and energy with 300 mg/l in the effluent, was used. One of the key investigated parameters was the manner of immobilization of the bacteria in polyethylene oxide cryogels. The two variants of the experiment were: 1) direct immobilization of the inoculation material (SBB-D) and 2) inoculation of the biomass after preliminary separation and further concentration (SBB-S).

The process was characterized on the basis of the following parameters: concentration of phenol in the influent, efficiency of phenol biodegradation, rate of phenol biodegradation, debit of purified water, loading of biofilters, rate of phenol degradation and efficiency, oxygenase enzyme activity of the cells immobilized in the cryogel and of the free cells in the effluent. The implantation of the gel with the immobilized microorganisms in a sequencing batch biofilter showed good biodegradation, kinetic, enzymological characteristics, as well as self-renovating adequate biofilm structure in laboratory conditions. The two biofilters functioned well and the efficiency of phenol elimination reached 100% in 15 days. The variant SBB-D showed a more stable process, as well as an easier way of preparing the initial PEO-plate biofilm. The SBB-D system is suitable for scaling and future implementation of the water purification processes in practice.

Keywords:

• sequensing batch biofilter
• polyethylene oxide cryogels
• immobilized Bacillus laterosporus BT-271
• phenol biodegradation