Biodegration of BPA and HHCB from Waste Water by Multi-Stage Biofilm Processes

Abstract

The removal of bisphenol A and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[γ]2-benzopyran (HHCB), which both are widely used chemicals and known endocrine disrupters, was studied applying two biofilm processes. One of the processes was a rotating bed biofilm process (RBBR) in which waste water and small plastic pieces were rotated in cylindrical reactors by air supply. The plastic pieces served as a carrier material for biofilm as the other process, fixed bed reactor (FBR) applied wood chips. RBBR was fed with municipal waste water and FBR with artificial gray water. Preliminary results show that both experiment setups remove efficiently BOD, COD and suspended solids from waste water. BPA and HHCB were added to municipal waste water and artificial gray water to study their removal in RBBR and FBR. In RBBR, BPA removal was 10 – 29 % in the first stage and 68 – 83 % in the second stage. HHCB was removed 3 – 4 % in the first stage and 70 – 79 % in the second stage of RBBR. In FBR, the first stage removed 31 – 97 % of BPA and the second stage 80 – 100 %. 84 – 95 % and 96 – 99 % of HHCB was removed in the first and second stage, respectively. However, the percentage of removed BPA and HHCB decreased over the course of time, which refers to adsorption and saturation of BPA and HHCB to wood chips at the beginning of BPA and HHCB addition. The experiments will be continued and adaptation of microbial is expected in the latter stages of the setups. Denaturing gradient gel electrophoresis is applied to study differences in bacteria and fungi diversities in different steps of the multi-stage RBBR and FBR. In future, also 454 pyrosequencing will be applied.