Study of fiber sensor for biofilm thickness online measuring based on optical absorption

In the low concentration volatile organic compounds (VOCs) process in bio-filter, as the carrier for microorganism attachment, the biofilm thickness size influences the organic gas processing efficiency directly. The paper presents a biofilm thickness online measuring technology based on optical absorption, which used the biofilm characteristic whose main compound could absorb ultraviolet, in a certain optical wave band, the biofilm absorbance value one to one corresponds to the biofilm thickness in direct ratio, so it can be used as the basis of quantitative determination. According to the photochemical phenomenon and theory the paper create a new online measuring method for biofilm thickness. The experiment data indicates that the method has high-precision, could realize the real-time online and non-contact measurement. If the online measuring technology and control to form a testing and control system, it will control the biofilm thickness effectively, then improving the bio-filter degradation efficiency.