| Summary: | 碩士 === 國立交通大學 === 產業安全與防災學程碩士班 === 91 === A Field Study of Biofilter for Treating VOCs
in A Hazardous Waste Facility
Student:Huang ,Chun-Yi* Advisor: Tsai Chuen-Jinn**
Degree Program of Industrial Safety and Risk Management
College of Engineering
National Chiao Tung University
Abstract
The composition of hazardous wastes produced from research laboratories is very complicated so is the composition of the toxic gases that are produced in the hazardous waste storage facility. In the waste storage facility, the volatile organic compounds (VOCs) can be collected by an exhaust system and treated with a biofilter for meeting the governmental regulations. The purposes of this research are to study a biofilter treating VOCs for the following topics : 1. Understanding of the optimum operating parameters. 2.Evaluating the removal efficiency (RE) of total hydrocarbons (THC). 3.Evaluating the removal efficiency & removal capacity (RC) of methyl ethyl ketone.
There are three stages for the study. The tasks for 1st stage are : 1. Analysis of exhaust gas to assure no methane in it and prove that the biofiltration process is an aerobic oxidation. 2.Growing and acclimation of microorganisms for MEK ,the average of RE for MEK is 63.20% because microorganisms having not been acclimated.
The tasks for the 2nd & 3rd stages are : 1. Detecting the THC of inlet and outlet to evaluate RE. We found that the average of RE for the 2nd & 3rd stages are 90.91% and 90.70%, repectively. 2. Manually generated MEK vapors in the inlet of the biofilter and measured the pollutant concentrations in the inlet and outlet. The RE of MEK for the 2nd & 3rd stages was found to be 90.12% and 91.43%, respectively. 3. By the experimental data, the volumetric mass loading (VML) and RE were calculated for curve fitting . It was found that critical removal capacity of MEK is 108 g/m3/hr,maximum overall elimination capacity of MEK is 115 g/m3/hr, and the performance decays when the loading exceeds 115 g/m3/hr.
In summary: 1. The optimum pH value of the filter media is from 6.5 to 8.5. 2. Proper moisture content should be maintained between 65% to 75% (wet base). 3. The exhaust flow rate shouldn’t exceed the design value. 4. The pressure drop has to be kept below than 20 mBar to ensure that the filter media have enough porosity.
It is the most effective and economic method for treating VOCs by the biofiltration process. The study demonstrated a standard procedure for evaluating the biofilter for VOCs treatment. The study of RC for every pollutant to find out design parameters can achieve the best RE economically.
|
|---|
