Sistema combinado anaeróbio-aeróbio para remoção de matéria orgânica de glicerol residual

Abstract

Glycerol is a waste liquid containing high organic load, which is originated from the process of transesterification of vegetable oils and animal fat used for the production of biodiesel. It is highly soluble in water, which facilitates its dispersion into the environment, generating several impacts on natural resources, especially on water bodies. While there are many commercial applications for glycerol, its application is limited to when it is generated from the production of biodiesel, because in this case glycerol contains many impurities. The purpose of this research is to evaluate the efficiency of organic matter removal from this waste in a system of combined anaerobic-aerobic biofilters, both bench scale. The anaerobic filter (ANF) has useful volume of 3.2 L, it also has a three-phase separator modified into the shape of the letter “Y”, which is connected in series to a submerged aerated filter (SAF) with an aeration tank with 5.9 L of capacity and to a secondary decanter. The anaerobic filter was inoculated with sludge from a UASB reactor, which was used for biogas generation from glycerol, and in the aerobic filter were placed halophyte species of bacteria, which were isolated from shrimp farm effluent. This study lasted 308 days and attained a COV of 10 kgDQO.m-3.d-1 with TDH fixed 7.46 h. The average removal efficiency of COD was 83 % for ANF, 90 % for SAF and 98 % for the combined system. The specific production of methane in ANF was approximately 0.220 L. CH4.g-1DQOrem. The biological digestion of residual glycerol from biodiesel production inside an anaerobic-aerobic combined system is an effective alternative for the treatment and revaluation of this waste, because this system was able to remove more organic matter in less time. However there was a demand for large quantities of water to dilute the glycerol.