Identification of Microbiota for Activated Sludge Acclimated By Paper Mill Effluent Kraft E1 Bioremediation

摘要

Conventional systems treating paper effluents and cellulose are quite efficient in the reduction of Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD). In general, there is primary stage clarification followed by secondary treatment, usually with a biological system (activated sludge). However, for the efficient degradation of some organic compounds in this effluent, adapted microorganism accomplish the treatment which are necessary resulting in effluents with low concentrations of recalcitrant compounds. There are two methods for microorganism acclimation: genes cloning or natural. In this work, the original biomass collected from a domestic sewage treatment plant was adapted for application in the bioremediation of paper mill effluent, Kraft E1. So, the aim of this work was verifying the correlation of protozoa organisms and physical-chemical parameters during the acclimation period. The acclimation of the biomass was verified mainly through the reduction of COD. The monitoring of biomass growth was followed by measurement of suspended solids and volatile suspended solids. Parameters such as pH, Dissolved Oxygen (DO) and temperature were also monitored daily. The biological study was accomplished microscopically through the identification of protozoa that are considered bioindicators of the activated sludge system. The biomass acclimation period was 39 days. The stabilization of the system was observed through constant rates of total COD (56%). The suspended solids at the beginning of the acclimation phase were from 1580 mg L-1 to 3580 mg L-1, indicating biomass growth. A small acclimation period was necessary to observe the diversity of protozoa, mainly free ciliates, but nematodes were also present, indicating poor sludge sediment. At the end of the acclimation phase predominantly rotifers, but some free ciliates, ciliated communities and fixed ciliated were observed, indicating a good purification capacity of the system. Within the organisms amoeba was observed and this indicates good quality to the final effluent. Then, it is possible to correlate the biota presence with the high capacity of COD removal from the activated sludge system.