ABSTRACT
The treatment efficiency of industrial effluents, after biological treatment by activated sludge in aeration tanks (AT), was assessed through the utilisation of respirometry tests at the Cetrel's-wastewater treatment plant (WTP). Samples of the equalised effluent (EE), prior to treatment, and of the treated effluent (TE), after treatment, were analysed. Twenty bioassays batch were carried out to AT (AT-2, AT-3 and AT-4). Each test consisted of: a basic test, a basic test with peptone added, a test using EE and a test using TE. The data showed that there was no statistically significant difference (p>0.05) in the respiration activity between the aeration tanks. Regarding the specific oxygen uptake rate there was a mean reduction of 70.8 percent between the tests performed with EE and TE. The results demonstratd that respirometry tests could successfully assess the efficiency of the activated sludge process and, therefore, be adopted as tool for the monitoring from the WTP.
Este trabalho avaliou, através de ensaios de respirometria, a eficiência do tratamento de efluentes industriais, após tratamento por lodo ativado em tanques de aeração (TA). Foram analisadas amostras do efluente equalisado (EE), antes do tratamento, e do efluente tratado (ET). Vinte baterias de ensaios foram realizadas com cada um dos TA (TA-2, TA-3 e TA-4). Cada bateria consistiu de um ensaio básico, contendo apenas o licor misto, um ensaio com adição de peptona, um ensaio com o EE e um com o ET. Não houve diferença estatística significativa (p>0,05) na atividade respiratória dos TA. Quanto à taxa de consumo de oxigênio específica houve uma redução média de 70,8 por cento entre os ensaios realizados com EE e ET. Os ensaios de respirometria determinaram com eficiência o nível de tratamento através de lodo ativado, e deve ser adotado no monitoramento dos efluentes da estação de tratamento de efluentes do Pólo Industrial de Camaçari.
Subject(s)
Airway Obstruction/diagnosis , Diskectomy/instrumentation , Intubation, Intratracheal/instrumentation , Adult , Airway Obstruction/etiology , Airway Obstruction/prevention & control , Diskectomy/adverse effects , Equipment Failure , Female , Humans , Intubation, Intratracheal/adverse effects , Lumbar Vertebrae , Prone PositionABSTRACT
The treatment efficiency, as toxicity removal, of complex effluents from the Industrial District of Camaçari (BA, Brazil), after biological treatment with activated sludge was evaluated using Microtox. Samples of the equalised effluent (EE) were collected prior to treatment together with samples of the treated effluent (TE), which remained 24 h in the treatment plant. Rehydrated colonies of Vibrio fischeri were exposed to sequential dilutions of EE and TE to assess luminosity interference. Values for EC50 were calculated, together with the respective toxicity units. In all, twenty assays of each effluent type were carried out and the mean toxicity removal was 92.71%, while the chemical oxygen demand (COD) presented mean reduction of 83.04%. There was a variability of an order of magnitude between the Microtox results for the two types of effluents. The mean EC50 values were 2.12 for EE and 47.78% for TE. In spite of its weakness in some conditions, the Microtox system demonstrated to work adequately in assessing effluent toxicity removal in this treatment plant and therefore can be used for further toxicity removal programs.
