Currently, industrial wastewater is characterized by a more complex composition and increased toxicity. Industrial wastewater treatment takes place mainly in biological treatment plants, the distinctive feature of which is the implementation of the process of extended aeration of wastewater. To ensure the required quality of biotreated water, it is prerequisite to know the status of activated sludge during the biological treatment process. Therefore, the purpose of the work was to assess the state of activated sludge in the process of biological treatment of industrial wastewater in a comparative aspect and to develop a new, more promising indicator for assessing the activated sludge status. The article assessed the status of two activated sludges: formed on wastewater from organic synthesis plants and on wastewater from petrochemical enterprises. A similar trend has been established for changes in the activated sludge status while biological treatment, assessed on a five-point scale and the Shannon hydrobiological index. The exception is the modified Cube index, for which the quantitative discrepancy of its changes compared to the above is shown. A certain subjectivity of the five-point rating scale, associated with the microbiologist qualification, and insufficient information content of hydrobiological indices which take into account only the presence of indicator organisms of activated sludge were revealed. For use in water treatment practice, a new quantitative indicator has been proposed. It is based on data from direct analytical measurements. It is equal to the ratio of the supernatant liquid turbidity to the generic Shannon index (combined indicator) value. The complete correspondence of the change in the activated sludge status on a five-point rating scale and a combined indicator characterizing the stress level of activated sludge during the biotreatment process is shown. Greater sensitivity of the combined indicator was noted, especially with a significant decrease in the assessment of the activated sludge status. A predictive model has been obtained that describes the change in the status of activated sludge formed from wastewater of organic synthesis plant during the water treatment and its recovery potential (coefficient of determination 97.06%).
ISSN 1995-4301
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