Evaluation and Comparison of Various Samples of Activated Sludge with Respect to Morphology and Efficiency for Implementation for a Start-Up of Pharmaceutical Wastewater Treatment Plant

The activated sludge flocs contain mostly bacterial cells as well as other microorganisms, and inorganic and organic particles. The most common microorganisms that participate in the biodegradation of organic matter are bacteria, protozoa and occasionally higher organisms. The presence of particular types of microorganisms is related to plant performance and effluent quality, so they can be used as indicators of sludge quality. Pharmaceutical wastewater contains specific substances which may be difficult to biodegrade, so it is important to have fundamental understanding of the microbial community structure and stability, as well its response to different chemicals entering the wastewater. The goal of this study was to investigate which activated sludge would be more suitable to be used as inoculum for start-up of pharmaceutical wastewater treatment plant. Three samples of activated sludge were analysed. Activated sludge AS1 is used for treating industrial wastewater ; activated sludges AS2 and AS3 are used in two different municipal WWTPs. The experiments were conducted in batch conditions, at initial concentration of organic matter in pharmaceutical wastewater 2100 mg dm-3 and 2690 mg dm-3, expressed as COD, and different initial concentrations of activated sludge 2.38, 2.94 and 3.62 g dm-3 for AS1-AS3. During the experiments COD, pH value, concentrations of dissolved oxygen and biomass were monitored. Microscopic analysis was performed in order to give a quick insight into the quality of activated sludge.