thickening of waste Activated Sludge by biological flotation

Waste Activated Sludge was thickened by biological flotation without polymer flocculant dosage. The BIOFLOT® process utilizes the denitrifying ability of Activated Sludge bacteria. Gaseous products of anaerobic nitrate reduction cause spontaneous flotation of the Sludge suspended solids. Laboratory tests confirmed the dependence of Sludge thickening efficiency on available nitrate concentration, flotation time and temperature. Full-scale experiments were performed in a fully automatized unit for discontinuous Sludge thickening from wastewater treatment plants with a capacity of up to 5000 I.E. Waste Activated Sludge from wastewater treatment plants at Pisek. Milevsko and Bjornlunda was thickened from 6.2, 10.7 and 3.5 g/l MLSS to 59.4, 59.7 and 66.7 g/t MLSS, respectively. Concentrations of COD, ammonium and phosphate ions were decreased in Sludge water. The average nitrate consumption for bioflotation was 21.2 mg NO1− per 1 g of MLSS of Activated Sludge. Flotation time ranged from 4 to 48 h.

Biopolymers Online – Production of Polyhydroxyalkanoates from Activated Sludge

Introduction
Activated Sludge Processes

Historical Outline
Studies on PHA in Activated Sludge
Microbial Studies

Chemical Structure and its Occurrence
Biochemistry of PHA Production by Activated Sludge
PHA Production by PAOs under Anaerobic Conditions
PHA Production by GAOs under Anaerobic Conditions

Microbiologic and Genetic Aspects of PHA Accumulation by Activated Sludge
Outlook and Perspectives
Patents

Keywords:

Activated Sludge;
polyhydroxyalkanoates;
polyphosphate-accumulating organisms;
glycogen-accumulating organisms;
unculturable organisms;
polyphosphate;
glycogen;
glycolysis;
TCA cycle;
3HV fermentation;
anaerobic-aerobic;
microbial ecology;
enhanced biological phosphorus removal

Recovery of biodegradable plastics from Activated Sludge process

In this research, PHA (polyhydroxyalkanoate) production system by Activated Sludge was studied. PHA behaves as carbon and energy storage material in bacteria. And PHA is a biodegradable plastic when extracted from bacteria. In this paper, the investigations from 3 aspects were reported; control of PHA composition, PHA production under coexistence of nitrogenous compounds, and influence of enrichment condition on PHA productivity. As results, it was possible to regulate PHA composition by utilizing acetate and propionate as carbon source and by regulating its composition. Nitrogenous compounds did not depress PHA productivities in the case of Activated Sludge, while nitrogenous compounds usually depress in general. PHA contents of MLSS were achieved up to 57% by using anaerobic-aerobic Activated Sludge. But microaerophilic-aerobic process could supply stably the Activated Sludge which accumulated PHA with high efficiency.

PHA production by Activated Sludge.

Abstract The production of polyhydroxyalkanoate by anaerobic–aerobic Activated Sludge was reviewed concentrating on the biochemical mechanisms and on the trials to increase polyhydroxyalkanoate (PHA) content in Activated Sludge. The anaerobic–aerobic Activated Sludge system selects microorganisms with the capabilities to couple glycolysis, polyphosphate degradation, and PHA accumulation for anaerobic substrate uptake. Some of the PHA-related metabolisms observed there have not been seen in pure cultures so far. Such metabolisms are the formation of PHA containing 3-hydroxy-2-methylvalerate, and ‘3-hydroxyvalerate fermentation’ in which glucose or glycogen is converted to 3-hydroxyvalerate-rich PHA while yielding energy. The PHA content of Activated Sludge can be increased up to 62% by applying a microaerophilic–aerobic Activated Sludge process. PHA production by Activated Sludge is worth investigation.

microbial ecology of Activated Sludge

Microbial Ecology of Activated Sludge, written for both microbiologists and engineers, critically reviews our current understanding of the microbiology of Activated Sludge, the most commonly used process for treating both domestic and industrial wastes. The contributors are all internationally recognized as leading research workers in Activated Sludge microbiology, and all have made valuable contributions to our present understanding of the process. The book pays particular attention to how the application of molecular methods has changed our perceptions of the identity of the filamentous bacteria causing the operational disorders of bulking and foaming, and the bacteria responsible for nitrification and denitrification and phosphorus accumulation in nutrient removal processes. Special attention is given to how it is now becoming possible to relate the composition of the community of microbes present in Activated Sludge, and the in situ function of individual populations there, and how such information might be used to manage and control these systems better. Detailed descriptions of some of these molecular methods are provided to allow newcomers to this field of study an opportunity to apply them in their research. Comprehensive descriptions of organisms of interest and importance are also given, together with high quality photos of Activated Sludge microbes. Activated Sludge processes have been used globally for nearly 100 years, and yet we still know very little of how they work. In the past 15 years the advent of molecular culture independent methods of study have provided tools enabling microbiologists to understand which organisms are present in Activated Sludge, and critically, what they might be doing there. Microbial Ecology of Activated Sludge will be the first book available to deal comprehensively with the very exciting new information from applying these methods, and their impact on how we now view microbiologically mediated processes taking place there. As such it will be essential reading for microbial ecologists, environmental biotechnologists and engineers involved in designing and managing these plants. It will also be suitable for postgraduate students working in this field.

Encyclopedia of Environmental Microbiology – Activated Sludge—The Process

Features of the Process

Configurations for Activated Sludge Systems

Conventional Activated Sludge Systems

Activated Sludge Systems Designed to Remove Nitrogen

Activated Sludge Systems Designed to Remove Phosphorus

The Future for Activated Sludge Processes?

Keywords:

Activated Sludge;
wastewater treatment

Encyclopedia of Environmental Microbiology – Activated Sludge—The Microbial Community

Why This Ignorance?

So What is Known So Far About the Microbial Communities in Activated Sludge Plants?

The Activated Sludge Food Chain?

Which Factors Decide the Fate of These Microbes in Activated Sludge?

Can Our Communities be Manipulated to Improve Plant Performance?

Keywords:

Activated Sludge;
wastewater treatment