Aerobic granular sludge: Scaling up a new technology

Aerobic granular sludge: Scaling up a new technology

De Kreuk, M.K.

Van Loosdrecht, M.C.M. (promotor)

Applied Sciences

2006-06-27

Most conventional wastewater treatment plants need a large surface area for the treatment of their sewage. This is due to the open structure of the biomass used to convert the polluting components in wastewater. Because of the flocculated growth, sludge concentrations in reaction tanks are low and settling times need to be long in order to keep the biomass in the system. This Ph.D. thesis describes the development of a new compact aerobic granular sludge technology, in which the biomass is grown in compact granular structures. The main advantage of this compact growth structure is the higher biomass concentrations that van be reached and that all processes, needed for the treatment of wastewater, can be performed in one (discontinuously operated) reactor. Therefore, 80% less area and 30% less energy is required for the treatment of the wastewater. This process is unique, since by the natural composition of the aerobic granular sludge, combined with different diffusion limitations, all processes for the conversion of the polluting agents can occur in the same granule simultaneously. In the laboratory, biological removal efficiencies of 100% COD (acetate), 94% phosphate and 94% nitrogen (of which full-nitrification) were measured. During the Ph.D. a large-scale design has been made by the engineers of the Dutch consultancy firm DHV. Bottlenecks from practice were translated to scientific research and the results of the research could directly be used in the design. Different bottlenecks that were studied in the laboratory scale research were the influence on conversions and granule morphology of i) the way of influent dosing, ii) the use of a bubble column or airlift (influence of high local shear forces), iii) influence of temperature, iv) type of wastewater. A model for aerobic granular sludge has been developed as well, in order to study the sensitivity of different process parameters on conversion rates and efficiencies. This fast procedure for developing innovations led to a successful pilot scale study at sewage treatment plant Ede, The Netherlands and to the market introduction of this new technology by DHV under the name of NeredaTM.

wastewater treatment
sewage
nutrient removal
modelling
biological phosphate removal
nitrification
denitrification
aerobic granular sludge
activated sludge

http://resolver.tudelft.nl/uuid:a23ba934-3b4a-476e-a781-798723a74056

978-90-9020767-4

Institutional Repository

doctoral thesis

(c) 2006 M.K. de Kreuk