Water and Wastewater Practitioner Series – serie

Recent technical innovations and significant cost reductions have sharply increased the potential for using Membrane Bioreactor (MBR) technology in municipal wastewater treatment. MBR technology displays several advantages compared to the traditional activated sludge processes, such as high effluent quality, limited space requirement and with the possibility of a flexible and phased extension of existing waste water treatment plants. Membrane Bioreactors for Municipal Wastewater Treatment describes the results of a comparative research programme involving four leading membrane suppliers: Kubota (Japan), Mitsubishi (Japan), X-Flow (Netherlands) and Zenon (Canada). Each supplier provided a pilot to represent a suitable scale - right up to full scale. These pilots were operated and optimised in the course of the research programme to achieve the best operating window under different operating regimes. The research focussed on the functionality of the membrane, the biological treatment, membrane fouling, achieved effluent quality, and system operability as well as other factors. In a number of side studies the required pre-treatment, membrane fouling/cleaning, energy usage, effluent quality and sludge processing were also addressed. The comparative pilot research was carried out by DHV Water on location at the wastewater treatment plant at Beverwijk in the Netherlands.

Biological phosphorus (bio-P) removal has become a reliable and well-understood process within wastewater treatment, despite being one of the most complex processes in the activated sludge process. Extended fundamental and full-scale research has been carried out into the bio-P process and the state-of-the-art is described in this report. A summarising historical overview gives insight into the establishment of the appropriate microbiological and biochemical basis of the process and the development of bio-P configurations in practice. Aspects of the bio-P process that have a direct influence on the efficiency of phosphorus removal are subjected to an in-depth investigation. This report presents guidelines for design and dimensioning in order to introduce and/or optimise the bio-P process in practice. Twelve bio-P installations are extensively described and the operational results and experiences are related to existing bio-P knowledge and guidelines. Based on a number of parameters, a comparison is made between the described bio-P plants. A steady state model is verified with extensive periods of practical experience of the plants. The bio-P model, which is provided on CD-ROM (available for download here), offers a reliable insight into the bio-P process, coupled with sensitivity analyses regarding wastewater characteristics and process parameters for the anaerobic volume and the P-ortho concentration in the final effluent. The report ends with a systematic approach to the design of the bio-P process, based on the background of the bio-P process itself, much practical experience and the analysis of operational bio-P plants. Also presented is a systematic approach to tackle operational aspects of the bio-P process in order to generate an acceptable low P effluent concentration. This optimisation of the bio-P process operation is supported by a decision diagram. Biological Phosphorus Removal will be an invaluable source of information for all those concerned with wastewater treatment, including plant managers, process designers, consultants and researchers.

A new development for the treatment of domestic wastewater is a technology based on aerobic granular sludge. Granular sludge can be developed under specific process conditions. Because of the unique properties of this granular sludge, high volumetric loading rates of aeration tanks can be applied. Thanks to excellent settling properties, the separation of treated wastewater and granular sludge can take place at high hydraulic loading rates. Depending on the chosen process configuration good effluent quality can be obtained, complying with the stringent effluent requirements regarding nitrogen and phosphorus, which can be expected in the future. In this way aerobic granular sludge has the potential to contribute significantly to wastewater treatment management. This report describes the results of research carried out at the Technical University of Delft.