Mark van Loosdrecht is Professor in Environmental Biotechnology at Delft University of Technology, The Netherlands. He graduated from and did his PhD research at Wageningen University. His PhD topic was a combination of microbiology and colloid chemistry. He was appointed at Delft in 1988 and became Full Professor in 1998. His research is characterized by the combination of scientific understanding of complex systems and development of new processes. Dr. van Loosdrecht’s scientific interests are mainly related to biofilm processes, nutrient conversion processes and the role of storage polymers in microbial ecology. In particular, he is interested in new processes related to wastewater treatment and resource recovery. His research has resulted in several processes currently applied on full scale such as the Sharon process, Anammox process and Nereda process. He is active member of the International Water Association (IWA) and past chairman of the Biofilm and the Nutrient removal specialist groups. He is Editor in Chief of Water Research. He obtained several prizes for his work, including the Lee Kuan Yew Singapore Water Prize and the IWA Grand Award. He is member of both the Royal Dutch Academy of Arts and Sciences and the Dutch Academy of Engineering. He was awarded a knighthood in the order of the Dutch Lion. He has published over 500 scientific papers, has 15 patents and has supervised over 50 PhD students.
Prof. van Loosdrecht offered the following lectures during his tour:Lecture 1: Aerobic Granular Sludge – The Next Generation Wastewater Treatment?
Wastewater treatment has for a century been based on flocculating activated sludge. This allows a stable and efficient process, but with a large footprint due to the slow settling rate of sludge flocs in water. Despite the obvious advantages, the alternative of immobilizing bacteria as biofilms in the reactor has never got a strong foothold in the market. This is partly related to intrinsic higher construction costs and a biofilm/water interface area being the rate limiting factor in the design. Growing bacteria as granular biofilms (1-2 mm particles) maximizes the mass transfer area and also allows operation and construction of the system as an activated sludge process but with very well settling sludge (up to 50 m/h). Growth of anaerobic bacteria in granular sludge has been known since the 1970s. Based on a fundamental understanding of the mechanisms behind sludge morphogenesis, it was possible to develop a process for aerobic treatment of wastewater. The normal functions of a treatment process (anaerobic, anoxic and aerobic zones) can be integrated in the sludge granules. Instead of different reactor compartments with recycle pumps, we have now different reaction zones inside the sludge granules where diffusion ensures the mass transport, resulting in a greatly reduced energy need for the treatment process. Also, because settling is very fast, it can be integrated into the treatment reactor. This results in a 1-step/1-compartment process without recycle or return sludge pumps or full COD and nutrient removal. The first municipal full-scale treatment plant was constructed 2 years ago and currently the technology is already in use in 4 different countries. The presentation will go into the background of granular sludge formation, process design and some aspects of the full scale treatment plants. The presentation could be tuned towards a more basic discussion of granular sludge formation or more application oriented aspects.Lecture 2: Waste Based Biorefineries
With the development of a bio-based sustainable society, there is a need to develop processes to recover as much as possible materials from waste; the cradle-to-cradle approach. Not only the organic carbon in wastewater, but also the green garbage as well as the agrowaste are sources of chemical compounds which could be recovered. The current focus seems to be on recovering material in the form of energy (biogas). This is however a low value and non-desired option. Minimizing entropy losses is a basic aspect of a sustainable society and organic compounds should therefore be recovered as chemicals. Partly a direct recovery of waste materials could be feasible, but the wide diversity of chemicals in waste urges to develop processes which convert these chemicals into basic building blocks. Since most of the waste has a very high water content this can best be done by a microbial conversion process, producing preferably an insoluble compound. These process will have to be designed on the basis of a microbial ecology approach. In order to be able to work on bulk scale non-sterile conditions are needed to make it technically and economically feasible. The lecture will start with discussing the potential of recovering chemicals from wastewater (nutrients, fibres, etc.) but then expand to processes to produce polymeric materials from waste. It will be discussed how alginates and hydroxyalkanoates can be effectively produced from waste in a cost effective manner as compared to present industrial processes.
Lectures were given in October 2013 at Cornell University, Yale University, Duke University, Virginia Tech, Johns Hopkins and Georgia Tech. In January/February 2014, Dr. van Loosdrecht visited the University of South Florida, Texas A&M, the University of Wyoming, the University of Washington, and UC Berkley. In March 2014, he visited University of Illinois, Carnegie Mellon, University of Wisconsin, Michigan State, and University of Notre Dame.