Goodbye to Professor Grietje Zeeman

On October 7th 2016 Professor Grietje Zeeman retired after 36 years of research at ETE. Her scientific field mainly focused on anaerobic treatment and the development and implementation of novel sanitation technologies to efficiently recover resources from wastewater from households.

Anaerobic waste water treatment
The first ten years of her career, Professor Zeeman worked on the anaerobic digestion of animal manure to produce biogas. She subsequently moved into the area of anaerobic low temperature domestic waste water treatment using the Up-flow Anaerobic Sludge Bed (UASB) reactor, an invention of Emeritus Professor Gatze Lettinga. She became convinced that the best long-term solution for recovering resources is treatment of source separated domestic wastewater streams.

Successful pilot project
Based on her scientific expertise, Zeeman strongly argued to phase-out the current central sewage systems. These should be replaced by a decentralized sanitation system, where undiluted waste was separated at the source and subsequently processed at the same location with the UASB reactor as the core technology. To maximize efficiency of this method, undiluted waste streams were separated into so called ‘grey water’ from shower and kitchen, and ‘black water’ from the toilet. Her strong belief in this ‘source-separate, decentralized sanitation’ combined with a lot of passion and hard work resulted in 2006 in a successful pilot project in the city of Sneek with 32 households, and later the successful implementation of this principle at a new location in Sneek of 250  households. In addition, her system was implemented in three office buildings: Villa Flora in Venlo, the NIOO building in Wageningen and the office building of the Ministry of Infrastructure and Environment in The Hague. A new location of ca. 450 houses in Amsterdam is in preparation.

Passion and solid arguments
ETE Professor Cees Buisman knows Grietje Zeeman for many years; they both worked on their Ph.D's in the late 1980'ies. Later, they joint forces in guiding new Ph.D. students together. According to Buisman she is very pleasant person with a typical Dutch directness. Buisman appreciates her vision about new sanitation systems. 'At first, I really didn't see that Zeeman's source-separate sanitation would lead to an improved sanitation system', Buisman admits. 'But she convinced me with her passion and solid arguments. Now I am a big fan of source separation!' Zeeman not only developed the technology, but also succeeded to implement her vision and know how in the ‘real world’ with several successful projects.