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Settling tests

This is the fourth of the seven courses in the series Experimental Methods in Wastewater Treatment. It contains four video units and a textbook chapter that can be accessed free of charge at this webpage.

Course Info

  • About

    This course focuses on the different settling regimes that a particle-liquid suspension can undergo and relates these regimes to the specific settling behavior observed in secondary and primary settling tanks, and granular sludge reactors. The course is designed for both academics and practitioners, including graduate and postgraduate students, researchers, laboratory staff, plant operators, consultants, and other sector professionals with a background in sanitary, civil, environmental or (bio)chemical engineering, environmental biotechnology or biochemistry. As the course is at graduate level, participants with knowledge of and experience with the basic concepts of biological wastewater treatment will particularly benefit from it.

  • Syllabus

    The following topics are part of the course:

    • Sludge settleability in secondary settling tanks;
    • The flocculation state of activated sludge;
    • The settling behavior of granular sludge;
    • Settling velocity distribution in primary settling tanks.

    For a detailed table of contents please click here.

  • Objectives │ Activities │ Assessment

    Learning objectives, activities and assessment depend on the delivery mode of the course. In general, learning objectives are more complex for instructor-led courses. This is particularly true for on campus courses and tailored training because they allow for guided, hands on, laboratory exercises and assignments. To view the learning objectives, activities and assessment of this course please click here.

  • Contact

    Carlos Lopez Vazquez, PhD
    +31 15 21 51 781


Settleability tests

This video shows how to determine the sludge volume index (SVI) of a mixed liquor activated sludge sample and how to perform the batch settling test with activated sludge. It also presents different approaches for the collection of samples at different locations in full-scale wastewater treatment plants for the execution of experimental methods.

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DSS and FSS methods

A dispersed suspended solids (DSS) test is executed to estimate the flocculation state of an activated sludge sample. By carrying out a flocculated suspended solids (FSS) test, the flocculation potential of an activated sludge sample is determined in this video.

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Download book chapter

Settling tests (4.3 MB)

Available in English, Spanish and Croatian. Coming soon in Russian, Hindi, Marathi and Tamil.

Settling tests

This chapter is an integral part of the textbook Experimental Methods in Wastewater Treatment. It is a complementary part of the course curriculum and includes background information on the processes of interest, details on experimental set-ups, preparation and execution, as well as a results discussion and interpretation, accompanied with examples and additional information. The book is also used for teaching the MSc specialization in Sanitary Engineering at IHE Delft and several other universities worldwide. It is the product of collaborative efforts by research groups and practitioners around the world. You can download your free copy of the book in one of currently available languages.
  • Van Loosdrecht M.C.M., Nielsen P.H, Lopez-Vazquez C.M., Brdjanovic D. Ed. (2016) Experimental Methods in Wastewater Treatment. IWA Publising, pg. 350, ISBN 9781780404745 (Hardback) 9781780404752 (eBook)