Comparison of the Traditional Slow Sand Filter (TSSF)
and the Manz Slow Sand FilterTM (MSSF)

Vertical Scale of the TSSF compared to the MSSF

  • All filters meet American Water Works Association Guidelines or Standards for ‘slow sand filter design’ and ‘specification of filter media’.

  • Maximum Loading of 200 to 400 litres per hour per m2 of filter surface as per local regulatory guidelines.

  • The depth of the filtering media in the MSSF equals the minimum depth recommended for the TSSF. The minimum depth is thought to be necessary for deactivation of viruses.

The MSSF meets the well-established performance characteristics of the TSSF but can also treat water of higher turbidity.  MSSF based treatment systems effectively remove:

  • Particulate matter (sand, silt and clay sized with or without use of coagulants)

  • Parasites including Giardia cysts and Cryptosporidium oocysts

  • Helminthes and their eggs

  • Spores

  • Bacteria

  • Viruses

  • TOC/DOC (taste, odour, colour)

  • Toxins

  • Algae

Pathogen Removal without Disinfection


Particulate Removal

  Removal Rate %     Removal Rate %
Pathogen TSSF MSSF   Parameter TSSF MSSF**
Helminthes Up to100 Up to 100     Turbidity<20 NTU Turbidity<400NTU
Parasites Up to100 Up to 100   Sand 100 100
Bacteria 90 - 100* 90 - 100*   Silt 100 100
Viruses 90 - 100* 90 - 100*   Organic Particles 100 100
Spores Up to100 Up to100   Clay Particles Up to 100 Up to100
*Formation of ‘schmutzdecke’ or ‘biolayer’ required for 90-100% removal of bacteria and viruses without disinfection.  Up to 100% with post-filtration disinfection   **Simple to clean and does not consume any filtering media.  Pretreatment using low concentrations of coagulant is very effective and practical.

Advantages of MSSF based treatment systems:

  • Low capital cost

  • Low operating cost

  • Scalable to suit any volume of demand

  • Simple and robust operation

  • No media replacement (very infrequent)

  • Manual or automatic operation

  • Maximum production from a slow sand filter

  • Minimum use of chemicals (can use chemicals – turbidity and colour removal)

  • Minimum production of wastewater (reuse/recycle)

  • Adjustable rate wastewater disposal

  • Easily used with other pre- and post-treatment technologies

  • Easily constructed on site or as part of a package plant

  • Appropriate for readily accessible and remote applications

  • Appropriate for treatment of a wide variety and range of water quality

  • Easily evaluated (bench scale and pilot)

  • Existing TSSF installations can be retrofitted to use MSF technology

  • Greater capacity

  • Much less effort to clean

  • Treatment and recycling of waste water from conventional water and waste water treatment plants

Oasis Filter International Ltd.
2525 Macleod Trail SW
Calgary, Alberta, Canada T2G 5J4

Phone: 1-403-269-1555
Fax: 1-403-264-6244

Last updated Saturday November 27, 2010
©2010 Oasis Filter International Ltd.  All Rights Reserved.