Materials List: Things That Matter to Flocculants

Photo shows a shelf with little jars labeled "Alum."
Alum is available at grocery stores.
Copyright © 2011 Denise W. Carlson, ITL Program, College of Engineering, University of Colorado Boulder

Each group needs:

  • test water with suspended solids, ~1 liter in a container with a lid
  • 7 clear plastic cups
  • aluminum sulfate solution, ~3 ml (prepared by teacher)
  • polymer flocculant solution, ~3 ml (prepared by teacher)
  • 4 plastic spoons or craft sticks, for stirring
  • marker, able to mark on the plastic cups
  • lemon juice, ~2 ml
  • volumetric measuring tool(s), for measuring 1 ml of additives (such as pipettes; clean between use)
  • lab journals, or paper and pencil, to record lab notes and observations
  • (optional) pH paper

For materials preparation (done by students or prepared by teacher in advance):

  • Containers in which to collect "dirty water" from a nearby river or pond; enough to collect ~ 1 liter per group; make sure to scoop up some riverbed silt and dirt during collection
  • 2 containers with lids for the aluminum sulfate solution and polymer flocculant solution
  • aluminum sulfate (aka alum; purpose: flocculant), a small amount, about the size of a quarter; available at grocery stores in the spice aisle, for example, McCormick's 1.9 oz [53 g] jar for $3.49
  • Super Blue concentrated pool water clarifier (purpose: polymer flocculant), a small amount, ~1 ml per 50 ml of water; available at pool supply stores or on the Internet for $13 per quart
  • tap water, ~10 ml per student group (purpose: flocculant suspension/dilution)
  • tape and marker, to label the containers