Carrying out flocculation experiments with VELP flocculator

Instructions to carry out flocculator experiments using the 6-unit VELP flocculator.

Storing of collected water samples

Water canisters etc. need to be stored in a dark climate room in order to reduce microbial activity, optimally at 4 degrees Celsius. If a dark room is not available, the canisters can be covered with black bags or similar.

Sampling

Take water samples and measure 500 ml into 1 liter beakers as experimental units. Up to six units can be used in one flocculation cycle. Make sure to only dilute the sample waters by a maximum of 10%, in order to not dilute the samples too much (in 500 ml max 50 ml of non-target water). Be consistent with starting temperatures of the experimental units, do not have units where the other one is room temperature at starting point and another one at fridge temperatures.

Preparations

Mix collected waters used as samples every day, for as homogeneous concentrations of dissolved matter as possible. Take daily conductivity measurements from collected water to ensure that no major changes have occurred during the different flocculation experiments. Prepare 500 ml of sample solutions into the experimental units, measure conductivity for each experimental unit.

Flocculation cycle

Place experimental units in VELP flocculator, and lower the blades into the beakers. The length of one flocculation cycle is 1 hour. Set the desired RPM from the panels of the flocculator. Be sure to rinse the blades with fresh MQ between flocculation cycles.

Clean-up

After daily flocculation cycles are completed, prepare dilute Deconex solutions in beakers. Have the blades rotate for around 1-2 hours at low RPM in the solution. Leave blades in the Deconex solution overnight without blade rotation. Rinse the flocculator the following day with fresh MQ.