Define the installed separation duty
Give the lamella arrangement, feed water, suspended-solids character, flow range and downstream requirement. The polymer must fit the actual hydraulic and solids path; a fast-settling laboratory floc alone does not qualify it.
The clarifier fault review helps separate chemical weakness from loading, distribution or withdrawal problems. Preserve current operating evidence before asking a supplier to solve every carryover event through a new grade.
Describe loading and variable feed
Record flow, solids concentration, production state, pH, temperature and coagulant sequence. Distinguish normal operation from difficult credible conditions. Include any feed recirculation or upstream changes that affect floc formation.
A nominal tank capacity is not an acceptance metric. The responsible process team should define the loading and operating envelope used for testing and field comparison.
Map polymer contact and shear
Identify make-down, injection, distribution, flocculation and transfer to the plates. Record whether formed floc passes a pump, valve or restrictive feed arrangement. The candidate should be tested after a representative handling path.
Use feasible grade-specific preparation and actual available contact time. Do not create an artificially gentle laboratory sequence that conceals breakage or distribution problems present in the plant.
Measure more than initial settling
Compare overflow turbidity or solids, floc resilience, underflow handling and observations relevant to plate accumulation. Record test timing and include the incumbent and untreated or coagulant-only controls as appropriate.
Inspect whether a candidate creates persistent deposits or a difficult solids layer under the agreed trial procedure. A high initial settling rate can be commercially unattractive if cleaning or underflow problems offset the water improvement.
Use a stable field comparison
Verify chemical feed, water flow and coagulant condition before the trial. Record operating changes, withdrawal and relevant separator observations on a common timeline. Let the plant team define safe monitoring and stop conditions.
Do not interpret one clear grab sample as proof of long-term performance. Include enough representative operation to examine the result the plant actually needs, while marking conditions not covered by the trial.
Compare delivered operating value
Use actual accepted polymer consumption and scoped delivered price, adding preparation, cleaning and solids handling where measured. Keep the incumbent's actual operating costs and limitations as the comparison baseline.
Use the treatment-cost worksheet and preserve uncertainty. An offer with a lower unit price is not necessarily a cheaper way to maintain acceptable overflow.
Release a lamella-specific supply identity
Connect the accepted code, form, active basis, preparation and hydraulic window to the quotation and receiving plan. Define recheck triggers for plate, feed, coagulant or material changes.
Send the separator arrangement, analyses and trial quantities through the lamella polymer quote request. Ask for a controlled screening proposal instead of a generic high-molecular-weight flocculant recommendation.
Keep a separator-specific inspection record
Link flow and solids conditions, polymer batch, coagulant baseline and calibrated addition with observations at the inlet, plates, overflow and underflow. Use the inspection points and methods approved by the process team rather than require unsafe access for a supplier comparison.
Record whether an observed deposit, carryover event or difficult underflow coincided with a feed or withdrawal change. That timeline supports a factual trial conclusion and prevents a generic statement that floc looked larger from obscuring the practical separator consequence that controls acceptance.