Knowledge Center

How UV-C treatment of laboratory wastewater works

UV-C light is the bacteriological treatment stage in four of the five TRESA systems. This article explains what it does and how the effluent is prepared for it.

What UV-C does

UV-C lamps emitting at 254 nm neutralize microorganisms by destroying their nucleic acids and disrupting their DNA. In TRESA units the effluent circulates in a closed loop through UV-C chambers so that it receives the required dose.

Why the effluent is conditioned first

TRESA systems condition the effluent before UV-C treatment so that the UV-C dose is effective for that type of effluent. They do this in one of two ways:

  • Controlled dilution (TRESA CI and TRESA H): level sensors and a solenoid valve add water to reach the required dilution ratio, 1:2 for CI and 1:10 for the more concentrated hematology effluent treated by H.
  • Filtration (TRESA CRD and TRESA CIH): active-carbon filtration, combined with resin ion exchangers in TRESA CRD, reduces chemical contaminants before UV-C treatment.

A typical UV-C cycle

  1. Effluent flows from the analyzer into the unit’s holding tank.
  2. It is diluted or filtered, depending on the model.
  3. The UV-C lamps switch on and preheat.
  4. A pump circulates the effluent through the UV-C chambers.
  5. The treated effluent is discharged to an approved drain or sewer connection, subject to local requirements.

Lamps and maintenance

TRESA CI and H use 2 × 95 W UV-C lamps, TRESA CIH uses 3 × 95 W, and TRESA CRD uses a 36 W UV-C lamp. All are rated for a 9,000-hour lamp lifetime.

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