2. Controls

The proper operation of the entire plant is monitored by discharge measurements and analyses carried out by the operator or an external body on representative samples of production.

• Samples are taken using equipment, usually automated, with the possibility of taking samples over specific periods of time and according to flow rate. Samples are stored in appropriate containers at low temperature in a refrigerator, and reagents can be added to block their evolution.

• Analyses are carried out as quickly as possible, particularly for organic matter. Cyanide and hexavalent chromium are determined daily, and metals once a week. With self-monitoring becoming increasingly widespread, these analyses are usually carried out in-house, using rapid methods such as UV-Visible spectrophotometry, or...