In the 1980’s Germany enacted strong environmental regulations for coal-fired power plants and waste incinerators. This created a need for treatment systems for the wastewater from these installations. GEA Messo PT developed, designed and supplied numerous tailor-made zero liquid discharge (ZLD) wastewater treatment systems to help the industry comply with this legislation.

These systems employ heavy metals precipitation, evaporation with seeding (as an anti-scaling measure) and crystallization. The handling of calcium, magnesium and sodium chloride solutions (contaminated with halides like bromine and iodine, or their salts) has provided GEA Messo with valuable experience on corrosion resistant materials for such applications.

The expertise in ZLD applications extends to the treatment of liquid effluents from ion exchange, cooling tower blow down, and wastewater from flue-gas-scrubber systems. In some cases, along with reuse of the condensate, some of these systems have been able to produce recyclable chemicals:

• Sodium chloride for the chlor-alkali industry
• Calcium chloride crystals (dihydrate) or solution for the chemical industry
• Sodium sulphate mixtures for the chemical industry