Flue Gas Desulfurization (FGD) Wastewater Treatment

Flue gas treatment contains different methods and scrubbing processes. Commonly used wet scrubber systems generates wastewater which contains high concentrations of ions with scaling potential, heavy metals, TSS and ammonia. This waste water stream needs to be treated before disposal and may even be re-used as process water. The treatment of waste water streams of flue gas desulfurization plants  becomes inevitable for countries where Zero Liquid Discharge (ZLD) treatment for the wastewater is required because of stricter regulations.

The composition of the FGD waste water stream is affected by the capacity of the boiler, the efficiency of the fly ash removal and the gypsum dewatering  system in case limestone forced oxidation (LSFO) is performed.

FGD wastewater treatment is challenging due to its particular properties:

• High concentrations of heavy metals, which can vary depending on the used coal
• High concentrations of suspended particles and dissolved solids
• Super saturated in sulphates
• High organic concentration due to chemicals added in the boiler
• High ammonia (NH4+) concentrations
• High temperature

Due to the complexity of the waste water, different stages are needed for the treated of the FGD blow down, in order to make it suitable for reuse or discharge in the environment.

Figure 1 – Example of a typical process diagram of a FGD process with complete near zero liquid discharge (ZLD) solution.

  Gypsum Cake

Effluent from SO2 absorber  is equalized and clarified to remove suspended solids.  treated with several chemicals to precipitate saturated components (CaSO4) as well as heavy metals, to prevent downstream equipment.

After clarification, waste water can be further treated with technologies which will polish the water and make it suitable for reuse as process water. Our solutions include a different range of technologies which allow to work at high temperatures, allowing to purify the waste water with energy reuse.

Contact Lenntech for the assessment of your FGD  waste water.  Lenntech provides sustainable and complete solutions for FGD waste water treatment and reuse considering a wide range of technologies and strategies. With worldwide growing water demand and water scarcity, our solutions are suitable for reducing cooling tower operational costs and water footprint.

Our solutions include a different range of technologies which allow to work at high temperatures, allowing to purify the waste water with energy reuse.

Our advantages

• Engineered and custom designed solutions
• Turn-key solutions including design, engineering, manufacturing, automation, installation, maintenance and training.
• State-of-art technologies for effective water and wastewater treatment, recycling, reuse, and disposal.
• Best on-line assistance and on-site service and support.