Waste water treatment

 

Polluted waste water from PV factories have to be treated according to environmental rules, and can be split in three main streams:

For the polluted process water a WWT system will be installed, making use of the chemical/physical principle. By supplement of coagulation substance micro-flakes will be formed. The supplement of neutralising substances will bring the pH-value up to an acceptable discharge level. The supplement of flocculation substance will take care of originated micro-flakes to agglomerate to macro-flakes.

A WWT system can be executed as a continuous flow system or as a batch system (only for a small waste water amount to be treated).

Basic

A standard continous flow WWT system with polluted water buffer tank, concentrate tank,  neutralisation system, plate clarifier and filter press.

In case of specific processes such as plating etc. specific elements have to be separated from the discharged waste water in a tailor-made WWT system. ProForSol can help you designing and realizing the WWT system, optimized for your factory.

HF/HNO3 acid concentrate  will be collected for external treatment.


Pros and Cons

  • Low start-up costs.
  • Operational shutdown in case of WWT problems.
  • High operational costs due to consumption of neutralisation chemicals.
  • Hard to control Fluoride level on outgoing stream, in case of irregular etch bath dumps during operation.

Regular

Similar to the Basic system with:

  • Separate waste tanks for acidic and alkaline based concentrate water streams. This to get more stability in the discharged waste water stream, concerning the environmental requirements of the element concentrations;
  • Installation of a bigger rinse water tank to guarantee stability in the treated outgoing water stream, concerning the environmental requirements of the element concentrations.
  • Installation of backup pumps for the different system parts.

Pros and Cons

  • A stable WWT process, even in case of irregular etch bath dumps during operation.
  • Environmental requirements concerning element concentrations will always be met.
  • No production shut down in case of technical WWT problems.
  • Minimized operational costs due to neutralisation by means of chemical use of collected waste concentrates.

Premium

Similar to the Regular system combined with a system for reclaim of rinse water to realise a substantial reduction in the use of city water and the discharge of waste water. This system is currently in the testing phase and is showing promising results. For more details see Ongoing Improvements.

Pros and Cons

  • Most sustainable solution using minimal water.
  • Big reduction of costs for watersupply and -discharge.