Chemical waste water treatment
pH-adjustment and neutralization
To influence the solubility of some components of the solution or to start a special reaction the pH of waste water can be adjusted by adding acids or bases.
Depending on the qualities of the wastewater and the treatment process it may be necessary to adjust the pH in order to protect parts of the facility.
Precipitation and flocculation
Precipitation may occur if the concentration of a certain compound exceeds its solubility limit. It is triggered by adding precipitation agents or by adapting the pH of the waste water.
Another option is to add a coagulant to a waste water to give colloids the chance to coagulate and thereby to form micro flocks. To attain flocks with larger diameter a flocculant (organic polymere) may be added.
Bigger flocks are easier to remove in a physical treatment step than micro flocks or colloids.
Dissolved air flotation reactor (DAF)
Disinfection
If required wastewater may be disinfected prior to discharging it into the sewage conduit. Therefore chlorous chemicals may be added – especially in the Central American countries.
Depending on the characteristics of the wastewater and the objective of the treatment (e.g. reuse) other disinfection technologies (UV, ozone, electrochemical disinfection) may be beneficial.