Dosing

Many different technologies are used in wastewater technology. To achieve optimal results, it may be necessary to condition the wastewater in different ways. The most common additives and their function are listed below.

 

Acid and base

Biological treatment processes work best at neutral pH. In the case of acidic or basic wastewater, pH neutralisation may be necessary. The most common acids are sulphuric acid or hydrochloric acid. Sodium hydroxide is usually used as a base.

 

Flocculants and flocculation aids

Even after biological treatment, colloids are still present in the wastewater. Colloids are very small particles that are not dissolved in the water. Due to their small size, these substances do not sediment and can only be filtered out of the water to a limited extent. Flocculants and flocculation aids form larger particles from the colloids, which ultimately form flocs. These flocs can then be removed by a sand filter or a membrane. Flocculants are also used to improve sludge dewatering. The most common flocculants are milk of lime, ferric chloride and polymer compounds.

 

Nutrients

The organic load present in wastewater is broken down by microorganisms. Nutrients are necessary for bacterial growth. Normally, sufficient nutrients are present in wastewater, but in some cases there may be a nutrient deficiency. Often nitrogen or phosphorus are the limiting components. In this case, nutrients must be added to the system. Nitrogen is usually added as a urea solution and phosphorus as phosphoric acid. If necessary, we provide nutrient solutions tailored to your needs.

 

Defoamer

The continuous injection of air into the wastewater can cause the wastewater to foam under certain circumstances. Especially the presence of surface-active substances (e.g. detergents) can cause excessive foam production. Foam development can also be an indicator of the cultivation of harmful filamentous bacteria in the activated sludge. Excessive foam development makes it difficult to remove the clear water and impairs the clarification performance. Defoamers guarantee a smooth process flow.

 

Disinfectant

Disinfection of the cleaned wastewater at the end of the clarification process kills any organisms present in the wastewater and can guarantee that the water is germ-free. Disinfection can be achieved either by adding a disinfectant (often chlorine dioxide), but the use of UV radiation has also proved effective.