Chemical-Physical Processes for Wastewater Treatment
Without chemical or physical processes, many substances could not be removed from wastewater. Depending on the wastewater’s composition, the process for chemical-physical wastewater treatment comprises several sub-steps. Often efficient solutions can only be achieved by combining those different process steps in the right order.
Processes for Chemical and Physical Water and Wastewater Treatment
If the wastewater contains water-insoluble substances or colloids, for instance, sedimentation, filtration or centrifugal separation become necessary to achieve efficient wastewater treatment. In order to retain solids we employ rakes, strainers or even membrane technology. Depending on the composition of the wastewater, DAS Environmental Expert also utilises flotation, a method using adhesion forces where finest particles are separated by sticking to small air bubbles.
Chemical wastewater treatment alters the chemical water conditions to a degree where harmful substances that are dissolved in the wastewater can be separated more easily. Other options to remove harmful substances from the wastewater are precipitation, ionic exchange, flocculation or UV-treatment.
Mechanical Pre-Treatment to Ensure Peak-Performance
Mechanical pre-cleaning is very important, particularly for municipal wastewater, in order to ensure the efficient functioning of the wastewater technology in the following treatment steps. The pre-cleaning will prevent blockages and damages and thus unnecessary maintenance schedules and superfluous cost. Depending on the level of soiling, drum screens and self-cleaning rakes designed by DAS Environmental Expert are proven procedures for wastewater treatment, before sand and other settable solids are separated in the downstream grit collector.
Wastewater Treatment Using Membrane Technology
Wastewater treatment using membrane technology concentrates and separates soluble and insoluble substances from the wastewater by using pressure. Depending on the method used, such as reverse osmosis, micro, ultra or nano filtration, a membrane with a specific permeability will retain molecules of a particular size.
The various processes can be employed for water treatment, recirculation into the production process and wastewater treatment, whereby ultra filtration is becoming more commonly used for wastewater treatment. There is economic ways to avoid the built-up of blocking coatings on membranes, and this is why ultra filtration, in some cases, is used as a so-called polishing step in addition to pre-existing processes for wastewater treatment.
When retrofitting older, classic wastewater treatment plants, ultra filtration can be added directly after the activated sludge tanks to replace downstream process steps or increase the capacity of biological wastewater treatment. If the wastewater treatment plant, however, needs retrofitting due to increased inflowing biological loads or increased stream volume, DAS Environmental Expert offers space saving solutions for biological wastewater treatment with the TFR technology.
Overview of Separation Processes
|Separation Process||Separation Size [µm]||Molar Mass [Da]||Kind of Particle|
|Reverse Osmosis||0.001 - 0.0001||< 100||Ionogenic|
|Nano filtration||0.01 - 0.001||100 - 1,000||Molecular to macro molecular|
|Ultra Filtration||0.1 - 0.01||1,000 - 500,000||Colloid to macro molecular|
|Micro Filtration||< 0.9||> 500,000||Colloid to dispersed|
The Advantages of Using DAS Environmental Expert Wastewater Technology
- Recovery of materials
- Recycling of process water
- Cost-saving retrofitting of pre-existing plants
- Water conservation