Processes
Chemical Dosing
Most water treatment processes need chemical dosing.
In general, membrane pumps at low discharge pressure, and plunger pumps at high discharge pressure.
Examples of metering pumps
- Membrane Pumps
- Plunger Pumps
- Plunger/Membrane Pumps
- Peristaltic Pumps
- Centrifugal Pumps
Flocculation
Flocculation Water treatment by means of Flocculation is a way to remove colloidal particles and organic compound (ex Humics) from the water.
Considerations to optimal flocculation
- Chemicals introduction
- Dose control
- pH-control
- Floc formation
- Floc separation
- Sludge removal
Dissolved Air Flotation (DAF)
Floc separation by flotation means that the floc is forced to the water surface by air and then is skimmed to sewer.
Considerations to optimal floc separation
- Flotation basin dimensions
- Water flow velocity
- Preparation of dispersion water
- Fistribution of dispersion water
Filtration
Filtration means separation of compound in the water than can cause problems. Examples of such compound are:
- Particels (sand, gravel, rust etc)
- Lime (”hard” water)
- Iron (causing brown deposits)
- Manganese (causing black deposits)
- Copper (causing green deposits)
- Organic compound (humus etc causing odor and bad taste)
- Salinity (causing corrosion)
- Bacteria (causing disease)
Often several unwanted compounds are present, and the filtration process must then be performed in steps. Some compound need a preparation prior to filtration. That preparation being chemical precipitation or oxidation.
Types of Filter
Direct Acting Filters. Examples:
- Bow Strainers
- Basket Filters
- Bag Filters
- Cartridge Filters
- Disc Filters
Media Filters, single media or multi media.. Examples:
- Sand Filters
- Activated Carbon Filters
- Alkaline Filters
- Ion Exchange Filters
- Special Media Filters
Media Filters are made as Gravity Filters or as Pressurized Filters.
Media Filters can be performed for manual or automatic back-washing.
Precoat Filters
Filters with elements for ”on-site” coating. Mainly used for condensate polishing.
Ion Exchange Technology
Water treatment by means of Ion Exchange Technology is a well known and used process.
Examples of application
- Softening
- Dealkalization
- Desalination
- Humic reduction
- Nitrate removal
- Heavy metal separation
- Etc.
Membrane Technology
Water treatment by means of Membrane Technology is a way to remove small particles, micro organisms, organic compound and salinity.
All membranes need an accurate pre treatment.
Examples of application
- Micro Filtration (MF)
- Ultra Filtration (UF)
- Nano Filtration (NF)
- Reverse Osmose (RO)
Electro Deionization (EDI)
Electro Deionization (EDI) can be described as a combination of Membrane Technology and Ion Exchange Technology.
The EDI contains Ion Exchange Resin that is continuous regenerated by electricity.
Examples of EDI
There are several types of EDI with different performance and capacity. Most of them are limited in size and must be module connected in parallel for higher capacity.
The most common types are:
- Lamella type (plate and frame)
- Spiral wound
UV Technology
UV Technology is used for disinfection, chorine/chloramine reduction and TOC destruction.
Examples of UV Systems
UV Systems can be performed with:
- Low Pressure Lamps
- Medium Pressure Lamps
- High Pressure Lamps
Most common type for drinking water disinfection are systems with low pressure lamps due to higher efficiency and lower power consumption.
Condensate Polishing
Polishing of condensate is mostly to remove particles and suspended solids.
Condensate Filters are mostly made for high pressure and high temperature.
Examples of Condensate Filters
- Bag Filters
- Cartridge Filters
- Precoat Filters
- Ion Exchange Filters