Removal of pollutants from primary waters
Metis Water has the most advanced technologies for sand filtration, deferrization, softening, metal removal on zeolite, and organic matter removal on activated carbon.
The plants, designed to the customer's specific needs, can handle flow rates from 1 to 1000 m3/h.
Sand filtration
Sand filtration is a technology widely used to remove suspended solids in water. The water passes through a bed consisting of layers of sand of different particle sizes.
Sand filters come in different sizes and materials and are available in two types, one fully manually operated and one fully automatic type.
Once clogged, the sand filter requires proper washing. Washing is carried out in countercurrent (a current of water flows through the sand bed in the opposite direction to that of filtration, removing and discharging particles deposited on the filter bed).
The 'removal efficiency of suspended solids is very high for particles having a particle size of 50 microns or more. For smaller particle sizes, removal methodologies based on micrometer-type filter cartridges are used.
The main applications for sand filtration are as follows:
Deferrization
Deferrization units are commonly used for the removal of iron from water. The technology used is very similar to that of sand filtration. The filter bed consists of a mixture of quartz sand and manganese dioxide, which acts as a catalyst for iron oxidation. In order to achieve high iron removal efficiency, it is necessary for the water entering the deferrization filter to have a pH above 7.5. Iron removal is also facilitated by a dosage of an oxidizing agent (such as, for example, sodium hypochlorite) injected upstream of the deferrifier.
Sand filtration is a technology widely used to remove suspended solids in water. The water passes through a bed consisting of layers of sand of different particle sizes.
Sand filters come in different sizes and materials and are available in two types, one fully manually operated and one fully automatic type.
Once clogged, the sand filter requires proper washing. Washing is carried out in countercurrent (a current of water flows through the sand bed in the opposite direction to that of filtration, removing and discharging particles deposited on the filter bed).
The 'removal efficiency of suspended solids is very high for particles having a particle size of 50 microns or more. For smaller particle sizes, removal methodologies based on micrometer-type filter cartridges are used.
The main applications for sand filtration are as follows:
- Final treatment of wastewater leaving treatment plants
- Filtration of drinking water, surface water and swimming pools
- Pre-treatment for reverse osmosis plants
Deferrization
Deferrization units are commonly used for the removal of iron from water. The technology used is very similar to that of sand filtration. The filter bed consists of a mixture of quartz sand and manganese dioxide, which acts as a catalyst for iron oxidation. In order to achieve high iron removal efficiency, it is necessary for the water entering the deferrization filter to have a pH above 7.5. Iron removal is also facilitated by a dosage of an oxidizing agent (such as, for example, sodium hypochlorite) injected upstream of the deferrifier.
Filtration on filter cartridges
Cartridge filtration systems are the most effective and economical solution in all applications where the suspended solids content in water is less than 80-100 PPM. Cartridge filtration is also very useful as a finishing stage to be installed downstream of sand filtration.
There are two main types of cartridges available:
1. Polypropylene wire-wound cartridges
2. Melt blown polypropylene cartridges.
The former, in the face of a lower filtration efficiency (75% nominal removal efficiency on particles greater than or equal to 50 microns), have a very low price, and are suitable for treatments that do not require "hard" removal of suspended solids.
The second ones, for a higher purchase cost, offer a much higher filtration efficiency, achieving a much higher degree of filtration (50 to 0.6 microns, depending on the required filtration cutoff) and an efficiency that can reach 99 percent. Melt blown cartridges are generally used as pretreatment (downstream of sand filters) on reverse osmosis plants.
Industrial softening
Water is the raw material in most industrial processes.
Raw water is usually taken from the public mains or from wells, and contains chemical elements, such as calcium and magnesium, which determine its hardness and create scaling in hydraulic circuits. At temperatures above 40°C, precipitation of calcium and magnesium salts creates scaling in pipes, greatly reduces the heat exchange efficiency of boilers and heating coils.
High water hardness also has the consequence in industrial laundries of making it difficult to dissolve soap (hindering foam formation) and results in high use of softeners.
It is therefore apparent that raw water conditioning results in significant management savings in industrial processes.
Water conditioning can be carried out average softening treatments.
Ion exchange water softening, that is, the removal of calcium and magnesium encrusting salts, is a well-established process found in multiple civil and industrial fields.
Cartridge filtration systems are the most effective and economical solution in all applications where the suspended solids content in water is less than 80-100 PPM. Cartridge filtration is also very useful as a finishing stage to be installed downstream of sand filtration.
There are two main types of cartridges available:
1. Polypropylene wire-wound cartridges
2. Melt blown polypropylene cartridges.
The former, in the face of a lower filtration efficiency (75% nominal removal efficiency on particles greater than or equal to 50 microns), have a very low price, and are suitable for treatments that do not require "hard" removal of suspended solids.
The second ones, for a higher purchase cost, offer a much higher filtration efficiency, achieving a much higher degree of filtration (50 to 0.6 microns, depending on the required filtration cutoff) and an efficiency that can reach 99 percent. Melt blown cartridges are generally used as pretreatment (downstream of sand filters) on reverse osmosis plants.
Industrial softening
Water is the raw material in most industrial processes.
Raw water is usually taken from the public mains or from wells, and contains chemical elements, such as calcium and magnesium, which determine its hardness and create scaling in hydraulic circuits. At temperatures above 40°C, precipitation of calcium and magnesium salts creates scaling in pipes, greatly reduces the heat exchange efficiency of boilers and heating coils.
High water hardness also has the consequence in industrial laundries of making it difficult to dissolve soap (hindering foam formation) and results in high use of softeners.
It is therefore apparent that raw water conditioning results in significant management savings in industrial processes.
Water conditioning can be carried out average softening treatments.
Ion exchange water softening, that is, the removal of calcium and magnesium encrusting salts, is a well-established process found in multiple civil and industrial fields.
How it works:
Calcium and magnesium ions, contained in the water, are absorbed by special resins with which the system is equipped, and give up sodium ions that do not give rise to hardness problems.
The resins, over time, exhaust their exchange capacity. It is necessary, therefore to "regenerate" them by performing a series of washes of the resins with water and a saturated solution of water and salt called "brine." All regeneration operations are performed automatically by the softener, except, of course, for the discharge of salt inside the brine vat.
Regeneration of the exchanger resins is normally performed on a time or volume basis. When the preset time expires or the preset volume of treated water is reached, the softener automatically performs a regeneration cycle.
Advantages
The advantages of the ion exchange softening system can be summarized as follows:
Calcium and magnesium ions, contained in the water, are absorbed by special resins with which the system is equipped, and give up sodium ions that do not give rise to hardness problems.
The resins, over time, exhaust their exchange capacity. It is necessary, therefore to "regenerate" them by performing a series of washes of the resins with water and a saturated solution of water and salt called "brine." All regeneration operations are performed automatically by the softener, except, of course, for the discharge of salt inside the brine vat.
Regeneration of the exchanger resins is normally performed on a time or volume basis. When the preset time expires or the preset volume of treated water is reached, the softener automatically performs a regeneration cycle.
Advantages
The advantages of the ion exchange softening system can be summarized as follows:
- technology that has been established for many years
- low purchase and installation costs