Water Purification & Filtration

Microfiltration • Ultrafiltration • Reverse Osmosis • Pre-treatment • Disinfection
There are an array of commonly experienced water problems among our various markets:

Whether fed from a municipal source, a borehole, a river, or the ocean, all water supplies contain dissolved mineral salts, microbiological contaminants and other materials. The amounts present determine the final analysis of the water, and ultimately whether the water is suitable for its intended application. In order to provide quality water for domestic and industrial use, the impurities that exceed acceptable levels have to be identified. Water treatment equipment should never be installed without a water analysis.

divider3

Ecotech Africa’s Water Purification and Filtration solutions address common water problems such as:

  • Bacteria and Viruses
  • Fluoride
  • Iron and Manganese
  • Nitrates
  • pH
  • Sodium
  • Sulphates
  • Taste and Odours
  • Total Dissolved Solids
  • Total Hardness

Ecotech Africa has fast and effective Water Purification and Filtration solutions for the following water types:

  • Potable Water
  • Distilled or Demineralised Water
  • Waste Water
  • Potable Water
  • Distilled or Demineralised Water
  • Grey and Black Water
  • Seawater
  • Cooling Water
  • Boiler Feed Water
  • Process Water
  • Service Water

Water Purification & Filtration Methods

Water Purification/Filtration is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water.

The goal is to produce water fit for a specific purpose. Most water is purified for human consumption (drinking water) but water purification systems may also be designed for a variety of other purposes, including meeting the requirements of medical, pharmacology, chemical and industrial applications.

Microfiltration

Microfiltration usually serves as a pre-treatment for other separation processes such as ultrafiltration, and a post-treatment for granular media filtration. The typical particle size used for microfiltration ranges from about 0.1 to 10 μm. In terms of approximate molecular weight these membranes can separate macromolecules generally less than 100,000 g/mol. The filters used in the microfiltration process are specially designed to prevent particles such as, sediment, algae, protozoa or large bacteria from passing through a specially designed filter.

More microscopic, atomic or ionic materials such as water (H2O), monovalent species such as Sodium (Na+) or Chloride (Cl-) ions, dissolved or natural organic matter, and small colloids and viruses will still be able to pass through the filter. Microfiltration usually serves as a pre-treatment for other separation processes such as ultrafiltration, and a post-treatment for granular media filtration. The typical particle size used for microfiltration ranges from about 0.1 to 10 μm. In terms of approximate molecular weight these membranes can separate macromolecules generally less than 100,000 g/mol.

The filters used in the microfiltration process are specially designed to prevent particles such as, sediment, algae, protozoa or large bacteria from passing through a specially designed filter. More microscopic, atomic or ionic materials such as water (H2O), monovalent species such as Sodium (Na+) or Chloride (Cl-) ions, dissolved or natural organic matter, and small colloids and viruses will still be able to pass through the filter.

Ultrafiltration

Ultrafiltration is a membrane filtration process similar to Reverse Osmosis, using hydrostatic pressure to force water through a semi-permeable membrane. Suspended solids and solutes of high molecular weight are retained in the so called retentate, while water and low molecular weight solutes pass through the membrane in the permeate. This separation process is used in industry and research for purifying and concentrating macromolecular solutions, especially protein solutions.  Ultrafiltration is not fundamentally different from microfiltration or nanofiltration except in terms of the size of the molecules it retains – it is defined by the Molecular Weight Cut Off (MWCO) of the membrane used. Common applications for ultra-filtration systems are food & beverage processing, pharmaceutical use, municipal, borehole and surface water treatment.

Reverse Osmosis

Reverse osmosis is a complicated process which uses a membrane under pressure to separate relatively pure water (or other solvent) from a less pure solution.

When two aqueous solutions of different concentrations are separated by a semi-permeable membrane, water passes through the membrane in the direction of the more concentrated solution as a result of osmotic pressure. If enough counter pressure is applied to the concentrated solution to overcome the osmotic pressure, the flow of water will be reversed.

Number 1:

Water molecules can form hydrogen bonds in the reverse osmosis membrane and fit into the membrane matrix. The water molecules that enter the membrane by hydrogen bonding can be pushed through under pressure. Most organic substances with a molecular weight over 100 are sieved out, i.e., oils, pyroxenes and particulates including bacteria and viruses.

Number 2:

Salt ions, on the other hand, are rejected by a mechanism related to the valence of the ion. Ions are repelled by dielectric interactions; ions with higher charges are repelled to a greater distance from the membrane surface. The nominal rejection ratio of common ionic salts is 85 - 98%.

Number 3:

The majority of the commercially manufactured Reverse Osmosis (RO) membranes are usually made from cellulose acetate, polysulfonate, and polyamide. The membrane consists of a skin about 0.25 microns and a support layer about 100 microns. The skin is the active barrier and primarily allows water to pass through.

Number 4:

The amount of dissolved solids in water produced by reverse osmosis is approximately a constant percentage of those in the feed water. For example, when the feed water contains 300 ppm total dissolved solids (TDS), the product water may have 15 to 30 ppm (95% and 90% rejection ratio respectively). A RO system design is based on a certain range of feed water TDS, the percentage of rejection and percentage of recovery desired. For a given system, the higher the percentage of recovery or the lower the percentage of rejection, the poorer the quality of product water becomes.

Ecotech Africa recognises the need

446000
Waste Water (Sewage) Treated (Liter)
369600
Wash bay Effluent Water Recycled (Liters)
51760
Asbestos Safely Removed & Disposed (Kilograms)
21318
Injury Free Hours

Pre-Treatment

Various methods exist for effective pre-treatment.

The objective of pre-treatment is to remove contaminants from raw water that will affect the stability and performance of the main treatment process and to remove contaminants that will affect performance of clients’ main process.

Filtration

Two main types of filter media are employed – surface filter, a solid sieve which traps the solid particles, and a depth filter, a bed of granular material which retains the solid particles as it passes. The first type allows the solid particles, i.e. the residue, to be collected intact; the second type does not permit this. However, the second type is less prone to clogging due to the greater surface area where the particles can be trapped. Also, when the solid particles are very fine, it is often cheaper and easier to discard the contaminated granules than to clean the solid sieve. Filter media can be cleaned by rinsing with solvents or detergents. Alternatively, in engineering applications, such as water treatment plants, they may be cleaned by backwashing. Self-cleaning screen filters utilize point-of-suction backwashing to clean the screen without interrupting system flow.

  • Dual media Filters
  • Multi Media Filters
  • Multi Grade Filters
Filtration Types
  • Surface Filtration
  • Disc Filtration
  • Bag Filters and Strainers
  • Cartridge Filters
  • Depth Filtration

divider3

Coagulation
  • Coagulation is the addition of chemicals to change the properties of these contaminants so they increase in size and can then be removed by flotation, filtration and settling.
  • Coagulation is the process that destabilises the particles by neutralising surface charges and forms micro floc.
  • Flocculation is the aggregation of microflocs into larger aggregates (Flocs)
Flocculation
  • Flocculation is the agglomeration of destabilized particles into a large size floc which can effectively be removed by sedimentation or flotation.
  • Addition of flocculating chemicals may help formation of the floc.

Disinfection vs Sterilization

Disinfection (Large Scale): Selective destruction or inactivation of pathogenic organisms and Sterilization (Small scale): Complete destruction of all organisms.

divider3

Chlorination

The primary purpose of chlorination is to disinfect water before it is used for drinking or other uses. Other purposes of chlorination are taste/odour control, prevention of algae growth, iron/manganese oxidation and destruction of hydrogen sulphide.

Ozone

Ozone is one of the strongest commercially available oxidising agents and is commonly used for the treatment of water in municipal and industrial process applications. The special advantage is in the environmentally friendly way in which it works, without the formation of harmful chlorinated by-products.

divider3

divider3

Flocculation
  • Flocculation is the agglomeration of destabilized particles into a large size floc which can effectively be removed by sedimentation or flotation.
  • Addition of flocculating chemicals may help formation of the floc.

Latest Asbestos Projects

Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam.

MAKE USE OF OUR EXPERTIES

Get your no obligation free quote today!