ENWA Process

Ultra Violet Disinfection

The use of UV light is an effective solution for disinfecting drinking water.

What are UV light and UV-C light?

Ultraviolet radiation (UV light) is present in the electromagnetic light spectrum with shorter wavelengths than visible light; wavelengths, λ ≈ 100-400 nm.

UV-C rays are characterised by wavelengths between 100-280 nm. The optimal wavelength for disinfection is in the range 250 – 270 nm, of which UV-C rays at 254 nm have the highest bactericidal effect. Our UV system has a radiant energy of > 40,000 (μWs / cm2)

Why is UV light used to purify water?

UV-C radiation penetrates an organism’s cell wall and destroys the cell’s ability to reproduce, by deactivating the cell’s genetic material (DNA and RNA), leading to cell death.

In a UV disinfection system, the UV-C rays are produced by special fluorescent tubes made of very pure quartz that contain mercury vapor. These gas mixtures containing mercury vapor emit light in the wavelength range that deactivate microorganisms. The disinfection efficiency of a UV system is determined by the UV dose (D). The UV dose is determined based on UV radiation (I); Intensity of UV-C radiation (strongly affected by water quality) and irradiation time (t); the time the microorganisms are exposed to the radiation (D = I xt).

A UV disinfection system should be able to give the water a UV dose that is sufficient to reduce the most common microorganisms in the water such as, chlorine-resistant bacteria Cryptosporidium and Giardia). UV disinfection systems should have a minimum UV dose of 300 J/ m2 (30mJ / cm2).

ENWA UV disinfection systems have a physical and non-chemical working principle and no harmful by-products are generated. The systems have low-pressure lamps (LP) that emit UV-C radiation with a wavelength of 254 nm, of which the disinfection efficiency is the highest. There are customised solutions for LSOH – Low Smoke Zero Halogen for specialist requirements.

Our UV systems are designed for easy installation, service and maintenance with applications within private, municipal and industrial water, and are food and drinking water approved. Our EPW series is  WRAS approved.

Advantages of ENWA’s UV range

  • Cost effective: Simple and time efficient for service and maintenance.
  • Effective: Immediate disinfection effect (microbial barrier).
  • Environmentally friendly: No chemicals are added or consumed.
  • Safe: No risk of overdose and change in water chemistry.

Softeners and softening water

The softening material (ion exchanger) is a polymer-based synthetic resin product that is capable of absorbing hardness-forming salts (ions) such as calcium and magnesium from an aqueous solution and at the same time release the same amount of sodium ions to the solution.

This chemical reaction is reversible.  After the softening material is saturated with ions, in this case calcium and magnesium, the material is returned to its original state by a regeneration with brine solution. The calcium and magnesium are purged and replaced with sodium ions. The ion exchanger is them primed and ready to start the softening process again.

  • Filter tank in Stainless Steel or composite material rated to 10 bar
  • Valve housing is in brass and / or Noryl.
  • Time-controlled or water meter-controlled;
  • Time-controlled and volume-controlled, respectively. The timed automatics can be set to regenerate every day to every twelfth day. Liquid-affected parts are made of completely corrosion-resistant materials.
  • The water meter-controlled automation starts a regeneration when the pre-set water volume has passed the filter. The connection between the water meter and the meter is mechanical or electrical. The automation is located centrally on top of the filter.
  • The automation is centrally located. The automation is operated with 24V / 50-60Hz
  • Single / Duplex models. Duplex allow continuous softening through the regeneration cycle.

Suitable for industries, small and medium-sized municipal waterworks, hospital, and laundries, residential properties and maritime use.  For potable water, process water and softening for fill water to Medium Temperature Hot water systems (MTHW) or to Low Temperature Hot Water (LTHW) systems in hard water area to reduce potential scaling risk. Contact us to get the right technical solution for your areas water quality and your application.

Desalination plants with reverse osmosis

We offer reverse osmosis desalination plants to produce drinking water, technical water and water injection by desalinating and purifying seawater, brackish water and fresh water.

We deliver for onshore applications within communities, industry and shipyards. With applications in fishing vessels, cruise liners, super yachts, shipping in general and offshore platforms. We can provide technical solutions using our standard ‘off the shelf’ range as well as customised desalination plants.

Filtration spectrum

What is reverse osmosis?

The word osmosis is Greek and means ‘pressure shock’ and it is the ability of liquids and solutes to penetrate a semi permeable membrane. Osmosis takes place when two solutions of different concentration are on each side of a membrane. The more concentrated solution always draws the water from the weaker one until the same concentration is reached on both sides of the membrane.

Osmosis is used to separate different substances and with the help of technology this process can be reversed. By increasing the pressure of the “contaminated” liquid, the water is forced through our synthetic, semi-permeable membranes, separating the smallest particles (molecules and ions) from the pure water molecules.
A major advantage of reverse osmosis water filters is that no chemicals are added during the ‘Purification’ process. The membranes are mounted in a pressure vessel called a ‘Module’.

Before water is desalinated within the membranes, it must be free of chlorine, iron, aluminium, silicic acid, particles, organic and biological contaminants, etc etc. It is therefore, vitally important for the raw water to be ‘Pre-treated’ before it passes through the reverse osmosis system.

The pre-treatment is intended to reduce particles and contaminants that would otherwise damage the membranes, clog the pipelines, or damage the high-pressure pump.

How does reverse osmosis work?

A raw water pump is required to raise the raw water pressure before it enters the filter. The water is then passed through a pre-filter (which removes smaller particles) and then through a high-pressure pump. This increases the pressure of the raw water so that it exceeds the ‘osmotic pressure’, before the water is desalinated in the membranes.

It is important that the water has the right working pressure. Otherwise, the pump may stop working. There is therefore a pressure switch in front of the pump which stops the system automatically if the pressure is too low.

After the RO module, the water is discharged into two streams, desalinated and salt concentrate water (Brine). The brine continues directly to the drain. The purified water passes through a cell that measures the conductivity and if this is too high, the water automatically drains through a 3-way solenoid valve.