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Desalination of seawater
 The need of pure water for drinking and process purposes is increasing in step with the technological progress. Numerous places on the globe can only present scanty quantities of ground water, or none at all, which means that pure water has to be carried over long distances or to be produces by desalination of seawater.
 Seawater desalination by means of reverse osmosis has been applied for more than 20 years. The process is primarily used in the parts of the world where natural ground or surface water for drinking water purposes is only present to a limited extent.
For more than 20 years HOH has produced and supplied desalination plants for industries and public water supplies. In order to facilitate installation, many of the water treatment systems af delivered in a container, fully assembled and thoroughly tested. This means that the cost of erecting a separate building for the system is saved and on site costs kept at a minimum
Concept:
By means of so-called "reverse osmosis", the plant can change any kind of water - from a polluted well, river, lake or the sea - into perfect drinking water. The polluted water - or pure salt water from the sea - is forced through a membrane under a heavy pressure, and out comes many thousands of litres of perfect drinking water every day.
The membrane only allows the very smallest water molecules to pass, whereas all other substances such as minerals and bacteria are retained. After treatment, the water is just as pure as distilled water.
Energy recovery
 HOH was the first company to introduce a reverse osmosis plant with built-in energy recovery with an efficiency larger than 95%. When using traditional energy recovery systems, the energy consumption by desalination of seawater (35,000 ppm) is 6 to 7 kWh/m3, whereas HOH is able to guarantee an energy consumption of 3 to 4 kWh/m3. The principle of the energy recovery system is based on a rotor which is capable of making the concentrate press the raw water to the membrane. In this way a very high efficiency is obtained, and thanks to the precision of the rotor, a mixing of raw water and concentrate is avoided.
Click here to see how the energy recovery unit works.
Most of HOH's containerisedRO-plants are equipped with the energy recovery system reducing the energy consumption to the absolute minimum.
The containerised systems are used for supply of water to hotels, camps, island communities, irrigation of golf courses and nursery gardens, industries, building sites and farms.
Referencer
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ABB Alstom, GAZA-PEA, Gaza
Power station 1999
Varying m3/d
Seawater desalination as pre-treatment for electricity works.
Included processes are UF, SWRO, RO and Mixed Bed
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Beachcomber St.
Anne Resort
When the internationally well-known hotel chain Beachcomber decided to build its first hotel outside Mauritius, the beautiful St. Anne Island in the Seychelles was chosen.
The island is located centrally immediately opposite the capital Victoria in Mahe, but having a status as nature reserve the island was inhabited and without water supply.
To obtain the greatest possible security of supplies, a 2-pipe solution with 2nd pass RO was chosen in order to obtain a water quality better than 100 mg/ℓ.
The plant is prepared for extension with a third line which would increase the capacity to 300 m³/day. The plant was commissioned in 2002 prior to the opening of the hotel and contributes to giving the guests of the hotel the highest obtainable water quality.
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Maldives
The government of Maldives in 1992 entered into an agreement with DANIDA about preparing a strategy plan for the water supply in Male’. The strategy plan in 1995 resulted in HOH entering into an agreement with the government of Maldives about supply of a complete water supply and distribution plant for the capital Male’. Furthermore, HOH took on running the water supply company after a so-called BOT-model (Build-, Operate-, Transfer-model).
The water supply plant in Male’ is designed for desalination of seawater by means of reverse osmosis. First phase of the project, which was taken into use in 1996, consisted of a plant with a capacity of 3,500 m3/day. Later on, the plant was extended in stages of another 1,000 m3/day and now has also been enlarged to compass the neighbouring villages Villingili and HulhuMale’. The capacity of the plant in Maldives is now 4,500 m3/24h.
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Indian Ocean Tuna, Seychelles
Since the local water supply in Seychelles could not live up to a constant supply of water of high quality, the tuna factory, Indian Ocean Tuna, appointed the Danish company HOH to be in charge of supplying a constant and stable supply of water. Indian Ocean Tuna is one of the largest companies in Seychelles and is owned by Heinz.
The plant in question is a medium-sized plant capable of supplying up to 1,100 cubic metres of pure, desalinated water around the clock. The contract between Indian Ocean Tuna and HOH includes supply of fresh water to the factory for a period of minimum 5 years. The operating company in Seychelles is formed by a joint venture between the Investment Fund for Markets in Growth, IFV, and HOH Water Technology A/S.
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Desalination of seawater to the Greek island Ios
The plant was supplied in 2001 and consists of a container-based reverse osmosis plant with a capacity of 1000 m3/day
The plant supplies clean drinking water to the inhabitants of the island
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Desalination of seawater to the Greek island Sifnos
The delivery includes 2 plants for desalination of seawater and brackish water respectively. The plants have a capacity of 250 m³/day for seawater and 500 m³/day for brackish water. The plants will be constructed in two 40 foot containers.
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Royal Danish Army Stores Command
In the 90’s HOH supplied a large plant to the American UN troops in Somalia. Besides HOH has, on a regular basis, sold simpler water treatment equipment to the Danish army. Also in connection with international emergency aid operations, e.g. after natural disasters, there will be a need for HOH’s plants. Even if there is only access to seawater or brackish water, HOH will be able to produce drinking water based on the given conditions.
Deficiency of clean water can be a big problem, when Danish soldiers in peace-keeping forces are sent out to the focal points of the world. Often it is to areas, where drinking water is already in short supply, and the problem grows worse due to a ruined infrastructure.
The water problem, however, is solvable by means of Danish technology. HOH Water Technology has supplied two mobile water treatment works to “Hærens Materiel Kommando” (Royal Danish Army Stores Command) to be used by Danish troops sent out under difficult conditions. Both plants have been assigned to the SHIRBRIG force under UN command, which is situated in the UN camp in Eritrea.
The compact plant is installed in two 20' containers that can easily be transported by air, sea or truck, wherever in the world there is a need for it.
The plant consists of pre-treatment with flocculation as well as sand filtration for 14 m3/h. Subsequently the water is led on either to the nano filtration plant or to the seawater plant. The nano filtration plant is capable of producing 100 m3/d clean drinking water from contaminated water from wells, rivers and lakes. The seawater plant is likewise capable of producing 100 m3/d clean drinking water from seawater.
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Copyright HOH Water Technology A/S, Geminivej 24, DK-2670 Greve - tel. +45 43 600 500
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