Water for Algiers

The residents of Algiers on average only enjoy two or three hours of potable water each day. The population of Algiers has now swollen to almost 4 million inhabitants, as a result.

To address the rising demand for water, the government has invested in new dams and reservoirs, but frequent droughts and the lack of natural surface and groundwater sources have conspired to ensure that water remains scarce in the country, which has no permanent rivers and where 95% of land is arid.

Efforts have also been made to upgrade the ageing water distribution network in the capital, cutting losses from 40% of the total water produced to 25% .

Nevertheless, the residents of Algiers on average still only enjoy two or three hours of potable water each day, and sometimes only receive water once every three days.

But that is all set to change with the startup of the new Hamma desalination plant.

The facility is one of a number of desalination units set to come onstream over the next couple of years as part of the Algerian government’s drive to tap into the drought-proof supply of water offered by the Mediterranean Sea and the country’s 1200 km coastline.

Hamma planning

The Algerian Energy Company (AEC) launched the tender process for the Hamma desalination plant in 2002.

The project was offered on a build-own-operate basis, with a 25-year operating term. Ionics (subsequently bought by GE) was awarded the project in October 2003.
 

The Hamma Water Desalination Company was set up to run the project, with GE Ionics owning a 70% shareholding and AEC taking the remainder.

The Overseas Private Investment Company, which helps US firms invest in new and emerging markets, agreed to provide US $200 million in financing for the project. This funding was confirmed in January 2005.

Orascom Construction Industries and Belgium’s BESIX were jointly given the EPC contract, worth US $189 million.

A brownfield site east of the Port of Algiers was chosen as the location for the plant, due to its proximity to the city’s water distribution network, power grid and transportation links.

The site was surrounded by a major motorway to the south, the coastline to the north, industrial facilities to the east and main port to the west.

UK environmental engineering consultancy Metoc carried out the environmental impact assessment.

Hamma technology

The Hamma plant is fed open intake Mediterranean seawater with a salinity of 38-40 grams per litre and a temperature of 15-27 degrees Celsius.

The system is designed to handle any variations in the quality of the feedwater, which might be caused by the nearby port. The facility draws seawater through two 550 m intake pipes to a pre-treatment system.

Here, the seawater enters a lamella clarifier and has coagulants added to help remove suspended solids.

After flocculation and settling, the water passes through a dual media filter and on into a clearwell.

Water from the clearwell is then pumped through five-micron catridge filters before being distributed among nine trains of single pass reverse osmosis membranes.
 

Of these trains, eight will run permanently and one will be on standby. The largest train will have a capacity of 25100 m3 per day.

Each train has a dedicated high-pressure pump, a booster pump and an array of 32 ERI pressure exchangers to ensure maximum energy recovery.

The high-pressure pumps have a design capacity of 1084 m3 per hour, while the booster pumps operate at 1351 m3 per hour.

Brine is discharged from the pressure exchanger units at 0.7 bar for transfer back to the sea via the outfall pipe.

In the post-treatment phase, the water is remineralised and disinfected before being sent out via three pumps into the city’s water distribution system.

The finished water is guaranteed to meet the following standards: total dissolved solids of less than 500 mg/l; alkalinity of up to 65 ppm; total hardness of 50-65 ppm; and a pH measurement of 8-8.5.

The plant is designed to work at a membrane recovery rate of 40-44.5% and has a daily production capacity of 200000 m3 or 53 million gallons of potable water.

The facility supplies water to 1.5 million residents, meeting 25% of Algiers’ water needs. The cost of the project was US $250 million. The total construction period was 24 months.

The Hamma plant is the largest seawater desalination facility in Africa and the second biggest in the world.

It was officially opened on February 25 by Algerian president Abdelaziz Bouteflika.

Speaking at the ceremony, GE’s president and CEO Jeff Garwood commented: “The Hamma desalination plant is a great example of how private and public partnerships can help solve urgent water needs.”