Israel’s Mapal Green Energy this week closed a deal with Britain’s largest water provider, Thames Water, to provide its bubble aeration technology water purification system for use in municipal and regional water supply systems. In the first stage of the deal, Mapal will set up a purification system in the city of Chesham, north of London. Later on, Thames Water will have the option of adding more Mapal systems to its network, as the water provider moves forward in its long-term project of replacing old and outmoded purification systems.
That expansion could see Mapal systems installed in London and its suburbs where Thames Water has some 15 million customers. Joint research by Mapal and Thames has shown that the water company could save as much as 15 million pounds a year by using Mapal’s technology.
In a Mapal system, bubbles – water infused with air — are used to clean water as part of aeration systems, and are considered very effective in removing pollutants and separating sludge from water, which can then be treated and released back into the environment. Among water professionals, bubbles are considered one of the more effective ways of treating sewage and water suffering from industrial pollution.
Bubble purification systems haven’t been popular, however, because they are generally limited for use in smaller, manmade pools and lagoons. In addition, they often require a lot of energy to run. But new technology from Mapal addresses those problems, allowing far wider deployment of aeration systems at a lower cost.
In a bubble purification system, a machine pumps oxygen into wastewater to enhance “aerobic digestion,” a bacterial process occurring in the presence of oxygen, in which bacteria consume organic matter and convert it into carbon dioxide, which is them released into the atmosphere.
But traditional aeration systems have limitations. In order to get the bubbles to all parts of the wastewater, water utilities have relied on mechanical aeration (large machines that are stationary or mobile that make bubbles by agitating the water) or jet aeration (jets pushing air into the water). Both are expensive to run, requiring large amounts of energy to diffuse the air into the water; in addition, jet aeration, while a little cheaper, is suitable only for small concrete-lined pools or lagoons.
Mapal’s system solves all these problems, according to company CEO Ze’ev Fisher. Mapal’s idea is to use floating aerators that “travel” across the surface of the water, diffusing oxygen throughout the pool (up to a depth of six meters). Unlike with floating mechanical diffusers, the Mapal version has a series of tubes that extend into the water, requiring far less energy to push the oxygen into the lower depths of the water. Thus, the oxygen gets to all parts of the wastewater, ensuring that aerobic digestion can occur equally in all parts of the pool. Because the tubes can get to all parts of the wastewater, the system doesn’t need as much energy to push the oxygen out.
According to studies cited by the company, its system can save as much as 70% of the energy used with other diffusion systems, as well as 80% of maintenance costs.
Mapal systems have been installed in Israel, as well as in Brazil, South Africa and India. Last June, the company announced its first European contract, closing a deal with the UK’s Anglian Water to deploy its solution for a water company serving 4 million customers. Mapal’s bubble-spreaders will be installed in as many as 400 of Anglian’s 1,100 wastewater treatment facilities. Now, with the Thames contract, said Fisher, the company hopes that other European water companies will conclude that Mapal’s system can do the large-scale water treatment they need, while saving them significant sums of money.
“Energy costs have a major factor in the expenses to run a wastewater treatment plant, because of the pressure on governments to cut budgets wherever possible,” said Fisher. “We believe that Mapal’s has the solution for effective water purification at a better price.”