Water purification technology has drawn increased attention from investors of late. HaloSource just became the most recent company to receive funding, taking a round of $11.5 million for commercialize its device in the developing world.

HaloSource uses a chemical called bromine to kill microorganisms in water. The bromine is encased in polystyrene beads, which release tiny amounts as water passes over them. Cartridges containing the beads purify about 3,000 liters of water and cost $7 to $10; the initial purchase of the system is $40 to $60, according to an interview John Cook of the Seattle PI had with the company.

Some 250,000 of the units have been distributed in India through a partner, Eureka Forbes. HaloSource is also working in China, Brazil and other countries. However, the company is not yet profitable.

Other water purification systems that seem to be doing well are Purfresh, which recently took a financing round, and then an add-on, for its ozone technology; Miox, which electrolyzes salt to kill microorganisms with sodium and chloride; and Seven Seas, a Caribbean desalination firm that is looking to acquire other companies.

The round HaloSource took included new investors Origo Sino-India and Origo Resource Partners Limited, a private equity firm that invests in China and India. Existing investors that participated included Unilever Technology Ventures, which is under the management of Physic Ventures.