Worldwide demand for water treatment products will increase by 6.4 percent annually, reaching $40 billion by 2011, says a study published this month by the Cleveland-based research firm The Freedonia Group, Inc.

“Advances will be particularly strong in the developing world, with countries such as China and India registering growth more than double the global average,” Freedonia said in a press release announcing the study.

Growth in the developing world will be spurred by, among other reasons, the introduction of municipal water treatment to previously unserved populations, Freedonia said. The company added that water treatment product gains in more established markets such as North America will be due to introduction of new technologies, “including wider use of higher-end membranes in desalination and other applications, specialty chemicals in industrial water treatment, and easier-to-use products for recreational water treatment.”

The study encompasses chemical and non-chemical water treatment products, the company said. It estimates that annual growth rates of the market from 2006 through 2011 will range from 4.0 percent in Western Europe to 9.2 percent in the Asia/Pacific region. Eastern Europe’s estimated growth rate in water treatment products, at 8.6 percent, will be second only to the Asia/Pacific region.

The North American market will grow at a rate of 5.3 percent per year, a figure unchanged from that region’s annual rate in the period 2001-2006, according to Freedonia.