* expects China rev to grow by 30 percent this year

* expects China order book to grow by 30 percent per year over next few years

*China to account for about 65 percent of total revenue this year, versus 81 percent last year

(Adds details)

By Sophie Taylor

SHANGHAI, March 6 (Reuters) - Singapore-listed water treatment firm Hyflux Ltd  <HYFL.SI>  expects its China revenue to grow by 30 percent this year over last year in the fast-growing market, a senior executive said on Thursday.

China, plagued by water shortages and worsening pollution, is thirsty for more clean water to feed its breakneck economic growth.

Hyflux also expects its order book for China to grow by 30 percent annually over the next several years, Sam Ong, Hyflux's chief financial officer, told Reuters in an interview.

China is expected to make up around 65 percent of the company's total revenue in 2008, compared with 81 percent of its S$192.8 million ($139 million) in revenue in 2007, as its rapidly growing Algeria operations take on a bigger chunk.

"(The China proportion) will go down slightly because we are building a massive desalination plant outside China, but the absolute amount will still be on the up," Ong said.

"The China market will remain the main growth driver for the time being," he added.

Hyflux said last year it had invested in a joint venture to build a desalination plant in Algeria, which is expected to make up 20 percent of revenue this year, he added.

Hyflux had an order book worth S$863 million in 2007.

The "strong order book of S$863 million was largely contributed by the desalination project in Algeria, new municipal projects in China and strong demand for its industrial sales from China's pharmaceutical, pharma and biotechnology sectors," Morgan Stanley analyst Shawn Kim wrote in a research note last week.

"We believe the 2008 outlook for Hyflux remains firm," added Kim, who has an "overweight" rating on the stock.

Hyflux's shares have risen by more than 2 percent so far this year through Wednesday's close, compared with a 16 percent fall in Singapore's benchmark Straits Times Index  <.FTSTI>  .

Hyflux, which has 39 plants in China, competes for projects with Chinese water firms such as China Everbright  <0257.HK>  and Tianjin Capital Environmental  <600874.SS>  , and foreign rivals including Darco Water  <DRWT.SI>  , Bio-Treat Technology  <BIOT.SI>  and Suez SA  <LYOE.PA>  .

"We feel (China) has sustainable growth, and for water, the strategic business for us, we see that the momentum is going up not just in waste water treatment and water recycling, but the desalination market is going to be accelerating," Ong said.

Hyflux has operations in Singapore, Southeast Asia, China, the Middle East, North Africa, and India.

Hyflux, which focuses on second-tier cities in China, has set up a trust based on 13 water treatment plants in China. Hyflux Water Trust  <HYWT.SI>  made its trading debut on Singapore's stock market late last year. JPMorgan  <JPM.N>  was the bookrunner for the deal.

For plant builders such as Hyflux, injecting the completed factories into a trust frees up capital for it to expand elsewhere.

($1=1.387 Singapore Dollar)

(Reporting by Sophie Taylor; editing by Ken Wills)