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About Us

Hydrex Asia Limited was found in 1977 in Hong Kong by Mr. Joseph Rahmanan, an American as a private water and wastewater treatment engineering company.


Joseph was educated in the United States and obtained his Master Degrees in Chemical Engineering and Business Administration before he started his career in water and wastewater treatment with a leading multi-national water treatment company. He had served that company for 20 years. From an sales engineer in the headquarter to a managing director of the Asian Regional Office in Hong Kong for his last 8 years of service.


Hydrex’s philosophy is to bring the advanced water and wastewater treatment technologies to Asia, further refine them to suit the demand of the developing counties in this region. System reliability and equipment quality assurance are the prime factors in all Hydrex’s design, engineering and construction activities. Hydrex set up its own quality control assurance system and control procedures in 1978 by Alfred Leung (Joseph’s successor since 2001) and consistently maintain and improve such control systems. Therefore, many multi-national companies or quality conscious organizations become Hydrex long-term clients.


The hundreds of advanced water and wastewater treatment plants installed by Hydrex and in efficient operation for many years are proof of our leadership in this area. Please refer Company Profile  for reference.

Our office is located in Hong Kong

One of the most dynamic, advanced and duty free cities

You are welcome to visit us!

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