Hydro International has received record-breaking orders for more than 100 of its Downstream Defender® advanced vortex separators which are now being used in an ambitious project to clean up Kuala Lumpur’s river system with stormwater technology.

The innovative vortex separators are being installed at strategic city-centre locations before the outflows of complex network of drains and tributaries discharging into the city’s Klang and Gombak Rivers.  Further significant orders are expected in support of the city’s far-reaching “River of Life” campaign to transform river water quality.

Kuala Lumpur is situated where the Klang and Gombak rivers meet and literally means ‘muddy confluence’. Widespread pollution prompted the Malaysian authorities to launch an ambitious project to improve 110kms of the river into a vibrant and liveable waterfront, moving from its current class III - V status (water quality not suitable for body-contact) to a Class IIb river clean enough for recreational use by the year 2020                      

 (Photo: A cleaned-up water course in Kuala Lumpur into which a Downstream Defender discharges)

Kuala Lumpur has an annual rainfall of nearly 2400mm with peaks up to 280mm in April and November.  Short duration showers can realise 100mm or more in an hour.   Urban Malaysia’s typical storm drainage comprises deep road side drains which discharge into high volume monsoon drains, and eventually into the river.

The tropical Malaysian climate is subject to high flash flow conditions under intense rain storms.  The environment also suffers from large amounts of discarded waste such as polystyrene food trays and other packaging, organic pollutants such as food and cooking oil, as well as hydrocarbons.   After storm events, the heavy load of silt and trash is visually evident in the rivers.

Graeme Fenton, Export Manager for Hydro International explained:

 “Kuala Lumpur has major pollution problems with litter and trash, and also with oils and other hydrocarbons being transported in silts via stormwater into the network of drains and river tributaries which eventually flow in to the River Klang.”

“The Downstream Defender® was originally developed for more temperate US and UK climates.Installed offline in strategic locations, the Downstream Defender® is proving a perfect solution to capturing the large amounts of polluted silts that run off Kuala Lumpur’s highways and for providing “first flush” protection in intense storm conditions.

“In addition to capturing sediments the Downstream Defender® is also effective in trapping the large amounts of floatables, such as  plastic bottles and polystyrene containers .   ” In this context, the ability of the Downstream Defender® to concentrate a range of pollutants to a single, accessible location is ideal. The process of maintenance is eased significantly and all performed at ground level using conventional vacuum truck equipment.”

The technology provides greater pollutant removal and retention in a smaller footprint compared to conventional gravity or simple swirl-type devices. Captured sediments are contained in an isolated storage area. A built-in trap retains oil and floatables. These key features prevent re-entrainment of pollutants even under extreme surcharge conditions.

The orders are the largest ever made for the Downstream Defender® and follow successful trials of the advanced vortex separation technology for the National Hydraulic Research Institute of Malaysia (NAHRIM)[1] .  Conducted by infrastructure and hydrological engineers Weida (M) Bhd,  NAHRIM, the study concluded that the Downstream Defender® is an effective gross pollutant trap which captured and stored nearly all gross pollutants carried in the storm drain over the trial period.

The Downstream Defender® is also an approved technology within the Malaysian government’s Manual Sahran Mesra Alam Malaysia (MSMA) which has placed increased emphasis in Malaysia on the need for stormwater control at or near source, and improve run-off quality.