A new diversion system has been developed to prevent runoff from industrial and commercial sites from entering stormwater sewers.
Developed by Fox Environmental Systems of Australia and distributed in the United States by Wastewater Diversion Systems, the equipment diverts contaminants for treatment, preventing them from entering the stormwater system and subsequent waterways.
Installation of an automatic diversion system has proven a cost effective method of preventing contamination of the stormwater system. The Fox systems are manufactured as self-contained units. Designed as diversion systems only, their function is to divert contaminated water to a "waste for treatment" outlet and clean water to the stormwater system.
System Components
A range of systems are manufactured to suit applications of all sizes. Base components include a heavy-duty polyethylene collection pit which comes complete with a built-in silt trap and grate. The collection pits are factory-fitted with all required components, including activation valves and a variety of sensors to suit the application.
Spill Control System
The Fox Spill Control System (SCS), is designed to divert contaminant spills including fuels and hydrocarbons, oils and non-soluble contaminants that float on water. The stormwater outlet from the SCS units' collection pit is near the bottom of the pit so that floating contaminants will not enter the storm sewer. The SCS unit is available with additional features including a stormwater shut-off valve and secondary bund valve option if required.
A pollution sensor, fitted to the inside of the pit, monitors the water. If the volume of hydrocarbons or other contaminants exceed the predetermined acceptable limit, the system's control station switches into alarm mode. The alarm can connect to existing monitoring systems, to activate procedures in a spill.
To prevent hydrocarbons from becoming trapped in the collection pit, the system has been designed to open the diversion valve and empty the pit at programmed intervals. The pollution sensor is automatically cleaned with high pressure water each time the diversion valve is opened, maximizing sensitivity and efficiency.
Constant Monitoring System
Specifically designed to monitor the levels of soluble contaminants in water, the Fox Constant Monitoring System (CMS), continually monitors storm runoff water for contaminants. The CMS unit detects a wide range of pollutants including acids, alkalines, blood detergents, soluble oils and cleaning agents, making it suitable for a range of applications.
As with the SCS unit, the CMS unit will switch into alarm mode if unacceptable pollutants are detected in the water. When in alarm mode, the standard CMS unit's diversion valve will open automatically, diverting flow of water to the "waste for treatment" outlet, thereby preventing the contaminated water from entering the stormwater system. The CMS also can be configured to activate any number of actions, including the automatic operation of an optional stormwater shut-off valve and/or secondary diversion valves (if fitted), when the system is activated into alarm mode. Both the SCS and CMS units are available with back-up sensor systems for added protection.
First Flush Feature
The Fox systems are available with a "first flush" feature for extra protection. This enables the diversion system to protect the stormwater system from any contaminants that may be washed by rainfall into the collection pit from the surrounding area.
Systems which incorporate the "first flush" feature are fitted with a float switch inside the collection pit. When sufficient rainwater has washed into the collection pit to activate the float switch, the system automatically opens the diversion valve for a flush cycle. With the diversion valve open, the polluted rainfall is released through the "waste for treatment" outlet, preventing any flow of pollutants into the stormwater system. This system is programmed to repeat this flush cycle a set number of times, diverting a predetermined quantity of first flush rainfall, which is calculated based on catchment area and collection pit size. This system is particularly suited for areas polluted with non-detectable pollutants that would normally wash to the stormwater drain during a rain event.
