The CSF 2000 Undershot Filter is designed to improve the management of combined sewer and stormwater flows during heavy rain events when the drainage network becomes overloaded and causes flows to discharge untreated into our waterways.

Unlike many available systems the CSF 2000 does not require a capture silo to hold screenings (see here for definition), instead using its truly-revolutionary non-blocking attributes to filter the screenings greater than 2.5mm prior to discharge to the waterway and allowing for the transportation of the pollutant-laden continuation flow to the sewage treatment plant (STP).

The CSF 2000 does this with unique breakthrough technology - a static non-blocking filter mesh, along with revolutionary new use of hydraulics, to ensure the screen does not require cleaning. Even troublesome toilet paper does not block the screen. Unlike other systems, the CSF 2000 filters down to 2.5mm, operates in all catchments and does not block under any circumstance.

The CSF 2000 is installed in-line on existing sewage lines upstream of a combined sewer overflow outlet or on the overflow line itself. It can be customised to suit different requirements based on flow, gradient and pipe sizes.

The unit meets or exceeds all accepted industry standards and guidelines for management of combined sewer overflows, and has been independently tested. Click here to view results.

Read more below about the CSF 2000 and how it works or use the specifying form to provide us with details about your project so that we can provide you with a quote.

Operation

The CSF 2000 Undershot Filter is designed specifically for use in combined sewer overflows, sanitary sewer overflows (SSOs), and also STPs. The key to its success is the intelligent use of hydraulics to optimise a new, proprietary mesh that filters raw sewage and combined sewage and stormwater flows.

The unit is installed directly in-line and remains inactive in dry weather flows, without any hydraulic impact on the network. In wet weather events, once the water in the pipe rises to critical levels, the unit treats the excess flows, which are then discharged to the waterway under free-flowing conditions, without the need for any pumping. Screenings greater than 2.5mm remain in the pipe, and along with the remaining flow, pass forward to the STP.

The flow rate at which the unit begins to treat incoming flows is determined by site hydraulics and by the maximum flow that the downstream system or STP can carry before overloading. One of the key features of the CSF 2000 is that it effectively acts as a pass-forward flow concentrator. This eliminates the need to store screenings and then pump into the pass forward flow when the rain event ends, a common failing with CSO filtration systems.

The unit also has an overflow by-pass that operates when the incoming flows exceed the designed pass-forward/spill flow ratio, effectively eliminating the risk of flooding. In line with accepted environmental agency guidelines, these excess flows discharge through the spill flow outlet untreated.

As the screening mesh never blocks it does not need to be cleaned. However, we recommend the screen is inspected regularly in the first year after commissioning to determine if it needs de-scaling, which will help preserve its life and ensure that the unit continues to operate at maximum efficiency.

Pollutant Removal Efficiency

Typical pollutants that the unit separates from the spill flow are:

Pollutants	Efficiency	Description
Litter	80 - 100%	Anthropogenic material such as cans, bottles, plastic bags and packing materials (generally > 5mm in diameter)
Vegetation	80 - 100%	Organic material, such as leaves and grass clippings
Coarse Sediment	80 - 100%	Solid materials of varying size (generally > 0.5mm) both mineral and organic
Fine Sediment	80 - 100%	Fine sand (generally < 0.1mm median diameter), both mineral and organic
Screenings	80 - 100%	Faecal matter, toilet tissue, condoms, sanitary pads etc.
Free oils and grease	40 - 60%	Free floating oils that do not emulsify in aqueous solution, such as cooking and motor oil
Nutrients (N & P)	40 - 60%	Total phosphorous and total nitrogen
Attached Pollutants	40 - 60%	Generally attached to fine sediments. Includes nutrients, heavy metals, toxicants, and hydrocarbons
Dissolved Pollutants	40 - 60%	Includes nutrients, metals, and salts, etc.

The defining advantages of the CSF 2000 are that it:

	Filters all screenings greater than 2.5mm
	Is a truly non-blocking screen that operates efficiently and continuously in all conditions
	Effectively eliminates flooding risk owing to its fail-safe bypass overflow
	Has minimal head/hydraulic loss
	Does not store the pollutants and so there is no need to pump forward the captured pollutants to the STP
	Reduces significantly the need for ongoing cleaning and
	Has no moving parts and does not need any power to run the unit, reducing whole-of-life costs

These advantages make the CSF 2000 so different and more effective than other comparable units available today in managing combined sewer overflows.

For more details about the CSF 2000 please consult our technical specification.
Download it here (538Kb, PDF).

To seek a quote or for advice for your project please complete the specifying form or contact your nearest office.