GB2407102A

GB2407102A - Drainage separator system

Info

Publication number: GB2407102A
Application number: GB0324012A
Authority: GB
Inventors: Quintin Anthony Murfin
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-10-14
Filing date: 2003-10-14
Publication date: 2005-04-20
Anticipated expiration: 2023-10-14
Also published as: GB0324012D0; GB2407102B

Abstract

The system 2 comprises two channels, inner channel 4 and outer channel 3, each with its own outlet 5, 6 respectively. Surface runoff drains into the system 2 from a surrounding paved drainage surface 1. The system comprises a flow control arrangement whereby the runoff can be diverted to one open outfall, the selection of outfall dependent upon the pollutant level of the runoff. Preferably when there is non-polluted runoff control valve 8 in outer channel outlet 6 is opened to dived the runoff towards a surface water disposal point. When pollution is generated in the vicinity of the paved drainage surface 1 control valve 8 is shut and the runoff is permitted to flow into the inner channel, to be discharged via outlet 5 towards treatment. The system may be used to separate drainage flows generated by an outdoor fire fighting aircraft training rig.

Description

- 24071 02

POLLUTED WATER EFFLUENT AND RAINFALL SEPARATING DRAINAGE

SYSTEM

The invention relates to an outdoor trough drainage system that provides the facility for separating flows of polluted water effluent and rainfall at separate times.

Polluted water effluent from industrial activities generally require significant treatment before disposal to the aquatic environment, however rainfall that lands on an outdoor paved area used for an activity may require lesser treatment before disposal to the aquatic environment, both effluents are commonly combined increasing the volumes to be treated significantly.

An object of the invention is to separate the activity generated polluted water effluent and rainfall flows occurring at separate times.

Accordingly, the invention provides two channels in one combined trough with a flow control system that allow the user to select which of two flow disposal routes the effluent is directed to. The invention also can accommodate features such as the separate attenuation of the activity generated polluted water flow within the channel and outfall for that flow.

An application for the invention is for the separation of drainage flows from an outdoor fire fighting aircraft training rig which creates short duration high flows of polluted water and foam effluent (requiring comprehensive treatment before disposal to the aquatic environment) during training and the drainage of relatively long duration lower flow rainfall from the adjoining contributing paved activity area at other times.

A preferred embodiment of the invention will now be described with references to the accompanying drawings in which: FIGURE 1 shows a plan view of the Polluted Water Effluent And Rainfall Separating Drainage System and the adjoining contributing paved drainage area.

FIGURE 2 shows a vertical cross section through the Polluted Water Effluent And Rainfall Separating Drainage System trough and the adjoining contributing paved drainage area.

FIGURE 3 show a vertical long section through the Polluted Water Effluent And Rainfall Separating Drainage System trough and the adjoining contributing paved drainage area.

As shown in Figures 1,2,3 the surrounding Contributing Paved Drainage Area 1 is the area needed to capture the activity polluted water and is laid to falls towards the central Polluted Water Effluent And Rainfall Separating Drainage System 2. Areas beyond the Contributing Paved Drainage Area I do not drain to the system. The Polluted Water Effluent And Rainfall Separating Drainage System 2 is constructed of water retaining materials and components (e.g. reinforced concrete designed to Water Retaining Design Codes and ductile iron pipe fittings).

As shown in Figures 173, during times of no polluted water generating activity (e.g. when there is no fire fighting training) the Outer Channel Outfall Control Valve 8 in Figure 3 is be set open and rainfall generated flows shed from the Contributing Paved Drainage Area 1 into the Polluted Water Effluent And Rainfall Separating Drainage System, entering through the Open Trough Top Or Optional Grating 7 in Figures 2,3 to the Outer Channel 3 and is be directed by the channel to the Outer Channel Outfall 6 in Figures 1,3 which connects to a surface water disposal point (e.g. a watercourse) to which the effluent flows after any appropriate oil separation or other treatment outside of this system. The Outer Channel 3 would be sized by civil engineering open channel flow design formulae to accommodate the peak flow rate for the design rainfall intensity for the location. The Outer Channel 3 may be shaped and laid to falls to the Outer Channel Outfall 6 if required to ensure self-cleansing of any entrained solid materials in the incoming flow. The Inner Channel Outfall Control Valve 9 in Figure 3 may be shut to prevent any rainfall falling into the Inner Channel 4 and extreme storm overtopping flow from the Outer Channel 3 from flowing out the Inner Channel Outfall 5 allowing pumping out of the water to the surface water disposal point if required; if this small element of pollution load were not a concern the Inner Channel Outfall Control Valve 9 could be omitted from the system to have a continuously open Inner Channel Outfall 5.

As shown in Figures 1,2,3 during times of human activity (e.g. fire fighting training on an aircraft rig situated generally above the Effluent And Rainfall Separating Drainage System) the Outer Channel Outfall Control Valve 8 is shut to prevent discharge from the Outer Channel Outfall 6 and the Inner Channel Outfal} Control Valve 9 (if fitted) is opened to allow discharge from the Inner Channel Outfall 5.

Activity generated polluted water effluent flows through the Open Trough Top Or Optional Grating 7 in Figures 2,3 and into the Inner Channel 4, or sheds off the Contributing Paved Drainage Area 1 entering through the Open Trough Top Or Optional Grating 7 into the Outer Channel 3 which fills and overtops into the Inner Channel 4, and discharges out of the Inner Channel Outfall 5 in Figures 1,3 to a treatment process beyond the system. The Inner Channel 4 is sized by civil engineering open channel flow design formulae to accommodate the design peak activity flow and any other factors (e.g. any desired fire fighting foam head volume storage). The Inner Channel 4 and the Inner Channel Outfall 5 may also be sized to store and attenuate peak flows, using hydraulic modelling techniques. The Inner Channel 4 may be shaped and laid to falls to the Outer Channel Outfall 5 if required to ensure self-cleansing of any entrained solid materials in the incoming flow.

On completion of the activity, the Inner Channel Outfall Control Valve 9 (if fitted) is closed to prevent discharge from the Inner Channel 4 and the Outer Channel Outfall Control Valve 8 is opened to allow discharge from the Outer Channel 3. The opening of the Outer Channel Outfall Control Valve 8 may result in a small plug of polluted water effluent laying in the Outer Channel 3 being released from the Outer Channel Outfall 6. Also, any residual surface pollutants that are washed off in the first flush of rainfall flow off the Contributing Paved Drainage Area will result in a plug of polluted water effluent being released from the Outer Channel Outfall 6. These small amounts of pollution for discharge to the surface water receiving waters may be environmentally acceptable and require no special procedure. Alternatively, to further reduce the amount of pollution for discharge to the surface water receiving waters, the Contributing Paved Drainage Area 1 may be washed down (e.g. with fire fighting hoses) to clean most of the activity surface residues from Contributing Paved Drainage Area 1 and to flush out the Outer Channel 3 before the Outer Channel Outfall Control Valve 9 is opened to allow discharge from the Outer Channel 3 of this flow. Another option to achieve a reduction in the amount of pollution for discharge to the surface water receiving waters is to add a switchable (e.g. a shut off valved) piped link from the Outer Channel 3 to the Inner Channel 4, or the Inner Channel Outfall 5, allowing opening for a short release of the plug of water and immediately closing it again before the Outer Channel Outfall Control Valve 8 is opened. The system is then be set again for rainfall only flows as described above.

Claims

1. A Polluted Water Effluent And Rainfall Separating Drainage System consisting of two channels, each with its own outfall, housed in one combined water retaining trough structure serving a contributing paved drainage area with a flow control system that allows the user to select which of two disposal outfalls the effluent flows out, allowing separation of two effluents of differing pollution levels for separate treatment.

2. A Polluted Water Effluent And Rainfall Separating Drainage System as claimed in Claim I which when there is no polluted water generating activity occurring at the facility is set to have the Outer Channel Outfall Control Valve open allowing rainfall flows from a Contributing Paved Drainage Area to flow into the Outer Channel and discharge out of the Outer Channel Outfall for disposal to a surface water disposal point outside of the system.

3. A Polluted Water Effluent And Rainfall Separating Drainage System as claimed in Claiml which when there is polluted water generating activity is set to have the Outer Channel Outfall Control Valve shut and the Inner Channel Outfall Control Valve (if fitted) open allowing human activity generated polluted effluent to flows into the Outer Channel which fills and overtops into the Inner Channel and discharge out of the Inner Channel Outfall for treatment and disposal outside of the system.

4. A Polluted Water Effluent And Rainfall Separating Drainage System claimed in any proceeding claim constructed from water retaining construction materials and components.

5. A Polluted Water Effluent And Rainfall Separating Drainage System as herein described above and illustrated in the accompanying drawings.