ECOSOL NET TECH

WATER SENSITIVE URBAN DESIGN & CONSTRUCTED WETLANDS

END-OF-LINE (UP TO 900mm DIAMETER RCP) PRIMARY TREATMENT SOLUTION

The Ecosol Net Tech is a robust and modern filtration system for use where there are cost or space constraints, or specialised cleaning equipment is not available. The Net Tech system is designed to specifically capture and retain large gross pollutants conveyed in stormwater runoff however in practice, it has been found to collect much smaller particles, including fine sediments.

Easily installed, into most drainage networks the unit’s simple design has a unique net release mechanism that eliminates any adverse hydraulic impact traditionally encountered with direct-screening trash racks. It can be installed not only end-off-line at almost any pipe outlet but also in-line where concrete structures such as manholes and junction boxes can house the unit. It is also a cost-effective and efficient pre-screening system for vegetated swales, wetlands, and on-site detention systems.

The Ecosol Net Tech consists of a stainless-steel sleeve extension that is fitted into existing, or new, outlets, and a removable polyethylene net, which, when full of pollutants, disengages during a rain event, effectively eliminating the risk of flooding during peak-flow storm events. The unit is easily cleaned using a small crane truck for lifting the net and emptying the pollutants.

NET TECH KEY FEATURES AND BENEFITS

The original net system with a unique fail safe release mechanism
Easily installed on most stormwater pipes and culverts
Easily maintained by vacuum truck or by crane truck
Efficiently captures and retains gross litter and vegetation
Durable robust product engineered for the environment in which it operates
Cost efficient primary treatment solution.

At Ecosol we can site measure, fabricate, install and maintain your Net Tech system making the whole process seamless.

The Ecosol Net Tech will treat 100% of all flows in both free-draining and submerged environments until the net becomes full and disengages from the main unit, effectively eliminating the potential for flooding. Independent testing has found that the unit has little, or no, impact on the hydraulic performance of the drainage network.

The holding capacity of the Ecosol Net Tech varies with the site specifics, including the outlet type and size. The holding capacity is designed to maximise the life-cost benefit to the asset owner. The unit’s design enables it to achieve its maximum holding capacity without adversely affecting the hydraulic design characteristics of the drainage network.

The following tables show the Ecosol Net Tech dimensions and the holding capacities for typical cylindrical pipe and box culvert outlets.

Ecosol NET TECH DIMENSIONS - CIRCULAR PIPES
Ecosol Net Tech Dimensions Circular Pipes - 2018
Unit CodesPipe Diameter Dimensions
(LxH) (mm)1,2,3
Approximate Unit Weight (Kg)Approximate Maximum
Pollutant Holding Capacity (m3)
Cylindrical Pipe Units
Net Tech 300Minimum 30041Up to 0.180
Net Tech 375Up to 37544Up to 0.208
Net Tech 450Up to 45053Up to 0.420
Net Tech 525Up to 52555Up to 0.570
Net Tech 600Up to 60075Up to 0.760
Net Tech 750Up to 75089Up to 1.210
Net Tech 900Up to 900108Up to 1.780
Ecosol NET TECH DIMENSIONS - BOX CULVERT PIPES
Ecosol Net Tech Dimensions Box Culvert Pipes - 2018
Unit CodesBox Culvert Dimensions
(LxH) (mm)1,2,3
Approximate Unit Weight (Kg)Approximate Maximum
Pollutant Holding Capacity (m3)
Box Culvert Units
Net Tech 300BMinimum 300 x 30045Up to 0.200
Net Tech 375BUp to 375 X 37553Up to 0.330
Net Tech 450BUp to 450 x 45059Up to 0.490
Net Tech 600BUp to 600 x 60075Up to 0.900
Net Tech 750BUp to 750 x 75091Up to 1.350
Net Tech 900BUp to 900 x 900108Up to 2.000

Notes

  1. The pipe diameters listed are internal pipe diameters
  2. The box culvert lengths (also commonly known as culvert span) and heights refer to the internal dimensions – box culverts are available at various heights up to the nominated culvert dimension
  3. Dimensions listed are for single units on single inlet pipes or culverts, for multiple inlet pipes or larger units please consult with your local Ecosol representative.

The Ecosol Net Tech will treat 100% of all flows in both free-draining and submerged environments until the net becomes full and disengages from the main unit, effectively eliminating the potential for flooding. Independent testing has found that the unit has little, or no, impact on the hydraulic performance of the drainage network.

The table below provide an indicative guide of the products treatable flow rate relevant to pipe sizes and gradient. With an empty filtration net the resistance is negligible and therefore the treatable flow rate is higher. However when the filtration net is full of pollutants and impervious the Treatable flow rate of the unit approaches zero at which point the unique release mechanism will disengage the next thereby enabling full pipe flows to continue without any hydraulic impact.

Treatable flow rate for the Ecosol Net Tech as a function of pipe diameter for a circular outlet conduits.

By-pass Capacity and Headloss

Headloss is defined as the hydraulic energy loss (embodied by the pressure reduction) experienced by the flow through the unit as a function of the flow rate through the unit. Testing by the Urban Water Resources Centre (The University of South Australia) confirmed that the release mechanism is constantly triggered before any significant build-up of pressure behind the filtration net.

In all cases the maximum head recorded was only 54mm above pipe obvert.

In summary independent testing has found that the Ecosol Net Tech has little or no impact on the hydraulic performance of the drainage network. Unlike other in-line or end-of-line systems, the unit’s unique release mechanism ensures there is no obstruction to flows in critical storm events, effectively eliminating the risk of flooding.

In 2002 preliminary performance testing was undertaken by the Urban Water Resources Centre at the University of South Australia to determine the system efficiency in the collection of gross litter and also the operational effectiveness of the release mechanism when full of pollutants.

In 2012 the University of Adelaide (Engtest Civil, Environmental and Mining) completed extensive testing and measurements of the products capture efficiency, hydraulic performance and durability at varying flow rates its and compiled a comprehensive product performance report (Performance Review of the Ecosol Net Guard) reviewing both past and present  field and laboratory testing data.

The results of this extensive product testing and verification phase is summarised in the table below

Ecosol NET TECH CAPTURE EFFICIENCY PERFORMANCE SUMMARY
Ecosol Net Tech Capture Efficiency Performance Summary - 2018
PollutantCapture EfficiencyDetails
Gross Pollutants (GP)93%Capture efficiency of gross pollutants by volume larger than the filtration netting apertures. Standard Netting consists of 50mm or 115mm apertures.
Ecosol NET TECH SEDIMENT COLLECTION EFFICIENCY
Ecosol Net Tech Sediment Collection Efficiency with the 50mm netting - 2018
Particulate Size (Micron)Capture Efficiency
2000 – 600020%
6000 – 1600048%
>16000 90%

In practice and as the filtration net begins to fill with gross litter and vegetation thereby forming a filter media within the net, finer particulate and attached pollutants are also captured.

However it is important to remember that this system has been designed as a cost efficient, easy to maintain primary treatment solution specifically targeting gross pollutants.

One of the key advantages of the Ecosol Net Tech is that a small crane truck can easily lift full filtration net for emptying. This eliminates any risks associated with manually handling captured pollutants. As the Ecosol Net Tech is predominately installed as a dry system there is a reduced likelihood of captured contaminants causing any significant adverse environmental impact or nuisance (such as odours and putrefaction).

The key benefit of this primary treatment device is its low capital cost along with its low ongoing cleaning and maintenance cost.

As with all filtration systems, the Ecosol Net Tech should be cleaned regularly. The cleaning frequency, and the cost, depends heavily on the surrounding environment, the unit’s proximity to a waste facility, its location, and the type of pollution it is designed to capture.

A key benefit of this primary treatment device is its low capital cost along with its low ongoing cleaning and maintenance cost. The Ecosol Net Tech can be easily inspected visually to determine whether it needs cleaning. Ecosol recommends the unit is inspected every two months or after any major rain event to determine if it needs to be cleaned. Cleaning is recommended before the filtration net reaches its capacity and disengages from the conduit, to avoid flows bypassing the unit discharging untreated stormwater to the receiving waterway. The figures below give a broad guideline about the catchment size and the number of cleans required annually.

Ecosol NET TECH CATCHMENT SIZES AND CLEANING FREQUENCIES
Net Tech Catchment Sizes and Cleaning Frequencies Cylindrical Pipes - 2018
Product CodeGross Pollutant
Holding Capacities
Optimal Catchment
Area (Ha)
Recommended Cleaning
Frequency
Cylindrical Pipesm3HaPer Annum
Net Tech 3000.1800.651
Net Tech 3750.2080.751
Net Tech 4500.4201.501
Net Tech 5250.5702.001
Net Tech 6000.7602.701
Net Tech 7501.1204.501
Net Tech 9001.7806.501

Cleaning frequencies are based on typical pollution loads of 0.280m3/ha/year for gross pollutants. Excludes coarse sedimentation typical urban pollutant loads.

Ecosol NET TECH CATCHMENT SIZES AND CLEANING FREQUENCIES
Ecosol Net Tech Catchment Sizes and Cleaning Frequencies Box Culverts - 2018
Product CodeGross Pollutant
Holding Capacities
Optimal Catchment
Area (Ha)
Recommended Cleaning
Frequency
Box Culvertsm3HaPer Annum
Net Tech 300B0.2000.751
Net Tech 375B0.3301.201
Net Tech 450B0.4901.701
Net Tech 600B0.9003.301
Net Tech 750B1.3504.801
Net Tech 900B2.007.201
lvenessEcosol Net Tech