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Enviroberm is a compost based filtration system applied directly on-site as a singular or series of berms. Placed perpendicular to sheet flow, the berm is used to trap sediment and other contaminates, slow sheet flow and control erosion on sloped sites.

This organic alternative can be used in place of standard sediment and erosion control tools such as traditional silt fences. Trapezoidal in cross section, the berm provides a three-dimensional filter with solid ground contact that traps and retains sediment.

 

Design Parameters and Specifications

The organic compounds in the berm form an interlocking matrix that capture pollutants such as suspended solids, metals, oil, and grease while allowing the filtered water to flow through into catchment systems.

Enviroberm is composed of engineered compost using a variety of inputs, including municipal green waste containing food residuals, municipal biomass, agricultural biosolids, and manure. All organic compound used must be pasteurised to NZ 4554.

Once site works are complete, unvegetated berms may be deconstructed and the compost spread around the site.

Application

As a general guide, berms are installed parallel to the base of the slope or perpendicular to sheet-flow 300 mm high by 600 mm wide. On elongated slopes and steeper gradients, subsequent berms shall be constructed at intervals to interrupt the slope and channel sheet flow.

Enviroberm™ as an organic remedial solution is most often left in-situ as a permanent filter, blending with the natural landscape. If permanent vegetative cover is required, seeding will take place at time of installation for establishment of a stabilising cover crop or a native seed mix. The engineer or landscape ecologist will specify seed requirements if eco sourcing is required.

Advantages

  • Can bind and absorb many common pollutants such as excess nitrates, phosphorus, heavy metals and hydrocarbons

  •  Trapping and removal of sediment

  • Useful in environmentally sensitive areas

  • Can be specifically seeded with native plant species with known phytoremediation properties to assist with nitrate removal from runoff to increase filtration ability close to natural water bodies

  • Can be inoculated with mycorrhizal fungi specifically beneficial to permanent vegetative cover

  •  Lower or no removal costs - disposal by dispersion and decomposition rather than by landfill

  • Slows and disperses storm water on sloping ground

  • Can be used on slopes up to 2:1 gradient

  • No trenching required

Guidelines

Environmental Uses

The distribution of particle sizes in the Enviroberm™ filter suspended solids and retain more sediment than standard perimeter control methods such as silt fences or hay bale barriers.

This compost matrix can absorb up to five times its weight in water which helps prevent and reduce rill erosion and provides an ideal growing medium for establishing vegetation on the berm.

Enviroberm™ vegetation can be specifically designed to absorb nitrates and is suitable for application along riparian margins.

Environmental Benefits

  • Binds and absorbs phosphorus, heavy metals and hydrocarbons
  • Trapping and removal of sediment and pollutants
  • Useful in environmentally sensitive areas
  • Can be specifically seeded with nitrate filtering native species to increase filtration ability close to natural water bodies and;
  • Can be inoculated with mycorrhizal specifically beneficial to permanent vegetative cover
  • Disposal by dispersion and decomposition rather than by landfill


Image below middle shows Silt Fence sedimentation and inefficiency at preventing water filtration.

 

 

Organic compounds derived from the composting process incorporated into Enviroberm™ retain pollutants, such as heavy metals, nitrogen, phosphorus, oil and grease, fuel, herbicides, and pesticides.

Enviroberm™ vegetation can be specifically designed to absorb nitrates and is suitable for application along riparian margins.

Nutrients and hydrocarbons adsorbed and/or trapped by Enviroberm™ can be recycled and decomposed through bioremediation rather than going into a landfill.

Image below right shows Enviroberm™ 2017 Port Hills successful sediment catchment and filtration.

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