- August
Posted By : Makhanana Nkhwashu


Brief Technology Description

The DEWdrop is a Decentralised Ecological Wastewater treatment system with modular design that provides convenient harvesting and reuse of domestic greywater. It can recycle up to 400L of greywater per day to a quality suitable for toilet flushing and garden watering – saving up to R5,000/annum.

Next Steps Required

Establish an efficient fabrication process in order to supply the system to hardwares, landscapers and plumbers.

Key Personnel

  • Ross Roberts
  • Jonny Harris
  • Mbongeni Mbabala

Company Background

DEWdrop has been developed as a product by Isidima Design & Development (Pty) Ltd. Check out Isidima website for more Info about the company.

Detailed Technology Description

  • The DEWdrop system uses biological treatment and indigenous plants to produce an ‘on-tap’ supply of recycled water, suitable for toilet flushing and garden watering. There are 5 key aspects to the design:

Collection of greywater

  • Installation by in-house team or certified plumber
  • Convey greywater through 50mm pipework from bathrooms and washing machine to the system

Anaerobic treatment – 1st tank

  • 4 filtration steps with increasing density
  • ‘Up-and-down’ flow between steps extending flow path, reducing flow velocity and preventing short-circuiting
  • Biological media for attached biofilm growth
  • Solids removal and initial COD reduction

Aerobic treatment – 2nd tank

  • Water flows through indigenous wetland plant root zone – high microorganism activity.
  • Multiple biological filter layers provide high surface area for polishing filtration and treatment.
  • Filter media supports plant growth for nutrient uptake as required.
  • Excellent COD reduction.

Temporary storage – 3rd tank

  • ‘floating aquatic system’ of wetland plants suspended above storage zone.
  • Roots grow down into storage zone to provide surface area for final polishing by microorganisms.
  • Aeration, foot valve to pump and float switch built in.

‘on-tap’ supply of recycled water

  • 230V or 12V (solar) pump provides supply of recycled water at 4 bar pressure.
  • Garden tap provided for convenient irrigation when desired: guilt-free gardening.
  • Recycled water connected to secondary cistern inlet to supply toilet for convenient flushing.

Technology Applications

  • Private homes, businesses and education Centers.
  • Modular design allows for scalable system.


14 working systems currently in use .

Testing and Demonstration Results

  • Water quality samples was taken in June 2017.
  • Visual water quality and odour good – attached image of a DEWdrop client flush.
  • User friendliness voluntarily noted by trial households.

Papers and Publications

  • There are no Publications yet

IP Status

Not under any patent yet

website Isidima

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