Why Vermifiltration?

Low cost wastewater treatment for the world


Vermifilters purify wastewater such as sewage. The "filter" is a media substrate such as sawdust, bark or woodchips, maintained by earthworms to remain aerobic and porous. Vermifilters are not just a filter, they are also an incredibly diverse living system made up of worms and microorganisms living in balance, consuming pathogens and organic substances from the water as it passes through the filter. The worms, as caretakers of the system, aerate the media with their burrowing, maintaining the porosity and producing castings (humus), the perfect media additive. 

The process requires virtually no maintenance and being aerobic, is rapid and generates no smell. The purified, odour-free, nutrient rich water is suitable for surface irrigation of crops or pasture. 

Vermifiltration is therefore well suited to both household treatment and also community-based treatment using simplified sewers.


Vermifiltration is a complete wastewater treatment solution producing humus and treated nutrient-rich irrigation water.

Vermifilters aerate wastewater. Aerobic digestion means no sludge and no methane. 

In contrast, septic tanks, dewats and pits all use anaerobic digestion, producing sludge and generating methane. Why is that bad?

The resulting effluent from anaerobic digestion is not of suitable quality for applying to the soil surface, but must instead be diverted to underground soakage fields or pits that contaminate water tables and inevitably fail in time.

Vermifiltration offers aerobic treatment with a difference. Because the effluent is trickled through a natural substrate, efficient aerobic treatment is achieved at low cost.

Find out more about oxygen and wastewater » 

Low cost

A complete household wastewater treatment system

By trickling effluent through a filtration substrate maintained by worms, oxygen naturally dissolves into the water for efficient aerobic treatment to a level suitable for surface irrigation of crops and trees.

In contrast, other on-site aerobic treatment systems use air pumps that blow bubbles into the water, or mechanical stirrers. These are energy intensive and costly to maintain.

Vermifiltration efficiently removes pathogens from effluent at the domestic scale. The result is:

Resources have become too precious to squander.

Find out more about the nutrient cycle »

Flush toilet + greywater

One system to treat all domestic wastewater

Vermifiltration is a complete solution for domestic wastewater, both greywater and blackwater. Flush toilets and vermifiltration work well together, either full flush or low flush.

Construction of treatment plants is simple and the process is easy to understand and can be customised for every application.

If water is available to flush and land is available for irrigating, then vermifiltration is the right wastewater solution.

Please note: there are two situations where vermifiltration is not suitable:

*Dry composting systems such as UDDT's (urine-diverting dry toilets) do not flush, so do not produce wastewater. However, water is required in most households.