Ecological Sewage Treatment 

In reality, there is no waste, we just have to find low impact, ecological pathways back to nature or ecological ways to recover useful resources from human and animal excrement

This page explores the treatment of human and animal waste using biological and ecological principles. Some systems recognize the energy and nutrient content in waste and process it to strip out harmful pathogens and extract biogas and nutrients from it while others apply principally use natural biotic systems to treat the waste and purify it, releasing purified water back into the environment.

Living Machines

Living Machines ® are the name of a well known waste treatment system that exploits ecological principles to transform human waste into purified water. It is a series of tanks with:

  • live plants,
  • trees,
  • grasses
  • algae,
  • koi and goldfish,
  • tiny freshwater shrimp,
  • snails,
  • a variety of microorganisms and bacteria

Each tank is a unique mini-ecosystem designed to decompose waste. The decomposition process takes about four days to turn mucky water crystal clear. Compared to conventional waste treatment plant, it is:

  • chemical-free,
  • odor-free,
  • far lower ecological footprint
  • far lower capital cost – no steel and concrete structures

Sewage arrives in a greenhouse containing a series of tanks containing the above flora and fauna- all interacting together as an interlocked system of ecologies. The  Living Machines ®  incorporates processes that occur in the natural world, but is designed to reduce treatment times. The resulting water flowing out of a  Living Machines ® is pure enough to discharge directly into the sea or to be recycled.


Findhorn Ecocommunity Living Machine

World renowned ecologist John Todd on Living Machines

Maharishi Institute Living Machine

Illustration of how Living Machine works

A project with ecologist John Todd: building a Living Machines

Dr. John Tood and Living Machine

Dr. Katja Hansen and the World’s First Bionutrient Recycling System for Waste Treatment


Culturing Sustainability Cookbook
Dr. Katja Hansen co-designed one of the world’s first bionutrient recycling systems which took human and animal waste and use natural biological processes to recover nutrients. She became a founding contributor to the Brazilian NGO “O Instituto Ambiental” which took over the technology and built facilities across Central and South America. Some facilities were built in Haiti where they survived a devastating earthquake and continued purifying water and recycling nutrients when other sanitation systems failed. The technology is now supported by UNEP in Haiti.

Biological treatment of human waste is defined as the natural processes of purification of wastewater with nutrient recycling for reclamation and agricultural and renewable energy (biogas) obtained in the process. Bionutrient recycling is an effective cradle-to-cradle biological treatment methodology that treats human or animal sewage and recovers a maximum amount of nutrients in a way that is healing to the environment. The sewage is filtered through biodigesters and then the treated effluent is dispersed into root zones for “fertigation”.

The effluent flows through digesters and contact filters, oxidation ponds, sedimentation, aeration, fish and macrophytes.

This technology heals the human habitat, adds value to the supply chain and preserves the environment, since the treatment water returns to the river in the state of bathing without contamination risks to nature.

  1. Step 1 The sewage produced is collected and taken to the biodigester closest to the residences.
  2. Step 2 The sludge is periodically removed, dried in the sun and used as organic fertilizer.
  3. Step 3 The gas is used in the kitchen of the Community Centres where the biosystem was deployed.
  4. Step 4 The water flows into the recycling station nutrients settling tanks with aeration and oxygenation green algae
  5. Step 5 In the next step, water passes through blades subtle, flowing into the fish tank where they grow tambacús, pacu, curimatãs, tilapia and follows gravity to the tanks macrophyte

Where there is constructed tanks, a biological filter is installed after the housing compensation digester, followed by the root zone by evaporation filtering and consume most of the effluent

Advantages of digesters:

  • Totally waterproof;
  • Cleaning the digester every 5 years on average: The material can be used as manure after drying in the sun for 30 days.
  • Cost: Although the higher initial cost, maintenance-free and generates nutrients and bio-gas.
  • It can be integrated into the landscaping is complete with lakes of aquatic plants and fish.
  • Its effluent can be utilized in irrigation ferti infiltration in roots.
  • It has approval from environmental agencies.

Digesters are airtight and equipment used to treat organic waste. Are able to reduce up to 70% organic matter and therefore are coupled to biofilters that increase their ability to remove organic load, reaching 90% efficiency. The digesters have three stages of fermentation: acidogenic, and methanogenic acetogênica. This latter is responsible for the production of biogas, a mixture of methane and carbon can be used as a heat source, fuel and energy. The resulting biosolids these fermentation processes is of high nutritional value for the plants and the liquid effluent generated can be used for drip irrigation and cultivation in general.Dr. Katja Hansen, senior researcher at the Rotterdam School of Management, Erasmus University co-designed, constructed and scientifically tested one of the world’s first bionutrient recycling systems presented at the 1992 UNCED Rio Earth Summit. From 1992 to 1998 she was the scientific and project director of an EU funded project for bionutrient recycling in Brazil and China. The pilot projects demonstrated safe and highly productive re-use of nutrients from effluent, generating clean water as a byproduct.

Figure 1: Digester construction (Source: O Instituto Ambiental)

Biomatrix is the Rushlight 2010 award winner for ecological innovation in water treatment and innovation. The Biomatrix system fuses a combination of engineering and natural ecological system design that results in a system capable of treating human waste  which does not involve any concrete or steel structural construction and hence has a very low carbon footprint and very competitive with traditional waste treatment plants. The biomatrix technology was employed to design a living machine to treat human waste at the world famous Findhorn ecocommunity. The facility was opened on October 1995 and was designed to treat sewage from up to 500 people living at the ecovillage.

Biomatrix Water is based at Findhorn and the founding partners of the Biomatrix Water team have over two decades of experience designing and delivering ecological engineering projects for the treatment and recycling of municipal and industrial wastewater and bioremediation. The design approach applies current best practice in modern wastewater treatment and process control with the latest developments in ecological engineering. The resulting research shows that the wise use of modern materials, biomimicry, and design innovation, provide an effective solution to the problems of urban water pollution and aquatic habitat degradation.

Biomatrix focuses its ecological systems in two areas:

  1. River restoration
  2. Human waste treatment

1. River Restoration System

Engineered floating ecology designed to optimize powerful ecological treatment processes within an attractive feature of the aquatic landscape.  The Biomatrix combines the latest developments in ecological engineering with new biofilm research and traditional wastewater treatment processes.  Whole system engineered ecologies provide an energy efficient, low life cycle cost treatment solution.

Biomatrix design for river restoration of heavily populated and polluted rivers in Manilla, Phillipines
Biomatrix systems are ideally suited for contaminated canals, rivers, lakes and reservoirs; as well as providing effective treatment of high strength waste in purpose built lagoons and treatment cells.

  • improve water clarity
  • remove and stabilize nutrients
  • reduce algae
  • breakdown industrial chemicals
  • remove biological/chemical oxygen demand
  • filter out suspended solids/particulate
  • Biomatrix Islands have a durable design and efficient construction
  • islands are a fraction of the cost of comparative systems
  • main system components can be manufactured off-site allowing large Biomatrix systems to arrive on construction site with all of the main components ready for assembly/ installation
  • systems designed in sections & configurable in attractive natural shapes
  • can be designed to blend with the existing waterscape in strategic locations where performance can be optimized
  • system can be configured along the edge of the waterway, or centrally as islands or archipelagos


Figure 2: A floating Biomatrix Island in the middle of a waterway (Source: Biomatrix)

The floating Biomatrix island provides the foundation and for diverse lifeforms from the phylogenetic kingdoms including:

  • bacteria,
  • fungi,
  • algae,
  • protozoa,
  • annelids,
  • mollusks,
  • insects,
  • vertebrates (including frogs and turtles),
  • higher plants

This carefully crafted multitude of life forms creates an ecology that rapidly and effectively treats wastes, pathogens and toxins. The basic technological and scientific principles employed in the Biomatrix design are well established principles in the scientific and engineering literature and the system is subject to ongoing scientific review.

Figure 2: Before and after pictures of rivers treated with the Biomatrix active island reactor

Download the active island reactor floating water treatment system brochure here.

2. Human Waste Treatment

The Biomatrix system treats human waste up to municipal waste scale and exists in two forms:

  1. pond based
  2. land based

2.1 Pond-based Water Treatment


The Biomatrix Cascade is an on-site wastewater treatment system, which combines the latest developments in ecological engineering with traditional wastewater treatment processes.  Its  key innovation is a floating platform system which provides a substrate for planted ecologies, specialized attached growth treatment media. This matrix provides an artificial home for aquatic life forms to thrive by metabolizing and removing nutrients from the waste stream.

Cost Effective Treatment
  1. capital and operational cast of a Biomatrix is competitive with conventional wastewater treatment technologies
  2. use of modular and easy to install systems and reduced construction time. are a key feature of the cost saving advantages
  3. operation is straightforward and can be adjusted to influent variations, either manually or automatically
  4. complex ecologies which provide the principle treatment are self-organizing and require minimal maintenance, reducing O&M costs and providing excellent value from construction to operation
The Process
  1. Biomatrix technology supports a robust diversity of biological treatment processes
  2. root zones of the higher plants play a central role in the process and provide a  live substrate attached growth treatment surfaces
  3. biofilms on the substrate of a Biomatrix contain a greater number of treatment process and wider range of conditions than in traditional treatment systems
  4. this  facilitates more efficient performance and less energy requirements than a conventional system
Minimal Sludge Production
  1. Biomatrix processes with relatively long hydraulic retention times produce minimal amounts of sludge
  2. biomass in the root zone is grazed from the root surfaces and treatment media before it sloughs off
  3. this causes the energy from the wastewater to be driven up the food chain
  4. instead of generating sludge, the food energy eventually exits the wastewater system as the products of metabolism (CO2 and H2O)
Features Summary
  • system components are manufactured off-site and delivered by truck in easy to assemble modular sections, minimize construction time and allow a highly cost competitive and treatment solution
  • suitable for applications ranging from under 10m3/day to over 5000m3/day
  • Biomatrix incorporates attractive ecological features and can be a key component in a sustainable water management plan
  • components of the system form a complex matrix of biological reactions and treatment processes
  • the system is a robust, ecologically engineered treatment solution
  • Biomatrix harnesses the complex power of nature to provide effective treatment of BOD, COD, TSS, nutrients and pathogens
  • efficient system with minimal sludge production

Figure 3: Biomatrix Cascade system architecture  (Source: Biomatrix)

  1. headworks designed according to the specific characteristics of the waste stream
  2. components can include screening, degritting and dissolved air flotation

  1. anaerobic, anoxic ad aerobic treatment occurs in the first stages of the system
  2. biologicial phosphorous removal and denitrification take place in these stages
  3. untreated incoming wastewater provides the necessary carbon for the denitrification process

  1. aerobic treatment occurs in a series of two to five aerobic reactors
  2. BOD and COD removal and nitrification occurs in the aerobic phase

  1. clarification stage – bacterial flocs and sloughed biofilms are precipitated
  2. settled sludge is recycled to inoculate the incoming waste and excess sludge is removed for sludge treatment
  3. clarified supernatant passes to polishing and disinfection

  1. polishing is provided as an optional step where high levels of treatment are required for reuse
  2. polishing options include micro-filtration and sand filtration

  1. disinfection is provided as an optional step where effluent is to be used for landscape irrigation or toilet flushing
  1. modular design of the Biomatrix system provides a cost competitive solution for wastewater treatment
  2. suitable for industrial, municipal, and food and beverage processing sites
  3. flows range in scale from medium sized development to high volume municipal or industrial application
  4. construction time is measured in weeks rather than months because the system does not require a building or concrete super structure

Staged Flexibility

  • key advantage of the Biomatrix cascade is its flexibility
  • sectional modular design with movable baffles and variable hydraulic retention in each stage make this system attractive for applications with phased loading, or an extended time scale


  • Biomatrix Cascade can upgrade existing treatment plants
  • flexibility of the system allows for prefabricated treatment islands to be added to existing lagoons and/or tanks



(Source: Biomatrix)