Wastewater Management at the Taman Petanu Eco Neighborhood
Why is waste water management so important?

Contaminated waste water is the leading cause of disease worldwide, cholera, dysentery, diarrhea, dehydration are all results of poor waste water management. Water, river and ocean pollution is contributing to loss of biodiversity worldwide and turning tourists away from Bali. Polluted water damages ecosystems and causes degradation of rivers, lakes, oceans and ground water.

Meanwhile human "waste products' such as urine and feces are actually important resources, that, when properly managed, can help to rehabilitate soil and "feed" our environment (and even us as we produce enough nutrients per year to grow the food we need for that same year!). An average human with a protein rich diet produces 1.2 liters of urine and 0.14 kg of feces per day. Those with vegetarian diets tend to produce 1.03 liters of urine and 0.4 kg of feces per day. The residents of Taman Petanu combined with create something along the lines of the following resources:

This page covers some of the simple eco-logical solutions that are being developed for the neighborhood to:

  • Optimize environmentally sound use of water at the neighborhood
  • Optimize practices that work with, rather than against, natural elements
  • Convert ‘human wastes’ into valuable resources on site
  • Increase the natural productivity of the site
  • Revegetate and enhance biodiversity on and around the site
  • Create a living model of sound wastewater treatment practices in Bali / Indonesia

What are Constructed Wetlands?
Constructed wetlands (here of Wastewater Gardens® (WWG) design) are an ecological low-cost beautiful solution for effective sewage and waste water treatment that mimics a natural wetland (called the "kidneys" of the earth for their role of purifying the Earth's hydrological cycle), highly productive and important ecosystems (such as coral reefs in the ocean or tropical forest on the land). Constructed wetlands enable to return nutrients and create green zones at no extra cost by treating and recycling residential sewage, while protecting the groundwater and preventing water contamination. Constructed wetlands are increasingly being acknowledged by public health officials as far more effective, affordable & long lasting than conventional (high tech) sewage treatment, particularly in remote areas and tropical zones such as Indonesia. Applications for Wastewater Gardens are for houses, businesses and communities. A constructed wetland can either treat blackwater (water containing fecal matter with or without urine) and/or greywater (laundry, dishwashing, and bathing water), although greywater doesn't justify the strength of treatment provided by a constructed wetland.

Constructed wetlands of WWG design treat black water in three stages: 
    • In the initial stage (step 1 below) liquids and solids are separated in a conventional, watertight septic tank.
    • In the second stage (step 2 below), the waste water from the septic tank, which is rich in nutrients, is fed into a water-proof lined, subsurface flow wetland. The sewage water is kept below the surface of a bed of clean gravel, which is planted with a variety of selected wetland plants.
    • The final stage (step 3 below) is called the leach drain, a beautiful garden, where the nutrients in the wast water supports plants, trees, shrubs and greenscapes.

In the second and final stage plants, microbes, sunlight and gravity transform wastewater into beautiful gardens and reusable water.

What are the advantages of Waste Water Gardens®?
    • Systems can be made that rely completely on gravity-flow, eliminating the need for pumps and electricity. 
    • Turns what was previously “waste” into green plants and reusable water. 
    • Wastewater Gradens® technology has been reviewed by the U.S. EPA & European Health authorities, and meets their wastewater treatment standards. 
    • Fecal coliform bacteria can be reduced by more than 99%, without the use of expensive, environmentally harmful chemicals like chlorine. 
    • Biochemical Oxygen Demand (BOD) is usually reduced 85-90% from influent levels, and removal of nitrogen and phosphorus can be substantial. 
    • Wastewater Gardens® are low-cost, low-tech & long-lived. 
    • Maintenance requirements are simple. 
    • There are no odors as the sewage is kept from contact with the air. 
    • There is no mosquito-breeding or other nuisances associated with open wastewater systems, such as sewage lagoons or surface-flow wetlands. 
    • The possibility of accidental contact with the sewage is eliminated (unless someone deliberately digs into the wetland gravel). 
    • Wastewater Gardens® systems are capable of extremely high rates of wastewater cleaning. In research over the past several decades, this type of system, even in its earlier design forms, has a well-documented track record of consistently cleaning water to levels better than municipal standards for wastewater treatment. The intensity of treatment is such that only 1/5 the area is required compared to a surface-flow wetland. Every particle of gravel becomes colonized by the natural variety of microbes that are effective in utilizing and treating wastewater, and root systems and water/nutrient uptake of the plants increase treatment efficiency. 
A few examples of established Wastewater Gardens projects on Bali (courtesy of Wastewater Gradens International).


For more information about Wastewater Gardens® go to the official Wastewater Gardens® website.

Here are some of the toilet fixtures that the neighborhood is currently researching:

What are Compost Toilets?

A compost toilet is a waterless or dry or, i.e. one that doesn’t use water to take the waste somewhere else; it relies on natural processes to produce useful compost, providing nutrient material for gardens. There are usually two chambers – one in use and one resting. A classic compost toilet would use one chamber for a year, then change to the second chamber and allow the first to decompose for a year before emptying. 

Compost toilets do not smell, as long as there is a vent pipe, and a drain for excess liquid. A handful of carbon material used as a 'soak” (rice straw or sawdust etc) is dropped into the toilet after each use. The “soak” also serves to allow oxygen and absorbs liquid in to the waste. Human pathogens don’t like conditions outside the human body, almost all will be dead after a few hours. It is a small risk though it is recommended to use compost from toilets on fruit trees and bushes and recreational gardens, and compost from organic kitchen for vegetable gardens.

What are the advantages of Compost Toilets?
    • Solid waste is dealt with on site
    • Low cost, low tech solution
    • No chemicals treatments in sewage farms
    • Waste does not end up in waterways
    • Water saving does not use a precious resource (water to be rid of another useful resource (organic fertilizer)
    • Organic matter returns to the earth, improving soil and nutrition, creating fertile land 
    • No chemicals or bleaches are used in the toilet
    • Does not add to the sewage that is often dumped in landfill’s, rivers, oceans or agricultural land
    • There are no greenhouse gas emissions as if the decomposition is aerobic,
    • No electricity is needed
    • There is no mosquito-breeding or other nuisances 
    • Very low resource use – no pipes are needed to transport waste to a sewage farm, and no truck needed to remove solid waste

Please feel free to download this document that explains the design plans for water management at the Taman Petanu Eco Neighborhood, including:
  • Rainwater harvesting
  • Water resource management
  • The neighborhood's water channeling paths
  • The Natural swimming pool
  • Black and Grey Water Treatment
For more complete information about the neighborhood's water and earthworks management plans please feel free to download this detailed document 'Taman Petanu Permaculture Water and Earthworks'.

Special thanks to Jeremiah Kidd, San Isidro Permaculture • Florence Catting of Wastewater Gardens International, and Dan and Aaron from Permaculture Solutions for their invaluable inputs on these plans.