Compost toilets have been around for quit a while and are becoming more and more popular. I will be the first to admit that the sound of a compost toilet does not sound very pleasant, but are a great money saver for the frugal gardener. Compost toilets have made great strides in the effort for using greener methods of living. Green living and frugality have become common lifestyles in today's world where global warming and rising energy costs dominate the news.

Compost ToiletComposting toilets are a great way to not only save on energy costs, but also supply your garden with plenty of rich nutrients. Composting toilets have a rather high start up cost, ranging from around $1,000 to over $3,000 per toilet.

Here is what has to say about the subject.

What Is A Composting Toilet?

Composting toilets are toilet systems which treat human waste by composting and dehydration to produce a usable end-product that is a valuable soil additive.

They come in a variety of models and brand names as well as different shapes and designs to enhance the natural composting process.

They use little or no water, are not connected to expensive sewage systems, cause no environmental damage and produce a valuable resource for gardening.

The systems can be broadly divided into two different types:

Batch Systems

With the batch systems, a container is filled and then replaced with an empty container. The composting process is completed inside the sealed container. The system may have a single, replaceable container. Or it may be a carousel system where 3 or 4 containers are mounted on a carousel and a new container is spun into the toilet area when the other is full. After a full cycle is complete, the first container is fully composted and ready for emptying.

Continual Process Systems

These systems are in a constant state of composting. Waste enters the system, composting reduces the volume and moves it downward where it is harvested after 6-12 months as fully composted material.

All systems are designed to treat the waste material by composting, worm processing, micro- and macro-organism breakdown, and by dehydration and evaporation of moisture.

There are a wide variety of systems including:

  • Owner-built, two chamber mouldering systems that are basic, but effective.
  • Owner-built from concrete blocks and concrete inclined base. Constructed in with the house foundations.
  • Manufactured, small, self-contained and remote systems suitable for vacation and full-time home use.
  • Manufactured, large tank, inclined base models suitable for heavy loadings.
  • Wide variety of small units which fit into existing bathrooms. Many have dehydration fans and heaters.
  • Vacuum flush unit for production of worm castings.
  • Full flush systems with centrifugal action to deposit wastes into composting chamber.
The Benefits of Composting Toilets

The advantages of natural waste treatment systems are many and varied.

The following section shows the benefits of the system in comparison to existing waterborne waste treatment systems. These benefits improve conditions for the individual, the community and the environment.

An understanding of how your system benefits the individual and the community will help you to maintain it and confidently explain it to others.

Benefits to the Individual

There are many great reasons to use a composting toilet!

Water Use Reduction (20-50%)

A significant savings in water storage will result if the household is not on reticulated water supply. Combine this with wastewater re-utilization in irrigation and other household water reduction techniques and water storage costs can be cut by up to 60%.

Shock Loading Capacity

Loading shock for large gatherings is achieved easily with correctly sized composting toilet systems.

Odor Problems Reduced

The suction air flow in most composting toilets takes toilet and bathroom odor out of the room and acts like a constant extraction fan.

Lower Household Maintenance Costs

Sewage rates and water rates (metered) can be in the order of $500 per year, a significant cost. This will only increase if the demand for sewage system upgrading increases. Other on-site systems have annual maintenance costs that are obligatory. Local authorities will be increasingly paying rebates to households who own composting toilets.

End Product Recycled

While only small in amount, the solid end product is a valuable humic fertilizer that can be utilized around trees and gardens.

Reduced Greywater Loading

Where composting toilets are installed instead of septic and mini-treatment systems, there is a large reduction in the "loading" on the effluent treatment system by the removal of "blackwater." Smaller, less maintenance, greywater systems are possible.


A household with a composting system is independent from potential problems of the waterborne sewage system. If future water shortage or system backup problems occur with conventional systems, there is not much that you can do personally about it. On-site composting systems are much more flexible, they are easier to fix and have less damage potential if operated incorrectly.


The composting toilet possesses the ability to recycle much of your household waste. Food scraps, paper, lawn clippings and grease from you grease traps and greywater systems can be composted back through the toilet. If you choose to put in a reed bed greywater systems, the annual clippings can also be composted. There is no wastage in this system.

Unusual Sites

Composting toilets can be installed in many different situations which would not accommodate other systems. Rocky sites, high water table, no water storage, environmentally sensitive, close to running watercourses, and swampy ground. All these difficult site situations can be accommodated with a small amount of alteration to the basic system design.

Benefits to the Community & the Environment

Together with the personal benefits of the composting toilet there are overall benefits to the society and the environment.

Water Use

A reduction in water use allows the large capital costs of dams and reservoirs to be spread over a greater population. It also enables decentralized water sources to be used.

Reduced Marine Pollution

Nutrient load on streams and rivers is almost negligible. This results in more oxygen being available in the water and a return to improved activity of marine life.

Pollution Detected Quickly

Without sewage systems to flush away wastes, It would be easier to ascertain where toxic wastes are being leaked into watercourses. Industry would be more willing to rectify these problems if it were easier to identify the sources.

Damage Limited

Miscalculation in individual composting systems has a much smaller impact than the same mistake in a large centralized system. It is also easier to rectify and return to normal operation.

Flexibility of Planning

Composting toilet systems are built only when the need arises. The high headwork and treatment costs of conventional sewage systems must be borne by the community ahead of development. If development does not go as planned, then money is wasted.

Less Environmental Impact

Compared to sewage systems, on-site composting and greywater treatment has less impact on the environment:
  • Large effluent releases into watercourses and oceans are avoided.
  • Disruption to soils systems through pipeline installation is eliminated.
  • Leakage of raw sewage into groundwater through pipe deterioration and breakage is eliminated.

Flexibility in Estate Planning

By eliminating the planning constraints of the sewage system underground piping and infrastructure, housing developments can be designed with more emphasis on environmental and social considerations, rather than how best to situate the blocks to make pipes run straighter.

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