CBC consulting has been approached to investigate the potential for deployment of a waterless sewerage and sanitation system. These systems are known by various names, the most common being a “composting toilet” or UDD toilets (Urine Diversion Dehydration)
In recent years, several commercial compost-toilet systems have begun to compete with and replace conventional water closets in high-use public facilities. There they have found a market because of their resilience and the environmental advantages of not discharging pollutants into the environment.
2. What is a Waterless Toilet?
Waterless toilets can be used as an alternative or addition to existing systems and have been designed specifically for deployment in areas where traditional water borne sewerage solutions are not available or where other sanitary solutions such as soak pits and “French” drains are not feasible .Reasons for traditional alternative sewerage solutions being disregarded can be listed as follows :
Severe ground conditions ( Rock or clay ) which prevent effective drainage
Maintenance is often non existent and often entails the use if chemical agents which can be detrimental to the environment as well as residents
Odours and flies present health hazards
Seepage into ground water systems
3. How does a waterless toilet work
Composting toilet systems (sometimes called biological toilets, dry toilets and waterless toilets) contain and control the composting of excrement, toilet paper, carbon additive, and, optionally, food wastes. Unlike a septic system a composting toilet system relies on unsaturated conditions (material cannot be fully immersed in water), where aerobic bacteria and fungi break down wastes, just as they do in a yard waste composter. Sized and operated properly, a composting toilet breaks down waste to 10 to 30 percent of its original volume. The resulting end-product is a stable soil-like material called “humus,” which can be used as a very effective, natural fertilizer
The primary objective of the composting toilet system is to contain, immobilize or destroy organisms that cause human disease (pathogens), thereby reducing the risk of human infection to acceptable levels without contaminating the immediate or distant environment and harming its inhabitants.
There are various types of composting toilet:
Continuous composting toilets – these have a single container beneath the toilet where waste is held for up to a year until it has decomposed and can be used as compost.
Batch composting – these have two or more containers, one that’s in use while the waste in the other decomposes
UDD toilets (urine-diversion dehydrating)UDD Toilets have 2 sections ; 1 for urine and another for faeces. UDD toilets have hardly any odour, because faeces can dry out better if not mixed with urine and water. Urine can be dissipated using a conventional soak pit methodology or can be stored in a sealed container for removal
The main components of a waterless toilet are:
a composting reactor connected to one or more dry or micro-flush toilets;
a screened exhaust system (often fan-forced) to remove odours, carbon dioxide, water vapour, and the by-products of aerobic decomposition;
a means of ventilation to provide oxygen (aeration) for the aerobic organisms in the composter;
a means of draining and managing excess liquid and leachate;
process controls, such as mixers, to optimize and manage the process
An Access door for removal of end products
Since there is no water to rinse the bowl how do you prevent “sticking”?
Due to the design and the use of modern non-stick plastics, the human waste falls directly into the processing drum and into the area where the air is extracted. As with any other toilet system, periodic cleaning of the bowl is recommended.
How is the odour contained so that the cabinet is not a stink hole.?
Extractor systems designed to remove odours and speed up the dehydration process effectively eliminate odours.
Extractor systems can be wind turbines, battery or solar powered devices
There are existing organic based treatments which can used to speed up the breakdown process .e.g. Enviro Flow ST has successfully been used in various rural areas for the treatment of pit latrines with good results
Does the system need any maintenance or special treatment?
No special maintenance of the toilet system is required. As with all other toilets it is recommended that the bowl is cleaned regularly with a soft brush and some soap or toilet cleaner.
Obviously depending in volumes some form of removal service will be required
Do I need special chemicals to clean the bowl?
No special chemicals are required and as a rule a small amount of soapy and water can be sued to clean the bowl. Provided the solid waste is not immersed in water the dehydration process will not be hampered
To be determined
We believe that a waterless toilet solution is not only a viable economic enterprise but also has far reaching social upliftment impacts.
We believe that implementing a program will:
Improve the lives of inhabitants of areas where modern waterborne solutions are not available.
Create employment and sustainable business opportunities within developing communities
Facilitate or speed up developments which have been hampered de to a lack of infrastructure and services
Have a positive impact from an environmental and health perspective
We recommend that a pilot project with specific deployment plans and monitoring schemes be set up as soon as possible .
We recommend that UDD type solution would be the most effective in the environments being considered.