Dry Toilet Systems

Dry toilets - a modern solution for an old problem

SANITATION and efficient water usage are closely linked, especially in an arid country such as Namibia.
Therefore alternative technologies and approaches are required, for example, to prevent the generation of effluent as a first option. Another requirement is to get rid of the bucket system, which is unhygienic and expensive to maintain. In cases where sewer systems have been constructed, the treatment and re-use of water and its by-products has to be considered. At the same time affordability is an essential issue in the delivery of services for service providers and the consumers (Wienecke 2007:2).

According to sources, 98 percent of urban and 80 percent of rural inhabitants of Namibia have access to safe water. About a third of the population has access to waterborne sanitation in particular in urban areas. Treatment of wastewater is usually done by means of oxidation dams. The exception is Windhoek, where effluent is treated to produce potable water. Outside the capital numerous problems have been identified in operating this system, such as high costs, maintenance, and scarce resources. To overcome these constraints, alternative approaches and technologies were devised, among them ecological sanitation (EcoSan).
 
EcoSan - the concept
The concept behind ecological sanitation (EcoSan) is that sanitation problems could be solved more efficiently, if the resources contained in excreta and wastewater were recovered and used rather than discharged into the water bodies and the surrounding environment.

The end-of-pipe sanitary systems that are used today are based on the modern misconception that human excreta are simply wastes with no useful purpose and must be disposed of.

Ecological sanitation is a new paradigm in sanitation that recognises human waste and water from households not as waste but as resources that can be recovered, treated where necessary and safely used again.
Ideally, ecological sanitation systems enable a complete recovery of nutrients in household wastewater and their reuse in agriculture. In this way, they help preserve soil fertility and safeguard long-term food security, whilst minimising the consumption and pollution of water resources.
The dried faecal matter obtained from an ecological sanitation system, has soil improvement qualities and increases water retention capabilities. It is a fertilizer, compost material or source of energy, for example, when used in a biogas digester. The wastewater can be utilised as fertilizer, potable water and gas production.

A further development of the dry sanitation system is the urine diversion toilet system (UDS). The principles promoted include the recycling of resources, lowers water consumption, substitution of chemical fertilizers, and is much more cost efficient and affordable. Due to the low volume, a UDS is collecting urine separately. Urine has a very high proportion of natural nutrients and can be directly applied to plants, as it contains about 90% of the total nitrogen, 55% of the total phosphorus, and a proportion of potassium contained in human excrement (Lienert & Larsen 2003:892).

Effluent or waste water are in essence resources, which can be utilized for a variety of purposes, such as fertilizer, gas production, and potable water. The dried faeces obtained from an EcoSan system have soil improvement qualities and increases water retention capabilities. It is a fertilizer, compost material or source of energy, for example, when used in a biogas digester.

In Kimberley, South Africa, a project is providing urine to farmers in the vicinity. They utilise this resource as fertiliser. The separation has another advantage: it considerably reduces odours emanating from the toilet compared to a unit where all residues are collected in one container. Gumbo et al. (2002:1) point out:
“The principal nutrients (Phosphorus and Nitrogen) flow in a circular, closed loop system in nature, but we perceive of nutrients in a linear, open-ended system. The danger is that once one closed loop system is opened, it may force open other closed loop systems elsewhere in the ecosystem (Esrey).
Short-cutting or closing P-cycles in the urban environment is closely related to closing of water cycles”.

The Sun Dome
The modern solution for an old problem
The sun dome uses the urine diversion toilet system (UDS). With this the excrement stays inside the drum that is buried below the surface.

The most economical waterless environment-friendly pit latrine!
It is ideal for farm and rural housing.

How it works...
Facing north, the black dome absorbs heat from the sun. This creates internal hot air to rise and escape through the vent pipe, and to draw fresh air in through the toilet seat and inflow air pipes.
This process creates a ‘circular’ air flow that removes smells; evaporate liquid and dry solid matter.
The whole system is contained to avoid polluting underground water and the environment. Decomposition inside the tank takes place through natural bacteria. The tank may need to be emptied after four to six years of use.

Advantages over a Pit Latrine:
The Sun Dome is installed within a few hours.
The Sun Dome contains the waste within the tank.
Pit Latrines also collapse. This is not possible with the Sun Dome.
The Sun Dome, due to the urine diversion does not smell.

The Sun Dome has been installed in many countries with different environmental conditions.
Users are ecstatic and can only give positive feedback with regards to all the advantages.
It is sustainable with a positive carbon footprint.
The Sun Dome has an indefinite lifespan.