ARTICLE

Ecological sanitation based on urine diversion technology (Dry sanitation) in Palestine: A pilot project

By Yousef M. Subuh, Palestine

Palestinian Hydrology group (PHG)

Palestine suffers from both water scarcity and water pollution. Water supply is dependent upon annual precipitation, which replenishes the aquifers, natural springs and streams in Palestinian territories. Groundwater and rainwater collected in cisterns is exposed to severe pollution, especially from untreated wastewater. This problem can be more evident in rural areas where no sewer systems exist.

The most common method for wastewater disposal in rural and suburban areas (represent 70% of population) is cesspits. This method of wastewater disposal has many adverse effects on public health and environment in addition to unnecessary consumption of water needed for flushing toilets to the cesspits.

An alternative sanitation technology, dry toilets with urine diversion, addresses the problem of water supply and pollution. Dry toilets are proven to be a good sanitation alternative especially in regions with hot climates and limited water supply.

Palestinian Hydrology Group (PHG) has implemented ecological sanitation pilot projects (based on urine diversion) in three villages in the Hebron district. The projects serve to test the viability and performance of dry sanitation technology in this particular climatic and cultural environment. These projects are the first dry sanitation concepts implemented in the Middle East region.

PHG resolved that this pilot project would be implemented with the full participation of the target communities. Earlier research by the PHG, especially in water supply and sanitation projects, proved community participation to be a major factor in the sustainability of these services.

On site sanitation management is accomplished by separation of urine and feces in custom designed squat plates and pedestals. .These toilets were locally produced, exclusively for this project.

25 indoor & 5 outdoor dry toilets (30 in total) were put in operation. Initial observations from these toilets indicate the project was successful. The key success factor was the full participation and cooperation of the community beneficiaries. Correctly operated, the toilets have no odours or fly breeding. Without the need for flushing water, the average household water consumption was decreased by 20-30%.. The desiccated feces is used as soil conditioner. Urine, being rich in nitrogen, phosphorous and potassium, is diluted 5-10 times and used as a liquid fertilizer.

2. Goals and Objectives

The goal of introducing dry sanitation technology in Palestine is to provide an ecologically, economically, technically intelligent way of alleviating drinking water scarcity and community health problems. Specific objectives of introducing dry sanitation technology through applied research and pilot projects are:

1.    Conduct research on the applicability or modifications that need to be made on the operation of dry sanitation systems in this region.

2.    Test the operation of dry sanitation models; community involvement and participation aspects, technical performance, financial benefits, and management criteria.

3.    Improve the knowledge base of Palestinian sanitation professionals, thus increasing the number of professionals capable of operating and maintaining dry sanitation systems.

3.Project description

Test site selection

This project aimed to test the application of various urine diversion sanitation technologies on a scale large enough to obtain a reliable assessment of its climatic and cultural suitability. Various villages in the southern area of Palestine (Hebron district) showed potential as suitable communities to test 30 toilet units. Each test location (households, schools, and communal buildings) were selected on the following criteria:

1. A balanced mix of households in different economic classes, so as to avoid the cultural problem of having dry sanitation technology being labelled as a cheaper system suitable only for the lower economic classes.

2. Buildings, which presently have no sanitation facilities It was acknowledged that selecting recently constructed buildings, or buildings with no sanitation facilities, was amore practical option than retrofitting existing facilities.

4. Description of Urine diversion technology (Dry sanitation)

Ecological sanitation represents a different approach-an ecosystem approach to sanitation. An ecosystem approach prevents disease by destroying pathogens prior to the introduction of excreta to the terrestrial environment. This approach also recovers and recycles plant nutrients and organic matter, thus closing the nutrient loop. Ecological toilets are designed with these goals in mind. In addition, little or no water is used to flush away human excreta, thus conserving water and preventing pollution. In contrast to conventional toilet systems (e.g. flush toilets and pit latrines), which are designed to dispose of excreta, flushing them away in water or burying them in deep pits. In ecological sanitation excreta are not discharged or buried in deep pits. These characteristics make the ecological toilet an important part of the ecosystem approach, or closed loop system.

Ecological dry sanitation can be defined as on-site disposal of human excreta without using water as the conduit. The technology of dry toilets has been used successfully for decades in many developing countries, such as Vietnam, China, Mexico, El Salvador and other Central American states. Even in highly developed countries, such as Sweden, there is a great deal of interest in this technology.

Palestinian Hydrology group (PHG) implemented a dry sanitation pilot project in three villages in Palestine to test the viability of this technology and its performance in this region.. In this technology, urine is diverted at the source, so as to remain separate from feces. This is accomplished by using a locally produced,  custom designed pedestal and squat plate (Figure 1a, 1b). Soaking material such as wood ash, lime, or saw dust is sprinkled over the feces after each bowel movement. This serves to absorb the moisture and control odours and flies. These soaking materials have a high pH that in turn accelerate pathogen destruction in the feces pile. The generally dry conditions in the feces receptacle facilitate the desiccation of the contents, making them safe for handling within a relatively short time. The desiccated feces is a good soil conditioner, while the nitrogen, phosphorous and potassium rich urine, when mixed with water is an excellent soil fertilizer.

Figure 1a: The urine diversion pedestal custom-manufactured for the project

Figure 1b: A squat plate, custom manufactured for the project

Thirty dry toilet units are currently in use. The first unit was put in use in July,2001 and the last one was put in use in September 2002. For the remainder of this report we will use the term "ecological toilet", or "toilet" to refer to the entire structure illustrated in figure (2).

We use the term toilet because of its function, not its appearance .All ecological toilets should be designed to prevent disease, recover and recycle nutrients and reduce water demand and contamination. Each toilet is comprised of at least three components:

a pedestal or squatting plate, a slab and a chamber, and in the case of outdoor toilets, a super structure (shown in Figure 3).

The chamber is below the slab, with at minimum depth of 600 mm (figure 4). It is constructed from concrete and bricks. The chamber was designed to provide sufficient space for at least two 80L collection containers. One container is used for collecting feces, and the other for collecting diverted urine.

The indoor toilet, installed in the home, may be located above the floor or level with the floor, when there is space available below the floor for constructing a chamber (in this case a chute runs from the slab to the chamber). The super structure is set above the slab (figure 4 a, 4b).

Figure 2: Dry toilet section

A screened 4-inch diameter ventilation pipe is installed in order to facilitate aerobic conditions in the feces chamber (figure 4).

To maintain proper ventilation of the feces chamber, the toilet lid (locally manufactured) has spacers attached. This creates a gap of 10 mm for the free flow of air from the toilet room, through the feces chamber, and out via the vent pipe.

Figure 3: An out-door dry toilet unit under construction

Figure 4a: The chamber and the vent pipe

Figure 4b: Another completed indoor dry toilet unit at a medical facility center)