Technical options in sanitation and reuse of toilet compost and urine in an African context. Peter Morgan

Transcription

1 Technical options in sanitation and reuse of toilet compost and urine in an African context. Peter Morgan 2009

2 The importance of improved sanitation throughout the developing world is currently being highlighted as one of the major challenges facing development In Africa alone, countless millions live without access to improved sanitation and also without adequate supplies of water In addition food supplies and fertilisers are dwindling. Is there any way in which these overwhelming problems can be linked to join forces to help solve problems?

3 This presentation deals with technical options for sanitation which provide some means of recycling nutrients contained in excreta. We all know that excreta contains valuable nutrients, both in the faeces and in the urine and also in a combination of them both. In fact there is almost no sanitation technology that is unable to provide nutrients in one way or another from the pit toilet to the flush!

4 By Nature or by human design? The Pilgrim Fathers who arrived in America planted trees on their abandoned toilet pits long ago. They had already learned how to tap the nutrients held in excreta! But long before this, Nature did it. Trees grow naturally in abandoned toilet pits without the intervention of man. Seeds fall in and grow! In many African countries trees are also deliberately planted on or near pits to accelerate their growth.

5 We can list the range of sanitation technologies where recycling of the nutrients held in toilet compost and urine is possible: *Shallower pit toilets *Medium depth pit toilets *Deeper pit toilets *Urine diversion toilets

6 Shallower pit eco-toilets *Arborloo (single pit composting toilet) These are shallow unlined pit toilets where composting of excreta is accelerated by the regular addition of soil and wood ash. Pit is protected by ring beam in many cases. Short life span of 1m deep pit. Slab and structure portable. Designed for tree planting. Large numbers in use in Malawi and Ethiopia. *Fossa alterna (alternating pit composting toilet) Use slightly deeper 1.5m pits. Usually two pits used, but can be more. Soil and ash are added regularly to increase rate of composting. Compost can be excavated after 12 months. Compost can be dug into beds, placed into tree pits, bagged etc. * Both can be upgraded to VIPs by reuse of the slab or by fitting vent pipe on semi dark superstructure.

7 Shallower pit eco-toilets The Arborloo a shallow pit toilet filling with excreta, soil and wood ash. At filling topped up with soil and a tree planted (tens of thousands are operating in Africa)

8 Shallower pit eco-toilets The Fossa alterna alternating or rotating shallow pit toilet filling with excreta, soil and wood ash. Pits allowed 12 months to compost and alternate. (Many of thousands are operating in Africa)

9 Medium depth eco-pit toilets *These pit toilets are dug down to a max depth of 2m and lined with bricks. A brick construction method known as corbelling is used so that pits can be wide at base, but narrow at the top so a smaller economical slab can be fitted. Once again soil and ash are added to promote composting. * These toilets can be built with the configuration of VIPs. To utilise nutrients during the pit filling phase, trees can be planted to the side of the lined pit. *Users have the option to use the VIP in an ecological way (by adding soil and ash) where excavation is possible later. Or by using the VIP in a non-ecological way (adding wash water and garbage) when the pit will be closed off permanently at filling. In this case the planted tree still removes pit nutrients to assist growth.

10 Medium depth eco-pit toilets A new generation of medium depth eco-pit toilets in which composting is promoted but where recycling of the nutrients does not depend on pit excavation. The method is associated with tree planting next to the toilet.

11 Deeper pit toilets *Traditional pit latrines Millions are in use. Toilets usually abandoned after use. Pit covered over. Pits usually unlined and composting takes about 5 years to complete. Traditional recycling by planting trees on abandoned pits. *Sanplats Huge numbers in use. Pits may be lined or unlined. When full, pits are usually abandoned. But excreta turns into compost eventually, after about 5 years in unlined pits and 10 years in lined pits. Potential for recycling by excavation or tree planting. Many san-plat slabs used as Arborloo s in countries like Malawi. *VIPs Large numbers in use. Normally pits are lined with bricks or blocks. Pits are abandoned when full in most cases. In higher density settlements pits are emptied, often with great difficulty. Lined pits may take up to ten years to turn into compost. Potential for recycling by excavation or tree planting.

12 Examples of deeper pit toilets

13 Urine diverting toilets *These units are being used more widely world wide. * Normally the urine and faeces are separated at source with a urine diverting pedestal or urine diverting squat plate. *However urine can be collected separately in plastic containers or bottles. Larger plastic containers can be fitted with a funnel and placed in pit or other toilets. These are called desert lilies or eco-lilies. lilies.** ** NOTE: A pit toilet which uses a urinal or desert lily is a type of urine diverting toilet!

14 Urine diverting toilets Examples from many countries

15 Urine diverting toilets More examples from many countries

16 Collection of toilet compost and urine *Toilet compost can be collected from shallow pit composting toilets like the Fossa alterna or in a dehydrated form from urine diverting vaults. * Urine can be collected directly in plastic bottles, or containers fitted with funnels or from urine diverting toilets.

17 Processing of toilet compost and urine *If toilet compost is handled it requires processing, like Secondary composting, to make it safe and humus like. Mixing with more soil and organic matter like leaves helps. * Urine can be normally be collected and used directly on gardens. It can be diluted with water first (for use on vegetables) or used undiluted (on maize). If there is doubt about the quality of urine it can be stored in sealed plastic containers

18 Usefulness of toilet compost *Tree growing (Usually from Arborloo) * Enhancing value of poor soil *Potting soil *growing tomatoes

19 Usefulness of toilet compost * Enhancing value of poor soil These photos show the effect of toilet compost (from a Fossa alterna) ) on plant growth in poor sandy soil. In the buckets on left spinach and lettuce are planted in poor soil. On right the poor soil has been mixed with an equal volume of toilet compost.

20 Usefulness of urine *Urine is a valuable source of nitrogen and other valuable plant food * Can enhance vegetable growth *Can enhance maize growth * Can enhance tree growth

21 Usefulness of urine and toilet compost in combination During the time when toilet compost is being formed in pits and vaults, it will be loosing nitrogen. Where vegetables and trees are planted in toilet compost or combinations of toilet compost and soil, they will still benefit from the addition of further nitrogen from urine. Trees for instance, planted on Arborloo pits will still need feeding once they are established. Compost, manure and urine can aid the growing process as the tree grows larger.

22 Basic principles to achieving MDGs The basic aims of achieving wider coverage of improved sanitation can only be achieved by selecting from a wide range of technical options which suit specific needs and requirements. To attain wide coverage, technical solutions must be low in cost and replicable with minimal outside support. One method is to start simple with the option of upgrading over time a principle being considered in Zimbabwe. Now we have a range of ecological toilets to assist us to achieve these goals. Now the value of a toilet can go beyond excreta management alone.

23 Education and training * To achieve these goals practical hands on education and training are essential. *Receptive institutions must be used to pass the message (schools and universities) *Problem based learning is essential - solutions should be linked to perceived problems. * Links to water supply, and agriculture are vital * If a health benefit is to be gained personal and family hygiene is essential.

24 Making links *The important links between sanitation and agriculture and forestry are important and have now been established *The help with improving food security They also may offer fuel, material for construction and fruit and medicine in form of various trees *Links to water supply and hygiene are also essential if the aims of a better life are to be achieved. * Protection of environment is also a priority in a world which is increasingly at risk.

25 Summary and conclusions *A A wide range of technical options are now available in sanitation which can suit an equally wide range of environments in Africa. *Careful choice is required to match the best technology to suit the specific need. *Even with the lowest cost options, toilets can provide far more than a sanitary disposal system alone. The compost derived from eco-toilets together with urine can enhance the production of fruit, vegetables and maize. *This new approach to sanitation may help solve problems far beyond that of excreta disposal alone. *These new approaches form valuable links between health, agro-forestry, agriculture and environmental protection.