2. Urine Diversion Systems 2.1 UDS: Advantages 2.2 UDS: Potential problems 2.3 UDS: General

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3 1. Septic Tanks 1.1 History of septic tanks 1.2 What does a septic tank look like? 1.3 How does it work? 1.4 How to build a septic tank How to build a septic tank How to build a septic tank Overview 1.8 Potential problems 2. Urine Diversion Systems 2.1 UDS: Advantages 2.2 UDS: Potential problems 2.3 UDS: General 3. VIP and PIT Latrines 3.1 Types of Sanitation: VIP 3.2 Types of Sanitation: PIT Latrines 3.3 Pit Latrine: What does a pit latrine consist of? 3.4 Pit Latrine: How to build 1: General 3.5 Pit Latrine: How to build 2: Digging 3.6 Pit Latrine: How to build 3: Squat hole 3.7 Pit Latrine: How to build 4: Covering 3.8 Pit Latrine: How to build 5: Shelter 3.9 Pit Latrine: What to do when the pit is full

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5 Septic Tanks - History As far as is known, the first time farm land was used to treat sewage in trenches or pits, was in Craigentinny Meadows in Edinburgh in The purpose was to remove the heavier solids prior to application, thereby reducing the load on the land. When they were filled they were covered over and others were dug. Next, in 1846, flat-bottomed clay-lined tanks were used. These tanks were filled with the contents of sewers and drains from cities, towns and villages and then the water was withdrawn by siphoning it off. The solid animal or vegetable matter were contained, solidified and dried in them. In the 1850 s the horizontal flow tanks were invented and there were also some bucket-and-winch operated systems for desludging in operation in the 1850s and 1860s. The septic tank was invented in the 1860 s by a Frenchman, John Louis Mouras. He designed a cesspool, contained in a masonry tank, with inlet and outlet pipes, which dipped below the groundwater surface, forming a water seal. After a dozen years, the tank was opened and it was found, contrary to all expectations, to be almost free of solids. It was concluded that the solids were liquefied by means of anaerobic action. This design, called the fosses Mouras, was first described, published and patented by Abbe Moigno, a priest-cum-scientist of the period, in Cosmos les Mondes in 1881 and was generally considered to be the precursor of the modern septic tank. It is believed that the septic tank was first introduced to the USA in 1883, to England in 1895 and to South Africa in Later in 1896, a Scotchman named Donald Cameron, the city Surveyor of Exeter, and F.J. Cummins patented a similar, but improved, system and Cameron called it a septic tank. They developed the modern sealed, (almost) airtight septic tank chamber in which anaerobic bacteria attack and destroy the pathogens in domestic waste water. The name septic tank gained favour and apparently with good reason, for originally the word septic meant simply bacterial, just as the word anti-septic means anti-bacterial In 1906 the German Karl Imhoff of the Emscher Drainage Board in Germany, designed a further advanced septic tank, the Imhoff tank. This improved upon the design of septic tanks by using two chambers which allowed the separation of the settlement and sludge digestion processes. The system was so successful that Imhoff tanks comprised nearly half the total treatment works in the US by the end of the 1930s and it is still in worldwide use. References: 1.Septic tanks and soakaways and conservancy tanks. Septic_Tanks,_Soakaways_and_Conservancy_Tanks_ _245.pdf 2. Historical aspects of wastewater treatment: Developing the basic treatment processes: 1870 to Reilly, M. (2007). The world & Milwaukee early sanitation history outhouses, privies, scavengers & sewers or privileged privy prattle Melosi, M V. (2000). The Sanitary City: Urban infrastructure in America from colonial times to the present, Johns Hopkins University Press, Baltimore, Maryland, p Wolfe, P. (1999) History of wastewater. In World of Water 2000, pp

6 Septic Tanks What does a septic tank look like? 1. A septic system consists of two main parts: A septic tank, which is a watertight box, usually made of concrete or fibreglass, with an inlet and outlet pipe. 2. A drain field: is also known as a leach field, a disposal field or a soil absorption system is a series of trenches or a bed lined with gravel or course sand is usually buried one to three feet below the ground surface. has perforated pipes or drain tiles, which run through the trenches to distribute the wastewater. The purpose of: 1. A septic tank is to treat the wastewater naturally by holding it in the tank long enough for solids and liquids to separate. The wastewater separates into three layers inside the tank. Solids lighter than water (such as greases and oils) float to the top forming a layer of scum. Solids heavier than water settle at the bottom of the tank forming a layer of sludge. This leaves a middle layer of partially clarified wastewater. 2. A drain field is to treat the wastewater by allowing it to slowly trickle from the pipes out into the gravel and down through the soil. The gravel and soil act as biological filters. Modern septic tanks generally consist of 2 tanks of between 1,000 and 1,500 gallons ( liters). These tanks are interconnected by a dividing wall which has openings located about midway between the floor and roof of the tank. The first tank is connected to an inlet wastewater pipe (usually from your toilet) at one end. The second tank is connected to a septic drain or leach field. Each tank has its own manhole at the top. References: Septic tank.

7 Septic tanks (two-compartment) How does it work? 1. Wastewater flows from the house (toilet and sink) and enters the septic tank. 2. In the septic tank the waste water is naturally treated. 3. The heavier solids settle to the bottom. 4. The lighter, greasier particles, such as fats or oils, drift to the top, forming a scum layer at the top of the waste water. 5. Anaerobic digestion of particles in the scum, as well as in the sludge decreases the volume of both the scum and the sludge. 6. The liquid component flows through the dividing wall into the second chamber. 7. In the second compartment, more solids settle from this liquid, leaving it relatively clear to seep through to the drainage field. 8. A piping network, often constructed in a stone filled trench distributes the wastewater throughout the drain field with multiple drainage holes in the network. 9. From these holes, the liquid component or partially treated waste water percolates into the soil (with the soil acting as a physical filter), from where it is eventually taken up through the root system of plants (plant roots filter out the nutrients) or added to the groundwater. 10. All of these processes happen naturally and all the flow is dependant upon gravity only. Where the topography does not allow for natural, gravitational flow, a pump can be used. 11. A standard drain field consists of a series of trenches or a bed lined with gravel or course sand and buried one to three feet below the ground surface. Perforated pipes or drain tiles run through the trenches to distribute the wastewater. The drain field treats the wastewater by allowing it to slowly trickle from the pipes out into the gravel and down through the soil. The gravel and soil act as biological filters. 12. The size of the drain field usually depends on the volume of the wastewater, thus the more the effluent, the larger the drain field. The absorbency of the substrate in which the drain field is build will also determine the size of the drain field. A sandy, well-draining substrate will require a smaller drain field, as opposed to a less permeable, clay substrate, where the drain filed will have to be more extensive. References: 1. Septic System information Miller, T.H. (2005). Septic System Maintenance.

8 Septic tanks How to build a septic tank? Materials required and Important things to remember WHAT DO YOU NEED TO BUILD A SEPTIC TANK? Materials: sand gravel perforated/regular PVC piping & ends PVC glue tank cement or plastic Tools: backhoe shovel string Stakes pencil/paper tape measure paint brushes of various sizes surveying equipment measuring pole Documents: Original house plans of complete premises Written approvals of the previous phases of the building process IMPORTANT THINGS TO REMEMBER WHEN BUILDING A SEPTIC TANK? It is very important to ensure that you get all the necessary approvals throughout the run of the project. Keep all original approvals in a safe place. It is good practice to make copies of all approvals and keep them close at hand so as to present with any inspection and save time. References: How to build a septic tank. How to build a septic system.

9 Septic tanks How to build a septic tank 1? 1. Sketches Use your original property map or house architectural house plan. If you do not possess one, try and obtain one from the municipality. Make rough sketches of the entire property. Do not clear or level the site at all before the municipal or health inspection. Have a survey done to ensure that setbacks from property lines are met. Indicate the location of: Plants or trees that may influence the drain field. Posts or poles on the property, that should not be disturbed.. Power transformers, which cannot be moved. Fences, which may lean towards and nearby excavation. Large rocks, which is not movable. Slopes and slope direction and drainage Paved areas Surface water Surrounding land uses. Surrounding septic systems that you know of. Roads. The proposed drain field area. Existing driveways or parking areas. Pipe line positions. Wells. Number and location of test pits. Once the scale drawing is complete, submit it to the local health department and insist that a licensed health officer does the inspection. 2. Apply to the building/health departments and receive preliminary approval for a number of test pits to be dug. Usually 2 test pits of 5 to 7 feet each is required by most authorities. Check with your local authority how many is required and where would be the best location for them. Local health will usually provide a package of forms and information explaining the process. 3. Test Pits A test pit must be at least 5 feet deep and wide enough and sloped so as to allow the inspector to walk into them and to take samples from the sides. Once the approved number of test pits has been dug, arrange for a municipal soil expert to come and inspect the test pits. The soil expert will pay particular attention to the soil at the 3 to 4 feet depth, since this is the level at which the drain field is going to be installed. This is also the level that will receive the bulk of the partially treated, clearer waste water effluent. This usually takes no more than 20 minutes, except for in the case where the soil is unsuitable. In which case more test pits will have to be dug. These will also need to be inspected and approved. Test pits can be dug by hand or with the help of a back-hoe. References: How to build a septic tank. How to build a septic system.

10 4. Design, Location and Digging Obtain requirements from health/building departments, concerning the size and depth of the septic tank as well as the drain field. Drain field size are determined upon the parameters of the soil type test and the house size (number of bed rooms). Draw the design to meet the specific requirements. Get approval for the location and the design of the septic tank. Start the digging process with a backhoe. Survey the layout to determine the final grade. 5. Grade, Stone and Pipe Follow all specifications of the design religiously. Make sure the grade meets the plan. Use sand and stones according to the design. If a cement tank is used, hire a crane to install it. Install the tank strictly to design. Connect the tank with the house with the specified piping. Once the tank is fitted and connected. Call for inspection and approval. 6. Backfill Prior to any backfilling you must ascertain that all necessary inspections have been done and all necessary approvals have been obtained. Make sure that all signatures on all documents are in the correct place. If you fail to obtain the necessary approval or signature for approval, you may have to dig up the whole system for re-inspection. Even the fill that you use need to be inspected. Follow the design to the dot. References: How to build a septic tank. How to build a septic system.

11 General - Overview WHAT IS A SEPTIC TANK? A septic tank is: the key component of a septic system. A septic system consists of two main parts, the septic tank and the drain field. a small scale, highly efficient, self-contained, underground wastewater compartment where treatment takes place. commonly used in areas with no connection to main sewerage systems supplied by municipalities or private corporations. often more economical than central sewer systems in rural areas, where lot sizes are larger and houses are spaced widely apart. environmentally friendly, because it does not require miles of sewer systems, which disrupts the environment. simple in design, rendering them generally less expensive to install and to maintain. The term "septic" refers to the anaerobic bacterial decomposition of the human waste in a septic tank. The term "septic tank" refers to a tank, designed to receive sewage, retain it for such a time and in such a manner that it secures adequate decomposition. WHAT DOES A SEPTIC TANK CONSIST OF? A septic tank can have one compartment only; with a waste water inlet from the house, an outlet to the drain filed and a manhole at the top.

12 General Overview (continued) Modern septic tanks generally consist of 2 tanks of between 1,000 and 1,500 gallons ( liters). These tanks are interconnected by a dividing wall which has openings located about midway between the floor and roof of the tank. The first tank is connected to an inlet wastewater pipe (usually from your toilet) at one end. The second tank is connected to a septic drain or leach field. Each tank has its own manhole. WHAT IS THE PURPOSE OF A SEPTIC TANK? Septic systems treat and dispose of household wastewater on site. In the septic tank the waste water is treated in the following way: The heavier solids settle into a sludge layer at the bottom. The lighter, greasier particles form a scum layer at the top. The liquid in-between is thus already treated in a way, before leaves the septic tank to be dispersed in the nearby drain field. This treatment process is a natural process. References: 1. Septic tank What is a septic system?

13 Septic Tanks potential problems and what to do Primary Symptom Secondary Symptom Reason Cause Solution Build-up of sludge in the septic tank. Clogged Drain field pipes. Bad odours around the drain field. Pollution of ground water Too little space in the septic tank resulted in waste water being forced to leave the septic tank too soon (not properly treated). The sludge in the forced water may clog the drain field pipes or fill the gravel in the drain field. Neglected to pump for more than 5 years. Remove the sludge by pumping. Repair (clean) or replace drain field pipes. Replace or clean gravel in drain field trenches Water rising to above the surface over drain field. Health risk of untreated sewage in your garden or driveway. Bad odours around the drain field. Three roots may have damaged/broken the drain field pipes. Water usage in the house exceeded the capacity of the drain field. Heavy trucks/vehicles parked directly above the drain field. Waste water was prevented to disperse properly through the drain field and therefore it was forced to rise to surface. Repair or replace broken drain field pipes. Obtain the advice of your local environmental authority for the most economic and effective solution for the problem. The toilets are running slowly and threaten to back-up. Unpleasant odours around drain field and above the septic tank Blocked sewer line to septic tank. Block in the inlet or outlet pipe of the septic tank. Full septic tank. Failing drain field Unauthorised items were flushed down the toilet. Neglect to pump the septic tank. Do not flush unauthorised objects down the toilet. Unblock the inlet and outlet pipes. Pump the septic tank. Repair the drain field. Inlet to septic tank is blocked Odour problems Difficulties with pumping the septic tank. Some unsaturated fats are in liquid form when rinsed down the drain, but they solidify into hard fats, almost like waxes when cold, forming blockages in the pipes. Non-biodegradable items got stuck in the inlet pipe and can even block the outlet and the drain field. Large amounts of oils, fats and grease were rinsed to the septic tank. Non-biodegradable items, such as sanitary towels and cotton buds were flushed down the toilet. Rinse inlet pipe clean with hot water. Refrain from washing oils and fats down the drain. Physically remove large fat solids from scum before pumping. Rather through away non-biodegradable items into a dry bin. Bad odours Septic tank requires more regular pumping. Organic matter in the scum and sludge layers increases dramatically and anoxic conditions prevail. Primary treatment of the waste water does not take place. Chemicals such as pesticides, bleach, caustic soda, paints and paint solvents kill the essential bacteria, necessary for digesting organic matter. Refrain from throwing these chemicals down the drain. Pump the septic tank to remove the chemicals along with the waste water. References: Septic tank.

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17 Urine Diversion Systems - General HOW DOES A URINE DIVERSION SYSTEM DIFFER FROM A VIP (Ventilated Improved Pit) The most important difference between UD and other composting toilets, such as a VIP, is the following: In an ordinary VIP toilet, the urine and faeces is disposed of in the same receptacle. Urine is rich in nutrients and when mixed with the faeces, it can cause the bacteria in the faeces to bloom, resulting in bad odours under aerobic conditions. In the urine diversion system, the urine is separated from the faeces, leaving the urine available to fertilise garden soil and the faeces are kept separate to dry out and eventually be burned, buried or used for soil conditioning. Urine diversion toilets have a partition in the toilet bowl for a urine drain at the front, and a bowl for faeces at the back. WHY IS URINE DIVERSION BETTER? A properly designed, dry, urine diversion system is one of the more natural ways to handle human waste. If we look at nature and the way that land mammals discharge their solid and liquid wastes separately and in an aerobic condition (free to air), we find that these wastes are degraded quickly and harmlessly. It diminishes the normal VIP s odour problem in the following way. Urine is full of valuable nutrients. Faeces contain most of the bacteria discharged from our bodies. If these faeces come into contact with the urine (as is the case with normal VIPs or pit latrines), the nutrients feed the bacteria. Under aerobic conditions, fermentation occurs and unpleasant odours, such as hydrogen sulphide and ammonia are produced. It is simple and easy to install. It requires little or no connection to other services. Properly handled the treated waste, being rich in nitrogen, phosphorus and potassium, can be a very valuable fertilizer or compost. References: 1. Separating urine for 'greener' wastewater treatment Why a dry system? 3. Separating urine for 'greener' wastewater treatment Cemforce Easy Loo Urine Diversion Toilet System 2003/300.

18 Urine Diversion Systems - Advantages WHAT ARE THE ADVANTAGES OF A URINE DIVERSION SYSTEM? Urine diversion systems (UDS): Can be used in areas where the substrate is too rocky and areas with a high water table, as it is installed above ground. Does not require water or treatment chemicals (therefore it is referred to as dry sanitation ). Are economical, because the diverted liquid urine can be used as valuable fertiliser, as it is rich in rich in nitrogen, phosphorus and potassium. Are eco-friendly as: All the pathogens are safely contained and the groundwater is not contaminated. They save water. Are easy to install: In existing and new homes As an outhouse For temporary or permanent purposes. Are easy to move from one place to another. It diminishes the normal VIP s odour problem in the following way. Urine is full of valuable nutrients. Faeces contain most of the bacteria discharged from our bodies. If these faeces come into contact with the urine (as is the case with normal VIPs or pit latrines), the nutrients feed the bacteria. Under aerobic conditions, fermentation occurs and unpleasant odours, such as hydrogen sulphide and ammonia are produced. Are easy to keep hygienic with normal household disinfectants. Are easy to replace a VIP (ventilated Improved Pit) as it can be installed in an existing VIP. Are easy to dispose of. The final sanitation product is dry and of minimal volume. It can be buried, burned or used for compost or landfills. Is a source of energy. The final dry end product does not require any additive to ignite, since it is highly combustible and generates intense heat. Are time saving, since the burning of the dried end products collected over 6 months will burn in only 15 minutes. Another potential benefit of UDS technology is the removal of pharmaceutical residuals that are excreted in urine. By separating urine from sewage wastewater, these pharmaceuticals will not be discharged along with the final treated sewage run-off, and will thus not harm the environment. References: Urine diversion advantages.

19 Urine Diversion Systems Potential Problems CULTURAL Initially many Africans refuse to have Urine Diversion (UD) Toilets in their yards, since it is against most African cultures to handle faeces. Some resistance should be expected from rural, old fashioned tribal groups. SEXUAL These toilets are used in the best way if the user sits down. Most men will not like to sit down to urinate. Urinating from a standing position might cause that the urine ends up in the faecal compartment or splattered over the seat, causing unhygienic conditions. IGNORANCE Some of the rural municipal managers have never heard of a UD toilet, let alone the residents. Residents should be informed of the benefits of these toilets and once it is decided to build them, the users should be properly trained to optimally use these UD toilets. SAFETY Children under the age of 10 are not allowed to use UD toilets, because: They are too small (physically) and too young to use the seat properly. They are too afraid that they will fall in the vault. They will defecate in the urine compartment. They do not know how to use the toilet. They might play in the faecal compartment. GENERAL OBJECTIONS During a survey approximately half the residents said that they object to emptying of the vault, because: They do not want to work with faeces. They think the municipality must empty the vaults. They find it difficult to dispose of the faecal contents. It is not easy to empty the vault. It is unhealthy to use excreta in the garden. Faeces smell, no matter how dry they are. Urine kills plants and is therefore not a good fertilizer. References: Duncker, L.C., Matsebe, G.N. and Austin, L.M. (2006). Use and acceptance of urine-diversion sanitations systems in South Africa. WRC Report No 1439/2/06. Urne diversion latrines pose cultural challenges. Garson, P. (2002). Flushing wasteful toilet technology. Address by Deputy Minister Derek Hanekom, at the Closing the Sanitation Loop seminar in Sweden (Date: :30)

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23 Types of sanitation - VIP WHAT IS A VIP? A VIP is a ventilated pit latrine, which varies from an ordinary pit latrine in that it has a chimney, through which the air ventilates and odours and flies are prevented. Ideally the pipe is high enough for the wind to blow over it, sucking air out of the pit while fresh air flows into the pit through the squat hole. This flow of air is helped if the door faces the direction from which the wind normally blows. Remember that in a VIP latrine the squat hole should not be covered. The main criteria for a VIP are that the interior of the shelter or superstructure should be darker than the daylight outside and it should be well ventilated, so as to allow the flow of air into the pit. The vent pipe should at least be 15cm in diameter. This pipe extends from the pit to approximately one meter above the roof. The top of the vent pipe is fitted with finemesh stainless steel, glass fibre or an aluminium fly-screen, in order to prevent corrosion by corrosive gasses. The flies will be attracted by the strongest light source, which will be through the chimney, provided that the inside of the superstructure or shelter is as dark as possible. Flies which are drawn by smell into the pit will be attracted up the vent pipe by the brightness of daylight at the top of it, but cannot escape because of the screen. Eventually the flies die and fall back into the pit. Wind passing over the vent pipe will cause an up-draught, removing any smell and helping to draw flies up to the top of the pipe. If the latrine is well designed, there should be less concern for disease as the latrine will be easy to clean, (clean-able floor and surfaces), as well as including a sanitary plate (SanPlat) or pour-flush system. The solution, to better use of latrines depends on sanitation, water supply and hygiene education. Hygiene is obviously an important issue wherever the toilet is located but more so where there are many users. Faecal-borne diseases take more lives and create more suffering than war or natural disaster, but do attract as much media coverage. Due to the number of fatalities, it is important to consider hygiene and cleanliness. A dirty latrine is not only unpleasant to use, especially bare foot, but smells and attract flies, bringing more diseases. The number of flies can be reduced by using a ventilated improved pit latrine. The ventilated pit latrine was introduced in Africa in the 1970 s. References: 1. Planning a pit latrine 2. Sanitation. efault.asp 3. Morgan, P. (2000). The arborloo.

24 Types of sanitation Pit Latrines WHAT IS A PIT LATRINE? A pit toilet is a method of collection of human waste, used for composting, controlled decomposition, or waste disposal used most often in rural and wilderness areas in developing countries with no sewer systems. DIFFERENT TYPES OF PIT LATRINES Traditional pit latrines are commonly used in developing countries, e.g. Africa, Latin America and Asia. consist of a simple pit, covered with logs sometimes have walls usually have no roofs are easy to build and require no specialist skills and cost practically nothing. Slit-trench latrines are the simplest type of pit toilet consist of a narrow (3 to 6 feet) trench, which is 1 to 2 meters deep are used by squatting, with ones feet on either side of the trench can have various structures for sitting on or leaning against, such a logs, planks, branches, all placed horizontally over the vertical pit. Conventional improved pit latrines are also similar to the traditional latrine, but built from more solid materials, such as bricks usually have walls and roofs can be improved by putting ashes in the latrine to reduce smells and flies VIP latrines Consist of the normal pit, but with a screened vent pipe fitted. Wind ideally blows over the vent pipe. Pour-flush latrines are most common in southern Asia have a water seal fitted to the drop hole, which prevents smells and flies from entering the shelter or superstructure through the pit. requires water, which needs to be poured into the water seal to flush the toilet could experience problems with the water supply and with fitting the seal. References: Pit toilet.

25 Types of sanitation Pit Latrines What does a pit latrine consist of? References: Pit toilet.

26 How to build a pit latrine 1 - General Where: It is convenient to build a pit latrine near to the home, but it should not be within 15m of a well or a spring source or it may pollute the water. Depth: The average pit should be dug approximately 3m deep. The deeper the pit, the longer it lasts. Important: allow for the spare 50 cm of depth in the calculation of pit size. It is not part of the effective pit volume. Position of the pits: When there is water supply for a pour-flush latrine, the pits can be outside of the shelter and connected to the toilet by means of pipes. With the sealed-lid latrine or the VIP latrine the shelter has to be partly over both pits. The advantage of two pits: Instead of one deep pit, two shallow pits can be dug. In this case the one pit will be filled until it is nearly full. This pit is then sealed while the second pit is in use. The sealed first pit must be left for at least one year, after which its contents can be emptied and used to fertilise the garden, rendering it empty and ready to repeat the cycle. Hygienic and safety considerations: Ensure that the cover is always replaced to avoid breeding of flies and bad smells around and inside the latrine. Clean the slab and surroundings every day, by washing it with a brush and soapy water. (Rinsing water from washing is ideal.) Make sure that hands are washed each time the latrine is used. If possible, provide lighting for use at night. Never put disinfectants such as chlorine products and Lysol in the pit. This will inhibit the natural decomposition of faecal material. Disinfectants must only be used in a pit in the case of a cholera epidemic. On the other hand it is recommended that fire ashes be put into the pit after each use. This gives a perceptible reduction of odors and accelerates decomposition. In the case of a single pit latrine, the pit must be: Filled with soil when nearly full (50 cm from the surface). Sealed when nearly full to mature for at least one year be fore the contents can be used for fertilizing gardens. The superstructure/shelter must be moved to a new pit. References: Franceys, R and Carter, (2005). Planning a pit latrine.

27 How to build a pit latrine II Digging and lining the pit Equipment required for digging: Shovel, pick, miner s bar Slab Cover (wood, metal or concrete) Material for superstructure and door Digging and lining the pit: When you are digging a hole, make sure that you throw the soil away from the hole, so that it does not fall back into the hole. First dig a trench for a foundation or lining, which will support the squatting slab and may also support part of the shelter. This need only be two or three courses of brick or approximately 0.5m deep or one concrete block. Build the foundation wall. Allow to set or harden and then continue to dig your pit down inside the foundation wall. All types of soil require such a foundation. In order to dig a hole straight, make a guide frame by tying or nailing together pieces of wood or bamboo to the chosen size. An octagon (8 sides) is a good guide for a round hole. Circular pits are stronger than other shapes. For the rest of the pit the need for lining will vary depending on the soil strength: Hard firm soil No lining below the top 0.5m is required. Rocky ground Part of the pit can be build above ground level and surrounded with a mound of earth and steps leading up to the latrine. Soft loose soil - Full lining will be necessary in order to prevent the sides from falling in. In the latter case, the lower part of a lining should have small holes so that liquid can seep through the holes and out of the pit. All kinds of different materials can be used to line the pit, e.g. bricks, blocks, empty oil drum, concrete rings, bamboo or similar basketwork and stones. References: Franceys, R and Carter, (2005). Planning a pit latrine.

28 How to build a pit latrine III Size of the squat hole The squat hole is an opening in the covering slab (rectangular or round), which supplies an entrance to the pit below the pit latrine. Position of the squat hole Size of squat hole A squat-hole is usually about 40cm long. If the hole is any shorter, it is likely that fouling will take place. The hole should not be too wide, or small children can fall into the pit. It is unlikely that a child will fall through a hole that is less than 18cm wide. Traditionally, squat holes come in different sizes, but the best shape is the keyhole shape. A keyhole shape 100mm wide and 400mm long with a 200mm diameter circular hole at one end is a good size. Squat hole cover A squat hole cover should only be used with the sealed-lid type of latrine and not in VIP latrines pit latrines with a ventilation chimney, since it would stop proper ventilation of a VIP latrine. This cover (lid) needs to be tightly fitting to control smells and flies. If they are used right from the beginning, then the problem of flies and mosquitoes will be greatly reduced. Covers can be made out of wood, or cement (see fact sheet WAB1aIV, How to build a pit latrine The covering slab ). References: Franceys, R and Carter, (2005). Planning a pit latrine.

29 How to build a pit latrine IV The covering slab Material: For sealed-lid and VIP latrines, the best material for the squat slab is strong, rot-proof and easily cleanable concrete. Cover slabs can also be build out of wood or bamboo, covered with mud, but sometimes hookworms infest the mud. The lid handle can be made out of wood or reinforcing steel. Size: Flat slabs will need to be at least 80mm thick with 6mm diameter bars every 150mm in both directions. The size of the slab can be the same size as the outer lining if this is built of brick. If the lining is made from an oil drum or basketwork it needs to be slightly larger so that at least 20cm of the slab rests on the ground all round the pit. Shape: Covering slabs can be round, square or rectangular. Flat concrete slabs with no reinforcements should be strong enough to support their own weight and the weight of the latrine users. Domed slabs 1500mm in diameter can be made 40mm thick at the edges, with the centre of the bottom rising 100mm. In most slabs, except for the domed slabs, the top of the slab should slope towards the hole allowing spilled water, or water used for cleaning, to drain into the pit. Lids: Lids must be tight-fitting, moulded the same shape as the squat hole in the covering slab. Footrests: Footrests are often provided for both squat-holes and pour-flush pans. They are usually about 10mm above the remainder of the surface of the slab, and keep users feet off the floor. They also enable users to find a good position for squatting, which is especially helpful at night. Hygiene: In order to maintain cleanliness, the surfaces of all slabs should be as hard and smooth as possible. There should not be any gaps under the slab, allowing flies and odours to escape from the pit. Tight-fitting lids will prevent the spreading of flies, smells and the risk of hookworm transmission.

30 How to build a pit latrine IV The covering slab- continued Position: Pour-flush pans can be placed directly above a pit in which case the floor needs to be strong. If two pits are used the pan and shelter floor do not need to be directly over the pits and need not be reinforced. Concrete slabs will still be needed to cover the pits. Safety: To ensure that the squat hole is too small for a young child to fall through, a brick can be used as a guide for size (see fact sheet WAB1aIII, Size of the squat hole ). To ensure that the slab is strong enough, 5 grown men should be able to stand on it, without any structure failure. References: Franceys, R and Carter, (2005). Planning a pit latrine.

31 How to build a pit latrine Shelter What does a shelter or superstructure consist of? The shelter can be built from any available material, such as bricks, earth, wood, plastic sheeting, etc., but preferably local materials, like poles and leaves of grasses. The main purpose of this structure is to make the toilet private, therefore it only requires walls. But to protect the toilet from rain and subsequently from flooding of the pit, a roof is necessary. The roof will also give protection against the sun. The roof should be fixed with a slope towards the back (away from the entrance) of the structure. It can be made of tin, thatch or planks covered in plastic, etc. The superstructure should have a door if local habits dictate. Otherwise a spiral form may be used. A drainage channel can be dug around the latrine to prevent run-off from entering the toilet and to protect the walls of the pit. Where to build a shelter/superstructure: 1. The shelter can be build with 4 posts, erected on the corner posts of the covering slab, provided that the covering slab has 4 secure posts, properly set in its base. These posts can be made out of stout reeds, bamboo or other suitable straight poles cut about 1.8m tall and wired on to the steel posts. Further supporting timbers in reed, bamboo or other materials are then made attached to the 4 posts to add strength. In its simplest form, reeds or grass can be added between the corner posts supported by wires which join the posts. Reed mats and woven fertilizer bags can also be used, although their appearance is not so good, but they can be used temporarily whilst more suitable material is being found. A roof can be added in reeds or grass thatch. This must be as light as possible. If not, the roof must be removable, so that it can be separated from the main structure before the latrine is moved. 2. Alternatively the superstructure can be built separate to the slab with poles and grass. This may be the preferred method of construction, although when the time comes to move the site of the latrine, both slab and structure will need to be moved independently. A roof may be added if desired, but this will add weight to the structure and take extra time to build. It must be kept in mind that the structure must be as light, strong and attractive in appearance as possible. References: 1. The shelter Sanitation. default.asp 3. The arborloo

32 Types of sanitation Pit Latrines What to do when the pit is full! WHEN THE PIT IS FULL TO 50CM FROM THE TOP Stop using the pit latrine Warn all users You have 2 options: References: Pit toilet.

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