U.1 Dry Toilet

A Dry Toilet is a toilet that operates without flushwater. The dry toilet may be a raised pedestal on which the user can sit, or a squat pan over which the user squats. In both cases, excreta (both urine and faeces) fall through a drop hole.Consists of urine and faeces that are not mixed with any flushwater. Excreta is relatively small in volume, but concentrated in both nutrients and pathogens. Depending on the characteristics of the faeces and the urine content, it can have a soft or runny consistency.Refers to (semi-solid) excrement that is not mixed with urine or water. Depending on diet, each person produces approximately 50–150 L per year of faecal matter of which about 80 % is water and the remaining solid fraction is mostly composed of organic material. Of the total essential plant nutrients excreted by the human body, faeces contain around 39 % of the phosphorus (P), 26 % of the potassium (K) and 12 % of the nitrogen (N). Faeces also contain the vast majority of the pathogens excreted by the body, as well as energy and carbon rich, fibrous material.The liquid produced by the body to rid itself of nitrogen in the form of urea and other waste products. In this context, the urine product refers to pure urine that is not mixed with faeces or water. Depending on diet, human urine collected from one person during one year (approx. 300 to 550 L) contains 2 to 4 kg of nitrogen. The urine of healthy individuals is sterile when it leaves the body but is often immediately contaminated by coming into contact with faeces.Any substance that is used for growth. Nitrogen (N), phosphorus (P) and potassium (K) are the main nutrients contained in agricultural fertilisers. N and P are also primarily responsible for the eutrophication of water bodies.
An organism or other agent that causes disease.User interface used for urination and defecation. The organic molecule (NH2)2CO that is excreted in urine and that contains the nutrient nitrogen. Over time, urea breaks down into carbon dioxide and ammonium, which is readily used by organisms in soil. It can also be used for on-site faecal sludge treatment. See. S.18Composés d’urine et de fèces non-mélangées à de l’eau de chasse. Leur volume est peu important, mais ils sont concentrés en nutriments et en agents pathogènes. Selon la qualité des fèces, leur consistance peut être molle ou liquide.

In this compendium, a Dry Toilet refers specifically to the device over which the user sits or squats. In other literature, a Dry Toilet may refer to a variety of technologies, or combinations of technologies (especially pits or container-based systems).

Design Considerations

The Dry Toilet is usually placed over a pit; if two alternating pits are used S.5 , the pedestal or slab should be designed in such a way that it can be lifted and moved from one pit to the other. The slab or pedestal base should be fitted to the pit so that it is both safe for the user and prevents stormwater from infiltrating the pit (which may cause it to overflow). The hole can be closed with a lid to prevent unwanted intrusion from insects or rodents. This also reduces odours from the pit.

General term for rainfall runoff collected from roofs, roads and other surfaces. Very often the term is used to refer to rainwater that enters a sewerage system. It is the portion of rainfall that does not infiltrate into the soil.The liquid that has passed through a filter.
An open channel or closed pipe used to convey sewage. See C.3 and C.4
The physical sewer infrastructure (sometimes used interchangeably with sewage).
The liquid that has passed through a filter.
Waste matter that is transported through the sewer.
The physical sewer infrastructure (sometimes used interchangeably with sewage).

Materials

Pedestals and squatting slabs can be made locally with concrete (provided that sand and cement are available). Fibreglass, porcelain, plastic and stainlesssteel versions may also be available. Wooden or metal moulds can be used to produce several units quickly and efficiently. Easy-to-clean surfaces are preferable, especially in public toilets.

User interface used for urination and defecation.

Applicability

A Dry Toilet is easy for almost everyone to use though special consideration may need to be made for elderly or disabled users who may have difficulties using the squatting version X.10. It is especially suitable where water is scarce or not available, or where nutrient recovery is foreseen. When Dry Toilets are made locally, they can be specially designed to meet the needs of the target users (e.g. smaller sizes for children). Where there is no need to separate urine and faeces, Dry Toilets are often the simplest and physically most comfortable option.

Refers to (semi-solid) excrement that is not mixed with urine or water. Depending on diet, each person produces approximately 50–150 L per year of faecal matter of which about 80 % is water and the remaining solid fraction is mostly composed of organic material. Of the total essential plant nutrients excreted by the human body, faeces contain around 39 % of the phosphorus (P), 26 % of the potassium (K) and 12 % of the nitrogen (N). Faeces also contain the vast majority of the pathogens excreted by the body, as well as energy and carbon rich, fibrous material.The liquid produced by the body to rid itself of nitrogen in the form of urea and other waste products. In this context, the urine product refers to pure urine that is not mixed with faeces or water. Depending on diet, human urine collected from one person during one year (approx. 300 to 550 L) contains 2 to 4 kg of nitrogen. The urine of healthy individuals is sterile when it leaves the body but is often immediately contaminated by coming into contact with faeces.Any substance that is used for growth. Nitrogen (N), phosphorus (P) and potassium (K) are the main nutrients contained in agricultural fertilisers. N and P are also primarily responsible for the eutrophication of water bodies.
An organism or other agent that causes disease.The organic molecule (NH2)2CO that is excreted in urine and that contains the nutrient nitrogen. Over time, urea breaks down into carbon dioxide and ammonium, which is readily used by organisms in soil. It can also be used for on-site faecal sludge treatment. See. S.18

Operation and Maintenance

The sitting or standing surface should be kept clean and dry to prevent pathogen/ disease transmission and to limit odours. Cleaning should be done with water and a small amount of detergent. The use of large quantities of chemicals should be avoided as it may affect the functioning of the pit below. There are no mechanical parts; therefore, the dry toilet should not need repairs except in the event that it cracks.

An organism or other agent that causes disease.User interface used for urination and defecation.

Health and Safety

Squatting is a natural position for many people and so a well-kept squatting slab may be the most acceptable option. Since dry toilets do not have a water seal, odours may be a problem depending on the collection and storage/treatment technology connected to them. Anal cleansing material should be provided, and a Handwashing Facility  U.7 has to be in close proximity.

Describes technologies for on-site collection, storage, and sometimes (pre-) treatment of the products generated at the user interface. The treatment provided by these technologies is often a function of storage and is usually passive (i.e. requires no energy input), except a few emerging technologies where additives are needed. Thus, products that are ‘treated’ by these technologies often require subsequent treatment before use and/or disposal. In the technology overview graphic, this functional group is subdivided into the two subgroups: “Collection/Storage” and “(Pre-)Treatment”. This allows a further classification for each of the listed technologies with regard to their function: collection and storage, (pre-) treatment only or both.Refers to the methods through which products are returned to the environment, either as useful resources or reduced-risk materials. Some products can also be cycled back into a system (e.g. by using treated greywater for flushing).A functional group is a grouping of technologies that have similar functions. The compendium proposes five different functional groups from which technologies can be chosen to build a sanitation system:
User interface (U), Collection and Storage/Treatment (S), Conveyance (C), (Semi-) Centralised Treatment (T), Use and/or Disposal (U).
A sanitation system is a multi-step process in which sanitation products such as human excreta and wastewater are managed from the point of generation to the point of use or ultimate disposal. It is a context-specific series of technologies and services for the management of these sanitation products, i.e. for their collection, containment, transport, treatment, transformation, use or disposal. A sanitation system comprises functional groups of technologies that can be selected according to context. By selecting technologies from each applicable functional group, considering the incoming and outgoing products, and the suitability of the technologies in a particular context, a logical, modular sanitation system can be designed. A sanitation system also includes the management and operation and maintenance (O & M) required to ensure that the system functions safely and sustainably. The means of safely collecting and hygienically disposing of excreta and liquid
wastes for the protection of public health and the preservation of the quality of public water bodies and, more generally, of the environment.

User interface used for urination and defecation. Used water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff/stormwater, and any sewer inflow/infiltration.

Costs

Capital and operating costs are low. However, depending on the storage system and the local conditions, sludge emptying and transport may be an important cost factor.

Mixture of solids and liquids, containing mostly excreta and water, in combination with sand, grit, metals, trash and/or various chemical compounds. A distinction can be made between faecal sludge and wastewater sludge. Faecal sludge comes from on-site sanitation technologies, i.e. it has not been transported through a sewer. It can be raw or partially digested, a slurry or semisolid, and results from the collection and storage/treatment of excreta or blackwater, with or without greywater. Wastewater sludge (also referred to as sewage sludge) originates from sewer-based wastewater collection and (semi-)centralised treatment processes. The sludge composition will determine the type of treatment that is required and the end-use possibilities.Describes technologies for on-site collection, storage, and sometimes (pre-) treatment of the products generated at the user interface. The treatment provided by these technologies is often a function of storage and is usually passive (i.e. requires no energy input), except a few emerging technologies where additives are needed. Thus, products that are ‘treated’ by these technologies often require subsequent treatment before use and/or disposal. In the technology overview graphic, this functional group is subdivided into the two subgroups: “Collection/Storage” and “(Pre-)Treatment”. This allows a further classification for each of the listed technologies with regard to their function: collection and storage, (pre-) treatment only or both.Refers to the methods through which products are returned to the environment, either as useful resources or reduced-risk materials. Some products can also be cycled back into a system (e.g. by using treated greywater for flushing).A functional group is a grouping of technologies that have similar functions. The compendium proposes five different functional groups from which technologies can be chosen to build a sanitation system:
User interface (U), Collection and Storage/Treatment (S), Conveyance (C), (Semi-) Centralised Treatment (T), Use and/or Disposal (U).
A sanitation system is a multi-step process in which sanitation products such as human excreta and wastewater are managed from the point of generation to the point of use or ultimate disposal. It is a context-specific series of technologies and services for the management of these sanitation products, i.e. for their collection, containment, transport, treatment, transformation, use or disposal. A sanitation system comprises functional groups of technologies that can be selected according to context. By selecting technologies from each applicable functional group, considering the incoming and outgoing products, and the suitability of the technologies in a particular context, a logical, modular sanitation system can be designed. A sanitation system also includes the management and operation and maintenance (O & M) required to ensure that the system functions safely and sustainably. The utilisation of products derived from a sanitation system.
A sanitation system in which excreta and wastewater are collected and stored or treated on the plot where they are generated.
The means of safely collecting and hygienically disposing of excreta and liquid
wastes for the protection of public health and the preservation of the quality of public water bodies and, more generally, of the environment.

Waste matter that is transported through the sewer.
An open channel or closed pipe used to convey sewage. See C.3 and C.4
Used water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff/stormwater, and any sewer inflow/infiltration.
Waste matter that is transported through the sewer.

Social Considerations

Although Dry Toilets are a widely accepted solution, it may not be appropriate in each cultural context and needs prior consultation with the users. Behaviour change rarely succeeds. Dry Toilets should reflect local user preferences ( sitter vs. squatter, anal cleansing practices, direction etc.) and should account for the accessibility and safety of all users, including men, women, children, elderly and disabled people X.10. In Muslim communities, Dry Toilets should be oriented in such a way that users neither face Qiblah (prayer point) nor face directly away from it when using the toilet. There is a frequent problem with users disposing of garbage in the toilet (such as plastic bottles) which should be addressed early on as part of the hygiene promotion activities  X.12 and solid waste management  X.8 as it negatively affects the later desludging of pits.

The process of removing the accumulated sludge from a storage or treatment facility.
A person who prefers to sit on the toilet.A person who prefers to squat over the toilet.
User interface used for urination and defecation. A person who prefers to sit on the toilet.A person who prefers to squat over the toilet.

Fact Sheet Overview

Inputs

Faeces
Urine

Outputs

Excreta

Response Phase

Acute Response + +
Stabilisation + +
Recovery + +

Challenging Ground Conditions

Suitable

Application Level

Household + +

Water-based or Dry Technology

Dry

Management Level

Household + +
Shared +
Public +

Technical Complexity

Low

Functional Group

User Interface

Required Space

Little

Objectives & Key Features

• Barrier between user and excreta
• No flushwater needed

Strength & Weakness

  • Does not require a constant source of water
  • Can be built and repaired with locally available materials
  • Low capital and operating costs
  • Adaptable for all types of users (sitters, squatters, washers, wipers)
  • Will accept a wide range of anal cleaning materials (such as stones, sticks, leaves etc.)
  • Odours are normally noticeable (even if the vault or pit used to collect excreta is equipped with a vent pipe)
  • The excreta pile is visible, except where a deep pit is used
  • Vectors such as flies are hard to control unless fly traps and appropriate covers are used

Selected References

Construction manual for different slab designs

Brandberg, B. (1997): Latrine Building. A Handbook for Implementation of the Sanplat System. Intermediate Technology Publications, London

Morgan, P. R. (2009): Ecological Toilets. Start Simple and Upgrade from Arborloo to VIP SEI, Stockholm, Sweden

Detailed construction manuals for slabs and pit lining

CAWST (2011): Introduction to Low Cost Sanitation. Latrine Construction. A CAWST Construction Manual. CAWST, Calgary, Canada

Morgan, P. R. (2007): Toilets That Make Compost. SEI, Stockholm, Sweden

Morgan, P. R. (2009): Ecological Toilets. Start Simple and Upgrade from Arborloo to VIP SEI, Stockholm, Sweden

Guidance and checklists for design, construction and maintenance

Reed, B. (2012): An Engineer’s Guide to Latrine Slabs. WEDC, Loughborough University, Leicestershire, UK

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