[[Image:WaterlessSystemAlternatingPits.png | 800px ]]
This system is designed to produce a densesolid, compostearth-like material by using alternating pits without or a [[Composting Chamber | Composting Chamber]] (S.8). Inputs to the addition system can include Urine, Faeces, Organics, Anal Cleansing Water, and Dry Cleansing Materials. There is no use of Flushwater.
The inputs to A [[Dry Toilet | Dry Toilet]] (U.1) is the recommended User Interface for this system can include , although a [[UrineDiverting Dry Toilet|Urine-Diverting Dry Toilet]] (UDDT, Faeces, OrganicsU.2) or a [[Urinal|Urinal]] (U.3) could also be used if the Urine is highly valued for application. A Dry Toilet does not require water to function and in fact, water should not be put into this system; Anal Cleansing Water, and Dry Cleansing Materialsshould be kept at a minimum or even excluded if possible.
A The User Interface is directly connected to a [[Dry ToiletDouble Ventilated Improved Pit|Double Ventilated Improved Pit]] is the only recommended User Interface for this system(S. A Dry Toilet does not require water to function and in fact4), water should not be input into this system; Anal Cleansing Water should be kept to [[Fossa Alterna|Fossa Alterna]] (S.5) or a minimum or even excluded from this system if possible[[Composting Chamber | Composting Chamber]] (S. Depending on the 8) for Collection and Storage/Treatment technology, the Dry Cleansing Materials can be added to the pit, otherwise they should be collected separately and directly transferred for disposal ([[Surface Disposal]]).
Excreta is produced at Two alternating pits, as in the User Interface. The User Interface is connected directly to a Collection and Storage/Treatment technology: a [[Double Ventilated Improved Pit|Double VIP]], [[or Fossa Alterna]] or a [[Composting Chamber]]. Alternating the pits gives , give the material an opportunity to drain, degrade, and transform into Pit Humus (sometimes also called EcoHumus), a nutrient-rich, hygienically-improved, humic material that which is safe to excavate. When the first pit is full, it is covered and temporarily taken out of service. While the other pit is filling with Excreta (and potentially Organics), the content of the first pit is allowed to rest and degrade. Only when both pits are full is the first pit emptied and put back into service. This cycle can be used or disposed of safelyindefinitely repeated. As the Excreta in the resting pit is draining and degrading for at least one year, the resulting Pit Humus needs to be manually removed using shovels, and vacuum truck access to thepits is not necessary.
While one pit is filling with Excreta (and potentially organic material), the other pit remains out of service. When the first pit is full, it is covered and temporarily taken out of service. The drained and degraded Excreta within the second pit is emptied and the pit is put back into service. The second pit collects Excreta until it is filled, covered and taken out of service and the cycle is repeated indefinitely. Although a [[A Composting Chamber]] is not strictly an alternating a pit technology, but it can also have multiple alternating chambers and , if properly operated, produces a safe, useable compost-ProductCompost. For these reasons it is included in this System Templatesystem template.
The [[Sanitation Products#Compost - EcoHumus|Pit Humus or Compost/EcoHumus]] that is generated from the Collection and Storage/Treatment Technology technology can be removed and transported for Use and/or Disposal manually using a [[Human-Powered Emptying and Transport]] Conveyance Technologyservice (C.2). Since it has undergone significant degradation, the humic material is quite safe to handle and use as soil conditioner in agriculture(D.4). If there are concerns about the qualityof the Pit Humus or Compost, it can be further composted further in a dedicated composting facility but before it is used. If there is no need to transport use for the Compost/EcoHumus to a product, it can be temporarily stored or permanently disposed of (Semi-D.12) Centralized Treatment facility as decomposition of the Excreta takes place onsite.
For This system is different from System 1 ([[Single Pit System | Single Pit System]]) regarding the product generated at Collection and Storage/Treatment level. In the previous system, the Sludge required further treatment before it could be used, whereas the Pit Humus and Compost produced in this system are ready for Use and/or Disposal of Compostfollowing Collection and Storage/EcoHumus, the [[Application of Compost - Eco-Humus]] technology is utilizedTreatment.
This ===Considerations=== Because the system is different than [[Single Pit System|System 1]] because of the Conveyance permanent and Use can be indefinitely used (as opposed to some SinglePits, which may be filled and/or Disposal options: in the previous systemcovered), the sludge requires further treatment before it can be usedwhere space is limited. Additionally, whereas because the Compost/EcoHumus produced in product must be manually removed, this system is ready suitable for Use dense areas that cannot be served by trucks for mechanical emptying (C.3). This system is especially appropriate for water-scarce areas and/or Disposal following Collection where there is an opportunity to use the humic product as soil conditioner. The material that is removed should be in a safe, useable form, although proper personal protection should be used during removal, transport and Storage/Treatmentuse.
==Considerations== Because The success of this system depends on proper operation and an extended storage period. If a suitable and continuous source of soil, ash or Organics (leaves, grass clippings, coconut or rice husks, woodchips, etc.) is available, the system decomposition process is permanent enhanced and the storage period can be reduced. The required storage time can be used indefinitely (as opposed to some single pitsminimized if the material in the pit remains well aerated and not too moist. Therefore, which may the Greywater must be filled collected and treated separately. Too much moisture in the pit will fill the air voids and covered)deprive the microorganisms of oxygen, it which may impair the degradation process. Dry Cleansing Materials can usually be used where space is limitedcollected in the pit or chamber together with the Excreta, especially if they are carbon-rich (e.g. Additionally, because the Product must be removed manuallytoilet paper, newsprint, corncobs, etc.) as this system is appropriate for dense areas that do not have access to mechanical emptying/trucksmay help degradation and air flow.
The success Guidelines for the safe use of this system depends on an extended storage period. If a suitable and continuous source of soil, ash or organic matter Excreta have been published by the World Health Organization (leaves, grass clippings, coconut or rice husks, woodchips, etc.WHO) is available, the decomposition process is enhanced and are referenced on the storage period can be reduced. The storage period can be minimized if the material in the pit remains well aerated and not too moist. Therefore, the Greywater must be collected and treated separately. Too much moisture in the pit will fill the air-voids and deprive the microbes of oxygen, which may impair the degradation processrelevant technology information sheets.
This system is especially appropriate for water-scarce areas and where there is an opportunity to use [[Functional Groups|More on the humic material. Dry cleansing materials can be discarded into the pit/chamberFunctional Groups: U, especially if they are carbonaceous (e.g. toilet paperS, newsprintC, corncobsT, etc.) as this may help with degradation and airflow. ==References==or D]]<br>* Elizabeth Tilley et.al (2008). [http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_high.pdf Compendium of Sanitation Systems and Technologies] ([httpImage://www.eawagwaterless pit chart - 2.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_low.pdf low res versionpng|none|1000px|]). Department of Water and Sanitation in Development Countries ([http://www.sandec.ch/ Sandec]) at the Swiss Federal Institute of Aquatic Science and Technology (Eawag). (Provides a full overview of sanitation systems.)