|style="width:50%;"|{{santable_new|
sys1=[[Single Pit System |1]]|
sys2=[[Blackwater Treatment System with Infiltration|56]]|sys3=[[Blackwater Treatment System with SewerageEffluent Transport|67]]|sys4=[[Blackwater Transport to (Semi-) Centralized Treatment System |78]]|sys5=[[Sewerage System with Urine Diversion |89]]|
sys6=|
sys7=|
ManShared=|
ManPublic=XX|
Input1=Faecal Sludge |Input2= |Input3= | Input4= |Input5=|Output1= Effluent | Output2= Faecal Sludge | Output3= | Output4= | Output5=
|english_link=Unplanted_Drying_Beds
|french_link=Lits_de_séchage_non_plantés
[[Image:Icon_unplanted_drying_beds.png |right|80px]]
'''An Unplanted Drying Bed is a simple, permeable bed that, when loaded with sludge, collects percolated leachate and allows the sludge to dry by evaporation. Approximately 50% to 80% of the sludge volume drains off as liquid. The sludge however, is not stabilized or treated.'''
<br>The bottom of the '''An unplanted drying bed is lined a simple, permeable bed that, when loaded with perforated pipes that drain away the sludge, collects percolated leachate. On top of the pipes are layers of sand and gravel that support allows the sludge and allow the liquid to infiltrate and collect in the pipe. The sludge should be loaded to approximately 200kg TS/m2 and it should not be applied in layers that are too thick (maximum 20cm), or the sludge will not dry effectivelyby evaporation. The final moisture content after 10 Approximately 50% to 15 days of drying should be approximately 6080%. A splash plate should be used to prevent erosion of the sand layer and to allow the even distribution of the sludgevolume drains off as liquid or evaporates. When the The sludge is dried, it must be separated from the sand layer and disposed of. The effluent that however, is collected in the drainage pipes must also be treated properly. The top sand layer should be 25 to 30cm thick as some sand will be lost each time the sludge is manually removednot effectively stabilized or sanitized.'''
<br>
{{procontable | pro=The bottom of the drying bed is lined with perforated pipes to drain the leachate away that percolates through the bed. On top of the pipes are layers of- Can be built gravel and sand that support the sludge and repaired with locally available materials <br> - Moderate Capital Cost; low operating Cost. <br> - Potential for local job creation allow the liquid to infiltrate and income generationcollect in the pipe. <br> - No electrical energy required. | con=- Requires large land area. <br> - Odours and flies It should not be applied in layers that are normally noticeabletoo thick (maximum 20 cm), or the sludge will not dry effectively. <br> - Long storage timesThe final moisture content after 10 to 15 days of drying should be approximately 60%. <br> - Requires expert design When the sludge is dried, it must be separated from the sand layer and operation. <br> transported for further treatment, end- Labour intensive removaluse or final disposal. <br> - Leachate requires secondary treatmentThe leachate that is collected in the drainage pipes must also be treated properly, depending on where it is discharged.}}
===AdequacyDesign Considerations===The drainage pipes are covered by 3-5 graded layers of gravel and sand. The bottom layer should be coarse gravel and the top fine sand (0.1 to 0.5 mm effective grain size). The top sand layer should be 250 to 300 mm thick because some sand will be lost each time the sludge is removed. To improve drying and percolation, sludge application can alternate between two or more beds. The inlet should be equipped with a splash plate to prevent erosion of the sand layer and to allow for even distribution of the sludge.
Sludge Designing unplanted drying is an effective way of decreasing beds has to consider future maintenance because ensuring access to people and trucks for pumping in the sludge and removing the volume of dried sludge, which is especially important when it requires transportation elsewhere for direct use, [[Co-composting]]essential. If installed in wet climates, or disposal. The technology is not effective at stabilizing the organic fraction or decreasing facility should be covered by a roof and special caution should be given to prevent the pathogenic contentinflow of surface runoff.
===Appropriateness=== Sludge drying beds are appropriate for small is an effective way to medium communities with populations up to 100decrease the volume of sludge,000 people and there which is inexpensiveespecially important when it has to be transported elsewhere for further treatment, available space that end-use or disposal. The technology is far from homes and businessesnot effective at stabilizing the organic fraction or decreasing the pathogenic content. Further storage or treatment (e. It is best suited to rural and periurban areasg. If it is designed to service urban areas, it should be on the edge [[Co-composting|Co-Composting]], T.16) of the communitydried sludge might be required.
The sludge Unplanted drying beds are appropriate for small to medium communities with populations up to 100,000 people, but larger ones also exist for huge urban agglomerations. They are best suited for rural and peri-urban areas where there is not hygienic inexpensive, available space situated far from homes and requires further treatment before disposalbusinesses. Ideally this technology If designed to service urban areas, unplanted drying beds should be coupled with at the border of the community, but within economic reach for Motorized Emptying operators. This is a Colow-Composting facility to generate a hygienic productcost option that can be installed in most hot and temperate climates. Trained staff for operation and maintenance is required to ensure proper functioningExcessive rain may prevent the sludge from properly drying.
This <br>{{procontable | pro=- Good dewatering efficiency, especially in dry and hot climates <br>- Can be built and repaired with locally available materials <br>- Relatively low capital costs; low operating costs <br>- Simple operation, only infrequent attention required <br>- No electrical energy is required| con=- Requires a lowlarge land area <br>- Odours and flies are normally noticeable <br>- Labour intensive removal <br>-cost option that can be installed in most hot Limited stabilization and temperate climates. Excessive rain may prevent the sludge from properly settling pathogen reduction <br>- Requires expert design and thickening.construction <br>- Leachate requires further treatment}}
===Health Aspects/AcceptanceAppropriateness===Sludge drying is an effective way to decrease the volume of sludge, which is especially important when it has to be transported elsewhere for further treatment, end-use or disposal. The technology is not effective at stabilizing the organic fraction or decreasing the pathogenic content. Further storage or treatment (e.g., Co-Composting, T.16) of the dried sludge might be required. Unplanted drying beds are appropriate for small to medium communities with populations up to 100,000 people, but larger ones also exist for huge urban agglomerations.
The incoming sludge They are best suited for rural and peri-urban areas where there is pathogenicinexpensive, available space situated far from homes and businesses. If designed toservice urban areas, so workers unplanted drying beds should be equipped with proper protection (bootsat the border of the community, gloves, and clothing)but within economic reach for Motorized Emptying operators. The thickened sludge This is also infectious, although it is easier to handle a low-cost option that can be installed in most hot and less prone to splashing and sprayingtemperate climates. The pond Excessive rain may cause a nuisance for nearby residents due to bad odours and prevent the presence of flies. Therefore, the pond should be located sufficiently away sludge from urban centresproperly drying.
===Maintenance=Health Aspects/Acceptance==Both the incoming and dried sludge are pathogenic; therefore, workers should be equipped with proper protection (boots, gloves, and clothing). The dried sludge and effluent are not sanitized and may require further treatment or storage, depending on the desired end-use. The drying bed may cause a nuisance for nearby residents due to bad odours and the presence of flies. Thus, it should be located sufficiently away from residential areas.
The Unplanted Drying Bed should be designed with maintenance in mind; access ===Operation & Maintenance=== Trained staff for humans operation and trucks maintenance is required to pump in the sludge and remove the dried sludge should be taken into considerationensure proper functioning. Dried sludge must can be removed every after 10 to 15 days, but this depends on the climate conditions. Because some sand is lost with every removal of sludge, the top layer must be replaced when it gets thin. The discharge area must be kept clean and the effluent drains should be regularly flushed regularly. Sand must be replaced when the layer gets thin.
===References and external links===
* Crites, R. and Tchobanoglous, G. (1998). Small and Decentralized Wastewater Management Systems. WCB/McGraw- Hill, New York, US.
* CritesHeinss, RU. and TchobanoglousKoottatep, GT. (1998). Small Use of Reed Beds for Faecal Sludge Dewatering. A Synopsis of Reviewed Literature and Decentralized Wastewater Management SystemsInterim Results of Pilot Investigations with Septage Treatment in Bangkok, Thailand. WCB Eawag (Department Sandec), Dübendorf, CH and McGraw-HillAIT, New YorkBangkok, USATH.:Available at: www.sandec.ch (Comparison to planted drying beds)
* HeinssMontangero, UA. and KoottatepStrauss, TM. (19982002). Use of Reed Beds for Faecal Sludge Dewatering – A Synopsis of Reviewed Literature and Interim Results of Pilot Investigations with Septage Treatment in Bangkok, Thailand. UEEM Program ReportLecture Notes, AIT/EAWAGUNESCO-IHE, DübendorfDelft, SwitzerlandNL. (Comparison to planted drying beds:Available at: [http://www.sandec.ch sandec.)ch]
* MontangeroStrande, AL., Ronteltap, M. and StraussBrdjanovic, MD. (Eds. ) (20022014). Faecal Sludge TreatmentManagement. Systems Approach for Implementation and Operation. Lecture NotesIWA Publishing, IHE DelftLondon, UK. (Detailed book compiling the current state of knowledge on all aspects related to FSM):Availableat: [http://www.sandec.chsandec.ch]
* Tchobanoglous, G., Burton, F.L. and Stensel, H.D. (20032004). Wastewater Engineering: Treatment and Reuse, 4th Edition. Metcalf & Eddy, 4th Ed. (Internat. Ed.). McGraw-Hill, New York, US.
===Acknowledgements===
{{:Acknowledgements Sanitation}}