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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]]|
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pic=Planted_drying_beds.png|
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ManPublic=XX|
Input1=Faecal Sludge |Input2= |Input3= | Input4= |Input5=|Output1= Effluent | Output2= Treated Sludge | Output3= Forage Biomass | Output4= | Output5=
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|[[Image:Planted_drying_beds.png |right|500px]]
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[[Image:Icon_planted_drying_beds.png |right|95px80px]]'''A Planted Drying Bed is similar to an [[Unplanted Drying Beds|Unplanted Drying Bed]] with the benefit of increased transpiration. The key feature is that the filters do not need to be desludged after each feeding/drying cycle. Fresh sludge can be applied directly onto the previous layer; it is the plants and their root systems that maintain the porosity of the filter.'''
<br>This technology has the benefit of dewatering and stabilizing the sludge. Also, the roots of the plants create pathways through the thickening sludge that allow water to easily escape. The appearance of the bed is similar to a [[Vertical Flow Constructed Wetland|Vertical Flow Constructed Wetland]](T.9). The beds are filled with sand and gravel to support the vegetation. Instead of effluent, sludge is applied to the surface and the filtrate flows down through the subsurface to collect where it is collected in drains. A general design for layering the bed is: (1) 250mm of coarse gravel (grain diameter of 20mm); (2) 250mm of fine gravel (grain diameter of 5 mm); and (3) 100–150mm of sand. Free space (1m) should be left above the top of the sand layer to account for about 3 to 5 years of accumulation.
Sludge should be applied in layers between 75 to 100 mm thick and reapplied every 3 to 7 days, depending on the sludge characteristics, the environment and operating constraints. Sludge application rates of 100 to 250 kg/m2/year have been reported in warm tropical climates. In colder climates, such as northern Europe, rates up to 80 kg/m2/year are typical. Two or more parallel beds can be alternately used to allow for sufficient degradation and pathogen reduction of the top layer of sludge before it is removed. The leachate that is collected in the drainage pipes must be treated properly, depending on where it is discharged.
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{{procontable | pro=
- Can handle high loading. <br> - Fruit or forage growing can generate income. Better sludge treatment than in Unplanted Drying Beds <br> - Can be built and repaired with locally available materials. <br> - Low Relatively low capital costcosts; low operating cost. costs <br> - Potential for local job creation and Fruit or forage growing in the beds can generate income generation. <br> - No electrical energy required. | con=- Requires a large land area. <br> - Odours and flies are normally may be noticeable. <br> - Long storage times. <br> - Labour intensive removal <br>- Requires expert design and operation. <br> - Labour intensive removal. construction <br> - Leachate requires secondary further treatment.
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===Appropriateness===
This technology is effective at decreasing the sludge volume (down to 50%) through decomposition and drying, which is especially important when the sludge needs to be transported elsewhere for end-use or disposal. Because of their area requirements, planted drying beds are most appropriate for small to medium communities with populations up to 100,000 people, but they can also be used in bigger cities. If designed to service urban areas, planted drying beds should be at the border of the community, but within economic reach for motorized emptying operators.
==Adequacy== This is an effective technology at decreasing sludge volume (down to 50%) through decomposition and drying, which is especially important when the sludge needs to be transported elsewhere for direct use, [[Co-composting]], or disposal. Planted drying beds are appropriate for small to medium communities with populations up to 100,000 people. It should be located on the edge of the community. The sludge is not hygienized and requires further treat ment before disposal. Ideally this technology should be coupled with a Co-Composting facility to generate a hygienic product. Trained staff for operation and maintenance is required to ensure proper functioning. ==Health Aspects/Acceptance=== Because of the pleasing aesthetics, there should be few problems with acceptance, especially if located sufficiently away from dense housing. Undisturbed plantations can attract wildlife, including poisonous snakes. Faecal sludge is hazardous and anyone working with it should wear protective clothing, boots and gloves. ==Maintenance== The drains must be maintained and degree of pathogen reduction in the sludge will vary with the climate. Depending on the effluent must be properly collected desired end-use, further storage and disposed of. The plants should drying might be periodically thinned and/or harvestedrequired.
==References=Operation & Maintenance=== Trained staff for operation and maintenance is required to ensure proper functioning. The drains must be maintained and the effluent properly collected and disposed of. The plants should have grown sufficiently before applying the sludge. The acclimation phase is crucial and requires much care. The plants should be periodically thinned and/or harvested. After 3 to 5 years the sludge can be removed.
===References and external links===* Elizabeth Tilley etCrites, R.al (2008). [http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_highand Tchobanoglous, G.pdf Compendium of Sanitation Systems and Technologies] ([http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_low.pdf low res version]1998). Department of Water Small and Sanitation in Development Countries ([http://www.sandecDecentralized Wastewater Management Systems.chWCB/ Sandec]) at the Swiss Federal Institute of Aquatic Science and Technology (Eawag)McGraw- Hill, New York, US. (Provides a full overview of sanitation systems.Book)
* CritesHeinss, RU. and TchobanoglousKoottatep, GT. (1998). Small [https://ocw.un-ihe.org/pluginfile.php/4081/mod_resource/content/1/HEINSS%20and%20KOOTTATEP%201998%20Use%20of%20Reed%20Beds%20for%20FS%20Dewatering.pdf 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.
* HeinssKengne Noumsi, UI. and Koottatep, TM. (19982008). Use Potentials of Reed Sludge Drying Beds Vegetated with Cyperus papyrus L. and Echinochloa pyramidalis (Lam.) Hitchc. & Chase for Faecal Sludge Dewatering - A Synopsis of Reviewed Literature and Interim Results of Pilot Investigations with Septage Treatment in Bangkok, ThailandTropical Regions [PhD dissertation]. UEEM Program Report , AIT/EAWAGUniversity of Yaounde, DübendorfYaounde, Switzerland. Available: http://www.sandecCM.ch
* Koottatep, T., et alSurinkul, N., Polprasert, C., Kamal, A. S. M., Koné, D., Montangero, A., Heinss, U. and Strauss, M. (20042005). [https://www.eawag.ch/fileadmin/Domain1/Abteilungen/sandec/publikationen/EWM/Project_reports/CW_7yearresults_AIT.pdf Treatment of septage Septage in constructed wetlands Constructed Wetlands in tropical climate Tropical Climate – Lessons learnt Learnt after seven years Seven Years of operationOperation]. Water Science & Technology, 51(9): 119–126119-126. Available: http://www.sandec.ch
* MontangeroStrande, AL., Ronteltap, M. and StraussBrdjanovic, MD. (Eds. ) (20022014). Faecal Sludge Treatment[https://www. Lecture Notes, IHE Delftsusana. Available: http:org/en/knowledge-hub/resources-and-publications/library/details/www3591 Faecal Sludge Management.sandecSystems Approach for Implementation and Operation].chIWA Publishing, London, UK. (Detailed book compiling the current state of knowledge on all aspects related to FSM)
* Tchobanoglous, G., Burton, FLF. L. and Stensel, HDH. D. (20032004). Wastewater Engineering: Treatment and Reuse, 4th Edition. Metcalf & Eddy, 4th Ed. (Internat. Ed.). McGraw-Hill, New York, pp US. p. 1578.(Book)