Akvopedia-spade, akvouser, bot, bureaucrat, emailconfirmed, smwadministrator, smwcurator, susana-working-group-susana-member, administrator, widget editor
697
edits
Changes
→References and external links
{|width="100%"
|style="width:50%;"|{{santable_new|
sys7=|
sys8=|
sys9=|
pic=Planted_drying_beds.png|
ApplHousehold=|
Input1=Sludge |Input2= |Input3= | Input4= |Input5=|
Output1= Effluent | Output2= Sludge | Output3= Biomass | Output4= | Output5=
}}
|[[Image:Planted_drying_beds.png |right|400px500px]]
|}
<br>
----
[[Image:Icon_planted_drying_beds.png |right|80px]]
'''A planted drying bed is similar to an [[Unplanted Drying Beds|Unplanted Drying Bed ]] (T.14), but has the added benefit of transpiration and enhanced sludge treatment due to the plants. The key improvement of the planted bed over the unplanted bed is that the filters do not need to be desludged after each feeding/drying cycle. Fresh sludge can be directly applied onto the previous layer; the plants and their root systems 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 where it is collected in drains.
===Design Considerations===
Ventilation pipes connected to the drainage system contribute to aerobic conditions in the filter. A general design for layering the bed is: (1) 250 mm of coarse gravel (grain diameter of 20 mm); (2) 250 mm of fine gravel (grain diameter of 5 mm); and (3) 100 to 150 mm of sand. Free space (1 m) should be left above the top of the sand layer to account for about 3 to 5 years of accumulation. Reeds (Phragmites sp.), cattails (Typha sp.) antelope grass (Echinochloa sp.) and papyrus (Cyperus papyrus) are suitable plants, depending on the climate. Local, non-invasive species can be used if they grow in humidenvironments, are resistant to salty water and readily reproduce after cutting.
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.
===References and external links===
* Crites, R. and Tchobanoglous, G. (1998). Small and Decentralized Wastewater Management Systems. WCB/McGraw- Hill, New York, US.(Book)
* Heinss, U. and Koottatep, T. (1998). [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 Interim Results of Pilot Investigations with Septage Treatment in Bangkok, Thailand]. Eawag (Department Sandec), Dübendorf, CH and AIT, Bangkok, TH.:Available at: [http://www.sandec.ch sandec.ch]
* Kengne Noumsi, I. M. (2008). Potentials of Sludge Drying Beds Vegetated with Cyperus papyrus L. and Echinochloa pyramidalis (Lam.) Hitchc. & Chase for Faecal Sludge Treatment in Tropical Regions [PhD dissertation]. University of Yaounde, Yaounde, CM.
* Koottatep, T., Surinkul, N., Polprasert, C., Kamal, A. S. M., Koné, D., Montangero, A., Heinss, U. and Strauss, M. (2005). [https://www.eawag.ch/fileadmin/Domain1/Abteilungen/sandec/publikationen/EWM/Project_reports/CW_7yearresults_AIT.pdf Treatment of Septage in Constructed Wetlands in Tropical Climate – Lessons Learnt after Seven Years of Operation]. Water Science & Technology 51 (9): 119-126.:Available at: [http://www.sandec.ch sandec.ch]
* Strande, L., Ronteltap, M. and Brdjanovic, D. (Eds.) (2014). [https://www.susana.org/en/knowledge-hub/resources-and-publications/library/details/3591 Faecal Sludge Management. Systems Approach for Implementation and Operation]. IWA Publishing, London, UK. (Detailed book compiling the current state of knowledge on all aspects related to FSM):Available at: [http://www.sandec.ch sandec.ch]
* Tchobanoglous, G., Burton, F. L. and Stensel, H. D. (2004). Wastewater Engineering: Treatment and Reuse, Metcalf & Eddy, 4th Ed. (Internat. Ed.). McGraw-Hill, New York, US. p. 1578.(Book)
===Acknowledgements===
{{:Acknowledgements Sanitation}}