Natural Wastewater Treatment Systems Professor Nick Gray Centre for the Environment Trinity College University of Dublin © Tigroney Press
Natural Wastewater Treatment Systems Learning Objectives: To explore the key NWT systems To understand the processes involved in such systems To be able to design reed beds and stabilization ponds
Natural Treatment Systems Biological treatment systems that require little or no energy and that have low ghg emissions. Options: Land treatment Macrophyte/emergent plant-based treatment Stabilization ponds
Natural Treatment Systems Land Treatment Surface irrigation Sub-surface irrigation Infiltration-percolation Overland flow Overland flow (170 acres) Sewage farming c1890
Natural Treatment Systems Land Treatment Surface irrigation
Natural Treatment Systems Land Treatment Sub-surface irrigation
Natural Treatment Systems Land Treatment Sub-surface irrigation
Natural Treatment Systems Land Treatment Infiltration-percolation
Natural Treatment Systems Land Treatment Infiltration-percolation Also widely used in SUDS Swales Infiltration ponds Infiltration trenches/ditches Retention-detention ponds https://www.ciria.org/Resources/Free_publications/Guidance_on_the_construction_of_SuDS_-_C768.aspx?Www.ciria.org/c768
Natural Treatment Systems Land Treatment Overland flow http://www.unep.or.jp/ietc/publications/techpublications/techpub-8f/c/Wastewater1.asp http://pubs.rsc.org/en/content/articlelanding/2002/em/b207482f#!divAbstract
Natural Treatment Systems Wetland treatment Natural wetlands, marshes and reed beds no longer used for treatment as it severely damages ecological balance of these delicate systems Essex marshes Norfolk broads
Natural Treatment Systems Wetland treatment Constructed Wetlands: Free water (FWS) or Surface flow (SF) Subsurface flow (SSF) either vertical or horizontal FWS treating farm runoff FWS wetland
Natural Treatment Systems Constructed Wetlands:
Natural Treatment Systems Reed Beds:
Natural Treatment Systems Liners can be puddled clay, butyl rubber or rigid plastic Reeds are planted in graded gravel, sand or soil
Natural Treatment Systems Reed beds can be located almost anywhere providing flexible design options Simple outlet with manhole section used as secondary settlement tank
Natural Treatment Systems Newly planted bed Septic tank and 9 reed bed tanks in series serving school
Natural Treatment Systems Treatment of mine waters Treatment of surface runoff from motorways
Natural Treatment Systems New Forest: Reed bed treatment system within National Park Reed beds now available as package units
Natural Treatment Systems Stabilization Ponds Anaerobic Lagoons Oxidation ponds Facultative pond High-rate aerobic lagoon Maturation ponds River purification lakes Aeration Lagoons
Natural Treatment Systems Anaerobic lagoons
Natural Treatment Systems Covered Anaerobic Lagoons A covered anaerobic lagoon utilises a floating geomembrane cover with integrated gas collection system and can be used as a cost effective alternative to the reactor type digesters for very high strength effluents where space is not an issue.
Natural Treatment Systems Typical design of Facultative pond
Natural Treatment Systems Action of Facultative pond
Natural Treatment Systems Fish Culture Tilapia Labeo rohita Catla catala
Natural Treatment Systems Tilapia Fish Ponds in Brazil
Natural Treatment Systems Duckweed ponds
Natural Treatment Systems Water Hyacinth
Natural Treatment Systems Indoor modular treatment cells
Natural Treatment Systems
Natural Treatment Systems References Anaerobic ponds: http://www.sswm.info/sites/default/files/reference_attachments/WAFLER%202008%20Training%20Material%20on%20Anaerobic%20Wastewater%20Treatment.pdf http://www.sswm.info/category/implementation-tools/wastewater-treatment/hardware/semi-centralised-wastewater-treatments/w Use chapter 13 in course text to expand on this brief lecture More details in Chapter 6 Biology of wastewater Treatment. http://www.slideshare.net/eugen1990/biology-ofwastewatertreatmentvol-4