Natural Wastewater Treatment Systems Professor Nick Gray Centre

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 (170 acres) Sewage farming c 1890

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 Ø Swales Ø Infiltration ponds Ø Infiltration trenches/ditches Ø Retention-detention ponds Ø https: //www. ciria. org/Resour ces/Free_publications/Guid ance_on_the_construction_ of_Su. DS__C 768. aspx? Www. ciria. org/ c 768

Natural Treatment Systems Land Treatment • Overland flow § http: //www. unep. or. jp/ietc/publications/techpub 8 f/c/Wastewater 1. asp § http: //pubs. rsc. org/en/content/articlelanding/2002/em/b 207482 f#!div. Abstract

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: Ø Free water (FWS) or Surface flow (SF) Ø 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 Reed beds now available as package units New Forest: Reed bed treatment system within National Park

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%20 2008%20 Training%20 Material%20 on%20 Anaerobic%20 Wastewater%20 Tre atment. pdf § http: //www. sswm. info/category/implementation-tools/wastewatertreatment/hardware/semi-centralised-wastewater-treatments/w v Use chapter 13 in course text to expand on this brief lecture v More details in Chapter 6 Biology of wastewater Treatment. http: //www. slideshare. net/eugen 1990/biology-ofwastewatertreatmentvol-4