{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,11]],"date-time":"2026-05-11T23:28:32Z","timestamp":1778542112821,"version":"3.51.4"},"reference-count":38,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2014,3,24]],"date-time":"2014-03-24T00:00:00Z","timestamp":1395619200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sustainability"],"abstract":"<jats:p>The wastewater of one third of Ireland\u2019s population is treated on-site using domestic treatment systems (DWWTSs) that usually consist of a septic tank and soil attenuation system. Within the past four years, the legislative framework for these systems has undergone a major change with a registration and inspection regime being introduced to identify legacy sites that will require remediation work, particularly in areas of the country underlain by subsoils of very low permeability. Against this background this study aims to assess the overall sustainability of existing DWWTSs as well as alternative treatment and disposal options. The results show that main CO2eq emissions are from the methane production in septic tanks. The reduced methane production in mechanically aerated secondary treatment systems was found to counterbalance the related emissions due to the additional energy requirements. In contrast, septic tank systems have the lowest construction and operational costs representing the most economically sustainable solution. Pressurised disposal systems are slightly more expensive but have the potential to reduce environmental impact on surface water and reduce greenhouse gas emissions. Clustered decentralised treatment solutions could be environmentally and economically sustainable but ownership, management and related financial and legal issues will need to be addressed and developed.<\/jats:p>","DOI":"10.3390\/su6031623","type":"journal-article","created":{"date-parts":[[2014,3,24]],"date-time":"2014-03-24T13:43:41Z","timestamp":1395668621000},"page":"1623-1642","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":33,"title":["Application of On-Site Wastewater Treatment in Ireland and Perspectives on Its Sustainability"],"prefix":"10.3390","volume":"6","author":[{"given":"Donata","family":"Dubber","sequence":"first","affiliation":[{"name":"Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1599-1105","authenticated-orcid":false,"given":"Laurence","family":"Gill","sequence":"additional","affiliation":[{"name":"Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2014,3,24]]},"reference":[{"key":"ref_1","unstructured":"CSO (Central Statistics Office) (2012). Census 2011, Principal Demographic Results."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1843","DOI":"10.2134\/jeq2007.0064","article-title":"The treatment performance of different subsoils in Ireland receiving on-site wastewater effluent","volume":"36","author":"Gill","year":"2007","journal-title":"J. Environ. Qual."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Hynds, P.D., Misstear, B.D.R., and Gill, L.W. (2012). Development of a microbial contamination susceptibility model for private domestic groundwater sources. Water Resour. Res., 48.","DOI":"10.1029\/2012WR012492"},{"key":"ref_4","unstructured":"Environmental Protection Agency (EPA) (2013). A Risk-Based Methodology to Assist in the Regulation of Domestic Waste Water Treatment Systems."},{"key":"ref_5","unstructured":"Environmental Protection Agency (2009). Code of Practice: Wastewater Treatment and Disposal Systems Serving Single Houses."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"677","DOI":"10.2166\/wst.2011.685","article-title":"The development of a Code of Practice for single house on-site wastewater treatment in Ireland","volume":"64","author":"Gill","year":"2011","journal-title":"Water Sci. Tech."},{"key":"ref_7","unstructured":"Keegan, M., Gill, L.W., Dubber, D., Johnston, P.M., and Misstear, B.D.R. (2013, January 28\u201330). Alternative infiltration systems for treatment of domestic wastewater in low permeability subsoils. Proceedings of the 11th IWA Conference\u2014Small Water & Wastewater Systems and Sludge Management, Harbin, China."},{"key":"ref_8","unstructured":"Curneen, S., and Gill, L.W. (2012, January 10\u201311). The treatment of on-site wastewater using willow bed evapotranspiration systems in Ireland. Proceedings of the International Symposium on Domestic Waste Water Treatment and Disposal Systems, Trinity College, Dublin, Ireland."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/j.jenvman.2013.12.004","article-title":"A comparison of the suitability of different willow varieties to treat on-site wastewater effluent in an Irish climate","volume":"133","author":"Curneen","year":"2014","journal-title":"J. Environ. Manag."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1007\/s11270-007-9606-7","article-title":"A comparison of gravity distribution devices used in on-site domestic wastewater treatment systems","volume":"191","author":"Patel","year":"2008","journal-title":"J. Water Air Soil Pollut."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2739","DOI":"10.1016\/j.watres.2009.03.024","article-title":"Nutrient loading on subsoils from on-site wastewater effluent, comparing septic tank and secondary treatment systems","volume":"43","author":"Gill","year":"2009","journal-title":"Water Res."},{"key":"ref_12","unstructured":"Dubber, D., and Gill, L.W. (2013, January 28\u201330). Wastewater treatment and management challenges related to surface water discharge for single houses and small decentralised systems in Ireland. Proceedings of the 11th IWA Conference\u2014Small Water & Wastewater Systems and Sludge Management, Harbin, China."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1520\/JAI102170","article-title":"Natural attenuation of Endocrine Disrupting Chemicals in on-site domestic wastewater treatment systems","volume":"6","author":"Gill","year":"2009","journal-title":"J. ASTM Int."},{"key":"ref_14","first-page":"126","article-title":"The attenuation of microorganisms in on-site wastewater effluent discharged into highly permeable subsoils","volume":"142\u2013143","author":"Gill","year":"2012","journal-title":"J. Contam. Hydrol."},{"key":"ref_15","unstructured":"Keegan, M., Kilroy, K., Gill, L.W., Nolan, D., O\u2019Flaherty, V., Dubber, D., Johnston, P.M., Misstear, B.D.R., and Barrett, M. (2013, January 28\u201330). Assessment of the impact of traditional septic tank soakaway systems on water quality in Ireland. Proceedings of the 11th IWA Conference\u2014Small Water & Wastewater Systems and Sludge Management, Harbin, China."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"628","DOI":"10.1111\/j.1745-6584.2005.0077.x","article-title":"Model parameters for simulating fate and transport of on-site wastewater nutrients","volume":"43","author":"McCray","year":"2005","journal-title":"Groundwater"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2741","DOI":"10.1021\/es1036095","article-title":"Methane, carbon dioxide, and nitrous oxide emissions from septic tank systems","volume":"45","author":"Leverenz","year":"2011","journal-title":"Environ. Sci. Tech."},{"key":"ref_18","unstructured":"Intergovernmental Panel on Climate Change (IPCC) (2006). Guidelines for National Greenhouse Gas Inventories, Institute for Global Environmental Strategies (IGES)."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"541","DOI":"10.1111\/j.1745-6584.2011.00857.x","article-title":"Natural attenuation of septic system nitrogen by Anammox","volume":"50","author":"Robertson","year":"2012","journal-title":"Groundwater"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1575","DOI":"10.1016\/j.ecoleng.2010.03.011","article-title":"Nitrate removal and greenhouse gas production in a stream-bed denitrifying bioreactor","volume":"36","author":"Elgood","year":"2010","journal-title":"Ecol. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"511","DOI":"10.1016\/j.ecoleng.2010.12.006","article-title":"Rates, controls and potential adverse effects of nitrate removal in a denitrification bed","volume":"37","author":"Waneke","year":"2011","journal-title":"Ecol. Eng."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1016\/j.agee.2012.06.015","article-title":"Groundwater: A pathway for terrestrial C and N losses and indirect greenhouse gas emissions","volume":"159","author":"Jahangir","year":"2012","journal-title":"Agr. Ecosyst. Environ."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"6646","DOI":"10.1007\/s11356-013-1729-3","article-title":"Abundance of denitrification genes under different piezometer depths in four Irish agricultural groundwater sites","volume":"20","author":"Barrett","year":"2013","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"36","DOI":"10.5539\/jsd.v2n1p36","article-title":"Carbon dioxide emission savings potential of household water use reduction in the UK","volume":"2","author":"Hackett","year":"2009","journal-title":"J. Sustain. Dev."},{"key":"ref_25","unstructured":"Dubber, D., and Gill, L.W. (2013). Water Saving Technologies to Reduce Water Consumption and Wastewater Production in Irish Households."},{"key":"ref_26","unstructured":"Water UK Towards Sustainability 2005\u20132006 (UK water industry Sustainability indicators 2005\/2006). Available online:http:\/\/www.water.org.uk\/home\/news\/press-releases\/towards-sustainability-report\/towards-sustainability-2005-2006-highlights.pdf."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Bedinger, M.S., Flemming, J.S., and Johnson, A.I. (1997). Site Characterization and Design of On-Site Septic Systems, American Society for Testing and Materials. ASTM STP 1324.","DOI":"10.1520\/STP1324-EB"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1080\/09593331608616318","article-title":"The influence of sludge accumulation rate on septic tank design","volume":"16","author":"Gray","year":"1995","journal-title":"Environ. Tech."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"57","DOI":"10.2166\/wst.1993.0205","article-title":"Septic tank sludges: Accumulation rate and biochemical characteristics","volume":"28","author":"Philip","year":"1993","journal-title":"Water Sci. Tech."},{"key":"ref_30","unstructured":"Canter, L.W., and Knox, R.C. (1985). Septic Tank System Effects on Ground Water Quality, Lewis Publishers Inc."},{"key":"ref_31","unstructured":"Environmental Protection Agency (2012). Focus on Urban Waste Water Discharges in Ireland."},{"key":"ref_32","first-page":"39","article-title":"Group Water Schemes in Ireland\u2014Their role within the Irish water sector","volume":"29","author":"Brady","year":"2010","journal-title":"Eur. Water"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Naughton, O., and Hynds, P.D. (2013). Public awareness, behaviours and attitudes towards domestic wastewater treatment systems in the Republic of Ireland. J. Hydrol., in press.","DOI":"10.1016\/j.jhydrol.2013.08.049"},{"key":"ref_34","unstructured":"Environmental Protection Agency (EPA) (2013). The Provision and Quality of Drinking Water Quality in Ireland: A Report for the Year 2012."},{"key":"ref_35","unstructured":"Dubber, D., Gill, L.W., Pilla, F., Smyth, D., Qazi, N., and McCarthy, T. (2013, January 28\u201330). Development of a GIS based decision support toolset to assess the feasibility of on-site wastewater treatment and disposal options in low permeability subsoils. Proceedings of the 11th IWA Conference\u2014Small Water & Wastewater Systems and Sludge Management, Harbin, China."},{"key":"ref_36","unstructured":"Department of Agriculture, Fisheries and Food (2010). Food Harvest 2020\u2014A Vision for Irish Agri-Food and Fisheries."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1016\/j.scitotenv.2011.10.012","article-title":"Low flow water quality in rivers, septic tank systems and high-resolution phosphorus signals","volume":"412\u2013413","author":"Macintosh","year":"2011","journal-title":"Sci. Total Environ."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"644","DOI":"10.1016\/j.envint.2011.01.002","article-title":"Quantifying the impact of septic tank systems on eutrophication risk in rural headwaters","volume":"37","author":"Withers","year":"2011","journal-title":"Environ. 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