Mixed Agricultural Pollutant Mitigation Using Woodchip/Pea Gravel and Woodchip/Zeolite Permeable Reactive Interceptors Tristan G. Ibrahim & Alexis Goutelle & Mark G. Healy & Raymond Brennan & Patrick Tuohy & James Humphreys & Gary Lanigan & Jade Brechignac & Owen Fenton Received: 22 July 2014 /Accepted: 2 February 2015 # Springer International Publishing Switzerland 2015 Abstract Dairy soiled water (DSW) is water from con- creted areas, hard stand areas and holding areas for livestock that has become contaminated by livestock faeces or urine, chemical fertilisers and parlour wash- ings. Losses of DSW occur as point (e.g. storage, pivot irrigators) and diffuse losses (e.g. during or shortly after land application). The concept of a permeable reactive interceptor (PRI), comprising a denitrifying bioreactor woodchip cell to convert nitrate (NO 3 - ) to dinitrogen (N 2 ) gas and an adsorptive media cell for phosphorus (P) and ammonium (NH 4 + ) mitigation, attempts to simulta- neously treat mixed pollutants. This study is the first attempt to test this concept at laboratory-scale. Washing of woodchip media prior to PRI operation produced low NO 3 - but high NH 4 + , dissolved reactive P (DRP) and dissolved organic carbon losses. Dairy soiled water was then treated in replicated PRIs containing woodchip in combination with zeolite or gravel compartments. In general, all PRIs were highly efficient at reducing NO 3 - , NH 4 + , DRP, dissolved unreactive phosphorus (DUP) and dissolved organic nitrogen (DON) from an influent water replicating DSW. Longitudinal and hydrochemical PRI profiles, as well as zeolite batch experiments, showed that woodchip can both enhance NO 3 - reduction and adsorb nutrients. Since woodchip is likely to become saturated, it is important to place the reactive media cell further into the sequence of treat- ment. Even though the majority of the dissolved nutri- ents were mitigated, the PRIs also emitted greenhouse gases, which would need further remediation sequences. Keywords Permeable reactive interceptor . Nitrogen, phosphorus . Ammonium . Agriculture Water Air Soil Pollut (2015) 226:51 DOI 10.1007/s11270-015-2335-4 Electronic supplementary material The online version of this article (doi:10.1007/s11270-015-2335-4) contains supplementary material, which is available to authorized users. T. G. Ibrahim Sustainable Land and Soils, Department for Environment, Food and Rural Affairs, London, UK A. Goutelle Elève ingénieur agronome Montpellier SupAgro, Montpellier, France M. G. Healy : R. Brennan Civil Engineering, National University of Ireland Galway, Galway, Co. Galway, Ireland P. Tuohy : J. Humphreys Animal and Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland G. Lanigan : O. Fenton (*) Teagasc, Environment Research Centre, Johnstown Castle, Co. Wexford, Ireland e-mail: owen.fenton@teagasc.ie J. Brechignac ENSAIA, Vandœuvre-lès-Nancy, France