This study was carried out for gathering qualitative information about the potential of photocatalytic oxidation for the removal of trace organics (analysed by gas chromatography coupled to mass spectrometry, GC/MS) from biologically pretreated greywater to make it suitable for high quality reuse applications like groundwater recharge. Additionally, fractions of bulk organics (humic substances, building blocks, and low molecular weight organic acids) were quantified by liquid chromatography with organic carbon detection. Biologically pretreated greywater was subjected to photocatalytic oxidation in open stirred vessel reactors with UV lamps positioned over the reactors. UV doses of 0, 5, and 15 Wh·L-1 and TiO2 P25 photocatalyst concentrations of 1, 5, 10, and 20 g·L-1 were investigated. Photocatalysis experiments with a 15 Wh·L-1 UV dose were also conducted in the presence of 1 g·L-1 powdered activated carbon. Subsequent to mere contact of the photocatalyst to biologically pretreated greywater without UV, GC/MS did not indicate a substantial removal of trace organics, while humic substances were increasingly adsorbed by increasing photocatalyst concentration. A UV dose of 15 Wh·L-1 and TiO2 concentrations > 5 g·L-1 were favorable conditions for photocatalytic oxidation resulting in the removal of most of the trace organics, especially chlorinated phosphate flame retardants. Also humic substances were efficiently removed under these conditions. Photocatalytic oxidation is thus a promising process for advanced greywater treatment prior to groundwater recharge. Addition of powdered activated carbon did not improve trace and bulk organics removal by photocatalysis with a UV dose of 15 Wh·L-1 and with photocatalyst concentrations > 5 g·L-1.
 E. Eriksson, E. Donner and A. Ledin, “Presence of Selected Priority and Personal Care Substances in an Onsite Bathroom Greywater Treatment Facility,” Water Science and Technology, Vol. 62, No. 12, 2010, pp. 2889-2898. doi:10.2166/wst.2010.988
 Z. Li, H. Gulyas, M. Jahn, D. R. Gajurel and R. Otterpohl, “Greywater Treatment by Constructed Wetlands in COM- BINATIon with TiO2-Based Photocatalytic Oxidation for Suburban and Rural Areas without Sewer System,” Water Science and Technology, Vol. 48, No. 11, 2003, pp. 101- 106.
 M. Ernst and M. Jekel, “Advanced Treatment Combination for Groundwater Recharge of Municipal Wastewater by Nanofiltration and Ozonation,” Water Science and Technology, Vol. 40, No. 4-5, 1999, pp. 277-284. doi:10.1016/S0273-1223(99)00509-0
 California Department of Public Health, “Groundwater Recharge Reuse DRAFT Regulation,” Division of Drinking Water and Environmental Management, Sacramento, 2008. http://www.cdph.ca.gov/certlic/drinkingwater/Documents/Recharge/DraftRechargeReg2008.pdf
 E. Donner, E. Eriksson, D. M. Revitt, L. Scholes, H.-C. Lützhoft and A. Ledin, “Presence and Fate of Priority Substances in Domestic Greywater Treatment and Reuse Systems,” Science of the Total Environment, Vol. 408, No. 12, 2010, pp. 2444-2451. doi:10.1016/j.scitotenv.2010.02.033
 E. Eriksson, K. Auffarth, A. M. Eilersen, M. Henze and A. Ledin, “Household Chemicals and Personal Care Products as Sources for Xenobiotic Organic Compounds in Grey Wastewater,” Water SA, Vol. 29, No. 2, 2003, pp. 135-146. doi:10.4314/wsa.v29i2.4848
 H. Gulyas, M. Reich and R. Otterpohl, “Organic Micropollutants in Raw and Treated Greywater: A Preliminary Investigation,” Urban Water Journal, Vol. 8, No. 1, 2011, pp. 29-39. doi:10.1080/1573062X.2010.528435
 B. Levine, K. Reich, P. Sheilds, I. H. Suffet and V. Lazarova, “Water Quality Assessment for Indirect Potable Reuse: A New Methodology for Controlling Trace Organic Compounds at the West Basin Water Recycling Plant (California, USA),” Water Science and Technology, Vol. 43, No. 10, 2001, pp. 249-257.
 H. Ozaki, N. Ikejima, Y. Shimizu, K. Fukami, S. Taniguchi, R. Takanami, R. R. Giri and S. Matsui, “Rejection of Pharmaceuticals and Personal Care Products PPCPs) and Endocrine Disrupting Chemicals (EDCs) by Low Pressure Reverse Osmosis Membranes,” Water Science and Technology, Vol. 58, No. 1, 2008, pp. 73-81. doi:10.2166/wst.2008.607
 J. Radjenovic, M. Petrovic, F. Ventura and D. Barcelo, “Rejection of Pharmaceuticals in Nanofiltration and Reverse Osmosis Membrane Drinking Water Treatment,” Water Research, Vol. 42, No. 14, 2008, pp. 3601-3610. doi:10.1016/j.watres.2008.05.020
 Y. Poussade, A. Roux, T. Walker and V. Zavlanos, “Advanced Oxidation for Indirect Potable Reuse: A Practical Application in Australia,” Water Science and Technology, Vol. 60, No. 9, 2009, pp. 2419-2424. doi:10.2166/wst.2009.665
 L. Hernández-Leal, H. Temmink, G. Zeeman and C. J. N. Buisman, “Removal of Micropollutants from Aerobically Treated Grey Water via Ozone and Activated Carbon,” Water Research, Vol. 45, No. 9, 2011, pp. 2887-2896. doi:10.1016/j.watres.2011.03.009
 Y. Boyjoo, M. Ang and V. Pareek, “Photocatalytic Treatment of Shower Water Using a Pilot Scale Reactor,” International Journal of Photoenergy, 2012, Article ID 578916. http://www.hindawi.com/journals/ijp/2012/578916/
 M. Sanchez, M. J. Rivero and I. Orti, “Photocatalytic Oxidation of Grey Water over Titanium Dioxide Suspensions,” Desalination, Vol. 262, No. 1-3, 2010, pp. 141- 146. doi:10.1016/j.desal.2010.05.060
 A. Armanious, A. Ozkan, U. Sohmen and H. Gulyas, “Inorganic Greywater Matrix Impact on Photocatalytic Oxidation: Does Flocculation of TiO2 Nanoparticles Impair Process Efficiency?” Water Science and Technology, Vol. 63, No. 12, 2011, pp. 2808-2813. doi:10.2166/wst.2011.614
 H. Gulyas, H. B. Jain, A. L. Susanto, M. Malekpur, K. Harasiuk, I. Krawczyk, P. Choromanski and M. Furmanska, “Solar Photocatalytic Oxidation of Pretreated Wastewaters: Laboratory Scale Generation of Design Data for Technical-Scale Double-Skin Sheet Reactors,” Environmental Technology, Vol. 26, No. 5, 2005, pp. 501-514. doi:10.1080/09593332608618540
 R. J. Braham and A. T. Harris, “Review of Major Design and Scale-Up Considerations for Solar Photocatalytic Reactors,” Industrial and Engineering Chemistry Research, Vol. 48, No. 19, 2009, pp. 8890-8905. doi:10.1021/ie900859z
 H. Gulyas, P. Choromanski, N. Muelling and M. Furmanska, “Toward Chemical-Free Reclamation of Biologically Pretreated Greywater: Solar Photocatalytic Oxidation with Powdered Activated Carbon,” Journal of Cleaner Production, Vol. 17, No. 13, 2009, pp. 1223-1227. doi:10.1016/j.jclepro.2009.03.008
 M. Abert, “LC-OCD-OND Analysis of Sewage Treatment Steps,” DOC-Labor Dr. Huber, Analytical Services and LC-OCD Systems, Karlsruhe, 2008. http://www.doc-labor.de/Example_Report_WASTE.pdf
 S. Liu, M. Lim, R. Fabris, C. W. K. Chow, M. Drikas, G. Korshin and R. Amal, “Multi-Wavelength Spectroscopic and Chromatography Study on the Photocatalytic Oxidation of Natural Organic Matter,” Water Research, Vol. 44, No. 8, 2010, pp. 2525-2532. doi:10.1016/j.watres.2010.01.036
 L. A. Tercero Espinoza and F. H. Frimmel, “A Simple Simulation of the Degradation of Natural Organic Matter in Homogeneous and Heterogeneous Advanced Oxidation Processes,” Water Research, Vol. 43, No. 16, 2009, pp. 3902-3909. doi:10.1016/j.watres.2009.04.028
 C. S. Uyguner and M. Bekbolet, “A Comparative Study on the Photocatalytic Degradation of Humic Substances of Various Origins,” Desalination, Vol. 176, No. 1-3, 2006, pp. 167-176. doi:10.1016/j.desal.2004.11.006
 R. J. Bryant and A. M. McClung, “Volatile Profiles of Aromatic and Non-Aromatic Rice Cultivars Using SPME/ GC-MS,” Food Chemistry, Vol. 124, No. 2, 2011, pp. 501- 513. doi:10.1016/j.foodchem.2010.06.061
 J. Meng, Y. Fang, J. Gao, A. Zhang, J. Liu, Z. Guo, Z. Zhang and H. Li, “Changes in Aromatic Compounds of Cabernet Sauvignon Wines during Ageing in Stainless Steel Tanks,” African Journal of Biotechnology, Vol. 10, No. 55, 2011, pp. 11640-11647.
 Miljostyrelsen, “Afgivelse og Vurdering af Kemiske Stoffer fra Udvalgte Elektriske og Elektroniske Produkter—del 2,” Kortlagning af Kemiske Stoffer i Forbrugerprodukter nr. 66, Danish Ministry of the Environment, Copenhagen, 2005. http://www2.mst.dk/common/Udgivramme/Frame.asp?http://www2.mst.dk/udgiv/publikationer/2005/87-7614-825-4/html/helepubl.htm
 J. E. N. Dolatabadi and S. Kashanian, “A Review on DNA Interaction with Synthetic Phenolic Food Additives,” Food Research International, Vol. 43, No. 5, 2010, pp. 1223-1230. doi:10.1016/j.foodres.2010.03.026
 BUND, “Rosen mit Pestiziden Belastet—Analyse des BUND,” Flyer of Bund für Umwelt- und Naturschutz Deutschland e.V., Berlin, 2012. http://www.bund.net/fileadmin/bundnet/publikationen/chemie/20120214_chemie_rosen_pestizide_hintergrund.pdf
 O. Delhomme and M. Millet, “Azaarenes in Atmospheric Particulate Matter Samples of Three Different Urban Sites in East of France,” Atmospheric Environment, Vol. 47, 2012, pp. 541-545. doi:10.1016/j.atmosenv.2011.06.044
 J. Lenicek, M. Sekyra, K. Bednárkova, I. Benes and F. Sipek, “Fractionation and Chemical Analysis of Urban Air Particulate Extracts,” International Journal of Environmental Analytical Chemistry, Vol. 77, No. 4, 2000, pp. 269-288.
 D. L. Courson, C. D. Flemming, K. J. Kuhlmann, J. W. Lane, J. H. Grabau, C. R. Miller, J. M. Cline, B. J. Larcom and J. C. Lipscomb, “Smoke Production and Thermal Decomposition Products from Advanced Composite Materials,” In: D. E. Dodd, Ed., 1996 Toxic Hazards Research Annual Report, United States Air Force Armstrong Laboratory, Dayton, 1997, pp. 133-147.
 M. Meyer zu Reckendorf, “Identification of Phenyl-Substituted Polycyclic Aromatic Compounds in Ring Furnace Gases Using GC-MS and GC-AED,” Chromatographia, Vol. 45, No. 1, 1997, pp. 173-182. doi:10.1007/BF02505557
 A. G. Bubnov, V. I. Grinevich and O. N. Maslova, “Barrier-Discharge Plasma Treatment of Surface Water to Remove Organic Compounds,” Russian Journal of Applied Chemistry, Vol. 79, No. 6, 2006, pp. 934-940. doi:10.1134/S1070427206060139
 X. Liu, K. Ji and K. Choi, “Endocrine Disruption Potentials of Organophosphate Flame Retardants and Related Mechanisms in H295R and MVLN Cell Lines and in Zebrafish,” Aquatic Toxicology, Vol. 114, 2012, pp. 173-181. doi:10.1016/j.aquatox.2012.02.019
 W. FOllmann and J. Wober, “Investigation of Cytotoxic, Genotoxic, Mutagenic, and Estrogenic Effects of the Flame Retardants Tris-(2-chloroethyl)-phosphate (TCEP) and Tris-2-chloropropyl)-phosphate (TCPP) in Vitro,” Toxicology Letters, Vol. 161, No. 2, 2006, pp. 124-134. doi:10.1016/j.toxlet.2005.08.008