Organic Hazardous Substances in Graywaterfrom Swedish HouseholdsHelena Almqvist1and Jörgen Hanæus2Abstract: The concentrations of several selected organic hazardous substances were investigated in domestic graywater. In total, 41 of81 organic hazardous substances were found in concentrations above the detection limits 共nonylphenol and octylphenol ethoxylates,brominated flame-retardants, organotin compounds, polyaromatic hydrocarbons, polychlorinated biphenyls, phthalates, linear-alkyl ben-zene sulfonate, and triclosan兲. Moreover, total solids, biochemical oxygen demand 共BOD7兲, chemical oxygen demand 共COD兲, totalnitrogen, total phosphorus, potassium, and sulphur were investigated and presented for graywater. Another objective was to suggestpotential household sources for a selected number of organic hazardous substances. The present and past investigations reveal householdsto be obvious contributors of organic hazardous substances to municipal wastewater, and that graywater is an important media in thistransport. The spreading derives from diffuse household sources like everyday activities 共laundry, cleaning, etc.兲, the wearing down ofthings such as pipe material and interior fittings, and from airborne deposition.DOI: 10.1061/共ASCE兲0733-9372共2006兲132:8共901兲CE Database subject headings: Wastewater management; Hazardous wastes; Municipal wastes; Organic chemicals; Sustainabledevelopment; Sampling; Sweden.IntroductionThe effluents of wastewater treatment plants have been shown tobe significant pathways for hazardous substances to enter anaquatic environment 共Daughton and Ternes 1999; Heberer 2002兲.A complete mineralization of xenobiotic compounds in treatmentsystems is rare, with the term biotransformation more accuratelydescribing the potential changes of such compounds 共Byrns2001兲. Some compounds are biotransformed into harmless prod-ucts and become degraded. Other compounds form metabolitesthat may be more or less toxic than the parent, while others maystill prove to be generally recalcitrant and persist within the treat-ment plant 共Byrns 2001; Heberer 2002兲. Hazardous substancesthat resist degradation in wastewater treatment plants 共WWTPs兲may remain in the effluent, and are either emitted to the receivingwater or enter the sludge directly. In areas where surface wateroriginating partly from the effluent wastewater is used as a rawwater source for drinking water production, concentrations ofthese substances may gradually build up and pose a risk to humanhealth 共van der Voet et al. 2004兲. Hazardous substances that es-cape water and wastewater treatment continue to raise increasingconcerns, especially regarding their potential effects in waterecosystems and on human fertility 共SIWI 2004兲. Numeroussources of wastewater generation exist in urban areas—households, enterprises, public locations, industries, storm drain-age, etc. Substances totaling 30,000 are regarded as everydaychemicals 共Commission of the European Communities 2001兲 thatare regularly used in households, with Eriksson et al. 共2002兲 fur-ther claiming that more than 900 xenobiotic organic compoundsmay potentially appear in graywater.Apart from the operation and maintenance of existing systems,wastewater management also includes the planning for futurewastewater strategies and investments. To evaluate existingwastewater systems and develop new wastewater strategies, reli-able information regarding the characteristics of domestic andmunicipal wastewater fractions 共urine, feces, graywater, andstormwater兲 is needed. Graywater is generally defined as house-hold wastewater without any input from toilets, i.e., wastewaterproduced from bathing, showering, hand washing, laundry, andthe kitchen sink. Present knowledge about the characteristics ofgraywater is rather limited and there is an urgent need for moreof this information to evaluate, e.g., the chemical risk potentialfor graywater reuse and its effects in receiving waterbodies共Jefferson et al. 1999; Eriksson et al. 2002; Palmquist 2004兲.According to Eriksson et al. 共2002兲, the literature data on gray-water characteristics clearly focuses on oxygen consumingcompounds 关biochemical oxygen demand 共BOD兲 and chemicaloxygen demand 共COD兲兴, nutrients, and some species of microor-ganisms. A small number of studies report on heavy metals, whileinformation about organic hazardous substances in graywater isvery limited.Objectives and ScopeThe objective of this paper is to present the concentrations ofseveral selected organic hazardous substances and macronutrientsfrom domestic graywater and add this data into the recognized1Lulea Municipality, Technical Dept., Water and WastewaterManagement, SE-97185 Lulea, Sweden. E-mail: [email protected], Dept. of Civil and Environmental Engineering, Division ofSanitary Engineering, Lulea Univ. of Technology, SE-97187 Lulea,Sweden. E-mail: [email protected]. Discussion open until January 1, 2007. Separate discussionsmust be submitted for individual papers. To extend the closing date byone month, a written request must be filed with the ASCE ManagingEditor. The manuscript for this paper was submitted for review and pos-sible publication on January 6, 2005; approved on December 5, 2005.This paper is part of the Journal of Environmental Engineering, Vol.132, No. 8, August 1, 2006. ©ASCE, ISSN 0733-9372/2006/8-901–908/$25.00.JOURNAL OF ENVIRONMENTAL ENGINEERING © ASCE / AUGUST 2006 / 901information gap in this area. A total of 81 organic compounds关nonylphenol and octylphenol ethoxylates, brominated flame-retardants, organotin compounds, polyaromatic hydrocarbons共PAHs兲, polychlorinated biphenyls 共PCBs兲, phthalates, linearalkyl benzene sulfonate 共LAS兲 and triclosan兴 were investigated,as well as total solids 共TS兲, biochemical oxygen demand 共BOD7兲,chemical oxygen demand 共COD兲, total nitrogen 共Ntot兲, total phos-phorus 共Ptot兲, potassium 共K兲, and sulphur 共S兲. A further objectivewas to suggest potential household graywater sources for a se-lected number of organic hazardous substances.MethodsA restricted number of substances were selected for the investi-gation, with the selection of organic hazardous substances prima-rily conducted from the following criteria 共Palmquist and Hanæus2004兲:• The substances being potentially hazardous,• The high analytical costs for organic and inorganic
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