Science of the Total Environment 348 2005 151 163 www elsevier com locate scitotenv Hazardous substances in separately collected grey and blackwater from ordinary Swedish households Helena Palmquist Jo rgen Han us Division of Sanitary Engineering Lulea University of Technology SE 971 87 Lulea Sweden Received 15 July 2004 accepted 22 December 2004 Available online 11 February 2005 Abstract The objective of this paper is to present the mass flows of a number of selected hazardous substances in raw separate greyand blackwater from ordinary Swedish households The Vibyasen housing area was selected for the investigation since its wastewater system has separate flows for grey and blackwater Due to the high analytical costs a limited number of hazardous substances had to be selected and the number of samples restricted The greywater flow was manually measured and the samples were collected at set time intervals The blackwater samples were randomly collected from a blackwater tank A total of 105 selected hazardous substances were measured in both fractions Of the 24 elements Ca Fe K Mg Na S Al Ag As Ba Bi Cd Co Cr Cu Hg Mn Ni Pb Pt Sb Sn Te Zn measured in both fractions 22 were detected in the greywater and 23 in the blackwater 81 organic substances were selected and measured in both fractions nonylphenol and octylphenol ethoxylates brominated flame retardants organotin compounds PAH PCB phthalates monocyclic aromatics and triclosan 46 organic substances were found in greywater and 26 in blackwater PCB was the only group found in neither grey nor blackwater The greywater flow fluctuated with a specific average flow of 66 L per person and day The composition of blackwater also fluctuated with shifting proportions of urine faeces and flush water The specific average blackwater flow was 28 5 L per person and day The mixture of substances in separate wastewater fractions from Swedish households was too complex to exactly distinguish their specific sources D 2005 Elsevier B V All rights reserved Keywords Blackwater Greywater Hazardous substances Households Mass flow Metals Organic compounds 1 Introduction The content of hazardous elements and organic substances in wastewater and sludge reflects a Corresponding author Tel 46 920 491452 fax 46 920 491493 E mail address hepa ltu se H Palmquist 0048 9697 see front matter D 2005 Elsevier B V All rights reserved doi 10 1016 j scitotenv 2004 12 052 society where large amounts of different chemicals are used for a variety of purposes For many of the numerous substances present in our society known and unknown paths to the municipal wastewater system exist In this paper substances were used in terms of bchemical elements and their compounds in the natural state or obtained by any production processQ while hazardous properties were used as 152 H Palmquist J Han us Science of the Total Environment 348 2005 151 163 the binherent capacity that a substance has to cause adverse effectsQ Commission of the European Communities 2001 Due to efforts to reduce point sources especially industrial discharges diffuse sources presently account for the majority of wastewater pollution indicating that the role of households as wastewater polluters has become more significant To deal with this situation instruments for wastewater assessment and management need to be developed One approach is to search for household sources in wastewater systems i e in separate wastewater fractions like urine faeces and greywater The qualitative and quantitative characteristics of separate wastewater fractions may serve as a base for various wastewater management approaches such as systems analysis risk assessment substance flow analysis and communication Greywater is generally defined as household wastewater without any input from toilets corresponding to wastewater from bathing showering hand washing laundry and the kitchen sink Greywater has been estimated to account for about 70 75 vol of domestic wastewater Hansen and Kjellerup 1994 Blackwater is characterised as toilet waste from water closets faeces urine toilet paper and flush water According to Jefferson et al 1999 and the comprehensive literature review by Eriksson et al 2002 there is a lack of reliable information with respect to both the composition of greywater and the treatment and recycling technologies available for greywater Increasing the knowledge of grey and blackwater characteristics is important to fill the information gap regarding the contribution of pollutants to wastewater from households This information is useful for the management of both traditional and alternative wastewater systems Cd Co Cr Cu Hg Mn Ni Pb Pt Sb Sn Te Zn and 81 organic compounds nonylphenol and octylphenol ethoxylates brominated flame retardants organotin compounds PAH PCB phthalates monocyclic aromatics and triclosan were investigated as well as the ordinary wastewater parameters biochemical oxygen demand BOD7 chemical oxygen demand CODCr total nitrogen N tot total phosphorus P tot total solids TS and volatile solids VS Data on the characteristics of wastewater fractions for a selected number of hazardous substances attained by the field measurements is essential to improve the prerequisites for performing substance flow analysis and chemical risk assessment of the wastewater systems A limited budget allowed measurements at only one site and due to the high analytical costs a limited number of hazardous substances had to be selected and the number of samples restricted The design and tiny dimensions of the sampling well did not allow automatic measurements of the greywater flow which instead was measured manually using a bucket and a stopwatch Consequently the greywater samples could not be collected proportional to the flow but rather at set time intervals The blackwater samples were collected from the blackwater tank randomly during mixing Raw greywater is very reactive and significant chemical changes may occur over time periods of only a few hours Jefferson et al 1999 Hence the time period for collecting the greywater samples in this investigation was restricted to 3 h The total number of samples was restricted to four for greywater and three for blackwater 3 Method 2 Objectives and scope 3 1 Selected hazardous substances This article focuses on the characteristics of greyand blackwater emphasizing the flow of hazardous substances from households The objective of this paper was to present the mass flows of a number of selected
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