Water use in the domestic sector: a review of evidence focusing on laundering and dishwashing

Transcription

1 Water use in the domestic sector: a review of evidence focusing on laundering and dishwashing Konstadinos Abeliotis Department of Home Economics and Ecology, Harokopio University, Athens, Greece Presenting author kabeli@hua.gr, Tel: Abstract The use of water in the domestic sector is mainly associated with issues related to essential human needs such as personal hygiene. Water is consumed in the domestic sector in the bathroom, in the kitchen activities (mainly cooking, drinking and dishwashing), for laundering, and in gardening and other recreational activities. Laundering and dishwashing are two everyday household activities that account for approximately 20% of the household water consumption. The aim of this paper is the presentation of the results of the review of the relevant literature regarding the factors that affect water consumption during these two household activities. Thus, literature indicates that the actual consumption of water in laundering and dishwashing is greatly affected, as expected, by the technological developments of the relevant appliances. However there is also a major impact caused by the consumer behaviour and everyday routines. Automatic washers, but especially dishwashers, are mainly seen as convenience machines. However, they should be seen as water saving machines, because the use of automatic dishwashers and laundering machines can result in water savings in the long run. Thus, policies are required to promote the increased market penetration of these machines or even the replacement of older machines. Keywords: domestic water use, laundering, dishwashing 1

2 Introduction Fresh water is a limited resource especially in water stressed areas such as the islands of the Aegean. Traditionally, water consumption is studied in terms of its breakdown among the agricultural, industrial and domestic sectors. Globally, water use in the domestic sector, is remarkably lower compared to the respective consumption for irrigation in agriculture. Recently, focusing on the 28 countries of the European Union (EU), it was reported that 4,265 L/cap/d (which corresponds to 88.6% of the total water consumed in the EU28) are consumed in agriculture, 436 L/cap/d (9%) are consumed in industry, while 114 L/cap/d (2,4%) are consumed at home for domestic purposes [1]. Traditional water use statistics, awareness campaigns and policy have always focused on increasing water efficiency in domestic and industrial water use. However, to put things in perspective, as explained earlier, much more water can be saved in the agricultural production processes, by reducing food waste and by introducing a change in the diet of the average EU consumer [1]. However, domestic water use is a key area of intervention because every person can relate to and act upon [2]. The aim of the present manuscript is the presentation of published empirical data focusing on the effect that clothes washing and dishwashing have on the consumption of water in the domestic sector. Both of these activities can be performed either automatically via the engagement of a washing machine or manually. The presentation is based on the review of recently published literature. Water consumption at home Water is consumed in the domestic sector for personal hygiene in the bathroom, in the kitchen activities (mainly cooking, drinking and dishwashing), for laundering, and in gardening and other recreational activities. Both laundering and dishwashing are classified as hygiene-related consumption of water, which falls within the subsistence level of consumption that satisfies essential household needs. The breakdown of water consumption at home depends on the income of the residents, the family size and structure, the habits of the residents, the type of the residence, i.e. being either a flat or a single home, and its location, which determines the ambient temperature [3]. The typical German household uses about 39% of its total water use for personal hygiene (bathing, showering, etc.), 30% for flushing toilets, 13% for laundry, 7% for dishwashing, 7% for room cleaning, washing cars and gardening and 4% for cooking and drinking [3]. A similar recent research from Australia reports 19% of total water consumption for clothes washer, 33% for shower, 17% for tap water, 1% for dishwashing, 4% for bathtub, 13% for toilet flushing, 12% for irrigation and 1% leaks [4]. Thus, based on the aforementioned data, approximately 20% of total household water consumption in modern western societies can be attributed to clothes washing and dishwashing. The optimization of water consumption in either clothes washing or dishwashing falls within the domain of Demand-Side Management (DSM). DSM can be based on (i) pricing measures and (ii) on non-pricing measures such as low-flow toilets and showerheads, water-efficient irrigation measures and water efficient devices such as washing machines and dishwashers. In general, water demand is found to be relatively price inelastic [5]. Especially, the section of consumption that is related to the hygiene of the members of the household, appears to be inelastic to variations in pricing or to water reduction campaigns [2]. Because of this poor responsiveness, non-price policies (such as low-flow equipment promotion, awareness campaigns, and education programs about water conservation) are suggested as better means for inducing consumers to use less water [5]. Laundering Washing clothes and other home textiles is one of the most widespread housework around the world. Years ago it required, and in many places around the world it still does, hard mechanical work by humans. Today, washing machines do this work in almost every private household in the developed world. The consumption of water in laundering is greatly affected, as expected, by the technological developments of the relevant appliances. However there is also a major impact caused by the consumer behaviour and everyday routines [6]. Thus, the 2

3 review of literature reveals great differences in terms of water consumption in different parts of the world due to the different degrees of technology saturation and variation of the cultural habits. Water consumption in laundering depends first of all on the technology of the washing machine. In horizontal axis machines, like the ones used in Europe, only the bottom of the wash tub is filled with water, while in vertical axis machines, which are still quite popular in the USA and Japan, the whole tub is filled with water [7]. Thus, vertical axis machines consume about double volume of water compared to horizontal machines per wash cycle [7]. In technological, again, terms the actual water consumption per wash cycle depends also on the age of the washing machine which practically indicates its year of manufacture. Figure 1 presents the evolution of water consumption for washing machines manufactured between 1970 and 2004 in Germany [8]. On a final note on technology: all the aforementioned figures refer to traditional household laundering processes which are based on the chemical interaction of laundry water and chemicals used as detergents, soil removers, etc. During the last decade, the use of ozone has emerged as an alternative for household laundering. The relevant literature indicates that ozone wash systems normally require fewer rinse steps, thus reducing water usage by an estimated 30 45%. Moreover, closed loop ozone laundering systems, which are, of course, more expensive from a capital cost point of view, are able to recover most of the water, so that reductions in water use can reach 70 75% [9]. 250 L Figure 1. Water consumption (in L) for washing machines (for 5 kg cotton load) manufactured between 1970 and 2004 [8]. Apart from technology, laundry washing habits and practices, such as the number of wash cycles per year and the average load size, greatly affect the water consumption. These are all determined by the behavior of the members of the households that are in charge of laundering. Not surprisingly, washing the clothes is still primarily a female domain globally, not that women necessarily do all the laundry, but in the sense that their norms often rule the standards of how to launder [6]. Moreover, the total number of wash cycles increase with increasing size of a household; however, the number of washes per person living in the household decreases with rising household sizes [7]. Laundering practices are constantly changing, influenced by social, cultural and moral norms such as the perception of cleanliness. Today body odours are considered repellent and daily washes and use of artificial perfumes is almost a norm [10]. These changes in social norms have led to increased washing frequency of our bodies and clothing [10]. As it is easily anticipated, another crucial factor in the washing load is the size and structure of each household. People living in individual households, a growing societal trend today, consume more water per capita compared to those living in couples or larger families. For instance, the number of wash cycles for a four-person household is almost double compared to a single household in Germany [7] while the per capita water consumption for clothes washing for a small family (up to 4 members) is almost half that of a single person in 3

4 Australia [4]; in the UK, one two-person household consumes 300 L of water per day, whereas a single occupancy consumes 210 L [2]. Also, families with teenagers have a higher total electricity consumption than others and use up 15% of their total electricity consumption on laundering [11]. Also, laundry habits vary among different cultures. The number of wash cycles per household varies in different parts of the world. For instance, 165 washing cycles are reported yearly for Western Europe, 289 for North America, 260 for Australia, 100 for China while the number climbs to 520 for Japan [7]. Based on the aforementioned interaction among the washing habits and the performance of the washing machine, overall, in different parts of the world huge differences are reported regarding electricity and water consumption for automatic laundry washing due to differences in numbers of wash cycles per year, wash temperatures, and differences in the washing technologies [7]. However, increased washing frequencies and the amount of clothing owned in Western societies offsets the technological improvements [10]. Dishwashing Automatic dishwashing is becoming more and more common in western societies. The superiority of machine over manual dishwashing in environmental terms, due to the lower consumption of energy, water and detergent, has been well documented [12]. In terms of water consumption, the authors demonstrate that more than 73% water savings can be achieved when using a dishwasher compared to manual dishwashing. The consumption of resources by a dishwasher depends on its technology. Regarding dishwasher technology, from 1990 to 2005, the average water consumption for standard size machines has been more than halved to around 13 L per cycle [13]. Also, a fifteen-year old washing machine consumes approximately twice as much energy and water to achieve the same performance as a new one, while a thirty-year old machine requires four times as much [8]. Despite the optimization of household machines, it is of paramount importance to use them correctly in order to save resources. Two researchers from Germany claim that consumers do not effectively use the new dishwasher technology, and that much water and energy are wasted in this way [13, 14]. For instance, soaking and prerinsing of the dishes, a strongly habitual practice, use at least some water and therefore this additional fraction should be added to the total consumption associated with automatic dishwashing [15, 16]. Water consumption in dishwashers, besides the age of the dishwasher, depends also on the actual program selected [15]. In order to demonstrate the advantages in water consumption of automatic over manual dishwashing, the results of resources consumption for manual washing 12 place settings soiled with seven soil types (milk, tea, minced meat, spinach, egg yolk, porridge and margarine) are presented [13]. The results of these authors, who applied Best Practice Tips for manual dishwashing, are then compared to two previous relevant studies. Focusing on water consumption, there is a great variation in its value, ranging from 42.6L for the study by Fuss et al. [13] to 113.9L reported by the previous studies [13]. Despite the presence of a dishwasher in a household, manual washing of the dishes does not become completely redundant. There are always dishes that are too bulky, or take too much space in the dishwasher, or are immediately needed, or finally, are not suitable for the dishwasher. Thus, best practices on manual dishwashing must be engaged in order to alleviate its environmental impacts. As a first step, numerous authors and consumer organizations advise for the dishes to be done in a filled sink or bowl, as they suggest that this is more economical than washing up under running tap water [13]. The situation in Greece regarding laundering and dishwashing Research on the domain of household technology in Greece is still in its infancy. Thus, the focus of this section is the presentation of some relevant data referring to Greece. According to Eurostat, the annual water consumption from public water supply by services and private households in Greece peaked in to 39 m 3 per inhabitant, or approximately 107 L per capita per day, close to the average reported for the EU28 [1]. Regarding laundering, it is reported that the ownership rate of washing machines in Greece is 95% and the average Greek household, which consists of 3 members, utilizes 177 wash cycles per year [7]. The water consumption per wash cycle is estimated as the western European average at 60 L which yields a total of

5 m 3 water consumption for clothes washing per household per year. This figure represents 22.2% of the total annual water consumption per household [7]. Figures 2 and 3 present a comparison of the data for Greece to the respective data of a few other selected EU countries. From Figure 2 it is evident that the ownership rate of washing machines in Greece is at the top of the EU countries, which means that the market can be considered as saturated. Also, the annual wash cycles in Greece are on the top of the respective number in other EU countries Greece Bulgaria Italy Portugal Spain Germany % washing machine ownership Wash cycles per year Figure 2. Washing machine ownership and annual wash cycles in Greece and other selected EU countries [7]. As a result of the high number of annual wash loads, Figure 3 presents the fact that the percentage of water consumed for laundering in Greek households is comparable to respective in Italy but it is more than double compared to respective figure is Germany, Portugal and Spain. Germany Spain Portugal Italy Bulgaria Greece 5,1 5,3 9,8 9,8 9,9 10,6 11 9,9 10,6 18,4 22,2 62, Water consumption for laundering compared to total household water consumption (%) Water consumption for clothes washing (m3) Figure 3. Water consumption for laundering in Greece and other selected EU countries [7]. Regarding dishwashing, in a recent research the rate of ownership for dishwashers in the urban region of Patras in western Greece was found to be 39% [17]. This value is close to the one reported by Richter (2010) for Italy (37%), below the 48% EU average [13] and way below the reported German average (64%) [15]. Also, the dishwasher owner in Patras belongs to the middle or older age group, belongs to the middle or higher income group, his/her family has at least 3 members, he/she owns the house [17]. Finally, the results indicate that the dishwashing machine is mainly regarded as a convenience domestic appliance by the Greek consumers, because its advantages regarding the consumption of resources are not well known [17]. 5

6 Conclusions Laundering and dishwashing are two very common households activities associated with water consumption, practiced throughout the world. The actual water consumption of the two aforementioned activities depends on the washing habits of the consumers, but also on the machine technology, if these activities are carried out by the use of automatic methods. Thus, even though modern machines are available, appreciable effects in the conservation of water still require adjustments or changes to the consumers lifestyle and usage behaviour. Given that the use of automatic dishwashers and laundering machines can result in water savings in the long run, policies are required to promote the increased penetration of these machines to more households or the replacement of older machines. Given the current financial recession in Greece, this is not very likely to be realised. References 1. D. Vanham, G. Bidoglio A review on the indicator water footprint for the EU28, Ecological Indicators, 26 (2013) G.-M. Elizondo, V. Lofthouse, Towards A Sustainable Use of Water at Home: Understanding How Much, Where and Why? Journal of Sustainable Development, 3 (1) (2010) J. Schleich, T. Hillenbrand, Determinants of residential water demand in Germany. Ecological Economics (2009) Willis R.M., Stewart R.A., Giurco D.P., Talebpour M.R., Mousavinejad A. (2011). End use water consumption in households: impact of socio-demographic factors and efficient devices. Journal of Cleaner Production, doi: /j.clepro OECD: Household Behaviour and the Environment: Reviewing the evidence. (2008). Accessed 10 July Κ. Gram-Hanssen, Consuming technologies - Developing routines. Journal of Cleaner Production, 16 (2008) C. Pakula, R. Stamminger, Electricity and water consumption for laundry washing by washing machine worldwide. Energy Efficiency, 3 (2010) R. Stamminger, A. Barth, S. Dorr, Old Washing Machines Wash Less Efficiently and Consume More Resources. Hauswirtschaft und Wissenschaft, 3 (2005) R. G. Rice, M. DeBrum, J. Hook, D. Cardis, C. Tapp, Economic and Environmental Benefits of Ozone in Ozone Laundering Systems. Ozone: Science & Engineering, 31 (2009) K. Laitala, I. G. Klepp, C. Boks, Changing laundry habits in Norway. International Journal of Consumer Studies, 36 (2012) Κ. Gram-Hanssen, Teenage consumption of cleanliness. Conference proceedings: Kitchen and bathrooms: Changing technologies, practices and social organization implications for sustainability, January 2005, The University of Manchester, UK. 12. P. Berkholz, R. Stamminger, G. Wnuk, J. Owens, S. Bernarde, Manual dishwashing habits: an empirical analysis of UK consumers. International Journal of Consumer Studies, 34 (2010) C.P. Richter, Automatic dishwashers: effective machines or less efficient consumer habits? International Journal of Consumer Studies, 34 (2010) N. Fuss, S. Bornkessel, T. Mattern, R. Stamminger, Are resource savings in manual dishwashing possible? Consumers applying Best Practice Tips. International Journal of Consumer Studies, 35 (2011),

7 15. R. Stamminger, C. Streichardt, Selected Aspects of Consumer Behaviour in the Manual and Mechanical Dishwashing in Germany. SOFW Journal, 135 (2009) J. Emmel, K. Parrot, J. Beamish: Dishwashing and water conservation: an opportunity for environmental education. Journal of Extension, 41 (1). (2003). Accessed 10 July K. Abeliotis, N. Dimitrakopoulou, M. Vamvakari, Attitudes and behaviour of consumers regarding dishwashing: The case of Patras, Greece. Journal of Cleaner Production, 62 (2012)