A survey of attitudes and acceptance of wastewater reuse in Iran: Shiraz City as a case study

People ’ s attitudes are a key issue in the use of reclaimed wastewater. Unfortunately, there is not enough research on the use of reclaimed wastewater in developing countries such as Iran. The present study aimed to investigate public acceptance and citizens ’ attitudes toward reclaimed wastewater in Shiraz, Iran. A two-part questionnaire, designed to collect demographic data and information about people ’ s willingness to reuse wastewater, was distributed among 562 citizens of Shiraz. The results showed that most respondents knew nothing about the chemical quality (67.4%) or microbiological quality (81.5%) of the wastewater treatment plant ef ﬂ uent. The maximum acceptance of treated wastewater use was related to public consumption (87%), car washing (85%) and ﬂ ush tank (80%), respectively. The minimum acceptance was related to cooking and drinking (8%). Also, a signi ﬁ cant correlation was observed between citizens ’ willingness to use reclaimed wastewater and variables such as level of education, gender, awareness of wastewater treatment process and awareness of quality of reclaimed wastewater. Shiraz citizens, like other people in the world, were less willing to use reclaimed wastewater for cooking, drinking, laundry and bathing, but their willingness was obviously greater in applications with less skin contact.


INTRODUCTION
During recent decades, increasing water demand on one hand and increasing droughts and imbalance in rainfall in different areas of the world on the other have clearly highlighted the importance of alternative sources of water (Menegaki et al. ; Bakopoulou et al. ). Reclaimed wastewater is a valuable alternative source (Bakopoulou et al. ). Using this valuable resource is an important way to reduce the pressure on water sources (Matos et al. ), and it is taken into consideration as an essential part of water resource management (Marlow et al. ).
In the past three decades, focus on wastewater reuse has significantly increased (Tram Vo et al. ) and today, in many areas of the world, wastewater reuse plans are being implemented (Baghapour et al. ). Several studies have been conducted on various aspects of wastewater reuse, but it should be noted that public acceptance is the most important factor for sustainable use of wastewater (Buyuk- been reported that in the 1990s in the United States, a number of wastewater reuse projects stalled due to strong public opposition and even then people had used terms like 'Toilet to Tap' and 'Sewage Beverage' to describe Shiraz is located in southwest Iran. The average annual precipitation in this city is about 335 mm. Its climate is arid and semi-arid and frequent droughts of different intensities are one of the main characteristics. Shiraz has a population of over 1.2 million people and is one of the six major cities in Iran. Electronics and petrochemical industries are the main industrial activities in Shiraz. Tourism is one of the main sources of people's income and agriculture also plays a major role in the city's economy. A municipal wastewater treatment plant which is located in the southeastern part of the city uses the conventional activated sludge process for wastewater treatment. The final coverage of inhabitants by this plant will be 584,000 and the current module covers 409,000 inhabitants. The Shiraz Regional Water Authority intends to use 29.5 million cubic metres of effluent from this plant for various applications (agricultural irrigation, landscape irrigation and groundwater recharge) (Baghapour et al. ).

Questionnaire and sampling
To measure Shiraz citizens' willingness to reuse reclaimed wastewater, a multiple choice questionnaire was prepared.
The questionnaire had three main parts: the first one determined the respondents' demographic data, including age, gender and level of education. The second part determined the level of respondents' awareness about environmental issues including awareness about wastewater treatment processes, treated wastewater quality (physical, chemical and biological) and shortage of water resources in Shiraz. The third part determined Shiraz citizens' willingness to use reclaimed wastewater for 11 different purposes: public consumption (landscape and parks irrigation, firefighting), car washing, flushing toilet, air conditioning, house cleaning, irrigation of crops which are consumed raw, irrigation of crops which are cooked, fish farming, washing clothes, cooking and drinking. Respondents who did not wish to use reclaimed wastewater for any of these purposes, were asked to specify their reason by choosing one of the options: religious, health concerns, aesthetic reasons (colour, odour and turbidity). Questionnaires were distributed in 10 districts of Shiraz Municipality and were completed by faceto-face interviews. The number of questionnaires distributed in each municipal district was determined based on its population size. At the first step, a number of streets were randomly selected in each district, then four houses were arbitrarily selected in each street and almost three questionnaires per house were completed. Participants were selected from 15-70-year-old residents.

Statistical analysis
Kruskal-Wallis and Mann-Whitney statistical tests were used to determine the relationship between citizens' willingness to use reclaimed wastewater and independent variables such as citizens' awareness of wastewater treatment processes, water scarcity and effluent quality. The chi-square test was used to survey the relationship between level of education and gender and acceptance of every reuse option, and one-way analysis of variance (ANOVA) test was used to study the relationship between age and acceptance. All statistical analyses were performed using SPSS version 21 and Microsoft Excel 2010.

RESULTS
A total of 562 questionnaires were completed by Shiraz citizens. The response rate of the participants was approximately 75%. Demographic data obtained from questionnaires are shown in Table 1. A slightly higher percentage of women than men participated. The 20-29-year-old group with 208 (37.0%) respondents had the maximum percentage of respondents; the 40-49 and older than 50-year-old groups with 73 (13.0%) and 72 (12.8%) respondents, respectively, had the minimum percentages of respondents. Moreover, almost half of participants (almost 57%) in this study had an academic degree.
Also, the results showed that citizens' awareness about physical, chemical and biological quality of wastewater treatment plant effluent was 51.0, 18.5 and 32.6%, respectively.
On average, 58.2% of respondents agreed with reclaimed wastewater reuse in various applications, only 24.1% of respondents disagreed and 17.7% had no opinion. Figure 1 shows the results of Shiraz citizens' willingness to use reclaimed wastewater for different purposes. As can be seen in Figure 1, 74.9% of respondents were opposed to using reclaimed wastewater for cooking and drinking, and only 8.9% agreed with using it. More than half of respondents agreed with the use of reclaimed wastewater in irrigation; 21.5 and 14.9% of people opposed its use in irrigation of crops which are consumed raw and irrigation of crops which are cooked, respectively. The data showed that 45.2, 32.0 and 39.3% of Shiraz citizens agreed with the use of reclaimed wastewater in fish farming, bathing and washing clothes. Also, the maximum willingness to use reclaimed wastewater was related to public consumption (87.7%), car washing (85.8%), air conditioning (70.1), flush tank (81.0%) and house cleaning (68.7%). Thus, the status of Shiraz citizens' acceptance for various applications was as follows: public consumption > car washing > flushing toilet > air conditioning > house cleaning > agricultural irrigation (crops which are cooked before eating) > agricultural irrigation (crops which are consumed raw) > fish farming > washing clothes > bathing > cooking > drinking.
The respondents who did not agree with any of the uses mentioned selected from the religious, health and aesthetic options as the reason for their opposition; their reasons are presented in Figure 2. As can be seen, the main reason for opposition was health concerns while religious and aesthetic concerns were less important. In addition, only in air conditioning, are aesthetic concerns significantly high (39.6%). From the religious point of view, the highest concern was related to public consumption (17.5%). In The results from our study also showed that in applications such as bathing, washing clothes, irrigation of crops that are consumed raw and house cleaning, men tend to favour reuse of wastewater significantly more than women. The results of studies by Wester et al. () and Dolnicar & Schäfer () were also similar.
Many studies have shown that, in general, women accept fewer risks than men, and men generally accept more new technologies. The reason of this is not been fully known but researchers believe that probably it is due to social and biological differences between women and men (Miller & Buys ). In the use of reclaimed wastewater, this difference could be due to women's greater concern about family and children safety.
Although some previous studies have shown that older people see more risks in reclaimed reuse than others (Wester et al. ), in this study, no significant differences were observed between different age groups. Friedler et al.
() also did not find a correlation between age and support of reuse.
Awareness about water sources scarcity and current or future drought phenomenon may also be an important factor in people's willingness to use reclaimed wastewater.
People who experienced water use limitations are more willing to use reclaimed wastewater (Wester et  In other words, when communities face the problem of water scarcity, reclaimed wastewater as an alternative water source is usually more accepted by people, but in communities where access to freshwater resources is more assured, people are less willing to use reclaimed wastewater (Exall et al. ). It is expected that in the future, by experiencing water scarcity, Shiraz citizens will consider reclaimed wastewater as an alternative source of water more seriously.
This study also showed that people who were more aware of wastewater treatment processes as well as physical, chemical and biological quality, had generally higher willingness to use reclaimed wastewater. This may be due to more positive impressions of treated wastewater in these people. They know that quality of treated wastewater is basically different from raw wastewater, and use of it may be oppose such projects. The study also revealed that, like the rest of the world, Shiraz citizens tend to use reclaimed wastewater in applications with low skin contact, such as public consumption (88%), car washing (86%), air conditioning (70%), toilet flush tank (81%), house cleaning (69%) and irrigation (crops that are consumed raw (56%), and cooked food crops (64%)). Nearly 75% of respondents opposed the use of this kind of water for drinking and cooking and they stated health concerns as the main reason for their opposition.
Overall, it can be said that Shiraz citizens support reclaimed wastewater reuse well, also education and awareness via mass media and advertising campaigns can increase this support and the likelihood of successful implementation of reclaimed wastewater reuse projects.