Department Environmental Social Sciences

Achieving long-term use of solar water disinfection in Zimbabwe

Project description

Household water treatment can guarantee safe drinking water to prevent diarrhea and cholera. However, high compliance and sustainable use is seldom achieved. The present study designed and evaluated several promotion strategies for solar water disinfection (SODIS), based on results from a baseline survey. Visits to inform households about the costs and benefits of SODIS combined with public commitment and memory aids were emerged as the best strategy, resulting in 80-90% of households using SODIS even 14 months after intervention.

 

Context

The consumption of unsafe water is one of the main causes of diarrhea, which leads to the deaths of an estimated of 760,000 children under the age of five worldwide each year. Households in the peri-urban areas of Harare, Zimbabwe drink unsafe water from wells, surface water, or intermittent piped water supply. Episodes of cholera are frequent in these areas. Household water treatment systems, such as solar water disinfection (SODIS), could prevent a large proportion of diarrhea cases. However they are neither frequently nor consistently used.



Objectives
The main objective of this study was to find out which behavior change strategy would be most effective in securing high compliance and sustained use of SODIS. For that purpose, first, SODIS was introduced in communities in peri-urban areas of Harare. Then, different behavior change strategies were developed and evaluated with regard to the population’s sustainable uptake of SODIS.



Activities
Step 1 + 2: Identify, measure, and determine behavioral factors of SODIS use.

  • A baseline survey was conducted.
  • A doer/non-doer analysis revealed the following behavioral factors to explain SODIS use: Knowledge about the safety of raw water (health knowledge), beliefs about the expensiveness, taste, and how time-consuming or difficult to perform SODIS is, belief about what others think about SODIS (others’ approval), and whether performing SODIS is intended in the future (intention) and perceived as a habit.


Step 3: Select behavior change techniques (BCTs) and design behavior change strategies to enhance SODIS use. The following behavior change strategies were designed:

  • Visits using the BCT inform households about and assess costs and benefits were followed by public commitment and the use of memory aids such as a reminder notice.
  • The BCT prompt talk to others was used for a pass-on task for which community members were trained to convince other persons to use SODIS, who in turn should convince more persons, generating a ‘snowball effect’.
  • The pass-on-task in combination with the BCT highlight the discrepancy between set goal and actual behavior contrasted desirable behaviors with actual practices.


Step 4: Implement and evaluate behavior change strategies for SODIS use

  • The behavior change strategies were evaluated through a before-after control trial.
  • The strategies were implemented in four different areas. A fifth area served as control group.
  • Behavioral factors and SODIS use were surveyed several times. The last survey was conducted 14 months after the latest intervention.
  • The effectiveness of the promotion activities was measured by observing whether the households had SODIS bottles exposed to the sun.


Findings
The most effective strategy was the visit to inform households about and assess costs and benefits in combination with public commitment and the use of memory aids such as a reminder notice.
In the areas receiving these strategies, 80-90% of the households were still using SODIS 14 months after the intervention had ended.


 
Conclusion
This project revealed that systematic behavior change strategies make it possible to achieve highly frequent and sustainable use of household water treatment and thus the safe water consumption levels necessary for improved health.

Publications

Achieving long-term use of solar water disinfection in Zimbabwe

Objectives: To use a psychological theory of behavioural change to measure and interpret the effectiveness of different promotional strategies for achieving long-term usage of a household water treatment and safe storage (HWTS) system in peri-urban Zimbabwe.
Study design: Solar disinfection (SODIS) was introduced into five peri-urban communities near Harare, Zimbabwe. Six different interventions were developed and were applied in four communities in different combinations, with the fifth remaining as a control area where no interventions were implemented.
Methods: Throughout the 26 months of the study nine longitudinal panel surveys were conducted in which SODIS usage was estimated using three separate metrics: reported, calculated, and observed. A total of 1551 people were interviewed.
Results: The three indicators of SODIS usage broadly agreed with one another. By any measure, the most effective intervention was household visits by trained promoters in combination with persuasion. Households which received household visits maintained SODIS usage rates of 65% or more, even six months after the cessation of all promotional activities. Households receiving other interventions were significantly less effective. Interventions like prompts or public commitment after the application of household visits were effective at maintaining good practices once these were established.
Conclusions: Household promotion in combination with persuasion appears more effective than other approaches, especially when followed with interventions targeting the maintenance of the new behaviour. With this intervention it is possible that around 65% of the households continue to use solar water disinfection (SODIS) more than two years after the initial promotion, and six months after the end of all interventions
Mosler, H. J.; Kraemer, S. M.; Johnston, R. B. (2013) Achieving long-term use of solar water disinfection in Zimbabwe, Public Health, 127(1), 92-98, doi:10.1016/j.puhe.2012.09.001, Institutional Repository

Effectiveness and effects of promotion strategies for behaviour change: solar water disinfection in Zimbabwe

Solar water disinfection (SODIS) is a sustainable method of water treatment. Despite the simplicity and many advantages of SODIS, past behaviour change campaigns have seen limited success. This study aims to compare intervention strategies in their efficiency in changing behaviour and to analyse which behavioural factors are differentially affected. The following factors were analysed in this study: intention, subjective norm, behavioural control, beliefs, habits, frequency of talking, knowledge and tension. The promotion strategies used in this intervention study were promoters, a pass-on task, prompts, public commitment and disseminating knowledge with inducing tension. Inhabitants of high-density areas near Harare, Zimbabwe, were interviewed at different points in time. High SODIS consumption was achieved when the promoter intervention was followed by a memory-aiding technique such as prompts or public commitment. Consequently, this combined-intervention strategy increased all behavioural factors and kept them at a high level. A continued pass-on task alone did not change behaviour and had decreasing effects on several behavioural factors. When the pass-on task was combined with disseminating knowledge with inducing tension, high SODIS water consumption was also reached, but several behavioural factors stayed at a low level. More effective intervention strategies are identified and discussed.
Kraemer, S. M.; Mosler, H.-J. (2012) Effectiveness and effects of promotion strategies for behaviour change: solar water disinfection in Zimbabwe, Applied Psychology, 61(3), 392-414, doi:10.1111/j.1464-0597.2011.00475.x, Institutional Repository

Which psychological factors change when habitual water treatment practices alter?

Aim. Household water treatment systems (HWTS) and safe storage systems are an effective measure to ensure safe water supply. The adoption of HWTS requires long-term changes in behavior. During campaigns for health related behavior change, many people appear to have fixed behavioral patterns that are difficult to change. Since behavior change originates in the altering of inner psychological factors, it is necessary to investigate the transformation of these factors. Five categories of psychological factors are identified as responsible for the formation of habitual behavior: risk beliefs, attitudinal beliefs, normative beliefs, ability beliefs, and maintenance beliefs. This study analyzes which factors change when long-term users of HWTS, non-users, or 'tryers' (using HWTS occasionally), transform their behavior type or remain in their current behavior type.
Subjects and methods. Data were obtained by conducting six panel interviews about the use of solar water disinfection (SODIS) over a period of 14 months, with 694 households, in the slum areas of Harare, Zimbabwe.
Results. The results reveal that progressing to a higher level of user type (one who increases their use of SODIS), or staying at a high level of use (maintaining their level of use) is associated with the user’s ability to avoid being hindered by other habits, to remember the behavior in respective situations, and to notice that other people are also using SODIS.
Conclusion. Suggested strategies which may foster these factors include the control of distracting stimuli, forming implementation intentions, daily routine planning, applying reminders, and using public commitments.
Mosler, H.-J.; Kraemer, S. (2012) Which psychological factors change when habitual water treatment practices alter?, Journal of Public Health (Berlin, Heidelberg), 20(1), 71-79, doi:10.1007/s10389-011-0435-1, Institutional Repository

Factors from the transtheoretical model differentiating between solar water disinfection (SODIS) user groups

Solar water disinfection (SODIS) is a sustainable household water treatment technique that could prevent millions of deaths caused by diarrhoea. The behaviour change process necessary to move from drinking raw water to drinking SODIS is analysed with the Transtheoretical Model of Change (TTM). User groups and psychological factors that differentiate between types of users are identified. Results of a 1.5 year longitudinal study in Zimbabwe reveal distinguishing factors between groups, from which it can be deduced that they drive the development of user groups. Implications are drawn for campaigns with the aim of bringing all user types to a regular use.
Kraemer, S. M.; Mosler, H.-J. (2011) Factors from the transtheoretical model differentiating between solar water disinfection (SODIS) user groups, Journal of Health Psychology, 16(1), 126-136, doi:10.1177/1359105310370630, Institutional Repository

Solar water disinfection (SODIS): a review from bench-top to roof-top

Solar water disinfection (SODIS) has been known for more than 30 years. The technique consists of placing water into transparent plastic or glass containers (normally 2 L PET beverage bottles) which are then exposed to the sun. Exposure times vary from 6 to 48 h depending on the intensity of sunlight and sensitivity of the pathogens. Its germicidal effect is based on the combined effect of thermal heating of solar light and UV radiation. It has been repeatedly shown to be effective for eliminating microbial pathogens and reduce diarrhoeal morbidity including cholera. Since 1980 much research has been carried out to investigate the mechanisms of solar radiation induced cell death in water and possible enhancement technologies to make it faster and safer. Since SODIS is simple to use and inexpensive, the method has spread throughout the developing world and is in daily use in more than 50 countries in Asia, Latin America, and Africa. More than 5 million people disinfect their drinking water with the solar disinfection (SODIS) technique. This review attempts to revise all relevant knowledge about solar disinfection from microbiological issues, laboratory research, solar testing, up to and including real application studies, limitations, factors influencing adoption of the technique and health impact.
McGuigan, K. G.; Conroy, R. M.; Mosler, H.-J.; du Preez, M.; Ubomba-Jaswa, E.; Fernandez-Ibañez, P. (2012) Solar water disinfection (SODIS): a review from bench-top to roof-top, Journal of Hazardous Materials, 235, 29-46, doi:10.1016/j.jhazmat.2012.07.053, Institutional Repository

Persuasion factors influencing the decision to use sustainable household water treatment

Solar water disinfection (SODIS) is a sustainable water treatment method. With the help of the sun and plastic bottles, water is treated and illnesses prevented. This paper aims to identify the factors influencing SODIS uptake, that is, why someone may become a SODIS user. This uptake decision can be influenced by persuasion. From behaviour theory, variables are recognised which have been proven to influence intention and behaviour and simultaneously can be influenced by persuasion. A total of (n = 878) structured interviews were conducted in a field study in Zimbabwe. Linear and binary logistic regressions showed that several of the initially proposed persuasion variables have significant influence. Persuasion factors have a stronger influence on the uptake of SODIS use and on intention to use SODIS in the future than on the amount of SODIS water consumed. Ideas are presented for using the effective variables in future SODIS campaigns and campaigns in other fields.
Kraemer, S. M.; Mosler, H.-J. (2010) Persuasion factors influencing the decision to use sustainable household water treatment, International Journal of Environmental Health Research, 20(1), 61-79, doi:10.1080/09603120903398301, Institutional Repository