Hans-Joachim Mosler

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 2L PET beverage bottles) which are then exposed to the sun. Exposure times vary from 6 to 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.

A systematic approach to behavior change interventions for the water and sanitation sector in developing countries: a conceptual model, a review, and a guideline

Public health practitioners increasingly agree that it is not enough to provide people with water and sanitation hardware. Numerous approaches are used to tackle the “software” which means to ensure behavior change necessary to come along with the sanitation hardware. A review of these approaches reveals several shortcomings, most importantly that they do not provide behavioral change interventions which correspond to psychological factors to be changed. This article presents a sound psychological model, which postulates that for the formation of new habitual behavior, five blocks of factors must be positive with regard to the new behavior: risk factors, attitudinal factors, normative factors, ability factors, and self-regulation factors. Standardized tools for measuring the factors in face-to-face interviews are presented, and behavioral interventions are provided for each factor block. A statistical analysis method is presented, which allows the determination of the improvement potential of each factor.

Personal, social, and situational factors influencing the consumption of drinking water from arsenic-safe deep tubewells in Bangladesh

Naturally occurring arsenic in groundwater in Bangladesh poses a well-known public health threat. The aim of the present study is to investigate fostering and hindering factors of peoples use of deep tubewells that provide arsenic-safe drinking water, derived from the Protection Motivation Theory and the Theory of Planned Behavior. Structured personal interviews were conducted with 222 households in rural Sreenagar, Bangladesh. Multiple linear regressions were carried out to identify the most influential personal, social, and situational behavior determinants. Data revealed that social factors explained greater variance in the consumption of drinking water from deep tubewells than did situational and personal factors. In an overall regression, social factors played the biggest role. In particular, social norms seem to strongly influence deep tubewell use. But also self-efficacy and the perceived taste of shallow tubewell water proved influential. Concurrently considering other important factors, such as the most mentioned response cost (i.e., time needed to collect deep tubewell water), we propose a socially viable procedure for installing deep tubewells for the extended consumption of arsenic-safe drinking water by the Bangladeshi population.

Differences in influence patterns between groups predicting the adoption of a solar disinfection technology for drinking water in Bolivia.

The lack of safe drinking water is one of the major problems faced by developing countries. The consequences of contaminated water are diseases such as diarrhea, one of the main causes of infant mortality. Because of its simplicity, solar water-disinfection technology provides a good way of treating water at the household level. Despite its obvious advantages and considerable promotional activities, this innovation has had rather a slow uptake. We conducted a field survey in which 644 households in Bolivia were interviewed in order to gain insights on motivations that resulted in adopting the technology. The aim was to examine possible differences in the predictors for adopting this technology during the diffusion process using the theory of innovation diffusion. Our findings indicate that early adoption was predicted by increased involvement in the topic of drinking water and that adoption in the middle of the diffusion process was predicted by increased involvement by opinion leaders and by recognition of a majority who supported the technology. Finally, late adoption was predicted by recognition that a majority had already adopted. Suggestions for future promotional strategies are outlined.

Water disinfection and hygiene behaviour in an urban slum in Kenya: impact on childhood diarrhoea and influence of beliefs.

In this research project, we studied factors that presumably affect the incidence of diarrhoea among young children in urban slums in developing countries: consumption of safe drinks, hygiene behaviour, cleanliness of household surroundings and the quality of raw water. Beliefs concerning the causes of diarrhoea were also related to health-improving behaviour, namely the application of the water-treatment method SODIS (solar water disinfection) and hygiene behaviour. We conducted a survey in a shanty town in Nairobi, Kenya. Field workers interviewed 500 households. Analysis with regression models revealed that two out of the four postulated factors were significant: children have a lower risk of contracting diarrhoea when they consume high percentages of safe drinks and live in households with good hygiene. As regards beliefs, we found that biomedical knowledge of childrens diarrhoea as well as the perceived social norm for treating water was associated with the use of SODIS and good hygiene.

Attitudinal and Relational Factors Predicting the Use of Solar Water Disinfection: A Field Study in Nicaragua:

Solar water disinfection (SODIS) is an uncomplicated and cheap technology providing individuals with safe drinking water by exposing water-filled plastic bottles to sunlight for 6 hours to kill waterborne pathogens. Two communities were visited, and 81 families (40 SODIS users and 41 nonusers) were interviewed. The relationship between several factors and the intention to use SODIS in the future and actual use were tested. The results showed that intention to use and actual use are mainly related to an overall positive attitude, intention to use is related to the use of SODIS by neighbors, and actual use is related to knowledge about SODIS; SODIS users reported a significantly lower incidence in diarrhea than SODIS nonusers. These results suggest that promotion activities should aim at creating a positive attitude, for example, by choosing a promoter that is able to inspire confidence in the new technology.

Self-dissemination of environmentally-responsible behavior: The influence of trust in a commons dilemma game

Abstract It is postulated that environmentally-responsible behavior can disseminate itself. If mutual trust becomes established between the anonymous individuals in a society, they themselves can exert mutual influence upon each other to behave in environmentally-responsible ways. The concept of ‘verifiable, public commitment’ as the operating mechanism responsible for this process is derived from pertinent social theories. In the experiment, subjects, as fishermen, must subsist on lake-fishing, together with 24 other (computer-simulated) fellow players of the game. In the verifiable, public commitment condition, subjects are informed as to which of their fellow players commit themselves to restricting their catch to a moderate quota. Results demonstrate clearly that persons playing under this condition exhibit changes in fishing behavior and in trust. Further analyses reveal that verifiable, public commitment has its greatest effect upon persons whose environmental consciousness is low.

Factors Affecting Farmers Decisions on Fertilizer Use: A Case Study for the Chaobai Watershed in Northern China

The Chaobai watershed in northern China is the most important source of drinking water for Beijing. The level of fertilizer use, especially overuse, as well as farming practices in the region have a great impact on the water quality downstream and affect an enormous number of people. This study analyzes the factors influencing the farmers’ decisions on fertilizer use and the implications for water quality. The analysis is based on a survey of 349 farm households. It takes into consideration both farm and farmer specific characteristics and farmers’ subjective evaluations of factors shaping their decisions. Regression models are used to examine the determinants of fertilizer use intensity across farm households and to investigate the factors influencing the overuse of nitrogen. The results suggest that many of these subjective factors have great significance in determining famers’ decisions. The results also show that irrigation, gains in crop yield and higher earning goals are positively correlated with fertilizer use intensity, while farm size, manure application, soil fertility and the distance to fertilizer markets are negatively correlated. Investigation of the overuse problem shows that higher education level significantly reduces the probability of over-fertilization. Based on these findings a few policy relevant implications are discussed.

Acceptance and Use of Eight Arsenic-Safe Drinking Water Options in Bangladesh

Arsenic contamination of drinking water is a serious public health threat. In Bangladesh, eight major safe water options provide an alternative to contaminated shallow tubewells: piped water supply, deep tubewells, pond sand filters, community arsenic-removal, household arsenic removal, dug wells, well-sharing, and rainwater harvesting. However, it is uncertain how well these options are accepted and used by the at-risk population. Based on the RANAS model (risk, attitudes, norms, ability, and self-regulation) this study aimed to identify the acceptance and use of available safe water options. Cross-sectional face-to-face interviews were used to survey 1,268 households in Bangladesh in November 2009 (n = 872), and December 2010 (n = 396). The questionnaire assessed water consumption, acceptance factors from the RANAS model, and socioeconomic factors. Although all respondents had access to at least one arsenic-safe drinking water option, only 62.1% of participants were currently using these alternatives. The most regularly used options were household arsenic removal filters (92.9%) and piped water supply (85.6%). However, the former result may be positively biased due to high refusal rates of household filter owners. The least used option was household rainwater harvesting (36.6%). Those who reported not using an arsenic-safe source differed in terms of numerous acceptance factors from those who reported using arsenic-safe sources: non-users were characterized by greater vulnerability; showed less preference for the taste and temperature of alternative sources; found collecting safe water quite time-consuming; had lower levels of social norms, self-efficacy, and coping planning; and demonstrated lower levels of commitment to collecting safe water. Acceptance was particularly high for piped water supplies and deep tubewells, whereas dug wells and well-sharing were the least accepted sources. Intervention strategies were derived from the results in order to increase the acceptance and use of each arsenic-safe water option.

Deriving Interventions on the Basis of Factors Influencing Behavioral Intentions for Waste Recycling, Composting, and Reuse in Cuba

In this article the authors study existing waste-disposal intentions and behavior-influencing factors at the household level in Santiago de Cuba. The authors analyze the perceived reputation of the behavior, two different attitude components (sentiment and cost-value ratio), and perceived difficulties. Our focus is to compare three types of waste-disposal behaviors and derive specific interventions. The behaviors most suitable to Cuba are recycling, composting, and reuse. Analysis with structural equation modeling (SEM) reveals relevant differences in factor influence for attitude components and perceived reputation. Recycling and composting are most strongly influenced by affective aspects of attitude, whereas the general attitude toward reuse seems to have a more rational basis. The influence of perceived reputation on recycling is strong, that on composting is moderate, and no influence at all is found for reuse. The authors combine the SEM results with those of the qualitative data analysis of problems and incentives assessed from the participants and suggest behavior-specific interventions.