Formation of halogenated disinfection by-products during ballast water chlorination

Halogenated disinfection by-products (DBPs) from ballast water treatment have attracted more attention owing to their potential threats to marine ecosystems. Chlorination is widely used in ballast water treatment, in which...

Can Simple Psychological Interventions Increase Preventive Health Investment?

Behavioral constraints may explain part of low demand for preventive health products. We test the effects of two light-touch psychological interventions on water chlorination and related health and economic outcomes using a randomized controlled trial among 3750 women in rural Kenya. One intervention encourages participants to visualize alternative realizations of the future; one builds participants’ ability to make concrete plans. After 12 weeks, visualization increases objectively measured chlorination, reduces diarrhea episodes among children, and increases savings. Effects on chlorination and savings persist after almost three years. Effects of the planning intervention are weaker and largely insignificant. Analysis of mechanisms suggests both interventions increase self-efficacy – beliefs about one’s ability to achieve desired outcomes. Visualization also increases participants’ skill in forecasting their future utility (Gabaix and Laibson 2017). The interventions do not differentially affect beliefs and knowledge about chlorination. Results suggest simple psychological interventions can increase future-oriented behaviors, including use of preventive health technologies.

Urban Water Disinfection and Mortality Decline in Lower-Income Countries

Historically, improvements in municipal water quality led to substantial mortality decline in today’s wealthy countries. However, water disinfection has not consistently produced large benefits in lower-income countries. We study this issue by analyzing a large-scale municipal water disinfection program in Mexico that increased water chlorination coverage in urban areas from 58 percent to over 90 percent within 18 months. We estimate that the program reduced childhood diarrheal disease mortality rates by 45 to 67 percent. However, inadequate sanitation infrastructure and age (degradation) of water pipes may have attenuated these benefits substantially. (JEL I12, I18, L95, O13, O18, Q25, Q53)

Chlorine As a Disinfectant in Water Treatment

Disinfection of treated water is a necessary process. For this, chlorine and its products are widely used. During the treatment process, chlorine is added to drinking water as elemental chlorine, sodium hypochlorite solution or dry calcium hypochlorite. When applied to water, each of these forms “free chlorine”, which destroys pathogenic organisms. If adequate water treatment is not readily available, the impact on public health can be devastating. Worldwide, about 1.2 billion people lack access to safe drinking water, and about 2.4 billion people lack sanitation. As per WHO, 3.4 million people die from waterrelated diseases. Drinking water chlorination will remain a cornerstone of disinfection. This is because of the wide range of benefits provided by chlorine. However, alternative disinfectants including ozone and UV radiation are available, all disinfection methods have unique benefits, limitations and costs. So, an engineer has to consider all the pros and cons of a disinfectant method properly before deciding the one to adopt. Keywords: Disinfection, Gaseous Chlorination, Sodium Hypochlorite, Calcium Hypochlorite, Ultraviolet, Ozone, Chlorine dioxide

Risk Factors of Cholera Transmission in AL-Hudeidah, Yemen (Preprint)

BACKGROUND Yemen has recently faced the largest cholera outbreak in the world since late September 2016. In 2019, 858,667 cases with 1,024 deaths were reported in 2019 where AL-Hudeidah was one of the most affected areas. OBJECTIVE This study aimed to determine the risk factors associated with cholera transmission in AL-Hudeidah city. METHODS A total of 104 cholera cases (57 females and 47 males) who presented to cholera treatment centers in Al Hudeidah city with three or more watery stools in a 24-hour period and with moderate or severe dehydration were identified. Each case was matched by age and gender with two controls who were living in the next house of the case. A semi-structured questionnaire was used to collect data on behavioral and environmental risk factors such as drinking water form public wells, storing water in containers, consumption of unwashed vegetables or fruits and sharing toilet. RESULTS The median age was 20 years (range: 5-80) for cases and 23 (range: 5-85) for controls. Only 6% of cases and 4% of controls were employed. Multivariate analysis showed that eating unwashed vegetables or fruits (OR 7.0, 95% CI: 1.6 – 30.6; P =0.012), storing water in containers (OR = 3, 95% CI: 1.3-7.3; P =0.013), drinking water from public well (OR= 2.5, 95% CI: 1.1-5.7: P= 0.022) and using public toilet (OR 5.2, 95% CI :1.1-24.4; P =0.038) were significantly associated with cholera. CONCLUSIONS Drinking water form public wells, storing water in containers, consumption of unwashed vegetables or fruits and sharing toilet are main risk factors of Cholera. Therefore, increasing awareness of population toward the importance of water chlorination and washing fruits and vegetables through health education campaign is strongly recommended.

The Potential Contamination Scenarios simulation in Case of the Water Chlorination Technological Process Violation in the Urban Environment

The research raise the question of the need to analyse and model the processes associated with the emission of the emergency-chemical hazardous substance (ECHS) in the urban environment. Because the assessment of the environmental pollution, the early and prompt prediction of the scale of contamination in the event of releases is the potent poisonous substance (PPS) into the environment in case of accidents (destructions) at chemically hazardous facilities remains an urgent issue. We emphasize that in order to ensure the life of any settlement, there is a need for the availability of drinking water that meets sanitary standards and hygienic rules. Chlorination is traditionally used in most of the country's settlements. To take timely measures to eliminate accidents with the emission of chlorine, the most accurate results of calculating the main indicators are necessary, such as the depth of the zone of contamination of PPS, the amount of the poisonous substance in primary and secondary clouds, the area of contamination, etc. The method of calculating these indicators is based on the use of reference tables and the coefficient method, which are convenient enough for the manual method. However, in emergencies, when serious threats to the life and health of people arise, and the situation can deteriorate rapidly, there is an acute shortage of time for a general assessment of the situation, making decisions on the organization of the rescue measures. It is obvious that the staff simply will not have enough time for scrupulous calculations, and a stressful situation, in addition, with a high degree of probability will provoke serious errors and inaccuracies.

Removal of Trihalomethanes from Water using Modified Montmorillonite

Trihalomethanes (THMs) are formed during the water chlorination process through the reaction between chlorine and the organic materials. In this research, montmorillonite (MMT) and its modified form were used to remove the THMs from the water. The optimum conditions for the best adsorption capacity were evaluated using the Taguchi design of experiments. The result of comparing MMT with its modified sulfonated form (SMMT) indicated that SMMT is a more effective adsorbent than MMT. The evaluations showed that the optimum conditions for the THMs removal occur at 20 °C, 10 mg of adsorbent, 1 mg/L of THMs concentration, and 120 min for the adsorption time. The maximum adsorption capacity of CHCl3, CHBrCl2, CHBr2Cl, and CHBr3 was achieved: 0.49, 0.45, 0.43, and 0.38 mg/g at C0 = 0.10 mg/L; 1.71, 1.62, 1.56, and 1.45 mg/g at C0 = 0.50 mg/L; and 4.43, 4.35, 4.23, and 3.67 mg/g for C0 = 5.00 mg/L, respectively. The THMs adsorption was compared between SMMT, powdered activated carbon (PAC), and granular activated carbon (GAC) and the results showed that SMMT is as effective as PAC and better than GAC and its production cost is lower than for the activated carbon.

Impact of Safe Water Programs on Water Treatment Practices of People Living with Human Immunodeficiency Virus, Ethiopia, 2008

Household water chlorination has been shown to reduce diarrhea incidence among people living with Human Immunodeficiency Virus (PLHIV). Some HIV programs in Ethiopia previously provided a socially marketed chlorination product (brand name WuhaAgar) to prevent diarrhea. To evaluate the program, we compared WuhaAgar use and water treatment practices between 795 clients from 20 antiretroviral therapy (ART) clinics and 795 community members matched by age, sex, and neighborhood. Overall, 19% of study participants reported water treatment with WuhaAgar. Being an ART clinic client was associated with reported treatment of drinking water (matched odds ratios (mOR): 3.8, 95% confidence interval (CI): 2.9–5.0), reported current water treatment with WuhaAgar (mOR: 5.5, 95% CI 3.9–7.7), and bottles of WuhaAgar observed in the home (mOR: 8.8, 95% CI 5.4–14.3). Being an ART clinic client was also associated with reported diarrhea among respondents (mOR: 4.8, 95% CI 2.9–7.9) and household members (mOR:2.8, 95% CI: 1.9–4.2) in the two weeks preceding the survey. Results suggest that promoting and distributing water chlorination products in ART clinics was effective in increasing access to and use of water treatment products among PLHIV. The positive association between ART clinic attendees and diarrhea likely resulted from the immunocompromised status of ART clinic clients.