Wastewater generation and treatment by various eco-friendly technologies: Possible health hazards and further reuse for environmental safety

The discharge of untreated wastewater as a result of various developmental activities such as urbanization, industrialization and changes in lifestyle poses great threats to aquatic ecosystems as well as humans. Currently, ∼380 billion m³ (380 trillion liters) of wastewater is generated globally every year. Around 70% of freshwater withdrawals are used for agricultural production throughout the world. The wastewater generated through agricultural run-off further pollutes freshwater resources. However, only 24% of the total wastewater generated from households and industries is treated before its disposal in rivers or reused in agriculture. The most problematic contaminants associated with ecological toxicity are heavy metals such as Cd, Cr, Cu, Ni, Zn, Fe, Pb, Hg, As and Mn. One of the most important issues linked with wastewater generation is the residual presence of pathogenic microorganisms which pose potential health hazards to consumers when they enter into the food chain. It is estimated that in India almost USD 600 million (48.60 billion INR) is spent per year to tackle waterborne diseases (WBD). In light of this, immediate action is needed to effectively treat wastewater and develop safer reuse prospects. Various wastewater treatment technologies have been established and they work well to provide an alternative water source to meet the growing demand. The main concern towards treating wastewater is to eliminate inorganic and organic substances and lower the nutrient concentration, total solids, and microbial pathogens to prevent freshwater pollution and health risks.

Water sanitation in Karachi and its impact on health

Karachi is the largest city and premiere industrial and financial center of Pakistan yet is subjected to major infrastructure deficits. Of primary concern is poor water sanitation which has predisposed a weak healthcare system and its citizens to increased infectious diseases. In Karachi, causes of this include a mismanaged sewage system, poor urban planning, and overcrowding. Several reasons such as lack of funding, corruption, and mismanagement have exacerbated circumstances placing extra strain on Karachi's already scarce water supply. In addition, lack of maintenance and regulation of the existing system has led to increased contaminated water delivery to citizens. Consequently, outbreaks of various water borne diseases such as typhoid, helicobacter pylori, malaria, diarrhea etc have severely impacted healthcare of citizens, especially with the COVID-19 pandemic. The situation is worsened by Karachi's rapidly growing population and lack of awareness among citizens regarding safe drinking water. Prior socioeconomic disparities, and illiteracy complicate access to medications and appropriate healthcare services. However, despite weak efforts from the government, several national and international organizations continue to strive to improve access to clean, drinkable water.

Prevalence and predictors of water-borne diseases among elderly people in India: evidence from Longitudinal Ageing Study in India, 2017-18

BACKGROUND

India suffers from a high burden of diarrhoea and other water-borne diseases due to unsafe water, inadequate sanitation and poor hygiene practices among human population. With age the immune system becomes complex and antibody alone does not determine susceptibility to diseases which increases the chances of waterborne disease among elderly population. Therefore the study examines the prevalence and predictors of water-borne diseases among elderly in India.

METHOD

Data for this study was collected from the Longitudinal Ageing Study in India (LASI), 2017-18. Descriptive statistics along with bivariate analysis was used in the present study to reveal the initial results. Proportion test was applied to check the significance level of prevalence of water borne diseases between urban and rural place of residence. Additionally, binary logistic regression analysis was used to estimate the association between the outcome variable (water borne diseases) and the explanatory variables.

RESULTS

The study finds the prevalence of water borne disease among the elderly is more in the rural (22.5%) areas compared to the urban counterparts (12.2%) due to the use of unimproved water sources. The percentage of population aged 60 years and above with waterborne disease is more in the central Indian states like Chhattisgarh and Madhya Pradesh followed by the North Indian states. Sex of the participate, educational status, work status, BMI, place of residence, type of toilet facility and water source are important determinants of water borne disease among elderly in India.

CONCLUSION

Elderly people living in the rural areas are more prone to waterborne diseases. The study also finds state wise variation in prevalence of waterborne diseases. The elderly people might not be aware of the hygiene practices which further adhere to the disease risk. Therefore, there is a need to create awareness on basic hygiene among this population for preventing such bacterial diseases.

Epidemiology of floods in sub-Saharan Africa: a systematic review of health outcomes

Background

Floods have affected 2.3 billion people worldwide in the last 20 years, and are associated with a wide range of negative health outcomes. Climate change is projected to increase the number of people exposed to floods due to more variable precipitation and rising sea levels. Vulnerability to floods is highly dependent on economic wellbeing and other societal factors. Therefore, this systematic review synthesizes the evidence on health effects of flood exposure among the population of sub-Saharan Africa.

Methods

We systematically searched two databases, Web of Science and PubMed, to find published articles. We included studies that (1) were published in English from 2010 onwards, (2) presented associations between flood exposure and health indicators, (3) focused on sub-Saharan Africa, and (4) relied on a controlled study design, such as cohort studies, case-control studies, cross-sectional studies, or quasi-experimental approaches with a suitable comparator, for instance individuals who were not exposed to or affected by floods or individuals prior to experiencing a flood.

Results

Out of 2306 screened records, ten studies met our eligibility criteria. We included studies that reported the impact of floods on water-borne diseases (n = 1), vector-borne diseases (n = 8) and zoonotic diseases (n = 1). Five of the ten studies assessed the connection between flood exposure and malaria. One of these five evaluated the impact of flood exposure on malaria co-infections. The five non-malaria studies focused on cholera, scabies, taeniasis, Rhodesian sleeping sickness, alphaviruses and flaviviruses. Nine of the ten studies reported significant increases in disease susceptibility after flood exposure.

Conclusion

The majority of included studies of the aftermath of floods pointed to an increased risk of infection with cholera, scabies, taeniasis, Rhodesian sleeping sickness, malaria, alphaviruses and flaviviruses. However, long-term health effects, specifically on mental health, non-communicable diseases and pregnancy, remain understudied. Further research is urgently needed to improve our understanding of the health risks associated with floods, which will inform public policies to prevent and reduce flood-related health risks.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12584-4.

Role of biofilms in the survival of Legionella pneumophila to sodium chloride treatment

Background and Objectives

Legionnaires' disease continues to be a public health concern. Colonized water distribution systems are often implicated in Legionella transmission, despite the use of various disinfection strategies, the bacterium is capable to persist and survive in water systems. The aim of this study was to investigate the persistence of Legionella pneumophila to sodium chloride over time at different temperatures and analysing the role of biofilms in the survival of this bacteria.

Materials and Methods

L. pneumophila serogroup 1 and L. pneumophila serogroup 2-15 were used to study the effect of sodium chloride on planktonic and sessile cells. The tested concentrations were: 0.5%, 1%, 2%, 3%, 4%, 6% and 8% (W/V) NaCl. Biofilms were grown on 24-well microplates.

Results

At 20°C, L. pneumophila planktonic cells were able to survive in sodium chloride concentrations up to 2%. However, at 37°C, a sodium chloride concentration over 1.5%, reduced systematically the numbers of bacterial cells. Biofilms were grown for 20 days in the absence and presence of sodium chloride. The results show that bacterial strains were able to survive and regrow after the sodium chloride shock (2-3%). Moreover, it seems that this effect is less expressed with the age of the biofilm; old biofilms were more persistent than the young ones.

Conclusion

Results from this study demonstrate that the sodium chloride disinfection strategy was effective on Legionella pneumophila planktonic cells but not on biofilms, which demonstrate the role of biofilms in the persistence and recolonization of L. pneumophila in water distribution systems.

The nexus between improved water supply and water-borne diseases in urban areas in Africa: a scoping review protocol

Introduction: Currently, an estimated two thirds of the world population is water insufficient. As of 2015, one out of every five people in developing countries do not have access to clean sufficient drinking water. In an attempt to share the limited resource, water has been distributed at irregular intervals in cities in developing countries. Residents in these cities seek alternative water sources to supplement the inadequate water supplied. Some of these alternative sources of water are unsafe for human consumption, leading to an increased risk in water-borne diseases. Africa contributes to 53% of the diarrheal cases reported globally, with contaminated drinking water being the main source of transmission. Water-borne diseases like diarrhea, cholera, typhoid, amoebiasis, dysentery, gastroenteritis, cryptosporidium, cyclosporiasis, giardiasis, guinea worm and rotavirus are a major public health concern. The main objective of this scoping review is to map the available evidence to understand the sources of water among residents in cities in Africa and the relationship between clean water sufficiency and water-borne diseases in urban Africa.

Methods and analysis: The search strategy will identify studies published in scientific journals and reports that are directly relevant to African cities that have a population of more than half a million residents as of 2014 AND studies on the ten emerging water-borne diseases, which are diarrhea, cholera, typhoid, amoebiasis, dysentery, gastroenteritis, cryptosporidium, cyclosporiasis, giardiasis, guinea worm and rotavirus.

Ethics and dissemination: This scoping review did not require any formal ethical approval. The findings will be published in a peer-reviewed journal.

Die-off of E. coli as fecal indicator organism on different surfaces after urban floods

A better understanding of the effects of different urban and recreational surfaces on the die-off of water-borne pathogens that can cause infections after urban floods if released from surcharged combined sewers and other sources of fecal contamination is needed. The die-off of fecal indicator Escherichia coli was studied under controlled exposure to simulated sunlight on a range of different surfaces found in urban environments: gravel, sand, asphalt, pavement blocks, concrete, playground rubber tiles and grass, using glass as control. The surfaces were inoculated with artificial flooding water containing 10⁵ colony forming units (CFU) of E. coli per mL and sampled periodically using the sterile cotton swab technique, after lowering the water level. The results show that dark inactivation was not statistically significant for any surface, suggesting that chemical composition and pH (varying between 6.5 ± 0.8 and 9.2 ± 0.4) did not affect the die-off rates. The highest light-induced die-off rates for E. coli after the floodwater recession, observed on rubber (>3.46 h^-1) and asphalt (2.7 h^-1), were attributed to temperature stress and loss of surface moisture.

21st century research in urban WASH and health in sub-Saharan Africa: methods and outcomes in transition

Tackling global inequalities in access to Water, Sanitation and Hygiene (WASH) remains an urgent issue - 58% of annual diarrhoeal deaths are caused by inadequate WASH provision. A global context of increasing urbanisation, changing demographics and health transitions demands an understanding and impact of WASH on a broad set of health outcomes. We examine the literature, in terms of health outcomes, considering WASH access and interventions in urban sub-Saharan Africa from 2000 to 2017. Our review of studies which evaluate the effectiveness of specific WASH interventions, reveals an emphasis of WASH research on acute communicable diseases, particularly diarrhoeal diseases. In contrast, chronic communicable and non-communicable health outcomes were notable gaps in the literature as well as a lack of focus on cross-cutting issues, such as ageing, well-being and gender equality. We recommend a broader focus of WASH research and interventions in urban Africa to better reflect the demographic and health transitions happening. Abbreviations: CBA: Controlled Before and After; GSD: Government Service Delivery; IWDSSD: International Drinking-Water, Supply and Sanitation Decade (IDWSSD); KAP: Knowledge, Attitudes and Practices; IBD: Irritable Bowel Diseases; MDG: Millennium Development Goals; NTD: Neglected Tropical Diseases; PSSD: Private Sector Service Delivery; SDG: Sustainable Development Goals; SSA: Sub Saharan Africa; SODIS: Solar Disinfection System; STH: Soil Transmitted Helminths; RCT: Randomised Control Trial; WASH: Water Sanitation and Hygiene; WHO: World Health Organization.

Food-borne and water-borne diseases under climate change in low- and middle-income countries: Further efforts needed for reducing environmental health exposure risks

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Food- and water-borne diseases (FWBD) are a major cause of mortality and morbidity.

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Africa counts 91 million people falling ill and 137,000 dying per year by FWBD.

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Climate change could increase FWBD through bad water, sanitation and hygiene (WASH).

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Floods’ vulnerability maps of drinking water systems are important for prevention.

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Appropriate WASH interventions can significantly contribute in reducing FWBD under climate change.

This paper provides a view of the major facts and figures related to infectious diseases with a focus on food-borne and water-borne diseases and their link with environmental factors and climate change. The global burden of food-borne diseases for 31 selected hazards was estimated by the World Health Organization at 33 million disability-adjusted life years (DALYs) in 2010 with 40% of this burden concentrated among children under 5 years of age. The highest burden per population of food-borne diseases is found in Africa, followed by Southeast Asia and the Eastern Mediterranean sub-regions. Unsafe water used for the cleaning and processing of food is a key risk factors contributing to food-borne diseases. The role of quality and quantity of water to the general burden of infectious diseases deserves attention, particularly in low- and middle-income countries, as its effects go beyond the food chain. Water-related infectious diseases are a major cause of mortality and morbidity worldwide, and climate change effects will exacerbate the challenges for the public health sector for both food-borne and water-borne diseases. Selected case studies from Africa and Asia show that (i) climate change extreme events, such as floods, may exacerbate the risks for infectious diseases spreading through water systems, and (ii) improvements related to drinking water, sanitation and hygiene could result in a significant reduction of intestinal parasitic infections among school-aged children. There is a need to better anticipate the impacts of climate change on infectious diseases and fostering multi-stakeholder engagement and multi-sectoral collaborations for integrated interventions at schools, community and household levels. The paper calls for giving priority to improving the environmental conditions affecting food-borne and water-borne infectious diseases under climate change.

Engineered nanomaterials for water decontamination and purification: From lab to products

Clean water is vital for life; it is required not only for drinking but also for the preparation of food and proper hygiene. Unfortunately, more than fifty percent of the world population mainly in China and India face a severe scarcity of water. Around 1.8 billion people inevitably drink water from sources having fecal contamination resulting in the death of about a million children every year. Scientists are developing various economic technologies to decontaminate and purify water. Nanomaterials-based technology offers an economic and effective alternative for water purification and decontamination. As nanomaterials are available globally, have remarkable antimicrobial activity and the ability to effectively remove organic and inorganic pollutants from water. This review discusses the potential role of nanomaterials in the purification of drinking water. As nanomaterials exhibit remarkable antimicrobial and antiparasitic activities against waterborne pathogens and parasites of primary concern like Shigella dysenteriae, Vibrio cholera, and Entamoeba histolytica. Nanomaterials also demonstrate the ability to absorb toxic chemicals like mercury and dyes from polluted water. However, for successful commercialization of the technology, some inherent bottlenecks need to be addressed adequately. These include nanoparticles aggregation, their seepage into drinking water and adverse effects on human health and the environment. Nanocomposites are being developed to overcome these problems and to combine two or more desirable properties for water purification. Widespread and large-scale use of nanomaterials for water purification soon may become a reality. Products containing nanomaterials such as Karofi, Lifestraw, and Tupperware for water purification are already available in the market.

Water-borne diseases, cost of illness and willingness to pay for diseases interventions in rural communities of developing countries

BACKGROUND

Almost one third of the global population is living in developing South Asia where disease occurrence is high especially in rural areas and people are unaware of water-borne diseases and cost of illness.

METHODS

The quantitative approach involved questionnaire based study (n=50 households). The community awareness, the occurrence of water-borne diseases with related cost of illness and community participation for the introduction of health interventions for water-borne diseases were evaluated through cross-tabulations, correlations, and ANOVA.

RESULTS

Majority (40%) of the community had no knowledge of water-borne diseases except some had little knowledge of diarrhea and typhoid. Diarrhea followed by stomach diseases was widespread in the community. Population below poverty level was bearing the cost of illness around US$ 0.6-1.2 (Rs 50-100) per day followed by low and average income level with direct cost of US$ 2.3 (Rs 200) per day. The indirect cost of illness had showed increasing trend between US$ 2.3-4.7 (Rs 200-400) per day with increase in income levels. Maximum willingness to pay (WTP) for water supply and sewerage system was US$ 3.6 (Rs 300) and US$ 1.2 (Rs 100) per month respectively. Income and water supply demand was strongly correlated with acceptability to pay for the facilities (r = 0.319, 0.307; P< 0.05). Income had a strong influence on WTP for water and sewerage system (r = 0.805, 0.797; P< 0.05).

CONCLUSION

To maintain rural health, water-borne diseases can be reduced by introducing health interventions like proper water and sanitation facilities.