Toilet chemical additives and their effect on faecal sludge characteristics

Fecal sludge characterization, treatment, and resource recovery options: a state-of-the-art review on fecal sludge management

A rise in population and urbanization demanded that a robust fecal sludge management (FSM) value chain be used to restructure the sanitation system throughout the world securely. A significant global need exists to adopt efficient and sustainable FSM. On-site sanitation systems (OSS) produce fecal sludge (FS). FS is produced when excreta and blackwater are combined and stored or treated, either alone or in combination with greywater. FS can be semisolid or slurry and raw or partially digested. Critical examination of FS characteristics, i.e., biochemical oxygen demand (BOD), chemical oxygen demand (COD), total solids (TS), and pathogen count, varies from 600-56,836 mg/l, 6656 to 201,200 mg/l, 830-123,000 mg/l, and 105 to 109 E. coli/l of FS respectively. Helminth eggs range from 2500-25,000/l of FS. Public health and the environment are negatively impacted by septic tank overflows and the careless discharge of FS into open spaces affecting groundwater quality, water bodies, irrigation fields, open drains, places outside villages, etc. Thus, deciding on a proper treatment technology for FS before discharging it into open land or reusing FS is essential to create a pollution-free environment. This paper highlights the practices adopted for FSM under its different processes, such as collecting, characterization, treating, and reusing of on-site FS and bibliometric analysis on documents on fecal sludge. A thorough analysis has been carried out by reviewing all important literature available globally.

Feasibility study of faecal sludge treatment by Geotube and jute tube-based technologies

The decentralized standalone treatment of faecal sludge is a generally cumbersome, energy-intensive, and expensive process. Particle size enlargement, dewatering, and disinfection are the crucial unit operations that contribute to the major portion of the operational expenditure. Therefore, the present study took up the task to investigate and yield a natural alternative to each of the above-delineated unit operations. Crushed seed powders of Moringa, Guilandina bonduc, Nirmali, tamarind, soap nut, nutmeg, jackfruit, and custard apple were experimented as natural coagulants, while a double-stitched cow dung-lined jute tube was utilized as the media for solid-liquid separation. Finally, the powder of Neem and custard apple seed and leaf were considered herbal disinfectants for the separated liquid and solid fractions, respectively. The findings of the physicochemical and biological analyses of the above unit operations were compared with a conventional polymer-based Geotube-driven treatment scheme. The natural alternatives registered some promising outcomes. However, the combined treatment efficiency of 79.32% (mean value of TS, TSS, TDS, COD, and BOD percentage removal) for pollutant removal and disinfection could not exceed the value of 97.98% offered by the conventional method. Further, the financial comparison for processing a 10 KL batch of FS indicates that the conventional scheme is considerably cheaper (USD 7.95) than the herbal alternate (USD 22.1). Therefore, though the present findings depict promising alternatives for sustainable and eco-friendly faecal sludge treatment, the authors advocate conducting further research to address the existing challenges to facilitate their seamless implementation on a field-scale level.

Anticipatory decision-making for cholera in Malawi

Climate change raises an old disease to a new level of public health threat. The causative agent, Vibrio cholerae, native to aquatic ecosystems, is influenced by climate and weather processes. The risk of cholera is elevated in vulnerable populations lacking access to safe water and sanitation infrastructure. Predictive intelligence, employing mathematical algorithms that integrate earth observations and heuristics derived from microbiological, sociological, and weather data, can provide anticipatory decision-making capabilities to reduce the burden of cholera and save human lives. An example offered here is the recent outbreak of cholera in Malawi, predicted in advance by such algorithms.

Predictive Intelligence for Cholera in Ukraine?

Cholera, an ancient waterborne diarrheal disease, remains a threat to public health, especially when climate/weather processes, microbiological parameters, and sociological determinants intersect with population vulnerabilities of loss of access to safe drinking water and sanitation infrastructure. The ongoing war in Ukraine has either damaged or severely crippled civil infrastructure, following which the human population is at risk of health disasters. This editorial highlights a perspective on using predictive intelligence to combat potential (and perhaps impending) cholera outbreaks in various regions of Ukraine. Reliable and judicious use of existing earth observations inspired mathematical algorithms integrating heuristic understanding of microbiological, sociological, and weather parameters have the potential to save or reduce the disease burden.

Using Isotopic and Hydrochemical Indicators to Identify Sources of Sulfate in Karst Groundwater of the Niangziguan Spring Field, China

Karst groundwater in the Niangziguan spring fields is the main source to supply domestic and industrial water demands in Yangquan City, China. However, the safety of water supply in this region has recently suffered from deteriorating quality levels. Therefore, identifying pollution sources and causes is crucial for maintaining a reliable water supply. In this study, a systematic sample collection for the karst groundwater in the Niangziguan spring fields was implemented to identify hydrochemical characteristics of the karst groundwater through comprehensive analyses of hydrochemistry (piper diagram, and ion ratios,) and stable isotopes (S and H-O). The results show that the karst groundwater in the Niangziguan spring fields was categorized as SO4·HCO3-Ca·Mg, HCO3·SO4-Ca·Mg, and SO4-Ca types. K+, Cl-, and Na+ are mainly sourced from urban sewage and coal mine drainage. In addition, SO42− was mainly supplied by the dissolution of gypsum and the oxidation of FeS2 in coal-bearing strata. It is noteworthy that, based on H-O and S isotopes, 75% of the karst groundwater was contaminated by acidic water in coal mines at different degrees. In the groundwater of the Niangziguan spring field, the proportions of SO42− derived from FeS2 oxidation were 60.6% (N50, Chengxi spring), 30.3% (N51, Wulong spring), and 26.0% (N52, Four springs mixed with water). Acid mine drainage directly recharges and pollutes karst groundwater through faults or abandoned boreholes, or discharges to rivers, and indirectly pollutes karst groundwater through river infiltration in carbonate exposed areas. The main source of rapid increase of sulfate in karst groundwater is acid water from abandoned coal mines.