The Use of Sodium Hypochlorite at Point-of-Use to Remove Microcystins from Water Containers

Indopolycarbocyanine dyes as perspective analytical reagents for spectrophotometric determination of nitrite by radical nitration

A spectrophotometric method for the quantitative determination of nitrite was developed, based on the radical nitration of indopolycarbocyanine dyes in the presence of 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO). The rate of the reaction of the studied dyes with nitrite increases with the lengthening of the polymethine chain and the presence of hydrophilic sulfo groups in the side chain of the dye. TEMPO acts as a co-reagent, significantly accelerating the reaction rate and increasing the sensitivity of nitrite determination. The proposed reaction mechanism is supported by spectrophotometric and HPLC/MS studies. For Ind2 (tetramethine indocarbocyanine cationic dye), the limit of detection for nitrite is 0.50 µM within a linearity range of 1-13 µM. The developed method is sensitive, with a LOD 130 times lower than the maximum contaminant level (MCL) of nitrite in drinking water (65 μM), as specified by the WHO. The method is of low-toxicity and good selectivity, as the determination of nitrite is not significantly affected by the main components of water. The method was successfully applied for the analysis of nitrite in natural and bottled water.

Microcystins in water containers used in the home: A review of their potential health effects

Cyanobacteria produce toxins that are harmful to humans. They are found mostly in surface water, which is the main water source for drinking water before treatment. However, most of the water treatment plants are inadequate to treat toxins such as microcystins in raw water sources from contaminated surface water that has blooming and/or decaying cyanobacteria. Microcystins are harmful toxins produced by cyanobacteria that cause both acute and chronic health problems in humans. However, little is known about microcystins in water containers at the household level. This article therefore focuses on a review of the effects of microcystins in drinking water containers at the household level, including types of microcystins, their health effects, and cases reported in both animals and humans. Therefore, there is a need to develop the water quality management for cyanobacteria toxins, particularly microcystins in household containers.

Antimicrobial dichloroisocyanurate-salts for controlled release of chlorine

Sodium dichloroisocyanurate (Na-DCC), a disinfectant known for rapid decomposition in water, loses its effectiveness with complete release of free available chlorine (FAC) in under an hour. To overcome this, a series of chlorine rich transition metal complexes/tetrabutylammonium (TBA) salts of DCC, including 2Na[Cu(DCC)₄], 2Na[Fe(DCC)₄], 2Na[Co(DCC)₄]·6H₂O, 2Na[Ni(DCC)₄]·6H₂O, and TBA[DCC]·4H₂O have been developed for extended chlorine release studies. The DCC-salts are synthesized based on the metathesis reaction process and are characterized using IR, NMR, CHN analyses, TGA,DSC, and Lovi bond colorimeter. The DCC-salts displayed poor water solubility and low decomposition chlorine release profile compared to Na-DCC. The water solubility of DCC-salts was reduced by a factor of 5.37 to 2500 compared to Na-DCC. The decomposition release of FAC from DCC-salts has been studied over time in comparison to Na-DCC in distilled water using a Lovi-bond colorimeter. DCC-salts displayed controlled FAC release profiles that varied from 1-13 days depending on the type of metal/TBA unit in them, whereas the parent Na-DCC displayed complete FAC release in about 0.91 h. For a proof of concept, the controlled release of metal from one of the DCC-metal complex salts, i.e., copper from the Cu-DCC is also investigated with a function of time in distilled water at RT. The 100% release of copper from Cu-DCC was identified over a period of 10 days. In addition, the applicability of DCC-salts as excellent antiviral agents against the bacteriophage T4 and antibacterial agents against Erwinia, Pseudomonas aeruginosa PA014 (Gram-negative), and Staphylococcus epidermidis (Gram-positive) compared to Na-DCC has been demonstrated.

Household water treatment practice and associated factors in Ethiopia: A systematic review and meta-analysis

The provision of potable water is crucial to ensuring the health and dignity of individuals. In many developing countries, including Ethiopia, waterborne disease has become a major public health problem. There is a significant gap in accessing comprehensive national-wide evidence on Household Water Treatment (HWT) practices and associated factors in Ethiopia. Therefore, this study aims to assess the pooled HWT practice and associated factors in Ethiopia. A comprehensive search of published studies before October 15, 2022, was identified using databases and other sources. Data were extracted using Microsoft Excel, and analysis was performed using STATA 14/SE software. A random-effects model was used to estimate the pooled proportion of HWT practices and the odds ratio of associated factors. The funnel plot and Egger's regression test were used to assess publication bias, and I2 test statistics was used to assess heterogeneity. Duval and Tweedie's "trim and fill" method was performed to adjust the pooled estimate. A subgroup analysis was also conducted to identify the sources of heterogeneity. In this study, a total of 708 articles were retrieved, and 16 eligible studies were included. The pooled proportion of HWT practice in Ethiopia was found to be 21% (95% CI: 17-24). Having a formal education (OR: 2.42, 95% CI (2.11-2.74)), being male (OR: 1.32, 95% CI (1.13-1.51)), owning radio (OR: 1.33, 95% CI (1.18-1.47)), having a higher income (OR: 1.73, 95% CI (1.41-2.04)), unimproved water source (OR: 1.71, 95% CI (1.41-2.01)), fetching water at more frequently (OR: 3.31, 95% CI (1.99-4.64)), dipping methods of water drawing (OR: 2.08, 95% CI (1.66-2.51)), and taken training of water treatment (OR: 2.15, 95% CI (1.55-2.75)) were all found to be associated with HWT practice. Based on the findings of this study, the pooled proportion of HWT practice in Ethiopia was found to be one-fifth, which indicated that it was significantly low. Therefore, the authors recommend that households could better receive adequate information about HWT practices through strengthened health education and intensive training on HWT.

Household Water Treatment Practice and Associated Factors in Rural Households of Sodo Zuria District, Southern Ethiopia: Community-Based Cross-Sectional Study

INTRODUCTION

In Ethiopia, access to safe drinking water is very low, and even safe water at the point of distribution is subjected to frequent and substantial contamination during collection, transport, and storage. The purpose of this study was to assess the level of household water treatment practices and associated factors in rural households of the Sodo Zuria district, southern Ethiopia.

METHODS

A community-based cross-sectional study was conducted in 836 households using a multistage sampling technique. A structured and pre-tested questionnaire was used. Binary and multivariate logistic regression analysis was used.

RESULTS

The household water treatment practice was 44.1%. Households having a higher estimated monthly income, AOR = 1.5 (1.23, 3.47), older age greater than 45 years, AOR = 1.69 (1.08, 2.64), fetching water twice a day, AOR = 2.8 (1.21, 9.17), weekly washing of the water storage container, AOR = 0.3 (0.11, 0.83), and using the dipping technique to draw water from the collection jar, AOR = 1.67 (1.14, 2.42) were significant factors in the practice of household water treatment in the study.

CONCLUSIONS

The household water treatment practice was low. Higher estimated monthly income, older household heads, fetching water twice per day, washing the water storage container weekly, and dipping techniques to draw water from water storage containers were significant factors of household water treatment practices. Thus, proper hygiene of water storage, and engaging the community in income-generating activities were recommended.

Household Water Treatment Practice and Associated Factors in Gibe District Southern Ethiopia: A Community Based Cross-Sectional Study

BACKGROUND

Household water treatment practice or managing water at the point-of-use provides a means of improving drinking water quality and preventing diarrheal diseases. However, evidence regarding household water treatment practice and associated factors in Ethiopia, particularly in Southern Ethiopia are limited. This study was, therefore, designed to assess household water treatment practice and associated factors among households in Southern Ethiopia.

METHODS

A community-based cross-sectional study design was conducted among 627 households in Southern Ethiopia. A stratified random sampling technique was used in this study and a pre-tested structured questionnaire was used to collect data about household water treatment practice and associated factors among selected households through face-to-face interviews. The data were analyzed using descriptive statistical tests and binary logistic regression was performed to assess the association between independent and dependent variables. Odds ratio with 95% confidence intervals were used to determine the level of association.

RESULTS

This study revealed that the level of household water treatment practice was 34.3% with 95% CI (30.7-38.1) and boiling was the most common method of household water treatment in the study area. Educational status of having formal education (AOR = 2.01, 95% CI = 1.34-3), withdrawing water from storage vessel by dipping (AOR = 1.86, 95% CI = 1.2-2.87) and frequency of fetching water 3 or more times and above a day (AOR = 2.65, 95% CI = 1.45-4.88) were significantly associated with household water treatment practice.

CONCLUSION

Household water treatment practice is low in the study area. Educational status of having a formal education, drawing water by dipping, and those who collect their drinking water 3 or more times a day were predictors of household water treatment practice. Thus, efforts should be made to increase the level of household water treatment practice especially among those with no formal education and further studies should be conducted to understand the behavioral factors associated with household water treatment practice.

Effects of chlorine disinfectants on the microbial community structure and the performance of anaerobic digestion of swine manure

The residual chlorine disinfectants (CDs) in swine slurry could negatively impact the anaerobic digestion (AD). The objective of this study was to investigate the effects of CDs on mesophilic and thermophilic AD. The results indicated that CDs exerted inhibition effects on methanogenesis at the initial stage of mesophilic AD, leading to the extension of lag time from 0.62 days for control to 0.85, 1.9, 3.8, and 5.5 days with the increasing CDs concentrations of 50, 100, 200, and 400 mg/L, respectively. Under thermophilic condition, the inhibition effects reduced significantly at the initial stage but a decrease of CMP_u at later stage was observed. The microbial analysis revealed that CDs resulted in the enrichment of chlorine-resistant bacteria (Clostridum_sensu_stricto_1) and archaea (Methanosarcina). Addition of activated carbon (AC), zero-valent iron (ZVI) and biochar (BC) was evaluated for alleviating the inhibitions of CDs and proved to be feasible strategies to alleviate the inhibited AD.

Development and appraisal of handwash-wastewater treatment system for water recycling as a resilient response to COVID-19

In this work, results from characterization of handwashing wastewater from selected stations in Kampala City, Uganda, revealed that handwashing wastewater did not meet permissible international standards for wastewater discharge to the environment. The ratio of BOD₅ to COD of ˂ 0.5 implied that handwashing wastewater was not amenable to biological treatment processes. Turbidity of ˃ 50 NTU pointed to the need for a roughing filter prior to slow sand filtration. Subsequently, a handwashing wastewater treatment system consisting of selected particle sizes of silica sand, zeolite, and granular activated carbon as filtration and/or adsorption media was developed and assessed for performance towards amelioration of the physicochemical and biological parameters of the handwashing wastewater. Treated water from the developed wastewater treatment system exhibited a turbidity of 5 NTU, true color of 10 Pt-Co, apparent color of 6 Pt-Co, and TSS of 9 mgL^-1, translating to removal efficiencies of up to 98.5%, 98.1%, 99.7%, and 96.9%, respectively. The residual total coliforms and E. coli of 1395 and 1180 CFU(100 mL)^-1 respectively, were totally eliminated upon disinfection with 0.5 mL NaOCl (3.5% wt/vol) per liter of treated wastewater. The treated water was thus suitable for recycling for handwashing purpose as opposed to letting handwashing wastewater merely go down the drain. This approach provides a resilient response to COVID-19, where communities faced with water scarcity can treat and recycle handwashing wastewater at the point of washing. It thus enables more people to have the opportunity to practice handwashing, abating the high risks of infection, which could otherwise arise.