sodium-hypochlorite and aluminum-sulfate

This study aimed to evaluate an alternative to reduce trihalomethane (THM) formation in brewing water. THM affects the organoleptic properties of water and, consequently, the produced beer. Water treatment based on common chemicals such as alum and free chlorine could potentially form THM. Therefore, we studied the replacement of chemicals used in water treatment: aluminum sulfate by a tannin-based coagulant and sodium hypochlorite by chlorine dioxide. Experimentally, jar tests were conducted, and the role of coagulants and oxidizing agents was evaluated for: the removal of apparent color, turbidity, natural organic matter (NOM) and microorganisms; the formation of trihalomethanes (THM); and the sensory quality of the water. Using tannin-based coagulant with chlorine dioxide was associated with the lowest THM in treated water (1.7 µg/L) and higher satisfaction in the sensory analysis. However, using these chemicals make the water treatment more expensive than the current strategy. Overall, using the tannin-based coagulant and chlorine dioxide treatment is an alternative to produce water with a lower THM concentration, better physical-chemical, and sensory quality. These findings motivate further brewing experiments and a deeper economics evaluation considering the process's sustainability.

Topics: Chlorine; Disinfection; Oxidants; Sodium Hypochlorite; Tannins; Trihalomethanes; Water Pollutants, Chemical; Water Purification

An enhanced bonding agent for papermaking was prepared by selective oxidation of a hemicellulose-rich byproduct of oat processing, which will be identified here by its primary component, β-D-glucan. The β-D-glucan was treated sequentially with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) and sodium hypochlorite, or alternatively just with sodium hydroxide. When added to a slurry of unbleached softwood kraft fibers, in combination with an optimal dosage of aluminum sulfate, the oxidized β-D-glucan yielded greater increases in tensile strength and folding endurance in comparison to untreated β-D-glucan. NaOH treatment also improved dry-strength performance of the β-D-glucan, except for folding endurance. The improvements were attributed to increased charge density of the treated polyelectrolytes, leading to better distribution and retention on fibers prior to sheet formation. Modified β-D-glucan also enhanced the strength of recycled sheets when the treated paper was repulped and formed into recycled paper with no further chemical addition.

Topics: Alum Compounds; Avena; beta-Glucans; Cyclic N-Oxides; Microscopy, Electron, Scanning; Oxidation-Reduction; Paper; Polysaccharides; Proteoglycans; Sodium Hydroxide; Sodium Hypochlorite; Spectroscopy, Fourier Transform Infrared

Microbial effects are believed to be a major contributor to membrane fouling in drinking water treatment. Sodium hypochlorite (NaClO) is commonly applied in membrane cleaning, but its potential use as a pretreatment for controlling operational fouling has received little attention. In this study, the effect of adding a continuous low dose of NaClO (1 mg/l as active Cl) in combination with alum, before ultrafiltration, was compared with only alum as pretreatment. The results showed that the addition of NaClO substantially reduced membrane fouling both in terms of the rate of TMP development and the properties of the membrane cake layer. Although the size of nano-scale primary coagulant flocs changed little by the addition of NaClO, the cake layer on the membrane had a greater porosity and a substantially reduced thickness. NaClO was found to inactivate bacteria in the influent flow, which reduced both microbial proliferation and the production of proteins and polysaccharides in the cake layer and contributed significantly to improving the overall ultrafiltration performance. NaClO dosing had no adverse impact on the formation of currently regulated disinfection by-product compounds (THMs and HAAs).

Topics: Alum Compounds; Bacteria; Biofouling; Disinfectants; Flow Cytometry; Halogenation; Membranes, Artificial; Polymers; Porosity; Sodium Hypochlorite; Thioacetamide; Trihalomethanes; Ultrafiltration

Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l(-1) sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of two locally available chemical water treatments-alum and Moringa oleifera flocculation-to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0-91.4%; moringa flocculation 14.2-96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01-0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters>or=30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.

Topics: Alum Compounds; Chlorine; Consumer Behavior; Developing Countries; Family Characteristics; Halogenation; Humans; Moringa; Sodium Hypochlorite; Water; Water Purification; Water Supply

Point-of-use drinking water disinfection with sodium hypochlorite has been shown to improve water quality and reduce diarrhoeal disease. However, the chlorine demand of highly turbid water may render sodium hypochlorite less effective.. We evaluated a novel combined flocculant-disinfectant point-of-use water treatment product and compared its effect on drinking water quality with existing technologies in western Kenya. In water from 30 sources, combined flocculant-disinfectant reduced Escherichia coli concentrations to <1 CFU100 ml(-1) for 29 (97%) and reduced turbidity to <5 nephelometric turbidity units (NTU) for 26 (87%). By contrast, water from 30 sources treated with sodium hypochlorite reduced E. coli concentrations to <1 CFU 100 ml(-1) for 25 (83%) and turbidity to <5 NTU for 5 (17%).. For source waters over a range of turbidities in western Kenya, combined flocculant-disinfectant product effectively reduces turbidity to <5 NTU and reduces E. coli concentrations to <1 CFU 100 ml(-1).. The novel flocculant-disinfectant product may be acceptable to consumers and may be effective in reducing diarrhoeal disease in settings where source water is highly turbid.

Topics: Alum Compounds; Developing Countries; Disinfection; Escherichia coli; Flocculation; Kenya; Nephelometry and Turbidimetry; Sodium Hypochlorite; Water Microbiology; Water Pollution; Water Purification; Water Supply

Topics: Alum Compounds; Bacillus; Humans; Sodium Hypochlorite; Sputum