Microbial reductions and physical characterization of chitosan flocs when using chitosan acetate as a cloth filter aid in water treatment

Abstract

The World Health Organization (WHO) estimates 2.1 billion people lack access to safely managed water. Cloth filtration is often employed in rural and developing communities of South Asia for point-of-use water treatment, but bacteria and viruses are too small for efficient removal by this filtration method. Chitosan is a biodegradable, cationic, organic polymer derived from the chemical treatment of chitin that acts as a coagulant and flocculant of contaminant of microbes and other particles in water, thereby facilitating filtration of microbes. This research 1) evaluated the use of chitosan acetate as a pre-treatment coagulation-flocculation process followed by cloth filtration for microbial reductions and 2) assessed floc particle size under three stirring conditions. E. coli KO11 bacteria and MS2 coliphage virus removals were quantified using culture-based methods. Chitosan acetate coagulation-flocculation pre-treatment of water, followed by cloth filtration, met or exceeded the protective (2-star) WHO performance levels for bacteria (2 log10 reduction) and viruses (3 log10 reduction), and filtrate turbidity was consistently reduced to < 1 NTU, meeting United States Environmental Protection Agency (EPA) and WHO targets.

The Impact of Chitosan and Tithonia Diversifolia Compost on the Growth and Yield of Peanut Plants (Arachis hypogaea L.)

“…The plants treated with 6 ml/l water chitosan had an average of 7.50 branches, while those treated with 3 ml/l and 0 ml/l water chitosan had averages of 7.33 branches and 7.28 branches, respectively. Although chitosan can enhance soil biological properties and promote better soil structure, as well as potentially increase nitrogen fixation, which is crucial for plant growth, it did not show a substantial impact on the number of primary branches in this experiment [20][21].…”

Evaluation of Chitosans as Coagulants—Flocculants to Improve Sand Filtration for Drinking Water Treatment

“…Three doses of chitosan were tested in the 57-day bench-scale treatment study along with a control condition with no chitosan treatment: 0 mg/L, 3 mg/L, 10 mg/L, and 30 mg/L. The choice of these chitosan doses was based on previous studies by our laboratory on the range of effective chitosan doses for microbial and turbidity reductions [ 14 , 15 , 16 , 18 ].…”

“…In previous laboratory studies the positively charged chitin derivative chitosan, a natural and biodegradable polysaccharide byproduct of the crustacean fishing industry and available as well from other natural sources, such as insect exoskeletons, has been proposed as a coagulant–flocculant POU treatment for use in multiple-barrier methods, such as with cloth and ceramic filters [ 14 , 15 , 16 , 17 ]. When chitosan is added to water, suspended colloidal material including viruses, bacteria, and spores are coagulated, allowing the coagulated particles to then flocculate together during slow mixing and then settle out of the water or be remove by subsequent filtration.…”

“…When chitosan was assessed as a coagulant, it effectively reduced bacteria and virus concentrations and turbidity in model and natural waters treated by chitosan coagulation followed by microporous ceramic filtration or cloth filtration, with no appreciable change in pH [ 16 , 17 , 18 , 19 ]. However, the extent to which chitosan coagulation–flocculation may improve microbial and turbidity reductions achieved via sand filtration has not been reported in model or natural waters, to our knowledge.…”

Antibacterial and antiviral chitosan oligosaccharide modified cellulosic fibers with durability against washing and long-acting activity

“…The antiviral activity of the modified fibers and paper sheets (2 mm × 2 mm pieces) was evaluated by the plaque reduction assay with bacteriophage MS2 according to Oza et al [35] with slight modifications. 1 × 10 6 PFU/mL MS2 bacteriophage solutions were inoculated in the form of 500 μL loads on 0.1 g fibers and modified fibers.…”