Removal of Sediment and Bacteria from Water Using Green Chemistry

• Published in: Environmental science & technology 2010-05, Vol.44 (9), p.3514-3519
• Main Authors: Buttice, Audrey L, Stroot, Joyce M, Lim, Daniel V, Stroot, Peter G, Alcantar, Norma A
• Format: Article
• Language: English
• Subjects: Applied sciences; Bacillus cereus; Bacillus cereus - metabolism; Bacteria; Cactaceae; Calcium Chloride - chemistry; Chemistry - methods; Dose-Response Relationship, Drug; Drinking water and swimming-pool water. Desalination; Environmental Restoration and Remediation; Environmental science; Exact sciences and technology; Green chemistry; Ions; Kaolin - chemistry; Opuntia ficus-indica; Pollution; Sediments; Sustainability Engineering and Green Chemistry; Waste Disposal, Fluid - methods; Water Microbiology; Water Pollutants; Water Pollutants, Chemical - chemistry; Water purification; Water Purification - methods; Water quality; Water treatment; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es9030744

Although nearly all newly derived water purification methods have improved the water quality in developing countries, few have been accepted and maintained for long-term use. Field studies indicate that the most beneficial methods use indigenous resources, as they are both accessible and accepted by communities they help. In an effort to implement a material that will meet community needs, two fractions of mucilage gum were extracted from the Opuntia ficus-indica cactus and tested as flocculation agents against sediment and bacterial contamination. As diatomic ions are known to affect both mucilage and promote cell aggregation, CaCl2 was studied in conjunction and compared with mucilage as a bacteria removal method. To evaluate performance, ion-rich waters that mimic natural water bodies were prepared. Column tests containing suspensions of the sediment kaolin exhibited particle flocculation and settling rates up to 13.2 cm/min with mucilage versus control settling rates of 0.5 cm/min. Bacillus cereus tests displayed flocculation and improved settling times with mucilage concentrations lower than 5 ppm and removal rates between 97 and 98% were observed for high bacteria concentration tests (>108 cells/ml). This natural material not only displays water purification abilities, but it is also affordable, renewable and readily available.