title: A pilot-scale study of Cryptosporidium-sized microsphere removals from swimming pools via sand filtration.
abstract: Cryptosporidium species are the most common cause of gastrointestinal illness in treated recreational water venues. In order to protect public health during swimming, Cryptosporidium-sized microsphere removals by high-rate sand filtration with six coagulants were evaluated with a 5.5 m(3) pilot-scale swimming pool. A sand filter without coagulation removed 20-63% of Cryptosporidium-sized microspheres. Cryptosporidium-sized microsphere removals exceeded 98% by sand filtration with five of the six tested coagulants. Continuously feeding coagulants A, B, and F (i.e., organic polymers) led to coagulant accumulation in the system and decreased removals over time (<2 days). Coagulant E (polyaluminum chloride) consistently removed more than 90% of microspheres at 30 m/h while the removals dropped to approximately 50% at a filtration rate of 37 m/h. Coagulant C was a chitosan-based product that removed fewer microspheres compared with other products, <75%, under the studied conditions. Results indicated aluminum-based coagulants (coagulants D and E) had an overall performance advantage over the organic polymer based coagulants primarily in terms of their tendency not to accumulate in the water and cease to be effective at improving filter efficiency.
authors.affiliation: Department of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China E-mail: luping_cumt@126.com; Civil and Environmental Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Lu
authors.affiliation: Civil and Environmental Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Amburgey
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry; D003458:Cryptosporidium / Q000302:isolation & purification*; D005374:Filtration / Q000379:methods*; D008863:Microspheres; D033661:Oocysts; D052638:Particulate Matter / Q000302:isolation & purification; D010865:Pilot Projects; D011108:Polymers / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013551:Swimming Pools; D018508:Water Purification / Q000379:methods*
chemical_list: D052638:Particulate Matter; D011108:Polymers; C016213:aluminum oxychloride; D000536:Aluminum Hydroxide; D012822:Silicon Dioxide; D048271:Chitosan