Current and proposed regulations require microbial removal efficiency as a criterion for evaluating water treatment processes. A maximum six-lot rejection of Cryptosporidium from surface water sources has been proposed by US Environmental Protection Agency (USEPA). Membrane and integrated membrane systems (IMSs) seemingly provide significant single barriers and even greater cumulative barriers to microbial contaminants but are largely untested for pathogen rejection. Large-scale Cryptosporidium testing is economically prohibitive. Consequently, this work describes the rejection of aerobic spores (Bacillus subtilis endospores) by several membranes systems as a surrogate for Cryptosporidium as recommended by USEPA. Eight different pilot-scale Integrated Membrane Systems were operated at the Hillsborough River WTP in Tampa, Florida, an assesssed for rejection of cultured Bacillus subtilis endospores. A Zenon microfilter, Memcor microfilter, Hydranautics thin-film composite nanofilter and Fluid Systems cellulose acetate nanofilter were used in the investigation. Both MFs were configured as hollow fiber (HF) membranes. Both NFs were configured as spiral wound membranes. Chloride and pH tracer studies were used to determine membrane resident times and sample collection times. Both MFs were challenged with and without in-line alum coagulation. The MF processes were evaluated as stand alone and pretreatment processes for both NF processes. Includes 5 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 210 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Published : | 01/01/1999 |
