Pending rules under the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) will
require water utilities treating surface water and groundwater under direct influence of surface
water (GWUDI) to provide treatment to remove or inactivate Cryptosporidium. The US
Environmental Protection Agency (EPA) has taken a technology-based approach to address the
requirements of the rule. Among the management and treatment techniques documented LT2
Preamble (EPA, 2001) "Microbial Toolbox" that can be granted the maximum Cryptosporidium
removal credits are membrane filtration, ozone, and UV disinfection.
The City of Two Rivers, Wisconsin currently operates a conventional water treatment plant on
the western shore of Lake Michigan. The plant was originally built in 1934 and currently uses
chlorine for disinfection. In anticipation of LT2, the City has been evaluating the process
alternatives for meeting the requirements. Based on cost estimates the City decided to retrofit its
existing 3.0-MGD conventional water treatment facility with low-pressure membrane filtration.
This approach will allow the City to both improve effluent turbidity and provide a physical barrier
to Cryptosporidium.
In order to expedite the project and reduce costs, the City explored means of minimizing the pilot
testing effort typically associated with low-pressure membrane evaluations. By leveraging the
wealth of membrane supplier experience on the water source, Lake Michigan, the City was able
to select a membrane system supplier prior to pilot testing, thereby limiting pilot testing to a
single system. The City and its engineers successfully executed this strategy, thereby saving
time and cost for the City, suppliers, and Regulatory Agency involved in the project. Includes 6 references, tables.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 180 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 03/05/2003 |
