Membrane and Desalination Technologies - TCE Moodle Website

346 N.K. Shammas and L.K. Wang
prior regulatory approval. For the purposes of regulatory compliance, product-specific
demonstration of Cryptosporidium removal efficiency is accomplished during challenge
testing, although microbial monitoring may be conducted during a pilot study for additional
verification of membrane performance at the discretion of the utility or if required by the
state. Although additional microbial testing can be conducted for any pathogen of concern
during piloting, typically, coliform bacteria, and sometimes heterotrophic plate count (HPC)
are used as an indicator for microbial removal efficiency.
2.3.4. Integrity Testing
The importance of integrity testing necessitates that greater emphasis be placed upon
integrity testing during piloting for applications of membrane filtration intended for
regulatory compliance. For direct integrity testing, the membrane manufacturer should
use a method approved or mandated by the state. The standard direct integrity test
sequences intended for the full-scale system should be incorporated into the pilot unit.
Direct integrity testing should be conducted at least as frequently as required by the
state for the full-scale facility. In the absence of a particular state requirement, it is
generally recommended that direct integrity testing be conducted on a daily basis. If an
integrity breach occurs during the piloting testing, then diagnostic testing and membrane
repair techniques may also be practiced. Continuous indirect integrity monitoring can
usually be accomplished using data that are collected during a typical pilot test program
(e.g., turbidity or particle count data). However, any state requirements regarding data
that must be collected for the purposes of continuous indirect integrity monitoring for
the full-scale facility should also be implemented during the pilot test, and may be
required by the state in any case.
Note that because the number of membrane modules to which an integrity test is applied
affects the sensitivity of the test (for both direct integrity testing and continuous indirect
integrity monitoring), any control limits established for a full-scale system will generally not
be applicable to a pilot unit, which typically utilizes only a small fraction of the number of
modules in a full-scale membrane unit. Guidance on establishing full-scale system control
limits for both direct integrity testing and continuous indirect integrity monitoring for the
purposes of regulatory compliance are provided in Chap. 7.
2.4. Report Development
After the pilot test is complete, a report should be prepared to summarize the procedures
and the test results. The pilot study report should contain sufficient detail to establish design
parameters for the full-scale plant to the extent for which the testing was intended. Flux,
chemical cleaning, backwashing, and integrity testing, should be addressed, where applicable.
Collected water quality data should also be included with emphasis given to unanticipated
test results. Details on the operational parameters for each filter run (i.e., between
chemical cleanings) should be summarized. The state may also have specific requirements for
the report if the piloting is required.