open issue - Plumbing Engineer

tures. In addition, membrane filtration is used to remove
color, which can occur from metal leaching and groundwater
contamination. This is also used on potable rainwater
systems to filter viruses, pyrogens and metal ions.
In the event that the catchment surface is a parking lot
or asphalt area, pretreatment for oil removal as well as
emulsion breakers may be added to remove these additional
contaminants.
If chemical contamination is a concern, such as from
heavy organic contamination, an oxidation process can
be utilized, as well as organic membranes and slow sand
filters (often referred to as bio-sand filters), which utilize
a schmutzdecke to remove organic and biological
impurities. (Schmutzdecke is a biological layer that
forms on the surface of a slow sand filter and aids in the
water purification process.)
It is important in rainwater harvesting system design
to understand upfront the source of the water as well as
its end uses. This upfront knowledge will allow for proper
system sizing to maximize the water that can be
reclaimed and to identify the correct level of treatment
for a safe and environmentally friendly system. n
Resources
1. Macomber, Patricia S. H., Guidelines for Rainwater
Catchment Systems for Hawaii, College of Tropical
Agriculture and Human Resources, University of
Hawaii at Manoa, 2010.
2. Texas Guide to Rainwater Harvesting, Texas
Rainwater Development Board, 2002.
3. Georgia Amendments to the 2006 International
Plumbing Code, Appendix 1, “Rainwater Recycling
Systems.”
Mark Girgenti (markgirgenti@burtprocess.com) is
the lead sales and design engineer for Burt Process
Equipment, an environmental process design and equipment
firm. Mark has spearheaded the design, integration,
project management and construction of water
treatment equipment for rainwater harvesting, graywater
and high-purity water systems in the governmental,
institutional, and pharmaceutical industries, both in the
United States and abroad. Mark has been a speaker at
numerous green building and plumbing events across
the country and was a presenter at the ASPE 2011
Technical Symposium. He holds a Bachelor’s degree in
Chemical Engineering from Rensselaer Polytechnic
Institute and a Master of Science in chemistry. He is
actively involved in academic circles as a professional
member of the Graduate Advisory Committee for
Southern Connecticut State University as well as serving
as a volunteer faculty member.
Circle 34 on Reader Reply Form on page 69
Plumbing Engineer April 2012/Page 53