[USCC] Disinfecting storm water for windrow irrigation

[Craig Coker]

Colleagues:

 

The NC Division of Water Quality is on the verge of requiring that
composters in North Carolina obtain a wastewater discharge permit for any
rainwater that comes into contact with composting, curing or product storage
areas (in lieu of a storm water discharge permit); unless the composter can
demonstrate that the captured storm water from the 25-yr, 24-hr storm can
all be reused on-site for moisture control in windrows or piles.
Hydraulically, this is generally achievable.

 

However, this raises the question of fecal coliform contamination of storm
water and the viable means to disinfect that storm water.  There is sparse
data available on fecal counts in storm water samples.  A 2003 sample by a
County yard waste composting facility in NC showed a fecal count of 43,000.
The 1997 study by E&A for Clean Washington Center at Phoenix Organic
Products (also yard waste only) indicated an average fecal count of 650,000.
I surmise the fecal is coming from animal feces in the grass clippings
and/or leaves.

 

When disinfecting equipment to prevent cross-contamination, I have used a
simple Clorox solution in a backpack sprayer, so I have been evaluating the
use of Clorox as a disinfectant for storm water.  However, I am uncertain of
the degree of residual chlorine concentration if Clorox (or similar
chlorine-based bleach) were used to disinfect a storm water irrigation
supply.  The folks at Clorox recommend a dose rate of 1 gallon of their
Ultra Clorox Germicidal Bleach (EPA Reg. No. 67619-8) per 30,000 gallons of
water for disinfecting swimming pools.  

 

Does anyone think that the residual chlorine from that level of dosing would
be detrimental to the composting process?

 

Does anyone know of other viable means for disinfecting storm water that
would not affect the composting process?

 

Many thanks,

Craig

 

Craig Coker

Coker Composting & Consulting

3331 Glade Creek Blvd.

Ste. 7

Roanoke, VA  24012

(540) 904-2698

Fax: (540) 904-6732

Cell: (540) 874-5168

craigcoker at cox.net

www.cokercompost.com