[USCC] Vol 29, #9--Regulation by various agencies

[The Rubins]

Dave:

Your comments are aimed at biosolids composting but these comments really 
apply to all composting  regardless of the feedstock.  Certainly you could 
make the same comments re. the composting of animal manure, animal rendering 
wastes, etc.  The issues of time/temperature and adequate monitoring of 
these parameters as well as resultant levels of microbes in the finished 
compost are also relevant to these other composting feedstocks.  As for the 
trace pollutant levels in biosolids, please show me a "waste" feedstock that 
doesn't have trace quantities of some chemical pollutants.  I remember the 
clopyralid issue a few years back from the use of lawn trimmings as a 
composting feedstock.  How about antibiotic levels and feed additives in 
animal manures.  Use of scrap tires, wall board, CCA treated wood, etc. 
Surely you are not implying that biosolids is the only feedstock for 
composting for which there are these concerns.

Further as far as I know, biosolids is the only compost feedstock that is 
regulated at the Federal level (Part 503 Standards) and by every State.  The 
standards set by these authorities are more than adequate to protect public 
health and the environment.  I am not aware of any regulatory network for 
other biosolids feedstocks.  The bottom line is that decades of use of 
biosolids-based composts have not resulted in any reported and documented 
human health impacts.

Cheers

Alan

----- Original Message ----- 
From: "dschelli" <dschelli at bellsouth.net>
To: "'US Composting Council Compost Discussion List'" 
<compost at composter.com>
Sent: Saturday, July 29, 2006 8:45 PM
Subject: Re: [USCC] Vol 29, #9--Regulation by various agencies


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Frank,

I agree to a certain extent that more intensive monitoring of the biosolids
composting process would improve current regulatory compliance. Many
problems with current regulatory monitoring system result from reliance on
the honor system for self monitoring of biosolids composting processes.  The
data presented to regulatory offices may be flawed either by design or
unintentionally.  I do not insinuate that "all" composting operations would
"fudge" monitoring results, but monitoring equipment for temperature may be
improperly maintained or calibrated leading to reduced accuracy of
temperature measurements.

Temperatures are rarely taken at different depths in composting materials
even though we know there will be differences.  Because windrows are three
dimensional, there are not only horizontal sections of the composting
windrows or piles that are often cooler than necessary, but also vertical
stratification of temperature differentials, and stratification of
temperatures with depth in the material.  I don't really know if improved
monitoring instrumentation would help or hinder the process of biosolids
composting monitoring unless it was fool-proof and did not allow tampering
with results, and if certified personnel calibrated instruments regularly.
Intensive monitoring as proposed would probably do more to show the
inadequacy of time/temperature composting process for biosolids than to
improve the composting process.

Whereas I am pro-sewage use as a feedstock in composting, I do not really
approve of the current regulatory treatment and monitoring program.  It does
not (as some opponents to biosolids use point out) account for many chemical
contaminants that may be found in biosolids. I realize that many
contaminants are destroyed over time in soils where biosolids are applied,
but composted biosolids are often used more in residential settings.
Chemical contaminants that could be found in sewage might include
pharmaceuticals, paints, cleaners, paint thinners, pesticides, herbicides,
oils, etc., many of which are hazardous if not toxic in nature.  Some may
also be recalcitrant in nature, requiring more exposure to the harsh
conditions and enzyme activity of microbiological activity during composting
than just three to fifteen days.  More aggressive testing for chemical
contaminants, in addition to the current regulated metals, might not be a
bad idea for any biosolids products to be land applied.

Some literature exposes a fault in the current regulatory composting process
because pathogens have been observed in finished products, at the point of
sale, above regulatory limits.  Whether due to growth of pathogens after
composting or to inadequate process control, high pathogen counts after the
process is complete shows that the current regulatory monitoring and testing
program is inadequate(This evidence also suggests that testing at the point
of sale has proven to provide better results for consumer safety).  Changes
in the current regulatory framework for composting and monitoring of the
process would seem to be in order; process management that would provide
more flexibility to compost producers but would accomplish the same goals
and provide a more stable and mature end product would seem to be a better
option.

We know that most anaerobic bacteria, pathogens included, can be killed by
sufficient exposure to air as well as to temperatures above 126°F (the
temperature at which proteins begin to become denatured).  You point out
that the current regulations require biosolids compost producers to
re-process materials that do not meet the regulatory 131°F temperature
regimen during the prescribed time.  I submit that reprocessing would not be
necessary if the composting process was extended, even at temperatures
between 126 and 131.  Assuming adequate biologically available nutrient
resources exist after 15 days, why not compost for longer durations (30
days) with scheduled turning twice weekly in windrows to reduce the
probability of pathogen survival, and to increase exposure of chemical
contaminants to enzyme activity?  Because aeration is also important in the
pathogen reduction and the overall composting process, monitoring pore space
oxygen in the composting materials may also provide evidence of composting
adequacy.

Personally, I would never want use of sewage that has composted for only a
few days in my yard. I think it may be time for regulatory reforms rather
than to try to doctor the current monitoring programs (pathogen testing at
the end of the composting process).  What may be intended as a way to help
improve the current system may actually not help compost producers who use
biosolids as a feedstock, and may bring about regulatory change anyway.

Dave Schellinger

Alternatives. L.L.C.