[USCC] Open composting and disease vectors

[Rufus Chaney]

Dear All:

Mr. McGowan, you show us how one can extrapolate from an illegal case to suggest a dangerous risk from well managed composting facilities. You raise the well known "not really composting" case in CA that was a subject of a cease and remove order from County and State governments. There can be no question that the situation there was in violation of many parts of 503 and CA laws, caused substantial malodor, and comprised potential runoff risks and perhaps some of the risks you discuss. 

So then you simply extrapolate from this infamous violation of essentially all regulations and common sense management of a composting facility for any feedstock to suggest that flies on piles of raw manure model risk from "any open air composting facility". Hogwash.

Managed composting facilities usually are a site where flies are drawn and die, not a site for reproduction and release of new flies covered with raw human wastes. 

Sure, if you put your finger in raw human wastes, and then put it in your mouth, you will be exposed to pathogens. But to imply this is a model for composting facilities or finished compost is an insult to the composting industry. Either you are so overzealous in your anti-biosolids or even anti-composting opinion that you can't see the error of your discussion, or altogether lost about the science of composting and public health.

I would have noted the green waste/yard debris composting facilities as being different from manure or biosolids composting facilities, but their feedstocks often contain pet and wildlife feces and may be as pathogen contaminated when they get started as manure or treated biosolids composting feedstocks.

If you want to find a composting facility which may comprise the risks you describe, look at your neighbors who may place food scraps in a home composting pile. Many such piles do not attain temperatures needed to kill pathogens for a long time, and attract vectors and cause malodor but in a small way rather than the large site in CA. 

Relative risk, and management to prevent risk should always be kept in mind when considering composting and other methods for handling of pathogen laden human or agricultural materials. Composting is a significant contribution to the solution to the well known problem of pathogens in manures, etc. Get a better argument or please keep it to yourself.

Regards all,

Rufus Chaney
Beltsville, MD


>>> Edo McGowan <edomcgowan at earthlink.net> 08/18/06 03:16PM >>>

The following may be of interest to those of you in the composting industry and may more specifically relate to open compost operations that are near or up-wind from urban areas. The case in mind is the open compost operation that was established and then later shut down by court order in Adalanto, California. The issues included uncontrolled flies. With a good wind, flies can travel for miles.

A new study which appeared in the New Zealand Medical Journal cited finding that flies act as serious as mechanical vectors of transmitted disease (nothing really new here). This discussion included disease attributable to the high levels of campylobacter transmission via flies and disease rates in New Zealand, including the high rate of campylobacteriosis (up to 14,000 reported cases annually). Laboratory scientist Ben Harris, who co-wrote the paper with research consultant Warrick Nelson, indicated that the occurrence of the illness was between 10 and 20 times higher than that reported because most people did nott report food poisoning. Thus the numbers might be between 140,000 to 280,000 cases---not an insignificant number 

The bacteria is transferred through fly fecal deposits on common surfaces such as hand rails and door handles. Campylobacter deposited on fingertips can survive for at least an hour, and have been recovered from dry surfaces 24 hours after being deposited. 

The issue of dust travel is also important here. Dust from these open operations have been linked to illnesses. Further, dust coats surfaces of homes and offices. Gerba and Rusin have published on the transmission of pathogens via finger to mouth. Gerba, unpublished work, also notes that contamination can be spread through the house by human contact with objects.

Cheers---------------Edo