Sludge Watch ==> Virginia - Sludge could face new regulations- should study pathogens

[Maureen Reilly]

Sludgewatch Admin:

Now that WERF studies show that many anaerobically digested centrifuged 
sludges have a massive pathogen re-emergence (5 or 6 orders of magnitude in 
just 20 minutes) it may well be that much of the sludge arriving onto rural 
farms exceeds the 2 million fecal coliform per gram limits set out in the 
Part 503 regs.  It is very inexpensive to test for total fecal coliform - 
generally less than $20 per sample.

Indeed, more testing and inspection is needed. See an update on the WERF 
pathogen study agenda after the news story below.


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Jan 2, 2007

Sludge could face new regulations
Proposed legislation could call for more random inspections of farms where 
sludge is used, with a goal of protecting waterways.

Legislation planned by a Northern Neck lawmaker could place restrictions on 
farmers who spread treated sewage sludge onto fields as fertilizer, an issue 
that has raised concerns in Bedford County.

The legislation could call for many more random inspections at sites where 
sludge is being spread, and include a role for the Department of 
Conservation and Recreation, which works with farmers on plans for keeping 
the nutrients in fertilizers and manure out of waterways.

Del. Robert Wittman, R-Westmoreland County, plans to introduce the 
legislation this month.

Sludge, the byproduct of treated human and industrial sewage, is processed 
to reduce disease-causing germs and is often given to farmers as free 
fertilizer. Supporters say it puts the dark, soil-like waste material to 
good use. But critics point to headaches and breathing difficulties among 
those living near fields where it is spread.

Bedford County's board of supervisors included sludge regulation among a 
list of priorities for legislators at the 2007 General Assembly session. 
Specifically, the board requested local governments be given authority to 
regulate the use of sludge in their jurisdictions and that state regulation 
and enforcement be transferred to the Department of Environmental Quality. 
The use of sludge in the county has generated complaints by Bedford County 
residents concerned about the odor, the impact on their property values and 
health risks.

Until now, while farmers who spread chicken manure as fertilizer have been 
closely monitored by state officials, farmers spreading sludge have been 
largely unchecked.

New guidelines would fall mostly in line with what other farmers must do to 
spread animal manure.

Wittman said he's considering the transfer of top-level oversight of sludge 
spreading from the Virginia Department of Health to the Department of 
Environmental Quality.

Ideally, the health department would continue to monitor the science of 
sludge's human health effects.

Bedford County spokesman Bill Hoy said one of the county's chief complaints 
about the current situation is that the health department isn't set up to be 
a regulatory agency. "With the DEQ, that's their job," he said. "They 
enforce."

Sludge spreading has come into the spotlight in recent years amid concerns 
about unknown environmental and health consequences.

Wittman said it's time to get serious about protecting waterways.

"I've always thought that it's kind of ridiculous that if we're really 
serious about managing nutrients, that we're not looking at biosolids," he 
said. "It really is a situation of treating all nutrients the same, so 
they're not ending up back in our waterways."

Staff writer Beth Jones contributed to this report.

On the Net: General Assembly: legis.state.va.us

http://www.roanoke.com/news/roanoke/wb/98342
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FROM WERF
Plans to study pathogen regrowth/re-emergence in centrifuged sludges


PROJECT SUMMARY – June, 2006
04-CTS-3T

PHASE II:  UNDERSTANDING MECHANISMS AND METHODS TO MITIGATE SURVIVAL, 
REACTIVATION AND REGROWTH OF VIABLE BUT NONCULTURABLE COLIFORMS

Background   The first phase of this research produced data which supported 
the hypothesis that FC (specifically E. coli) bacteria can become viable but 
nonculturable (VBNC) during digestion. This means that the bacteria are 
still present and considered viable, however, they cannot be grown, nor 
enumerated, by standard culturing methods (SCMs). These bacteria can be 
reactivated or resuscitated under certain conditions, which means they 
become culturable and are able to grow.

The objectives of the second phase of research are to repeat some of the 
Phase 1 experiments, to verify and to better understand the reactivation and 
regrowth phenomena and to develop mitigation strategies by answering the 
following questions:

What combinations of wastewater process technologies lead to this observed 
increase in fecal coliforms?
What specific process designs and operating conditions contribute to this 
increase in fecal coliforms?
What are the mechanisms for reactivation?
What conditions contribute to regrowth?

Phase II Study Plan  The Phase II study includes seven different plants: two 
with thermophilic anaerobic digestion, and five with mesophilic anaerobic 
digestion. The thermophilic digestion plants include one with four reactors 
in series, and one with parallel, single-stage reactors.  Both utilize 
centrifuge dewatering.  The mesophilic plants include single-stage and 
two-stage reactors.  Also, three of the mesophilic plants utilize belt 
filter press dewatering and two utilize high solids centrifuges.

The Phase II study is addressing the following.  “Sampling and analysis” 
(employing both standard culture methods and polymerase chain reaction test 
methods) is used at full-scale facilities to evaluate various aspects of the 
observed reactivation and regrowth phenomenon:

Mesophilic digestion reactivation and regrowth (sampling and analysis)
Die-off of coliforms during storage (sampling and analysis)
Potential for reactivation with belt filter presses (sampling and analysis)
Effects of digestion reactor hydraulics on reactivation and regrowth 
(sampling and analysis)
Time-temperature studies on Processes to Significantly Reduce Pathogens 
(laboratory-scale)
Time-temperature studies on Processes to Further Reduce Pathogens  
(laboratory-scale)
Sampling quality control experiments (to optimize preservation techniques 
for samples requiring shipping)
Mechanistic studies (to examine methods to grow VBNC bacteria)


Future Directions  Future (and on-going) work will include:

1)	Sampling of additional field sites which will ideally include the 
following processes:
a.	Acid/gas digestion;
b.	Additional plants with thermophilic digestion;
c.	Additional plants with mesophilic digestion.
2)	Performance of laboratory-scale batch digestion tests to further examine 
the role of reactor hydraulics on bacteria entering the VBNC state and their 
ability to be reactivated.
3)	Examine several cake amendments such as low dose lime to control regrowth 
in the cake.
4)	Examine regrowth mechanisms