Sludge Watch ==> LA Residents Produce Nation's Stinkiest Sludge

[Maureen Reilly]

Sludgewatch Admin:

Funny, eh?  LA has the US's stinkiest sludge and Toronto has Canada's 
stinkiest sludge.

Bear in mind that these centrifuged sludges have a tendency to exhibit 
astonishing rates of pathogen reactivation.  So there is evidence that the 
pathogens
in sludge are not killed - just starved into a viable but non culturable 
state and they resusatate in the presence of nutrient.....like centrate or 
even once land applied.

 Here is more on that.

http://www.werf.us/pdf/ReactivationFactSheet.pdf

This has implications not only for odor but for public health and food 
safety associated with sludge spreading.

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If a Package Stinks, It Belongs to Me"


The cost of biosolid treatment and hauling is a major expenditure for 
wastewater treatment utilities. Pathogens and odor problems may restrict the 
biosolid disposal options and affect hauling costs. A Virginia Tech 
environmental engineer is identifying processes for the destruction of 
organic solids and the elimination of disease causing organisms in 
biosolids.


Virginia Tech Photo
John Novak, Virginia Tech's Nick Prillaman Professor of Civil and 
Environmental Engineering, works to identify better processes for the 
destruction of organic solids and the elimination of disease causing 
organisms in biosolids.






Newswise - The county of Los Angeles may not like this distinction, but 
Virginia Tech environmental engineer John Novak says the sludge from this 
area of California has the "worst odor of any I have ever tested." A walk 
inside his laboratory, sealed-off from other testing facilities on the 
Virginia Tech campus, produces instant agreement.
"This county can haul its sludge hundreds of miles into the desert, and it 
still gets complaints," Novak smiles.

On the East Coast, a $400 million sludge handling system, slated to be built 
along the Potomac River by the Washington D.C. Water and Sewer Authority by 
2010, may not be able to completely thwart the odor problems if it uses 
current technology.
Novak, the Nick Prillaman Professor of Civil and Environmental Engineering, 
is working with both localities, as well as others, to identify better 
processes for the destruction of organic solids and the elimination of 
disease causing organisms in biosolids.
Any time a treatment plant works with water or wastewater, sludge is 
generated. And twice a week, Novak's lab receives two shipments of the 
processed solids from the sewage. Novak laughingly admits that if "a package 
stinks, it belongs to me."
"Biosolids management is one of the most important aspects of wastewater 
treatment because of economic and health and safety issues," Novak says. 
"The cost of biosolid treatment and hauling is a major expenditure for 
wastewater treatment utilities. Pathogens and odor problems may restrict the 
biosolid disposal options and affect hauling costs."
Biosolids applied to land in the form of fertilizer can also impact ground 
water quality, primarily through nitrogen contamination.
Novak's approach to reduce the volatility of waste and to remove nitrogen 
from the process differs from some of the previously tried techniques. His 
work is based in part on some successful treatments of wastewater where a 
sequential anaerobic and aerobic digestion, called a dual-digestion process, 
is used.
"Recent studies suggest that some solids in sludge are degraded only during 
the anaerobic digestion and some only during the aerobic digestion 
treatments," Novak explains. "Therefore, a dual digestion, using both 
anaerobic and aerobic treatments would be expected to provide a reduction in 
the volatile solids beyond that achieved when using only one of the 
processes."
His initial studies indicate that his theory is correct. The dual treatment 
achieved up to a 65 percent volatile solids reduction, compared to 46 and 52 
percent when using one of the single anaerobic digestion processes. His 
studies also showed that more than 50 percent of the nitrogen and 80 percent 
of the ammonia can be removed from anaerobic effluent after digesting it 
aerobically.
He reported his findings at the 2006 Residuals and Biosolids Management 
Conference in Cincinnati, Ohio.
Novak has also investigated the role that two specific metals, iron and 
aluminum, play in odor coming from sludge treated anaerobically. Working 
with researchers from Carollo Engineers and CH2M-Hill, they used a 
centrifuge simulation method developed at Virginia Tech to anaerobically 
digest a blend of primary and waste activated sludge from 12 different 
wastewater treatment plants.
Their findings indicated that aluminum reduced the odor potential for 
sludges that were high in iron.
The Water and Environmental Research Foundation has supported Novak's 
research on odors from sludges since 2000, As he conducted his studies, the 
35-year veteran of water, sludge, solid and hazardous waste treatments, has 
learned that some new technologies are partially responsible for an increase 
in odors.
"In recent years, companies started selling sludge dewatering systems that 
consist of new centrifuges that reduce the amount of water in the process, 
thus reducing costs," Novak says. However, the odor increases. A $600,000 
facility in Charlotte, N.C., with the more recently developed centrifuge 
technology is an example of a new plant hearing complaints about its foul 
aroma.
"The production of odors from sludges is a complex biochemical process," 
Novak says. "Odors, primarily from organic sulphur compounds, can be 
produced from anaerobically digested dewatered sludge cakes, especially when 
high solids centrifuges are used for dewatering. Even when digestion is 
effective, centrifugation can generate headspace concentrations of total 
volatile organic sulphur that are quite high and likely to cause odor 
problems."
If odors remain a problem, the dewatering process may need to be changed, 
Novak asserts.