[USCC] Energy and incineration of biosolids, and validity of name "biosolids"

[Rufus Chaney]

Dear Ms. Rielly and USCC Listserve Participants:

The name "Biosolids":
A name is established by usage. Yes, "biosolids" is a plural noun selected in a contest to find a word which more appropriately communicated the material produced by water pollution control facilities, and was prepared for beneficial utilization. That does not make the word so inherently bad as you suggest. After review, major dictionaries agreed that the word "biosolids" was established by usage and it is in the dictionary for all to see for themselves [another list of 100 or more new words entered the dictionary this week, and I heard an interview that described the kinds of usage on a national scale that cause a word to qualify for listing in the dictionary.] . And no matter how unkindly you like to refer to sludge (including "Toxic sludge is good for you" an absurd overstatement of the science of biosolids in the environment), it remains proper to use the word "biosolids" as a plural noun for the solids generated during wastewater treatment and prepared for land application. As another commented today, biosolids are predominantly microbial products of metabolism of the materials removed during sewage treatment and solids stabilization. And of course, in digested biosolids, the inorganic solids (clays, silts, oxides, phosphates, etc.) are 40% or greater of the total dry solids. Some chemicals and oils are not metabolized under anaerobic conditions commonly used at POTWs, but are rapidly metabolized in aerobic systems. 

-----------------------------------------------------------
Another evidence of the "normal" status of the word "biosolids" is its inclusion in Wikipedia:

Biosolids (From Wikipedia, the free encyclopedia):
	"The Water Environment Federation (WEF) formally recognized the term biosolids in 1991 and it is in common use throughout the world as of 2004. The Water Environment Federation is the water and wastewater industry's main trade and lobby organization in the USA. "Biosolids" is the term created in 1991 by the "Name Change Task Force" at WEF to make the land application of processed sewage sludge more acceptable to the U.S. public. Biosolids are the nutrient rich solid material that is produced during the treatment of domestic wastewater at a treatment facility. Solid materials are removed from sewage during the wastewater treatment process. During treatment, bacteria and other microorganisms break components in the wastewater down into simpler and more stable forms of organic matter. Non-organic matter also settles into sludge. For instance, heavy metals and other toxic materials, including flame retardants (PBDEs) and persistent organic pollutants, are commonly found in sewage sludge. What does not settle into sludge leaves the treatment facility as a treated wastewater effluent. According to USEPA, biosolids that meet treatment and pollutant content criteria "can be safely recycled and applied as fertilizer to sustainably improve and maintain productive soils and stimulate plant growth." EPA policy on sewage sludge recycling is highly controversial. Often thought to consist of only "human waste," sewage sludge, or its public relations term, "biosolids," in fact contains all materials from cities which the treatment can remove from wastewater. After the 1991 Congressional ban on ocean dumping, the USEPA instituted a policy of disposing of sludge on agricultural land. EPA promoted this policy by presenting it as recycling. But with more and more incidents of illness reported, there has been increasing concern among scientists about the disposal of sewage sludge on land."
	"Biosolids in their liquid form look like muddy water and contain 1-10% solids. Biosolids may be dewatered in a second step of the treatment process, which turns it into a "cake" with the texture of a wet sponge. In this stage it contains 11-40% solids.
	"In the United States as of 2002, about 60% of all biosolids is "beneficially applied" to land as fertilizer for growing crops. Biosolids that meet the Class B treatment and pollutant criteria, in accordance with USA "Standards for the use or disposal of sewage sludge," Title 40 Code of Federal Regulations Part 503 (40 CFR 503) can be land applied with formal site permit restrictions and strict record keeping. Biosolids with lower pollutant content have less restrictions. Biosolids that meet Class A pathogen reduction requirements or equivalent treatment by a Process to Further Reduce Pathogens (PFRP) have the least restrictions on use. PFRPs include composting, heat drying, heat treatment, thermophilic aerobic digestion, beta or gamma ray irradiation and pasteurization. Processes to reduce pathogens have no effect on heavy metals and other pollutants in sewage sludge."
	"The National Research Council published "Biosolids Applied to Land: Advancing Standards and Practices" in July 2002. They concluded that there is no documented scientific evidence that biosolids regulations have failed to protect public health, but there is persistent uncertainty on possible adverse health effects. The NRC noted that further research is needed and made about 60 recommendations for addressing public health concerns, scientific uncertainties, and data gaps in the science underlying the sewage sludge standards. The USEPA claims to have had insufficient funding to implement NRC recommendations as of 2004, though has funneled millions of dollars to the Water Environment Federation to promote the land application of sewage sludge."
	"In the United States municipal wastewater treatment plants annually produced about 7.7 million dry tons of biosolids in 1997, and about 6.8 million dry tons in 1998 according to sources relying on USEPA estimates. According to the NRC, about 5.6 million dry tons was the normal US annual biosolids production rate as of 2002."


Thermal Processing of Biosolids:
You insist on seeing the worst about biosolids, while others try to find the technically valid balance. I stand by my comment about recovering energy from biosolids. And building incinerators in cities is unlikely to increase unless the anti-biosolids forces push so hard that the usual lower cost alternatives (composting; land application) are no longer available. If one looks at the fraction of US biosolids processed by incineration vs. heat drying and sale vs. land application vs. composting and beneficial use, one finds that only a small fraction is incinerated. Incinerators at many locations are simply not operated, or were constructed during the POTW construction boom, tested, paid for by government, and put in mothballs because of the high cost of operations. Higher fuel costs make them even less competitive today. Other POTWs operate incinerators because of their "sunken investment", and often because they have no capability to stabilize undigested biosolids with their current facilities. Emission controls, safe disposal of the incinerator residues, and public acceptance or urban incinerators make it difficult to permit new incinerators.

You should be more careful about relying on the claims of advertisers of sludge incinerators. The Saint Paul incinerator was selected in a complex process that many questioned when they had good acceptance of land application, and had established industrial pretreatment which gave a much better quality biosolids for land application. But if you don't have the anaerobic digestion or composting capacity, and have been incinerating as the major technology used for decades in St. Paul, it is possible that a committee would select incineration. As I noted above, an examination of the fraction of biosolids incinerated vs. other processing shows the weak competition that incineration offers for processing biosolids. I believe a similar balance exists in Canada. Do you have any data showing the fraction of Canadian biosolids processed by the different technologies? Or showing new construction of incinerators in Canada?

I'll ask the US-EPA managers for data on the fraction of solids treated by the different processes in the US and report what I find. Continuing interest in composting biosolids is evident in the marketplace, so I think it is fair to say that Mr. Reilly has not yet won the war against beneficial use of biosolids and composted biosolids products on land in the US or Canada.

Energy inefficiency for safe incineration:
As I noted earlier, the energy of incineration is not positive. A great deal of energy is invested to remove water so that less fuel is required during the burn. And fuel is required to attain temperatures needed to destroy or minimize dioxins and other adverse compounds formed during burning of organic matter. Less hot fires (e.g., household wood fires, forest fires, etc.) generate PAH and dioxins which need careful disposal. When we sought wood ash to be mixed with biosolids to achieve revegetation of the long barren Zn toxic mountainside soils at Bunker Hill, Idaho, we worked with US-EPA and biomass power facilities to find wood ash with desired low levels of dioxins. What I am trying to say is that starting with wet undigested wastewater treatment solids, one cannot make a net recovery of energy while "thermal processing" of the solids.

The energy issue is akin to that of composting. Some thought years ago that we should be able to recover energy from composting biomass. And some tried to do so. But most of that energy is required to maintain thermophilic temperatures with imperfect insulation, and to evaporate water present in the feedstocks or formed during the composting. Although composting produces heat, it has only low grade heat from which one cannot recover value (e.g., generating electricity).

Rufus Chaney
Beltsville, MD
-----------------------------------------------------------------
>>> maureen.reilly at sympatico.ca 07/07/06 06:12AM >>>

The technical term for the residuals from sewage treatment plants is 'sewage sludge'. The terminology in the US regulations that describe and direct the permitting requirements for these residuals is 'sewage sludge'.

Since the public relations word 'biosolids' appears nowhere in the Part 503 regulations on sewage sludge, I think it makes sense to use the 'sewage sludge' terminology in the US context.

The term 'biosolids' is used by some to denote sludge that is treated to land application standards, some say it means any kind of wastewater residual including papermill sludge, and some refer to any biomass including manure as 'biosolids'.  So the term 'biosolids' has no national or
international definitional integrity.

If you want to call your sewage sludge by the term 'biosolids' or 'petunias' or any other pet name, well, I guess that is your affair.  The term 'biosolids' as most of the readers here are aware, is the winning name in a PR contest to make 'sewage sludge' sound nicer.  See Toxic Sludge 
is Good for You. Chapter 4: The Sludge Hits the Fan.  http://www.ejnet.org/sludge/sludge.html 

If you want to be part of that public relations campaign : use the term 'biosolids' If you want to use terms with national regulatory and definitional integrity: use the term 'sewage sludge'

-------------------------------------------------------
On 6/20/06, C. Snyder <cgsnyder at post.harvard.edu> wrote:

This is to reply to Mike Morin's message about dumping sludge into the ocean.  There are much better 21st century solutions to dispose of contaminated waste products, such as municipal sewage sludge, beneficially, other than spreading it on healthy farmland or turning it into "compost."

Ultra-high thermal chemical decomposition of sludge is truly beneficial without all the risks and uncertainties of land application. This new  technology produces clean renewable energy;  unlike incineration, it meets the strictest air emission standards anywhere; and it  leaves a ceramic like material that can be used for construction.

These state-of-the-art gasification plants solve several  problems: they process  hard-to-handle contaminated waste; they produce clean and renewable energy; and they protect public health and the environment.

Caroline Snyder