Posts Tagged ‘biosolids drying’

Ecotechnology, Ltd. (Ecotech Systems) analyzes the terms that make up the world—the cliché, the misunderstood, and the “don’t tell your mama” variety—and how they play in today’s society. Today’s word is the product of an image makeover, but when you find out the truth, you may wish you’d not eaten already.

What comes to mind when you think of biosolids?

If you’re like most people, the answer is nothing, and that blank slate is exactly what proponents of biosolids want you to have in mind, because the last name brought up all kinds of negative connotations. That term? Sewage sludge.

http://www.city-data.com/forum/members/bs13690-83559-albums-animated-gifs-pic43435-green-sick-face.htmlThat’s right, biosolids are human fecal matter mixed with everything else that goes from a household water line to the wastewater treatment plant. Granted, biosolids are treated to varying degrees (and therefore changed), but sometimes you can’t shake the yuck factor. Thus far, it seems biosolids can’t get away from their origin to become the great sustainable energy resource some think they should be.

As long as wastewater plants treat water, biosolids are an inevitable byproduct. After much of the water is separated, you’re still left with a semi-solid material (containing fats, oil and greases [FOG] — matter that is difficult to treat and the number one source of drain/pipe clogs). The main solutions for biosolids disposal are landfill (which is getting less prevalent and more expensive as they get full), heat treatment (which goes up to $250/dry ton for incineration), non-heat treatment (lime, aerobic and anaerobic digesters — $85/dry ton and up, though drying biosolids at a rate much slower than heat) and land application. Regardless of what you do with the biosolids, however, some level of drying (and therefore some level of energy expenditure) is required.

Amusingly enough, although green supporters love recycling, even they often oppose biosolids use. Thing is though, biosolids are readily available, and unless something radically evolves in the human gastrointestinal tract, they’re going to continue to be around (everyone poops indeed). Fear not; biosolids are not allowed for use with food growth applications (wouldn’t that be creepy?* might actually be — see the comments), but huge, multi-year papers have concluded that biosolids are sustainable and can improve soil and crops. That said, for every 20-year pro-biosolids study I find, there are just as many touting the harmful effects.

In 2006, a U.S. E. coli outbreak from spinach spread over 26 states, causing 206 illnesses and three deaths. Though the incident didn’t involve biosolids — the outbreak was attributed to irrigation water contaminated by (untreated) cattle feces — the damaging effects gave critics a close example of what could happen with improper use.

(I’m still waiting for the news story of the angry hippie defecating on a wastewater treatment plant’s lawn, pouring chemicals on the lot and screaming, “Here’s your biosolids!” before getting hauled off in cuffs. Thus far, my Google searches have come up empty… What I did hear of, however, is when my boss visited a local biosolids plant and was warned that if he fell off the narrow plank high above the large, aerobic digester and into the muck, no one would come get him out.

Death by biosolids — not the way you want to go.)


These bare-hands-holding-biosolids pics are common, but not enough to overcome the yuck factor

Here are the main regulations involving biosolids: In 1993, the Environmental Protection Agency (EPA) introduced the Clean Water Act. Part 503 of this regulation authorized the continued use of biosolids on land while addressing the public’s concerns with the reuse of human waste. The greatest potential health risk is pathogens—a disease-producing agent linked to E. coli, hepatitis A, salmonella, Giardia and parasitic worms—carried in untreated sewage. That said, pathogens are also an issue with other organic fertilizers.

Part 503 defined different types of treated biosolids: Class A biosolids contain no detectable levels of pathogens and can be applied to land the same way as fertilizers. Class B biosolids are treated, but still have detectable levels of pathogens. (There are restrictions on their use and availability to the public.) The main reason for these different standards is the efficiency of the treatment process versus the amount of time available. As wastewater volumes increase, there is not enough time to treat to class A standards. Since the Clean Water Act, an even higher standard of biosolids has come about — class A EQ (exceptional quality) — requiring lower metal counts.

Despite what you think of biosolid use, with FOG still an issue that needs to be dealt with at any stage, drying biosolids is an essential part of the process, regardless of where they end up. As a result of that, Ecotechnology Ltd. (Ecotech Systems) launched its patented drying system into the biosolids market. With a low-grade heat (~150 F) and a patented air flow, Ecotech is able to non-thermally dry biosolids for less than $1/ton. Considering the above ranges of $85-$250/ton, this is the value savings the biosolids industry is looking for.

More on that another time. Enjoy your dinner.

*EDIT: Corrections, chatter and linked-up responses (oh my!) in the comments.


Colin McKay Miller is the Marketing Manager for the SpiroFlo Holdings group of companies:

SpiroFlo for residential hot water savings (delivered 35% faster with a 3.5% volume savings on every hot water outlet in the home) and industrial water purification (biofilm removal).

Vortex Tools for extending the life of oil and gas wells (recovering up to 10 times more NGLs, reducing flowback startup times, replacing VRUs, eliminating paraffin and freezing in winter, etc.).

Ecotech for cost-effective non-thermal drying (for biosolids, sugar beets, etc.) and safe movement of materials (including potash and soda ash).


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