W henever we use a kitchen sink garbage disposal or flush a toilet connected to a municipal sewer line, we’re sending solid waste and water to a wastewater treatment plant. While our little problem of sanitation may have been remedied in our minds

after sending waste down the drain, the problem of how to treat the biosolids (domestic wastewater residuals) remains.

The national concern over biosolids disposal affects every state gov-ernment. In the state of Florida alone there are nearly 4,000 wastewater treat-ment facilities that process this material (over 230,000 metric tons per year) containing high concentrations of potentially harmful substances (pathogens) such as fecal coliforms, Salmonella, enteric viruses, and helminth ova. In 1998, 8% of Florida’s biosolids were burned or incinerated, 9% were distrib-uted and marketed, 17% were landfilled, and 66% were land applied. Federal and state laws require that biosolids must be stabilized to meet minimum stan-dards before they can be land applied. Rising costs for energy and transporta-tion, fears of groundwater contamination, concern for health issues, and the need to follow stricter governmental regulations have made it difficult to con-tinue to apply biosolids to land areas. Additionally, with ever increasing popu-lations and the decline of suitable application areas, the need for low-cost, but effective stabilization technology is great. Alternative methodologies must be pursued.

Research in using earthworms to effectively sanitize biosolids

(vermistabilization) began in the 1970s through the work of Roy Hartenstein at the State Univer-sity of New York in Syracuse. While there have

been a few scattered attempts in the U.S. to vermicompost biosolids (see accompanying article), in 1996 Florida’s Orange County Environmental Protection Division, in asso-ciation with other local agencies, began to explore the feasibility of using vermiculture as a pathogen stabilization method. 1996 Pilot Project On March 8, 1996, a pilot project began at the City of Ocoee’s wastewater

Vermicomposting Biosolids: Earthworms Reduce Pathogens in Sewage Sludge

Will Vermistabilization of Biosolids Make a Comeback? A Brief Review of US Efforts

F rom the late 1970s and throughout periods of the 1980s, experiments in using earthworms to process biosol-ids seemed to reach a peak, as labo-

ratory researchers, municipal authorities and entrepreneurs worked together to explore economical and profitable ways to vermi-compost municipal sewage sludge. A brief review of this flurry of activity in the history

of US Vermiculture shows that interest was scattered throughout a handful of US states, with participants holding on to great prom-ise. In the end, none of these projects pro-duced long-term economic effects, judging by their total disappearance from the vermi-composting scene. What occurred to stimu-late interest in this area and what are the fac-tors that brought the demise of the prospect

Casting Call

V E R M I C O ’ S B I M O N T H L Y N E W S L E T T E R

Volume 4, Issue 5

February, 2000

See Biosolids Review page 2

See Florida Project page 2

Also in this issue…

• Interview with Bruce R. Eastman see page 6

• Upcoming Seminar

in Portland, Oregon March 24-25, 2000 see page 10

treatment facility where approximately eight tons of dewa-tered residuals were laid out into two rows, five feet wide by thirty feet long and one and one-half feet deep. For the pilot, biosolids were dewatered to around 17 percent solids with a belt press aided by a biodegradable polymer. For leachate control, the sludge was layered on a bed of filter sand with a layer of impermeable clay under it. Leachate, if produced, would be collected in a plastic trashcan at one corner of the sand pad. A canopy shed was erected over the rows to keep out rainwater and aid in moisture control. A chicken wire fence was installed to keep out animals. One of the two windrows served as the control for the project while the other row was seeded with 50 lbs. of Eis-enia fetida earthworms (about one-third pound of worms per square foot of biosolids). The project was scheduled to last for 90 days based upon calculations that earthworms would consume their body weight per day in biosolids. However, the study was cut short at 62 days because, according to Bruce Eastman, Assistant Manager of Orange County EPD, “it appeared the worms were eating upward of two times their body weight [per day].” During the project each row was wa-tered equally with a garden hose and turned with a pitchfork as needed for inspection of worms. No leachate was gener-ated from the project and there were no unusual occurrences. Samples of the residuals and the worms were tested for pathogen reduction. Researchers reported that all samples from the test row in which earthworms were present were negative for E. coli, Salmonella, helminth ova and enteric vi-rus. In the control row, all pathogen indicators were reduced except helminth ova which was negative. The worms tested negative for all parameters. Successful Two-Year Test Project

After the preliminary pilot study had been con-ducted in the City of Ocoee, Florida, the USEPA issued a 2-year experimental permit in March 1997. Class B biosolids were laid out in two windrows and spiked with four human pathogen indicators. One of the rows was inoculated with Eisenia fetida earthworms while the other row was used as a control to measure pathogen counts without earthworms.

In order for vermicomposting to be considered a vi-

able means for achieving Class A pathogen stabilization, the USEPA determined that a three to four-fold reduction of pathogen indicators must be achieved. Results from the field experiment conducted at the City of Ocoee’s Wastewater Treatment Facility were significant. Within 144 hours, test row samples taken from the earthworm-worked windrow showed a 21-fold reduction in fecal coliforms, a 28-fold re-duction in Salmonella spp., a 15-fold reduction in enteric vi-ruses and 6-fold reduction in helminth ova. Researchers con-cluded, “These results show that vermicomposting could be used as an alternative method for Class A biosolids stabiliza-tion.”

Processing biosolids puts a costly burden on munici-

palities. To ensure that public health concerns about biosolids disposal are met, state-of-the-art features must be installed in wastewater treatment facilities to meet federal and state regu-lations, or biosolids must be transported to facilities where stabilization can be achieved. Researchers in the Florida ver-micomposting project suggested “The subsequent adoption of vermicomposting as an alternative method would provide a cost-effective, reliable and safe stabilization method for any wastewater treatment facility to use, as opposed to more ex-pensive and complicated methods of stabilization.”

According to Eastman, co-author of the latest pub-

lished study of this project, vermicomposting biosolids re-quires a few acres of land, a canopy structure to cover the windrows, a tractor, a spreader, and a water wagon to help keep the biosolids from drying out. Compared to costs for other technologies that would stabilize this material, vermi-composting is extremely cost-effective.

Researchers on the Florida biosolids project were

effusive in their estimation of how radical a transformation might take place through implementing their recommenda-tions. “Vermicomposting,” they declared, “will revolutionize biosolids processing. Wastewater treatment facilities would find operational costs of vermicomposting low enough that small package plants could easily use the technology. This could enable the small and large facilities to produce equiva-lent Class A biosolids. The small facilities’ current need to haul biosolids for further stabilization will be reduced or eliminated. The health and welfare of the public and the envi-ronment will be ensured by this methodology. Throughout the world less technologically capable nations will also bene-fit from vermiculture use with biosolids.”

Florida Project from page 1

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to stabilize biosolids with earthworms on a large-scale? New York Lab Research Paves the Way Research into the use of earthworms to manage sew-age sludge (biosolids) began at the State University of New York (SUNY) in Syracuse, New York under Dr. Roy Harten-stein. With financial support from the National Science Foundation amounting to approximately half a million dol-lars, according to one reliable source, Hartenstein’s laboratory research used earthworms in petri dishes to examine their af-fect on sewage sludge. Later, extrapolations from these re-sults were made by some who suggested that earthworms might play a significant role in stabilizing wastes from mu-nicipal water treatment facilities. Interestingly, Hartenstein himself warned against the temptation to leap from lab studies to large-scale projects: “It must be stated at the outset that all of the information presented is based on small scale labora-tory experimentation under controlled conditions and cannot

Biosolids Review from page 1

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necessarily be interpreted as being extrapolable to large-scale conditions” (his emphasis). (Hartenstein, 1981).

It was at Syracuse in 1978 that a landmark confer-ence was held entitled “Utilization of Soil Organisms in Sludge Management,” focusing on the processing of sewage sludge by earthworms. During these first few years of re-search Dr. Hartenstein published a handful of papers on this promising subject, but he and Edward F. Neuhauser, a co-investigator in some projects, are no longer active in earth-worm research today. Dr. Hartenstein retired from his posi-tion in the early 1980s due to illness. Dr. Neuhauser who had been a graduate student under Hartenstein, went on to Cor-nell, and then pursued other interests, becoming the director of a power company, according to Dr. Clive Edwards of Ohio State University. As a result of Hartenstein’s work, interest in the pos-sibilities of vermicomposting biosolids began to spread. Some within the British government became interested and urged Dr. Clive Edwards to pursue investigations in this area. Perhaps coincidentally, there developed increasing interest at this time in investment opportunities advertised by vermicul-ture promoters, suggesting that raising earthworms could be profitable while serving to benefit the environment as well. In a sense, the claims being made for financial success pro-vided fuel for those who believed vermicomposting provided a means for stabilizing biosolids. The vision shared by scien-tific investigators and entrepreneurs alike was brought into clearer focus at a conference in Michigan in 1980. Michigan Conference Attracts Scientists, Entrepreneurs In April 1980, Mary Appelhof organized a Workshop on the Role of Earthworms in the Stabilization of Organic Residues, held in Kalamazoo, MI. Attended by 22 academic scientists, 14 entrepreneurs and 2 municipal agents, a good deal of the research presented there dealt specifically with biosolids vermicomposting. For example, three researchers (Pincence et al, 1981) reported on seven vermicomposting facilities they visited. A whopping five of the seven US op-erations used earthworms to process sewage sludge (Keysville, MD; Lufkin, TX; Ridgefield, WA; San Jose, CA; and Titusville, FL). While concluding that vermicomposting municipal solid waste (MSW) was not an economically feasi-ble technology (because of low tipping fees and high capital costs for grinding equipment), these researchers suggested that costs for vermicomposting sewage sludge “are quite rea-sonable compared to other conventional disposal methods at similar sized facilities,” since treating, land-spreading or land-filling costs were estimated at $150 to $250 per ton depending on transportation. Indeed, the economic forecast from the group of three researchers representing the waste management consulting firm of Camp, Dresser and McKee, Inc. was opti-mistic.

Biosolids Projects in Texas, California and Florida

Also at the Kalamazoo workshop, Ed Green and Shirley Penton of Lufkin, Texas reported on the success of spraying biosolids on earthworm beds consisting of a sawdust substrate (Green and Penton, 1981). Yet, after returning to Texas, these two researchers could proceed no further as funding dried up and support waned. Similarly, Jack Collier and Diane Livingstone presented a review of Collier’s work in vermicomposting wastewater sludge that began with re-search in his backyard and expanded to contracts with the cit-ies of San Jose and Santa Clara, California. In 1977-78, Col-lier received approximately $25,000 in grant funding to use earthworms to convert sludge into usable topsoil. Collier’s Earthworm Compost Systems, Inc. of Santa Cruz, CA proc-essed 257 cubic yards of sun-dried sludge, reducing it to 175 cubic yards of castings, a 32% volume reduction (Collier and Livingstone, 1981). However, disagreements with local po-litical factions coupled with lack of funding served to discour-age continuation of the project. According to Diane Living-stone, who still lives in Santa Cruz, the operation could not continue because it lacked local municipal funding. She also blamed the then-incoming Reagan administration for rescind-ing the budget proposed under the USEPA’s “innovative and alternative technology funding.” Livingstone claims “Reagan brought that budget to zero [and] on our own we didn’t have the money to continue.”

Another presenter at the 1980 Kalamazoo confer-

ence, Wesley Barnell Logue of American Earthworm Co., Florida reported that his 3-year project produced a system whereby earthworms disposed of up to 125 tons of residential solid waste and up to 150,000 gallons of wastewater per week per 5 acres at a cost below previous disposal methods (Logue, 1981). Today, only Logue, it is believed, is continuing to work in the area of biosolids vermicomposting, yet not on a large scale. He supplies earthworms for a wastewater treat-ment facility in the City of Ocoee, Florida, a project currently spearheaded by Bruce Eastman of the Orange County Envi-ronmental Division (Eastman et al, 1999). Worm Scams Deflate Vermiculture Interest

Popular interest in vermiculture reached its apex in the early 1980s but quickly fell into a tailspin as various States’ Attorneys General began a campaign to investigate “worm scams” that had been reported. In June 1978, national attention was brought to the subject in an article printed in the Wall Street Journal, “Many States Worry About Using Worms to Lure Investors” (Machalaba, 1978). Several re-ports of investors having been bilked in earthworm Ponzi schemes led authorities to bring charges against those accused of duplicity. Within only a couple years after this article had been published, the positive results of laboratory research had been largely overshadowed by the increasing tide of skepti-cism that came from several state governments’ pursuit of the “worm scam” artists. Popular interest in large-scale vermicul-ture subsided temporarily as a result.

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Vermicomposting Focus Shifts from Bio-solids to Small-Scale Systems In spite of bad publicity, a cadre of individuals re-mained undaunted in their belief that earthworms supplied the best answer to waste problems. Maintaining her inner convic-tion that earthworms would someday consume tons and tons of municipal waste, Mary Appelhof wrote Worms Eat My Garbage in 1982 as a way to impact the larger waste issue, one household at a time. In the early 80s, municipal-scale vermicomposting systems, probable in theory, never material-ized. Writing a simple, straightforward book with an unpre-tentious title allowed Mary to circumvent the hype of invest-ment schemes that had been coupled with the glorious hope of solving global or municipal environmental problems. The old formula, “How do you eat an elephant? (Answer: One bite at a time) was now translated to “How do you solve global or-ganic waste problems? (Answer: One vermicomposting household at a time). Shortly after conducting oversight of the 1980 Kalamazoo conference, Mary self-published Worms Eat My Garbage in 1982, setting forth in clear fashion princi-ples of small-scale vermicomposting that would eventually reach tens of thousands of households. While publicity of the “worm scams” tainted the im-age of business opportunities in growing earthworms, hope remained, persisting in almost underground fashion as “worm workers” focused on small-scale, home vermicomposting. Many had given up the ideal that municipal-scale vermicom-posting might soon be implemented. Yet there were those who went back to re-visit the research that had been done, intrigued with the possibilities that earthworms offered an

economical way to stabilize biosolids. In the temperate cli-mate of California, where population growth meant a corre-sponding increase in waste disposal, the potential for outdoor, low-cost vermistabilization of biosolids was again put for-ward. Vermicomposting Biosolids in Fallbrook, CA In 1986, after conducting a successful pilot-scale vermicomposting program, the Fallbrook Sanitary District embarked on a full-scale program to use earthworms (Eisenia fetida and Lumbricus rubellus) for stabilization of bio-solids. The District produced approximately 0.6 dry tons (544 kg) of sludge per day on its 43-acre site in a community of about 16,000 people located in Northern San Diego County. The two-stage process included pre-composting the material to comply with USEPA’s standards to reduce pathogens. After approximately 30 days in a static pile, material was removed to vermicomposting beds where it was applied at the rate of four to six inches (10-15 cm) per week to the 8-foot (2.4 m) wide windrows of varying length. To maintain porosity, straw bulking material was added about once per month. In about six months, windrows reached a height of approxi-mately three feet (.9 m) and were ready for harvesting. The top six to eight inches (15-20 cm) of material, containing the greatest concentration of earthworms, was removed and used to establish new windrows. The remainder, stabilized vermi-compost, was screened and placed in storage where it was allowed to cure for an additional 30 days. The District sold its static pile compost for $15 per cubic yard (.76 m3) and its vermicompost for $35 per cubic yard (.76 m3). It reported

A Brief Glossary of Terms Annual Pollutant Loading Rate The maximum amount of a pollutant that can be applied to a unit area of land during a 365-day period. Biosolids The product of microbially digested sewage sludge Heavy metals Trace elements whose concentrations are regulated because of the potential for toxicity to humans, animals, or plants, and includes arsenic (As), chromium (Cr), molybdenum (Mo), selenium (Se), copper (Cu), nickel (Ni), cadmium (Cd), lead (Pb), mercury (Hg), and zinc (Zn) if present in excessive amounts. Can be found in considerable concentrations in sewage sludge and several other waste materials. High concentrations in the soil can lead to toxic effects in plants and ani-mals ingesting the plants and soil particles. Federal and many state regulations restrict the land application of materials that contain high concentrations of heavy metals. Process to Further Reduce Pathogens PFRP was originally developed for composting sewage sludges but has been widely applied to solid waste composting. Compost safety standards specify that compost be subjected to PFRP, a process standard, not a product standard that can be measured by testing finished compost. Composting PFRP is defined in the federal regula-tions as: “Using either the within-vessel composting method or the static aerated piled composting method, the temperature of the sewage sludge is maintained at 55 degrees Celsius or higher for three days. Using the windrow composting method, the temperature of the sewage sludge is maintained at 55 degrees or higher for 15 days or longer. During the period when the compost is maintained at 55 degrees or higher, there shall be a minimum of five turnings of the windrow.” (40 CFR Part 503 dated February 19, 1993, Appendix B item (B) (1). POTW Publicly owned treatment works Sludge Any solid or semi-solid waste and associated supernatant generated from a municipal, commercial, or industrial wastewater treatment plant. Stabilize The degree to which material can be stored or used without giving rise to nuisances (odors, vector attraction, groundwater contamination, etc.)

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that it could not keep up with local demand (Harris, et al., 1990). Many aspects of this project were deemed success-ful. Fallbrook Sanitary District’s directors reported evidence that vermicomposting could serve to remove heavy metals from bio-solids. They were also encouraged by the plant growth potential of vermicompost stating “earthworm excreta (castings) are an excellent soil-conditioning material with a high water holding capacity and ‘natural time release’ for re-leasing nitrogen into the soil” (Harris, et al., 1990). But other factors, such as increased requirements for production and processing, an increase in time required for vermicomposting, and an increase in surface area, meant that vermicomposting made greater demands than conventional composting.

The Fallbrook vermicomposting project was forced to close as local residential development increased. The once rural community became a suburban community. However, interest in vermicomposting continued in San Diego County as Resource Conversion Corporation (RCC) obtained some 5,000 lbs. (2,268 kg) of earthworms from Fallbrook and brought them to Canyon Recycling in San Diego. Earth-worms that had once feasted on biosolids were then “re-trained” to consume yard debris compost and manure from Southern California attractions such as San Diego Wild Ani-mal Park and Del Mar thoroughbred racetrack. Scientists Continued to Study the Subject in the Late 80s Another round of scientific interest occurred in 1988 at a conference held in Cambridge, England, the First Inter-national Conference on Earthworms in Waste and Environ-mental Management. Two papers appearing in the proceed-ings, Earthworms in Waste and Environmental Management (Edwards and Neuhauser, 1988) examined the effects pro-duced by earthworms in stabilizing biosolids. Stabilization of Liquid Municipal Sludge Using Earthworms, (R.C. Loehr et al, 1988), reported the work of scientists who designed reac-tors to process three types of sludge with earthworms. Cur-rent sludge management methods, they reported, are energy and capital intensive. These scientists were interested in learning whether earthworms could reduce processing costs of biosolids. A second paper, The Potential of Earthworms for Managing Sewage Sludge (E.F. Neuhauser et al, 1988), looked at sludge characteristics and the ability of different earthworm species to grow and reproduce in sludge. As a whole, the proceedings published from this conference rank as the best, most convincing statement from a scientific per-spective that earthworms are capable of managing organic wastes of all types. Where Have All the Projects Gone?

Yet, in spite of the success of laboratory researchers who have demonstrated the potential for earthworms to stabi-lize biosolids, there is no ongoing municipal project for ver-micomposting wastewater sludge in the US. “We know very

well how the process works and generally get the results we expect to get, however, as a proven technology there haven’t been enough field studies done to say if this process will be beneficial as an alternative technology,” says researcher Ray-mond Loehr of the University of Texas at Austin (Canody, 1997). So-called “pilot projects” have come and gone throughout the past two decades, usually started on an entre-preneurial shoestring or through short-term grant funding. Reasons most often given for failure include 1) lack of contin-ued funding; 2) lack of local government commitment; and 3) problems with siting. Dangerous Elements for Earthworms There remains some skepticism, even among usually optimistic researchers, that vermicomposting biosolids can be performed without problems. Perhaps the chief worry in this area lies with the risk of introducing toxic substances to wastewater that would kill off earthworms. Municipal waste-water treatment systems are open systems, not subject to con-trols concerning what may be flushed down the drain. “All it would take would be some insecticide,” offers Dr. Clive Ed-wards, “and you would have dead earthworms. That’s the reason we looked at the possibility of doing this at a camping/conference center [Hume Lake Christian Conference Center] in California, because there would be some control.” Ed-wards consulted with campground representatives there a few years ago, but no project has since materialized. In municipal areas, large-scale vermicomposting of biosolids may not be possible so long as the possibility of an “earthworm kill” re-mains. Even one instance in which a high concentration of dangerous chemicals might be indiscriminately poured down the drain could result in complete loss of the “worm herd.” And fixing the problem of thousands of dead earthworms is considerably different than repairing a mechanical failure. Until that possibility can be removed, vermicomposting mu-nicipal biosolids might be too risky for some project manag-ers.

But at least one optimistic proponent remains. Bruce R. Eastman, Associate Manager for the Orange County Flor-ida Environmental Protection Division believes that beyond the good that earthworms do in stabilizing biosolids, they also could serve effectively as early indicators of dangerous sub-stances that might otherwise become land applied. “If that stuff is going down the drain somewhere in a municipal sys-tem,” Eastman offers, “then I would just as soon have the worm indicator telling me that those residuals are that toxic—as opposed to having them spread out on a field somewhere without knowing. I believe I would really rather have vermi-composting as the process than not. I think that as an indica-tor, it gives us that type of information that we need.” References Appelhof, Mary. (Ed.) (1981) Workshop on the Role of Earthworms in the Stabilization Of Organic Residues. Vol. 1. Proceedings, Beech Leaf Press, Kalamazoo, Michigan. Canody, Jeremy. (1997) Vermicomposting Biosolids with Earthworms, in Small Flows, National Small Flows Clearinghouse, Spring 1997, 11(2), 1-3.

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Collier, J.E., and Livingstone, D. (1981) Commercial Vermicomposting: A Better Solution to Organic Waste Conversion in Workshop on the Role of Earthworms in the Stabilization Of Organic Residues, (ed. M. Appelhof), Beech Leaf Press, Kalamazoo, Michigan, vol. 1, 255-259. Eastman, Bruce R. (1996) Vermiculture as a Domestic Wastewater Class A Stabilization Methodology, in Florida Water Resources Journal, September 1996: 27-28. Eastman, Bruce R. (1999) Achieving Pathogen Stabilization Using Vermi- composting. BioCycle, November 1999, 62-64. Eastman, B.R., Kane, P.N., Edwards, C.A., Trytek, L., and Gunadi, B. (1999) The Effectiveness Of Vermiculture in Human Pathogen Reduction for USEPA Class A Stabilization. (draft) Edwards, C.A. and Neuhauser, E.F. (1988) Earthworms in Waste and Envi- ronmental Management, SPB Acad. Publ., The Hague, The Neth- erlands, 388 pp. Florida Water Resources Journal (1996) Vermiculture for Sludge Stabiliza- tion, June 1996, 23. Green, E., and Penton, S. (1981) Full Scale Vermicomposting at the Lufkin Water Pollution Control Plant, in Proc. Workshop on the Role Of Earthworms in the Stabilization of Organic Residues, (ed. M. Appelhof), Beech Leaf Press, Kalamazoo, Michigan, vol. 1, 229- 231. Harris, G.D., Platt, W.L., and Price, B.C. (1980) Vermicomposting in a Rural Community. BioCycle, January 1980, 48-51. Hartenstein, Roy. (1981) Use of Eisenia foetida in Organic Recycling Based on Laboratory Experiments, in Proc. Workshop on the Role Of Earthworms in the Stabilization of Organic Residues, (ed. M. Appelhof), Beech Leaf Press, Kalamazoo, Michigan, vol. 1, 155- 165. Loehr, R.C., Martin, J.H., and Neuhauser, E.F. (1988) Stabilization of Liquid Municipal Sludge Using Earthworms, in Earthworms in Waste and Environmental Management (ed. C.A. Edwards and E.F. Neu- hauser), SPB Acad. Publ., The Hague, The Netherlands, 96-110. Logue, W.B. (1981) Practical Experiments in the Disposal of Residential Solid Waste And Sludge by Means of the Earthworm , in Proc. Workshop on the Role Of Earthworms in the Stabilization of Or- ganic Residues, (ed. M. Appelhof), Beech Leaf Press, Kalamazoo, Michigan, vol. 1, 261-262. Machalaba, D. (1978) Many States Worry About Using Worms to Lure Investors. The Wall Street Journal, June 5, 1978. Neuhauser, E.F., Loehr, R.C. and Malecki, M.R. (1988) The Potential of Earthworms For Managing Sewage Sludge, in Earthworms in Waste and Environmental Management, (ed. C.A. Edwards and E. F. Neuhauser), SPB Acad. Publ., The Netherlands, 9-20. Pincince, A. B., Donovan, J.F. and Bates, J.E. (1981) Vermicomposting of Municipal Solid Wastes and Municipal Wastewater Sludges, in Proc. Workshop on the Role Of Earthworms in the Stabilization of Organic Residues, (ed. M. Appelhof), Beech Leaf Press, Kalama- zoo, Michigan, vol. 1, 207-19. Riggle, David. (1996) Worm Treatment Produces “Class A” Biosolids. BioCycle, October 1996, 67-68. Water Environment Federation. (1997) Worms Accelerate Biosolids Com- posting, in Operations Forum, 14(8), August 1997, 6.

Interview with Bruce R. Eastman

B ruce Eastman is Assistant Manager of the Orange County Environmental Protection Division in Or-lando, Florida. Mr. Eastman is the principal inves-tigator in a USEPA-funded pilot project that was

recently conducted to determine whether vermicomposting biosolids will achieve pathogen destruction to meet Class ‘A’ stabilization requirements. In the first half of our interview, Mr. Eastman answered questions about biosolids processing, how he became aware of the possibilities of vermicomposting this material, and the technology used in his research.

Casting Call: In your research paper soon to be published, “The Effectiveness of Vermiculture in Human Pathogen Re-duction for USEPA Class A Stabilization,” you drew attention to the seriousness of the issue of biosolids disposal. There are “inherent environmental and health hazards of unstabilized human waste [that] can be seen in the third world nations. Rampant diseases that have debilitating consequences are common for people living in these countries.” Additionally, you stated that “Disposal of biosolids has become a national concern,” for Americans. Can you offer any particular in-stances that illustrate the harm that’s been done or the cause for alarm by regulators? Bruce R. Eastman: I think the overall attitude of the agen-cies and the passage of the more stringent rules and regula-tions, such as USEPA, 40 CFR; Part 503 (biosolids rule) and here in the state of Florida the rewriting of Florida Adminis-trative Code 62-640 (Domestic Wastewater Residuals) and local governments writing even more stringent local codes, is definitely an example of the national concern. I think it’s pretty obvious that we have medical concerns for untreated wastes that are pretty common, like I said [in the paper], in third world countries. But also I went on to say that’s not necessarily the case here in the United States. Obviously, I think, our system of treatment for wastewater residuals is far superior to most. But the public still perceives the land appli-cation of domestic wastewater residuals as a negative. I’ve run up against this for the past ten years dealing with the pub-lic in my job. It’s been a very difficult job to try to educate the public that the re-use of biosolids is really a very environ-mentally sound practice. There are some problems that still need to be addressed though. But I think those are mostly regional situations and problems, part of that being the use of food service sludges or grease-trap pumpings for land appli-cation. We recently prohibited the land application of grease unless they go to a Class A stabilization methodology. One of the reasons is that surface application of food service sludges, even when they’re blended with domestic wastewater residuals, has a tendency to destroy the crop that’s being put-ting on them, i.e., mostly pasture grasses and sods. There have been some studies done. One of the more outstanding ones that I recall was done in Maryland, I think by their De-partment of Environmental Protection, where they were using greases for soil augmentation. But they were doing injection. They were letting the greases break down through microbial action after it was injected into the soils. That’s not the prac-tice here in Florida. CC: Just to recap then, on this issue of human health con-cerns about treated wastewater residuals, have there been any reports of individuals coming in contact with this material where they have been compromised in their health in any way? BRE: No, there have not [been any incidents] of the general public. I think that is due to the rules and regulations that have been passed to restrict public access to these areas. However, I can tell you that we actually had one of our em-ployees come down with shigellosis [a form of dysentery]

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twice, who has worked in the sludge fields. A number of years back, the rules weren’t as explicit about pathogen stabi-lization. At one time all they had to do to meet the regula-tions was just to throw some lime in the pump truck. And that was considered sufficient. Of course we realize now that that’s not necessarily the case. CC: How did you first become aware of the possibility that earthworms might reduce pathogen levels of biosolids? BRE: It was purely by accident. I met a gentleman by the name of Mr. Barnell Logue who is the President of the American Earth-worm Company. He was, unbeknownst to me, using wastewater residuals to raise earth-worms. I found out about [earthworms] from my regulatory angle and I had to inform [the worm farmer] that he could not do that. It started out that we were actually going to take enforcement action. And he advised me of what he knew, from his years of experience. And from that, it sparked my interest. So that’s when I started looking into it and doing more research and pulling up as many papers as I could on the subject. And I believe that it was [Dr. Roy] Hartenstein’s [studies] I originally found that suggested that it might be use-ful. From that point that’s how our project actually came about. CC: There’s some irony here in that you were about to pro-ceed against someone in a regulatory fashion and wound up learning something instead. BRE: Absolutely. And I think [there should be] the old ‘pat on the back’ to our agency. I think that it’s a credit to us that we were able to take that route, instead of being so stiff-necked about the whole thing. CC: Your field test was conducted in an enclosed structure with biosolids spread out in windrows. Eisenia fetida earth-worms were supplied by Mr. Barnell Logue of the American Earthworm Company who kept them in Florida peat prior to their inoculation in the windrows. (As an aside, your paper mentions, “Slower reductions may have occurred because the earthworms already had a food source in the peat.”) Would you recommend staying with the same technology (windrows) for wastewater treatment facilities? BRE: No, I do not advise it. For very small operations, that’s probably a perfectly acceptable method. But for larger facilities, and I think we should kind of draw a line here somewhere, you know, what size facility are we talking about? The City of Ocoee that we’re dealing with right now is a three million gallon-a-day facility. They’re currently only operating at about a million [gallons] a day. And they pro-duce somewhere in the area of 42-45 wet tons of solids a week. With that in mind, we have approximately half an acre that we have in windrows. It’s difficult, at best, to control the

quality of the end product, the castings. I think a more feasi-ble method is to use some type of reactor. And then, there’s the question after, of having to go into some sort of a curing

process. In windrows, the worms tend to leave some food behind; some of the residuals [are left] un-stabilized in the lower portions of the wind-row, as you’re adding food to the top of them. It’s a timing matter. Now, [at] the wastewater plant, they’ve got a waste [product] then and there—they can’t wait forever. So a vermiculturist has to be able to take that material immediately. If the worms have not worked the windrows properly, because of fluctuating popula-tions or whatever, it doesn’t make any sense to go ahead and feed them, because they’ll leave the food source that they’re in at that point and move to the top of the windrow in the new food source. Also, with windrows when you add new residu-als to the top of the row some of the mate-

rial falls down the sides and is never eaten by the worms. So we don’t get good standardization throughout the whole mass of biosolids. Whereas with a system like Dr. Edwards’s wedge system, or with different reactors [that have] a continu-ous feeding process, worm populations tend to be more stable. That’s, I think, the real key to being able to produce a stabi-lized product and a consistent quality product. That’s cer-tainly my recommendation. CC: Have you been able to see any of Dr. Edwards’ continu-ous flow reactors in use? BRE: No, I haven’t, other than seen diagrams. But I have seen some others. There’s a gentleman here in Gainesville Florida, by the name of Harry Windle. He has one called the Worm Gin. It’s a very ingenious machine. And it seems to work quite well. He has a couple of them throughout the country. One of them is up in Maine. He’s got another one somewhere in Montana that I know of, and several around the state. And they seem to be working quite well so far. CC: If you went to that technology, with biosolids, would you need to use some sort of bulking agent? BRE: No. We have not found that you need to add any kind of bulking agent at all to the biosolids. The worms seem to get along in it quite well. CC: In Fallbrook California, where they were vermicompost-ing biosolids in the late 1980s, they were mixing biosolids with straw. They seemed to be concerned with keeping the material properly aerated for the earthworms. In your experi-ence, if you build up the pile height, wouldn’t it increase the likelihood of going anaerobic or getting too compacted? BRE: The rows never get very high. They only get about eighteen to twenty inches high. So you never really have that much material on top of it to compress it down. The worms

“I found out about [earthworms] from my

regulatory angle and I had to inform [the worm farmer] that

he could not do that. It started out that we were actually going to take enforcement action.”

8

are keeping that top six or better inches aerated. We haven’t had too much problem with that process. I can certainly see that if they start getting into larger piles, that would be counter-productive. CC: The biosolids were taken off a belt press and applied with manure spreaders over the windrows at 85% moisture content (15% solids). How was this ratio determined? Did the high moisture content pose any leachate problems? BRE: That has to do strictly with the operations of the waste-water treatment facility. [That this ratio seemed optimum for earthworms] was pure coincidence. We never did that on pur-pose. Actually, EPA required us to have 15-20% solids mate-rial to work with. The belt press at the City of Ocoee was brand new and works very well. They’re able to get a very good product out of it. That’s what the engineers told us we were

averaging—was 15%. Of course as the process goes on we do have a lot of volatilization of water off from the rows. We have to continue to water the rows, even after they’ve been laid down. CC: When would you do your first watering after the material was first applied off the belt press? BRE: Usually within a week. I think Mr. Logue waters the rows every week. A lot of his work is done just by years of knowledge. He doesn’t go out and measure moisture content. We were doing some of that—we have some of that information in house. CC: So, did the initial high moisture content of the biosolids pose any leachate problems? BRE: No. As a matter of fact, in the initial pilot project we put down a clay liner with a sand filter on top of it. We had it slope down to a corner of the pad, and plumbed it in so that it would go into a recapture bucket. We never had any leachate recovery at all. CC: The frequency for adding water to the windrows would depend upon the climate of a particular region. It looks like, in your case, it was necessary to add water regularly. BRE: It gets pretty hot, especially during the summer. It’s also very humid. Of course we have rainstorms every afternoon, in general, during the rainy season. So it can get very wet at

times. But the residuals, they hold water very well. They just don’t seem to leach out [liquid] very much. I might be more concerned if we were using ground-up green waste like garbage and such. It probably would not retain the water as well. We might very well have a leachate problem with that type of mate-rial. CC: In a report from the pilot phase of this project, (“Worm Treatment Produces ‘Class A’ Biosolids,” BioCycle, October 1996), earthworms had been expected to consume the equiva-lent of their body weight in biosolids per day. Surprisingly, earthworms consumed an even greater amount of feedstock, for it was said “the worms actually ate upwards of two times their body weight each day which required that the project be stopped at 68 days, rather than the full 90 days initially pro-posed.” Now, in the final report of your two-year test project, the “official” calculated consumption rate for earthworms is

stated as “1.5 times their biomass every 24 hours.” A 1:7 ratio of earthworm biomass to biosolids was suggested for a weekly rate. Are you convinced that an earthworm consumption rate for biosolids of one to 1.5 times their body weight per day can be sustained indefinitely? BRE: No, it can’t be. These numbers that we put together were strictly artificial. In order to have a balanced ratio of worms, as Dr. Edwards and I dis-cussed a number of times, we believe that an ideal ratio is probably somewhere around two pounds of

worms to one square foot of material. Somewhere in the area of 1:10 or 1:12 ratio [biomass of worms to biosolids]. CC: At what rate would you add feedstocks? Once you had a system inoculated with two pounds of earthworms per square foot of area, what amounts and how frequently would you add to that area? BRE: You could probably go ahead and start feeding every two weeks and wind up with good stabilization. We were try-ing to push this at an accelerated rate. Number One, we wanted to get the experiment done as quickly as we could. The longer it took, the more money we had to spend. So finances were part of the problem. And, at that time, we weren’t necessarily con-vinced, when we first started out, that you couldn’t sustain that type of ratio. But we found, as we were going along, that espe-cially with the windrow method, that that’s probably unrealis-tic. You wind up with ‘dead spots’ in the windrows. The worms, for whatever reason, don’t want to be there—migrated to other areas, and such. The other thing, that kind of skewed some of our ideas was, that Mr. Logue was also trying to har-vest worms for sale during the process—and you cannot do that. You’ve got to leave the worms alone. It was really rather difficult. We put these numbers in here because we showed artificially, that if we inoculate our rows with those amounts of worms, this is what we get in this period of time. But naturally and realistically, that’s probably not what is going to work in the real world. Again, we go back to that ‘two pounds of worms per square foot.’ Probably every couple of weeks—feeding time.

9

CC: And how would you calculate how much you would feed? BRE: Again, you would have to apply very thin layers. CC: But do you weigh it? Is it a volume measurement? BRE: Well, not by weight, simply by hav-ing people put the residuals on top of the bed. And the best thing is, in the area of two to three inches at a time—you could probably go up to five to six inches feeding per time. But ideally, it’s only two to three inches at a time. It is going to be a much slower process than what we originally hoped for. CC: Well, based on that, if we don’t know the weight of worms there, or if we don’t measure the weight that you’re applying, we really can’t know for certain, at this stage, what rate per day the worm consumes. BRE: I have to go back to references in other papers that I’ve read. It was stated there that they believed that worms could con-sume up to two times their weight in a 24-hour period. And, of course, our pilot indicated that that might be so. Now, do they always consume that amount or not? I don’t know. Honestly, I really and truly don’t know. CC: What was the greatest length of time that you sustained the additions of fresh material? BRE: In the spiked project itself, we never fed the worms. It was a one-time turnaround. We gave them a definite amount of food and simply put them into it. That’s why the numbers were artificial. CC: So it really hasn’t been demonstrated on a field scale. Go-ing back to the papers you might have read, please correct me if I’m wrong here, but that might have been done in a laboratory situation, where they might have consumed two times their weight in a petri dish. BRE: And they may not do that in the field—that’s very true. The other thing is, what is their food source? If they have a food source like biosolids, they have a large amount of bacteria, which is actually what they’re eating, are they going to consume more than what they would if they were in a food source that was not as nutrient-rich in bacteria? CC: Aren’t there different stages in wastewater treatment in which the biosolids are sometimes better suited for vermicom-posting and, also, stages where they are not well-suited? BRE: Anaerobic biosolids may not be suitable. What we’d like to do is to try using some solids from the bottom of the clarifier. I don’t know that they’d have enough oxygen in them to sustain

the worms, or if the worms would even go into it. We haven’t tried that yet. The biosolids we used were aerobically digested. Prior to that the biosolids were in an anaerobic situation at the

bottom of the clarifier. We’d like to try to see if there’s enough oxygen in that material to sus-tain the worms. It may be and it may not. It may require some aeration. I believe, personally, that the worms would probably do quite well in it. But we have not actually tried it. CC: In conducting your field test, you began by spiking both the test and con-trol windrows with pathogens and helminth ova eggs to establish a base-line. Can you explain why this was done? Was it necessary to increase the amount of pathogens from those al-ready present? BRE: Normally speaking, our waste-

water treatment facilities, especially our publicly owned waste-water treatment facilities, do a very good job at stabilization. They’re very effective—but at a great cost. Of course that’s where we believe vermicomposting can help—by reducing that cost. When we received the residuals, that’s why we had to spike them, for two reasons. Number One, EPA wanted us to show a three- to fourfold reduction. That was very difficult to do—we already had “B” Class residuals. So we had to spike them extremely high, in order to be able to show that reduction rate. And again, by doing that, we also proved that we probably could stabilize residuals directly from the bottom of a clarifier that had not had any type of aerobic digestive process per-formed on them. CC: Yes, I heard from Dr. Edwards that you had spent quite a few dollars to obtain helminth ova to spike the windrows. BRE: We spent $5,000—it was the biggest expense of the pro-ject other than the actual analysis. And it took us forever to get them. If it’s that rare and that difficult, why do you use them as an indicator? It would seem to me that EPA would want to use something else that’s a little more common as an indicator.

This is the end of the first half of the interview. In the next (April, 2000) edition of Casting Call, we’ll print Mr. Eastman’s answers to our questions about earthworms and heavy metal uptake, the use of continuous flow reactor technology, the need for pre-composting, what to do about the problem of weed seeds, the coming “revolution” in biosolids processing, the po-tential dangers involved in killing earthworms, and marketing the process and product.

“Normally speaking, our wastewater treatment facilities, especially our

publicly owned wastewater treatment facilities, do a very good job at

stabilization. They’re very effective—but at a great cost. Of course that’s

where we believe vermicomposting can help—by reducing that cost.”

Casting Call is a bi-monthly newsletter pub-lished in February, April, June, August, October and December. Subscrip-tion rate is $18.00 US ($24 outside US) for six issues. Our principal fo-cus areas are: vermicul-ture, composting, soil fer-tility and related issues of organic waste. Copyright © 2000 Peter Bogdanov. No part of this newsletter may be reproduced with-out permission in writing from the editor. Send comments and per-

tinent information to: Peter Bogdanov

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Merlin, Oregon 97532. (541) 476-9626

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Best Management Practices in Vermicomposting Seminar Coming to Portland, OR

A two-day seminar featuring practical sessions in starting an earthworm project will be held at the Silver Cloud Inn Portland Airport on March 24-25th, 2000. Seminar leaders will include Kelly Slocum, Associate Editor for Worm Digest, Peter Bog-danov of VermiCo, and other yet-to-be-announced guest speakers. Presentations

using computer-generated Power Point graphics, slides, overhead transparencies and video-tapes will be used in order to maximize the learning experience. Every participant will receive the Vermicomposting in Waste Management Best Practices Manual, a 3-ring binder com-prehensive notebook containing over 250 pages. This resource, according to those who have attended before, is worth the price of the course alone. Catered lunch for both days is included in the low registration fee of just $249. Reservations for discounted room rates at the Silver Cloud may be made by calling the toll free number (800) 205-7892. Free shuttle to and from the airport saves you the cost of taxi or car rental. Don’t miss this rare opportunity to attend this outstanding two-day event. For registration or more information call VermiCo at (541) 476-9626 or go to www.vermico.com\school

Chapters in the Best Management Practices in Vermicomposting notebook include: 1. Introduction: Waste Management 2. Composting: The Process 3. Compost: The Product 4. Biology & Ecology of Earthworms 5. Vermicomposting: Process & Product 6. Compost Marketing 7. Financing 8. Site Design 9. Operations 10. Business Plan 11. Regulations 12. Resources 13. Glossary of Terms

“Great speakers, wealth of written info. to fall back on. [I] learned a great deal about composting and vermicomposting…. I came away with many ideas on what to do.” M.D., Canton, Kansas

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