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Where sewage sludge is serious business

The topic of solid waste treatment rarely makes for an engaging presentation, but Ben Nydegger, the biosolids program manager for the city of Boise’s Public Works department, actually has a pretty interesting story to tell about what happens to what’s flushed in the city of Boise.

Nydegger dispenses with the most unsavory realities first: that the city takes the biosolids, mostly human waste, from the city’s two main “water renewal facilities” (once known as wastewater treatment plants), treats it to remove the pathogens, and then trucks it out of town to a property the city owns in unincorporated Ada County. There, the treated solids, which look like dirt, are used to fertilize 4,200 acres of alfalfa, corn and wheat at a farm called the 20 Mile South Biosolids Application Site.

In a good year, the farm’s crops make $3 million to $4 million, which helps pay for some of the costs of the city’s wastewater treatment.

“That’s why we’re in the farming business,” said Nydegger of the city. With farm commodity prices down this year, Nydegger experts the crops to make $2.8 million this year.

The Boise biosolids farm program, which treats 30 million gallons of wastewater per day, is unusual because it’s tied to a city-owned farming operation that itself is a model of environmental sustainability. Many cities, such as Denver and Calgary, treat biosolids for farm field application, but no other city had the foresight to purchase a farm in 1994 as the city of Boise did, says Maile Lono-Batura, executive director of the Northwest Biosolids, the industry interest group in Seattle.

“Most utilities don’t buy huge tracts of land,” said Lono-Batura. “Buying a farm is something people at many utilities wish they had thought of when land prices weren’t what they are now.”

Not only is the city farming with biosolids, but its small administration building is the state’s first energy-neutral commercial building. Completed in July 2016, it uses triple-paned windows, solar panels and geothermal energy for heating and cooling. Farm irrigation is provided by 12 wells.

There’s just not a whole lot outside of farming that you can do with biosolids. Most cities treat them somehow so they can be used as fertilizer or compost; incinerate them; or – as in the case of Nampa and Caldwell, Nydegger said – send them to the landfill.

The 20 Mile South farm, which employs 14 people, is also the place where the city of Boise stores the compost it has received  since it started its composting program in June 2017. After it has been sorted and left to heat up, killing the weed seeds and pathogens, the composted organic matter is trucked back to Boise to be given out to local gardeners who take part in the composting program.

In May, Nydegger led a tour of the Boise farm to a group of Treasure Valley residents who had signed up for the city’s Livability Ambassador program, a new venture that’s the work of the city’s office of community engagement. The Livability Ambassador program was created to address the fact that the city is running a handful of innovative sustainability projects that nobody in the area seems to know about. For reasons unknown, the city generally eschews the more common public awareness tactic of talking to the media in favor of creating a program over which it feels more control. Sustainability Coordinator Jami Goldman said the purpose of the program is to create messengers who will spend the occasional Saturday morning learning about these projects, one at a time, and then spread the information about the projects organically, through their own community, family and friend networks.

Indeed, when I told colleagues, friends and family about my eye-opening trip to the biosolids farm, the first reaction was inevitably, “why haven’t I ever heard about this?”

The 18 or so Livability Ambassadors are all professionals from around the Treasure Valley, and many have a background in sustainability or science or both. The program is inexpensive; for our trip to the farm, the driver of our small bus was Public Works Director Steve Burgos, who gave up his Saturday morning to tour the farm with the ambassadors. Among other things, the program also includes excursions to the city’s innovative Dixie Drain phosphorus removal project in Parma; the Foothills Learning Center; the Ada County Landfill and Hazardous Waste Facility; the Boise WaterShed and River Campus; and a tour of the geothermal energy facilities in Boise’s Central Addition.

Nydegger’s been in his position since December 2010. He’s become very good at explaining what he does for a living, and where.

“When I talk to people on a personal basis, I have to get into the details, because I get a lot of blank stares when I tell them the city is involved in a farming operation,” Nydegger said. “The fact that we’re using waste to sustainably grow crops that can be sold and offset the cost of wastewater treatment for our rate-payers is a pretty cool thing.”

Anne Wallace Allen is the editor of the Idaho Business Review.





About Anne Wallace Allen

Anne Wallace Allen is the editor of the Idaho Business Review.


  1. Dear Anne Wallace Allen: You state in your article the following: “Indeed, when I told colleagues, friends and family about my eye-opening trip to the biosolids farm, the first reaction was inevitably, “why haven’t I ever heard about this?””

    Perhaps the reason that NO ON HAS EVER HEARD OF THIS…. is that the “sludge industry” does not want the public to know what is in CONCENTRATED TOXIC SEWAGE SLUDGE…. “BIOSOLIDS” is concentrated toxic waste of a municipality…. In North Carolina, where I live, the Department of Health and Human Services tested a sample of toxic sludge and here are a few things that they found: Heavy Metals – Aluminum, Antimony, Arsenic, Barium, Beryllium, Bismuth, Boron, Bromine, Cadmium, Cerium, Cesium, Chromium, Copper, Dysprosium, Erbium, Europium, Gadolinium, Germanium, Gold, Hafnium, Holmium, Iron, Lanthanum, Lutetium, Lead, Magnesium, Manganese, Mercury, Molybdenum, Nickel, Niobium, Palladium, Praseodymium, Rhodium, Rubidium, Ruthenium, Samarium, Scandium, Selenium, Silver, Strontium, Tantalum, Tellurium, Terbium, Thallium, Thorium, Thulium, Tin, Titanium, Tungsteen, Uranium, Vanadium, Yttrium, Ytterbium, Zinc Pathogens – Bacteria – Fecal Coliform, Salmonella 2000 types, Shigella 4 spp., E. coli 0157:H7, Staphylococcus aureus, Enteropathogenic E. coli, Yersinia enterocolitica, Campylobacter jejuni, Vibrio cholera, Leptospira, Listeria, Helicobacter, Mycobacteria, Aeromanonas, Legionella, Burkholderia, Endotoxins, antibiotic resistant bacteria Viruses – Adenovirus, Astrovirus, Calcivirus, Coronavirus, Enterovirus, Poliovirus, Coxsackie A, Coxackie B, Echovirus, Enterovirus 68 – 72, Hepatitis A virus, Hepatitis E virus, Norwalk Virus, Reovirus, Rotavirus, Protozoa – Cryptosporidium, Entamoeba histolytica, Giardia lamblia, Balantidium coli, Toxoplasma gondii, Helminths (Parasites) – Ascaris lumbicaides (roundworm), Ancylostoma duodenale (hookworm), Necator americanus (hookworm), Tainia saginata (tapeworm), Trichuris (whipworm), Toxocara (roundworm) Strongyloides (threadworm), Ascaris suum, Toxocara canis, Taenia solium, Hymenolepis nana, Fungi – Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Epidermophyton spp., Trichophyton spp., Trichosporon spp., Phialophora spp.,, Prions (spongiform encephalopathy), Synthetic Chemicals – Dioxins & Furans Octachlorodibenzo-P-Dioxin, 1,2,3,4,6,7, 8-Heptachlorodibenzo-P-Dioxin, Octachlorodibenzo Furan, 1,2,3,4,6,7,8, Heptachlorodibenzo-Furan (71), 2,3,7,8-Tetrachlorodibenzo-Furan, 1,2,3,6,7,8 Hexachlorodibenzo-P-Dioxin, 1,2,3,4,7,8-Hexachlorodibenzo-Furan, 1,2,3,7,8,9-Hexachlorodibenzo-P-Dioxin, 1,2,3,6,7,8-Hexachlorodibenzo-Furan, 2,3,4,6,7,8-Hexachlorodibenzo-Furan, 1,2,3,4,7,8,9-Heptachlorodibenzo-Furan, 2,3,4,7,8-Pentachlorodibenzo-Furan, 1,2,3,4,7,8-Hexachlorodibenzo-P-Dioxin, 1,2,3,7,8-Pentachlorodibenzo-Furan, 1,2,3,7,8 Penta-chlorodibenzo-P-Dioxin, 1,2,3,7,8,9-Hexachlorodibenzo-Furan, 2,3,7,8-Tetrachlorodibenzo-P-Dioxin, Polychlorinated Dibenzodioxin/Polychlorinated Dibenzofuran (PCDD/PCDF), Tetrahydrofuran, 2,4-D, 2, 4,5-T, dioxin (TCDD) Organics (carbon-based) Acetones, Chloroform, Cyclohexanone, Bis(2-ethylhexyl) Phthalate, Bis(2-ethylhexyl), tetrabromophthalate, Di-n-undecyl phthalate, Alkyl benzyl Phthalate, Di-(2-Ethylhexyl) Phthalate, (DEHP). Butyl Benzyl Phthalate, Toluene, 2-Propanone, Methylene Chloride, Hexanoic Acid, 2-Butanone, Methyl Ethyl Ketone, Alcohol Ethoxylate, Alkylphenolethoxylates, Phenol, Nonylphenol, 2,2’-methylenebis{4-methyl-6-nonyl-Phenol, p-Nonylphenol, 4,4’-butylidenebis{2-(1,1-dimethylethyl)-5-methyl-,4-Methylphenol, Phenol, 4,4’-(1-methylethylidene) bis{2-(1,1-dimeth, Phenol, 4,4’-(1-methylethylidene) bis(2-(1,1-dimeth, 2,4-dicumylphenol, p-Dodecylphenol, 2,4,5-Trichlorophenol, N-Hexacosane, N-Tetracosane, N-Dodecane, N-Tetradecane, N-Triacontane, N-Eicosane, N-Hexadecane, N-Octacosane, Carbon Disul_de, N-Decane, N-Docosane, ,N-Octadecane, P-Cymene, Benzo(B)_uranthene, Fluoranthene, P-Chloroaniline, Pyrene, Tetrachloromethane, Trichloro_uoromethane, 2-Hexanone, 2-Methylnaphthalene, 4-Chloroaniline, Benzo(a)pyrene ,Pesticides &Insecticides Aldrin, Chlordane, Cyclohexane, Heptachlor, Endosulfan, Endosu_an-II, Lindane, Dieldrin, Endrin, DDT, DDD, DDE, 2,4,5-Trichlorophenoxyacetic Acid, Acetic Acid (2,4-Dichlorophenoxy), 2,4,5-Trichlorophenoxypropionic Acid, Pentachloronitrobenzene, Chlorobenzilate, Beta-BHC, Kepone, Mirex, Methoxycholor, PCBs- PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, PCB-1260, PBDEs (PolyBrominated Diphenyl Ethers) BDE-28, BDE-47, BDE-66, BDE-85, BDE-99, BDE-100, BDE-138, BDE-153, BDE-154, BDE-183, BDE-209, Hydrocarbons, Petrochemicals, Organochlorines PCBs, PCT, PBB, PBT, Anthracene, Pentachlorophenol, Benzo(g,h,i)perylene, Benzene, Benzene, C14-C24-branched, Polyethylbenzene residue, Octane, Hexachlorobenzene, Ethylbenzene, Chlorinated Benzenes, Naphtha (petroleum), turpentine-oil, Hydrotreated kerosene, Hydrocarbon oils, Hydrocarbons, C10 and C12, Distillates (petroleum), Fuel oil, Creosols, P-Cresol, O-Cresol, 2-(2H-Benzotriazol-2-yl)-p-cresol, Hexachlorobutadiene, N-Nitrosodimethylamine, Toxaphene, Trichloroethane, Tetrachloroethane, Hexachloroethane, Carbon Tetrachloride, Dichloroethylene, Trichloroethylene, Tetrachloroethylene, Xylene Pharmaceuticals 1,7-Dimethylxanthine, 4-Epianhydrochlortetracycline, 4-Epianhydrotetracycline, 4-Epichlortetracycline, 4-Epioxytetracycline, 4-Epitetracycline, Acetaminophen, Albuterol, Anhydrochlortetracycline, Azithromycin, Ca_eine, Carbadox, Carbamazepine, Cefotaxime, Chlortetracycline, Cimetidine, Cipro_oxacin, Clarithromycin, Clina_oxacin, Cloxacillin, Codeine, Cotinine, Dehydronifedipine, Demeclocycline, Digoxigenin, Digoxin, Diltiazem, Diphenhydramine, Doxycycline, Enro_oxacin, Erythromycin-Total, Flumequine, Fluoxetine, Gem_brozil, Ibuprofen, Isochlortetracycline, Lincomycin, Lome_oxacin, Metformin, Miconazole, Minocycline, Naproxen, Nor_oxacin, Norgestimate, O_oxacin, Ormetroprim, Oxacillin, Oxolinic Acid, Oxytetracycline, Penicillin G, Penicillin V, Ranitidine, Roxithromycin, Sara_oxacin, Sulfachloropyridazine, Sulfadiazine, Sulfadimethoxine, Sulfamerazine, Sulfamethazine, Sulfamethizole, Sulfamethoxazole, Sulfanilamide, Sulfathiazole, Tetracycline, Thiabendazole, Triclocarban, Triclosan, Trimethoprim, Tylosin, Virginiamycin, Warfarin, Steriods & Hormones 17 Alpha-Dihydroequilin, 17 Alpha-Estradiol, 17-Alpha-Ethinyl-Estradiol, 17-Beta-Estradiol, Androstenedione, Androsterone, Beta Stigmastanol, Campesterol, Cholestanol, Cholesterol, Desmosterol, Epicoprostanol, Equilenin, Ergosterol, Estriol, Estrone, Ethinylestradiol, Norethindrone, Norgestrel, Progesterone, Stigmasterol, Sitostanol, Beta-Estradiol 3-Benzoate, Beta-Sitosterol, Equilin, Testosterone

    Perhaps you would like to learn more about SEWAGE SLUDGE…. go to or see Sewage Sludge Action Network on Facebook

  2. Don is correct. Why don’t you ask Ben about the 85,000 chemicals and growing found in sewage. Here a little commentary Ben will not be able to answer questions about.

    For the record Ben is a sewage con artist and Ms Wallace you run a close second because you did not research the risk to inform your readers of the dangers. You are NOT immune to the dangers because you are editor of the Idaho Business Review and you woe them the fact Ben will not tell you.

    Also Ben can not “treats (biosolids) it to remove (all) the pathogens.” You are naive if you believe that.

    **Every US industry connected to a sewer can discharge any amount of hazardous and acute hazardous waste into sewage treatment plants as long as they report it. Yeow right! There are over 85,000 chemicals in commerce and growing even today. It ends up in biosolids and effluent and even bags taken to the consumer’s home and used in their garden. See also the Targeted National Survey of Sewage Sludge 2009 Just Google it.

    **US EPA Office Inspector General (OIG) Report # 14-P-0363 in 09/2014 / Google and read it for yourself. To sum up, industrial pretreatment is not working and has never worked and nothing has been done about it. It ends up in biosolids and sewage plant effluent. “The priority pollutants list has not been updated since 1981.”

    **So when you hear anyone from the multi-billion dollar sewage industry or anyone with monetary ties to any part of the sewage industry say the chemicals (in-organic) in biosolids are minimal and inconsequential or that they support composting with biosolids, ask them for any test showing the degree of hazard and concentrations of 85,000 chemicals that are found in biosolids or a composted biosolids like Milorganite from Milwaukee.

    A anaerobic digester will not degrade in-organic man made chemicals

    The chemicals in these biosolids dumps on our farms, ranches and forest are a large contributor to cancer, chronic diseases, and birth defect.

    So Ms Wallace ignore this warning and when you or a family member or friend is setting in the chemo chair losing all their hair and vomiting violently hoping you will be cured of cancer, you had better remember one of the causes.

  3. It is so important to understand that sewer sludge aka biosolids is NOT just human excrement – it is a concentration of all domestic and industrial pollutants that go down drains and sewers. It has some good stuff in it, which plants can use, but a huge load of thousands of other contaminants.  Please read what independent scientists have to say on this issue –

    Dr. Caroline Snyder – “Land-applied municipal sewage sludge (biosolids) is a highly complex and unpredictable mixture of biological and chemical pollutants. Biosolids generated in our large industrialized urban centers is very likely the most pollutant- rich waste mixture of the 21st century.”

    Dr. Richard Honour – “”Few in any governments appreciate that nearly all chronic diseases are caused by long-term exposure to low levels of environmental contaminants and pollutants. We should be trying to minimize this exposure, not amplifying it. It is time to end land disposal of Toxic Sewer sludge, and look at cleaner, greener alternatives – gasification / pyrolysis.”
    Let’s get on the right side of history, and use this waste resource to make energy. It is time to stop covering Mother Earth with our cities’ toxic sewage.

    Prominent Scientists and Universities outline the Dangers of Biosolids –
    Canadian Scientists –
    UK Scientists- Aberdeen / Glasgow Universities –
    Cornell –
    See this link on regulatory failures and risks –
    Overview of the issues – by Dr. Thomas Maler
    Scientific American –

    Author Lidia Epp (manager of the Molecular Core Lab in the Biology Department of College of William and Mary in Williamsburg) speaks to the House Democratic Committee Hearing –

    “There is little doubt that there are direct human health consequences of land application of sludge. Several published public health reports clearly link the sludge application sites to the overall decline of health by the surrounding communities. Czajkowski et al in a publication from 2010 “Application of GIS in Evaluating the Potential Impacts of Land application of Biosolids on Human Health” concludes that there is a statistically significant increase in ill-health symptoms and diseases near the biosolids permitted fields. Exposed residents were defined as those living within the one mile radius of filed applied biosolids, the illnesses included certain respiratory, gastrointestinal and other diseases.”

    It is evident that the long term exposure to a host of the environmental pollutants is the foundation of many chronic conditions that are now at the epidemic levels. Rather than focusing narrowly on determination of specific sets of toxins present in biosolids from different sources – the research needs to shift to the epidemiological studies assessing the overall impact of complex mix of pollutants present in sludge.

    It is true that biosolids contain beneficial elements like phosphorus, nitrogen, organic matter and trace nutrients. But the benefits derived from introducing those components to the soil via biosolids are by far overshadowed by the detrimental effects of toxins and pollutants that comprise the vast majority of the biosolids content.

    Many countries adopted and implemented a new approach to the disposal of biosolids; methane production, energy source, recovery of metals and microelements. It is well past the time when we start to look at those alternatives as the only sustainable solution to the growing problem – what to do with the sludge our society produces.”