A Contextual History of Digester Technology 

Nov 7th presentation: (email out – includes SOP at bottom)

A Contextual History of Digester Technology 

            This will be a contextual history of digester technology, where it came from, how it was originally used, what was transferred with it and what was not when it was transferred to industrial agriculture. This presentation will include a conversation about regulations, or their absence, federal and state legislation, a major waste stream which will be used as a feedstock for these digesters, the human health and environmental problems from that waste stream, and a discussion of recent problems, including a death.  

            This presentation will end by identifying an unlimited, and unregulated, source of methane from industrial agriculture which can be accessed without building new digesters or transporting any waste streams.

            I was a member of the Iowa Department of Natural Resources committee that was writing draft regulations for industrial agricultural anaerobic digesters. There were no regulations for digesters in ag. Although called Waste Conversion Technology in ag, these were anaerobic digesters based on wastewater digesters that were part of wastewater treatment processes. A draft document was partially done when I joined that committee.

            My first contribution to the committee was mentioning that even though the draft regulations said that no hazardous waste was to be allowed in these ag digesters, hog confinement waste, a major waste stream for these digesters, fit Iowa’s definition of hazardous waste to a “T”.

Iowa Code 455B.411 subsection 3:
a. “Hazardous waste” means a waste or combination of wastes that, because of its quantity, concentration, biological degradation, leaching from precipitation, or physical, chemical, or infectious characteristics, has either of the following effects:
(1)  Causes, or significantly contributes to an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness.
(2)  Poses a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed. “Hazardous waste” may include but is not limited to wastes that are toxic, corrosive or flammable or irritants, strong sensitizers or explosives.

            The gasses hydrogen-sulfide and ammonia, the green house and explosive gas methane, antibiotic-resistant organisms, particulates, and toxic VOC’s are cooked up during anaerobic digestion in hog confinements and are contained in hog confinement waste. This pollution is blown or vented out of hog confinements 24/7/365 so the pigs inside won’t die.

            High concentrations of hydrogen-sulfide can cause respiratory paralysis and may cause coma after a single breath and may be rapidly fatal. Also convulsions, acute conjunctivitis with pain, lacrimation, and photophobia; rhinitis, pharyngitis, bronchitis, and pneumonitis among others are mentioned. Ammonia vapor is a severe irritant of the eyes, especially the cornea, the respiratory tract, and skin. Also mentioned are dyspnea, bronchospasm, chest pain and pulmonary edema which may be fatal; bronchitis, pneumonia, and asthma are also problems. There can be health problems when people are colonized by antibiotic-resistant organisms such as MRSA. There are respiratory problems from particulates. And the 20 or so toxic VOC’s also are harmful to human health. These fit the Iowa hazardous waste definition.

            I will mention three studies that move these health problems from “can happen” to “do happen” to Iowa people. The Sigurdarson-Kline study shows that if a rural school has a confinement within 10 miles, 11.7% of the children exhibit asthma health outcomes – nearly two times the state rate. If a confinement is within ½ mile of a school, 24.6% of children exhibit asthma health outcomes – nearly four times the state rate. The Merchant study shows that if you are a kid that lives on a farm with a confinement that adds antibiotics to feed, there is a 55.8% chance you will experience asthma health outcomes – more than eight times the state rate.

            The Smith study shows that if you are a veteran who lives within one mile of a confinement in Iowa, you are almost three times more likely to be colonized by MRSA than a veteran who lives outside that 1 mile limit. This can lead to serious health issues where antibiotics will not help you.

            I met Dr. Kelley Donham in the early 2000’s. One thing we were both looking at were deaths in hog confinements from hydrogen-sulfide. Because confinements are not covered by OSHA, deaths do not have to be recorded, so we were looking through Iowa newspapers counting up the deaths we could find. Adding our counts together, we counted some 25 deaths which more than likely were not the complete numbers at that time.  

            These health problems, and deaths, of Iowans from hog confinement waste should give you serious pause because hog confinement waste is a major feedstock of the digesters this conference is about. Similar to other bandaids for industrial ag like CO2 pipelines, edge of field practices, and ethanol, ag digesters used this way are a bandaid that tries to give industrial hog confinements relevance, but actually enable those confinements to continue polluting no matter the inherent ongoing human health and environmental problems that exist by using them. But, you are here at this conference, so maybe this is new information for you.

            When I made the DNR Chair of the committee aware of this hazardous waste problem, his answer to me was that the feds and the state say that because this is ag, this waste cannot be described as hazardous. I quote: “The Code citation is a legislative decision and matches the federal exclusion. I don’t believe Iowa DNR can do anything contrary to the state and federal statutes.”

            So something that is known to be a hazardous waste is not a hazardous waste in ag just because the feds and the state say it isn’t. Think about that for a second. Are people whose health is affected by these hazardous wastes told they are not really affected? Are Iowa families who have lost family members told that the deaths were not from a hazardous waste? The statement that “this is not really hazardous waste so we don’t protect you from it” is not really a satisfactory response for families who have had members die, and for people who have serious health issues from this waste.

            The 2014 Jillian Fry Johns Hopkins study goes into great detail showing and discussing the gap between known public health threats from industrial agriculture and what is being done to protect the public through regulations from those known health threats. From the study: “Research has found that the main foci of environment agencies have shifted to permitting, enforcement, record keeping, and standard setting, and away from public health evaluations.” In other words, no one seems to care about the health of people in proximity to hog confinements, and there are no regulations protecting them. 

            I didn’t hear anything from the committee after that and figured I was dropped from the committee for mentioning that observation. I found out subsequently that I wasn’t dropped from the committee, but rather the Iowa Legislature passed Senate File 534 in 2019 that said the DNR couldn’t regulate agricultural digesters, and the committee was disbanded.

            Imagine my surprise when a couple of years later, the Legislature passed a law, House File 522, that said that anaerobic digesters could be used in conjunction with hog confinements in Iowa. The state also said that they would subsidize these digesters with taxpayer funds. In articles supporting this move, it was stated that the wastewater industry has used anaerobic digesters for decades with success.

            Well yes, but those digesters are only one part of a treatment process, and those treatment plants are run by licensed, think education levels, operators. Wastewater digesters have to follow design standards. Operators have DNR regulations that they have to adhere to. They have to follow federal OSHA occupational safety and health regulations, and OSHA considers digesters a “confined space”, which are the most dangerous places in the treatment process. Remember, the Iowa Legislature said that ag digesters could not have DNR regulations applied to them, and in Iowa, OSHA does not regulate agriculture. So there are no regulations protecting workers or the public.

            Because of regulations, this is an example of an SOP (standard operating procedure) when working on an anaerobic digester at a wastewater treatment plant. (SOP is printed below this presentation) Remember, ag digesters don’t have regulations.

            Well, what could happen when there are no regulations for ag digesters? A headline in the CR Gazette: “No OSHA probe of man who died in dive into farm digester.” “Questions raised abut diver’s equipment and temperature of tank” by Erin Jordan, CR Gazette, June 17, 2021. “Bob Baenziger Jr., 54, of East Moline died around 10am June 8th when he was unable to return to the top of the liquid in the tank at Sievers Family Farm in Stockton, according to New Liberty Fire Chief Chad Petersen.” “As his fiancée was trying to pull him up, there were complications and he didn’t surface,” Scott County Sheriff’s Capt. Joe Caffery said. “For whatever reason, he relayed to her through radio communications that he was taking his helmet off. So when she pulled the rope up, the helmet came up.” Since OSHA regulations were not involved, the investigation was closed. No education, no safety equipment. In a rather morbid irony, the day he died was the same day that Gov Reynolds signed the law that allowed on-farm digesters, House File 522. House File 522 also led to this conference.

            A little know fact is that even though the Iowa Nutrient Reduction Strategy (INRS) is completely voluntary for ag, it is not voluntary for wastewater treatment plants which do have actual new nitrogen and phosphorus limits. To meet the required INRS limits, many plants in the wastewater industry are changing their treatment processes and moving away from anaerobic digesters. Agriculture is going to use digesters as a stand alone piece of equipment when that technology is historically only one part of a wastewater treatment process. Ag is going to use a technology that many in wastewater are moving away from. Ag is going to use a very dangerous “confined space” technology without any of the regulations that protect the workers and the public.

            This ag digester legislative sleight-of-hand is similar to the legislative sleight-of-hand that happened with hog confinements, which ag digesters are supposed to enhance, but actually will be enabling that continuing confinement use. In passing the law which directed the DNR to regulate hog confinements, the Legislature only wrote language which allowed the water pollution avenue to be regulated, and not the other pollution avenue, the air pollution avenue. Because of this legislative omission, it is illegal in Iowa to regulate air pollution which is, and has been, coming out of hog confinements 24/7/365 for years causing the deaths and human health problems I have mentioned. This pollution is blown or vented out of the confinement so the pigs inside won’t die, but with no regard for the people who live in proximity, or the larger environment.

            So now the Legislature and the Reynolds’ Administration are patting themselves on the back, and you are attending this conference, for coming up with the idea that ag digesters can capture methane from hog confinement waste transferred to ag digesters and help in the climate crisis. Meanwhile the Legislature made it illegal to regulate any of the pollutants, including methane, already spewing out of the some 13,000 Iowa hog confinements. Ag producers don’t have to worry about regulations. And, Iowans will have to help pay for these ag digesters through our tax money being used as subsidies.

            Ag digesters are a bandaid attempt to give the inherently polluting industrial ag model relevance, and a “climate washing” attempt to mislead the public into thinking hog confinements and ag digesters can help clean up the environment and therefore are a good thing for Iowa. 

            I have discussed digester technology, where it came from, how it was originally used, what was transferred with it and what was not when it was transferred to industrial agriculture. I have discussed regulations, or their absence, both federal and state legislation, a major “hazardous waste” stream which will be used as a feedstock for these digesters, human health and environmental problems from that waste stream, and a discussion of recent problems, including a death.  

            As I mentioned at the beginning, I will end this presentation by identifying an unlimited, and unregulated, source of methane from industrial agriculture which can be accessed without building new digesters or transporting any waste streams.

            In our lawsuit trying to get the DNR to regulate the air pollution avenue coming from hog confinements, the judge noted the legislative omission of not writing language that would allow the DNR to write air pollution regulations. The Court’s judgment stated because of that omission, you can’t regulate hog confinement air pollution in Iowa. Essentially it is illegal to regulate the air emissions coming out of hog confinements which happens 24/7/365 and includes methane.

            Therefore, there is an unlimited, unregulated supply of methane that can be captured at the some 13,000 hog confinements that exist in Iowa. You don’t have to build new taxpayer subsidized ag digesters. You don’t have to transport any waste. Just put your methane capture equipment on any hog confinement you want.

            I’ll leave you with this thought, using anaerobic digesters in ag is a moral and ethical quagmire.

            Thank you.

Bob Watson

SOP Digester Work:

Pre-Arrival to Job Site:

    • Tank is structurally safe. Lid is safe. The lid will support a 700 Lbs pump and 400 lbs. of manpower and additional equipment.

    • The tank lids, if required, have been opened by the customer. Ventilation is in process. There are no unusual or high readings by customer’s gas monitoring equipment.

    • Access to the tank or tanks is clear of equipment and traffic.

    • The customer has arranged for a qualified lifting devise and operator for placement of or pumping equipment on the tank lid.

    • The customer has arranged for qualified elections who know the plant power specifications and our pump specification for 3- phase power.

    • The customer has supplied a telephone list of plant personnel for contact by our crew.

    • Emergency telephone numbers for Fire, Ambulance and Police have been provided by the customer.

    • Power source has been identified for 3-phase and 110 power.

    • Tank design specifications can be obtained from the customer.

    •  The customer has identified any potential hazards in and around the plant.

    • Lock-out tag out information has been identified by the customer for any feed lines to the tank to be cleaned.

    • The contractor’s gas monitor has been calibrated to specification.

Set-up for Tank Work/Cleaning.

* The atmosphere around the tank has been tested. The tank atmosphere has been tested.

* All power cords to pumps, lights and repairable air systems have been inspected. Cords have been covered for chaffing or wear.

    • Pumps have been inspected for proper clearances from impeller to chopper plate.

    • The chain hoist has been inspected for proper operation.

     • The Fall protection winch has been inspected.

     • Harnesses have been inspected. Web, seams, D-Ring, and buckles

     • The repairable air system has been inspected for proper operation. Both filters have been inspected.

    • SCBA (self contained breathing apparatus) system has been inspected. Tank volume is sufficient. Face mask has been cleaned.

    • The power panel has been inspected and the ground rod installation is complete with the proper cord connection.

    • Ladders and rope ladders have been inspected. Stokes retrieval basket is on site and inspected.

    • While the tank is being cleaned continuous gas monitoring will be completed by a (4) gas meter BW-Gas Alert Micro Clip X3 or the equivalent.

    • Gases monitored while staff are in the tank or around the tank shall be the following: Hydrogen Sulfide, Flammable gases, Carbon Monoxide, Oxygen in the event of an alarm all personnel shall immediately exit the tank until tank is ventilated further and safe entry can be completed.