Data evidencing slow anaerobic digestion in emergency treatment and disposal of infectious animal carcasses.

Burial of infectious and potentially infectious livestock and poultry animals is the most common response to an emergency situation. The data set summarizes 22-week-long experiment that simulates the environment found within conventional burial trenches for emergency disposal of animal carcasses, worldwide, sometimes with a topical application of quicklime as it is required in the Republic of Korea. This data set shows the rarely presented evidence of the extremely slow decay of animal carcasses. Besides visual evidence of no visible breakdown of carcass material, i.e., carcass (or carcass quarters and coarse cuts) still resembled the initial material at the end of the study, we present data characterizing the process. Specifically, temporal variations of digestate quality (pH, ammonia, volatile fatty acids), biogas production, and the persistence of odorous volatile organic compounds are summarized. The data provide important evidence of undesirable, slow progression of the digestion process. The evidence of failure to achieve practical endpoints with the anaerobic digestion provides the impetus for seeking alternative, improved methods of disposal that will be feasible in emergency context, such as aerated burial concept (Koziel et al., 2018 [1]).


a b s t r a c t
Burial of infectious and potentially infectious livestock and poultry animals is the most common response to an emergency situation. The data set summarizes 22-week-long experiment that simulates the environment found within conventional burial trenches for emergency disposal of animal carcasses, worldwide, sometimes with a topical application of quicklime as it is required in the Republic of Korea. This data set shows the rarely presented evidence of the extremely slow decay of animal carcasses. Besides visual evidence of no visible breakdown of carcass material, i.e., carcass (or carcass quarters and coarse cuts) still resembled the initial material at the end of the study, we present data characterizing the process. Specifically, temporal variations of digestate quality (pH, ammonia, volatile fatty acids), biogas production, and the persistence of odorous volatile organic compounds are summarized. The data provide important evidence of undesirable, slow progression of the digestion process. The evidence of failure to achieve practical endpoints with the anaerobic digestion provides the impetus for seeking alternative, improved methods of

Value of the data
The digestate quality data summarizing temporal variations pH, ammonia, volatile fatty acids were compared with the optimal range recommended for anaerobic digestion. Comparing and reflecting on these operating parameters can help to explain the apparent lack of carcass decay.
The data could be used to design an improved, more successful emergency carcass disposal that must relay of an in-trench burial with anaerobic treatment. The in-trench burial is the most common worldwide approach for emergency carcass disposal.
The data documents ranges of design parameters (pH, ammonia, and volatile fatty acids) that describe the environment of a common in-trench burial. In-trench burial environment that can be very different from typical anaerobic digestion operations used for waste management on a municipal or industrial scales.
The data can be also used for estimating costs of implementing various physical and chemical pretreatments and interventions that would be needed to adjust the in-trench carcass burial environments into the range of operating parameters associated with the industrial or municipal scale anaerobic digestion process. Such estimations are needed to determine if proposed solutions are practical during outbreaks of infectious livestock or poultry diseases.
The evidence of failure to achieve apparent practical carcass decay with the anaerobic digestion provides the impetus for seeking alternative, improved methods of disposal that will be feasible in emergency situation context, such as aerated burial concept for accelerated digestion [1][2][3].

Data
This section summarizes the key operating parameters in a 22-week long anaerobic treatment of poultry carcasses: measured pH levels, volatile fatty acids concentrations, ammonia concentrations, bulk biogas production rates, and the evidence of the persistent presence of offensive odorous volatile organic compounds (VOCs) in reactor headspace and the lack of odor mitigation.
The assessment of digestate quality summarizes pH (Fig. 1), volatile fatty acids (Fig. 2), and ammonium (Fig. 3) allows for comparison with the optimal range recommended for industrial processes involving anaerobic digestion. Data summaries for these resulting parameters describing in-trench burial environments can help to explain apparent slow carcass decay.
Free ammonia (generally considered bactericidal) dominates at pH 4pKa, which was the case in the reactor with added quicklime (Fig. 3). Measured ammonia concentrations were well above (bacterial) inhibitory concentrations (Fig. 3).
There was no measurable bulk biogas (CO 2 , CH 4 ) production (Fig. 4). VOCs identified in the reactors headspace were offensive odorants (Fig. 5) many of which increased in concentration concomitant with treatment.

Experimental design, materials, and methods
The experiments were conducted over 22-week-long trial using reactors simulating anaerobic digestion that is typical in conventional burial trenches. Some countries (e.g., the Republic of Korea) recommend or require a surficial application of quicklime (CaO) as a means to mitigate odor and pathogens. Materials and methods are described in greater detail elsewhere [1]. Briefly, the reactors were constructed from 0.154 m diameter Â 0.305 m tall Plexiglas cylinder, with sealed top and bottom (Fig. 6) fitted with ports for the collection of liquid and gas samples. Three types of treatments were used: (Reactor 1) whole poultry carcass (998 g, whole chicken) with quicklime added (150 g), (Reactor 2) one quarter (1/4) portioned of whole poultry carcass (389 g), no quicklime, (Reactor 3) coarse cuts of whole poultry carcass (1000 g of total mass, chopped chicken), no quicklime.     Approximately 1.2 to 1.5 L of water was added to each reactor to simulate a burial trench environment containing whole and partially decayed carcasses and the digestate. The reactor temperature was maintained at 35°C (Fig. 6). The translucent tops of reactor allowed for periodic visual inspection of the digestion process and the apparent lack of visible breakdown of carcass material, even at the end of the experiment. Reactors were housed inside a biosafety cabinet to lower the risk of accidental spread of potentially infectious pathogens and an accidental release of odorous gases.
Measurements of pH, volatile fatty acids and ammonia in digestate were measured on week 7, 17, and 22. Measurements of volatile organic compounds (VOCs) in reactor headspace were conducted on week 8, 19, and 23 (Reactor 1), and on week 6, 16, and 20 (Reactors 2 and 3). Headspace gas was collected using solid-phase microextraction (SPME) and analyzed using gas chromatographymass spectrometry (CG-MS). Data were analyzed qualitatively by comparing MS detector response to VOCs abundance measured by peak area counts. VOC sampling conditions for SPME were identical for all reactors. Biogas was collected from reactor syringe using 1 mL Pressure-Lok gas syringe and analyzed on a CG-FID-ECD.

Acknowledgments
This research was funded by Republic of Korea Rural Development Administration through a grant from the National Institute of Animal Science (Project title: Development of environmentally friendly livestock mortality disposal system using aerobic digestion, Project no.: PJ90713006). The authors gratefully acknowledge Joann Kinyon and Susan Cramer for their help with conducting microbiological analyses. The authors gratefully acknowledge Dr. Susan Lamont (ISU, Animal Science) for providing euthanized poultry carcasses (IACUC log #4-03-5425-G). Special thanks to Devin Maurer for his help with MS data analyses.

Transparency document. Supporting information
Transparency data associated with this article can be found in the online version at https://doi.org/ 10.1016/j.dib.2018.12.001.