Methane emissions from anaerobic ponds on a piggery and a dairy farm in New Zealand

2008 ◽  
Vol 48 (2) ◽  
pp. 142 ◽  
Author(s):  
R. Craggs ◽  
J. Park ◽  
S. Heubeck

Over 1000 anaerobic ponds are used in the treatment of wastewater from farms and industry in New Zealand. These anaerobic ponds were typically designed as wastewater solids holding ponds rather than for treatment of the wastewater. However, visual observation of these uncovered ponds indicates year-round anaerobic digestion and release of biogas to the atmosphere. The release of biogas may be associated with odour nuisance, contributes to greenhouse gas (GHG) emissions and is a waste of potentially useful energy. The aim of this study was to measure the seasonal variation in quantity and quality of biogas produced by an anaerobic pond at a piggery (8000 pigs) and a dairy farm (700 cows). Biogas was captured on the surface of each anaerobic pond using a floating 25 m2 polypropylene cover. Biogas production was continually monitored and composition was analysed monthly. Annual average biogas (methane) production rates from the piggery and dairy farm anaerobic ponds were 0.84 (0.62) m3/m2.day and 0.032 (0.026) m3/m2.day, respectively. Average CH4 content of the piggery and dairy farm biogas was high (74% and 82%, respectively) due to partial scrubbing of CO2 within the pond water. The average daily volume of methane gas that could potentially be captured by completely covering the surface of the piggery and dairy farm anaerobic ponds was calculated as ~550 m3/day and ~45 m3/day, respectively (assuming that the areal methane production rate was uniform across the pond surface). Conversion of this methane to electricity would generate 1650 kWh/day and 135 kWh/day, respectively (with potentially 1.5 times these values co-generated as heat) and reduce GHG emissions by 8.27 t CO2 equivalents/day and 0.68 t CO2 equivalents/day, respectively. These preliminary results suggest that conventional anaerobic ponds in New Zealand may release considerable amounts of methane and could be a more significant point source of GHG emissions than previously estimated. Further studies of pond GHG emissions are required to accurately assess the contribution of wastewater treatment ponds to New Zealand’s total GHG emissions.

2007 ◽  
Vol 55 (11) ◽  
pp. 257-264 ◽  
Author(s):  
J.B.K. Park ◽  
R.J. Craggs

New Zealand has over 1000 anaerobic wastewater stabilisation ponds used for the treatment of wastewater from farms and industry. Traditional anaerobic ponds were not designed to optimise anaerobic digestion of wastewater biomass to produce biogas and these uncovered ponds allowed biogas to escape to the atmosphere. This release of biogas not only causes odour problems, but contributes to GHG (greenhouse gas) emissions and is wasteful of energy that could be captured and used. Biogas production from anaerobic stabilisation ponds treating piggery and dairy wastewater was measured using floating 25 m2 HDPE covers on the pond surface. Biogas composition was analysed monthly and gas production was continually monitored. Mean areal biogas (methane) production rates from piggery and dairy anaerobic ponds were 0.78 (0.53) m3/m2/d and 0.03 (0.023) m3/m2/d respectively. Average CH4 content of the piggery and dairy farm biogas were 72.0% and 80.3% respectively. Conversion of the average volume of methane gas that could be captured from the piggery and dairy farm ponds (393.4 m3/d and 40.7 m3/d) to electricity would reduce CO2 equivalent GHG emissions by 5.6 tonnes/d and 0.6 tonnes/d and generate 1,180 kWh/d and 122 kWh/d. These results suggest that anaerobic ponds in New Zealand release considerable amounts of GHG and that there is great potential for energy recovery.


2008 ◽  
Vol 48 (2) ◽  
pp. 104 ◽  
Author(s):  
Mark Lieffering ◽  
Paul Newton ◽  
Jürgen H. Thiele

Greenhouse gas (GHG) emissions from New Zealand dairy farms are significant, representing nearly 35% of New Zealand’s total agricultural emissions. Although there is an urgent need for New Zealand to reduce agricultural GHG emissions in order to meet its Kyoto Protocol obligations, there are, as yet, few viable options for reducing farming related emissions while maintaining productivity. In addition to GHG emissions, dairy farms are also the source of other emissions, most importantly effluent from milking sheds and feed pads. It has been suggested that anaerobic digestion for biogas and energy production could be used to deal more effectively with dairy effluent while at the same time addressing concerns about farm energy supply. Dairy farms have a high demand for electricity, with a 300-cow farm consuming nearly 40 000 kWh per year. However, because only ~10% of the manure produced by the cows can be collected (e.g. primarily at milking times), a maximum of only ~16 000 kWh of electricity per year can be produced from the effluent alone. This means that anaerobic digestion/electricity generation schemes are currently economic only for farms with more than 1000 cows. A solution for smaller farms is to co-digest the effluent with unutilised pasture sourced on the farm, thereby increasing biogas production and making the system economically viable. A possible source of unutilised grass is the residual pasture left by the cows immediately after grazing. This residual can be substantial in the spring–early summer, when cow numbers (demand) can be less than the pasture growth rates (supply). The cutting of ungrazed grass (topping) is also a useful management tool that has been shown to increase pasture quality and milk production, especially over the late spring–summer. In this paper, we compare the energy and GHG balances of a conventional farm using a lagoon effluent system to one using anaerobic digestion supplemented by unutilised pasture collected by topping to treat effluent and generate electricity. For a hypothetical 300-cow, 100-ha farm, topping all paddocks from 1800 to 1600 kg DM/ha four times per year over the spring–summer would result in 80 tonnes of DM being collected, which when digested to biogas would yield 50 000 kWh (180 GJ) of electricity. This is in addition to the 16 000 kWh from the effluent digestion. About 90 GJ of diesel would be used to carry out the topping, emitting ~0.06 t CO2e/ha. In contrast, the anaerobic/topping system would offset/avoid 0.74 t CO2e/ha of GHG emissions: 0.6 t CO2e/ha of avoided CH4 emissions from the lagoon and 0.14 t CO2e/ha from biogas electricity offsetting grid electricity GHGs. For the average dairy farm, the net reduction in emissions of 0.68 CO2e/ha would equate to nearly 14% of the direct and indirect emissions from farming activities and if implemented on a national scale, could decrease GHG emissions nearly 1.4 million t CO2e or ~10% of New Zealand’s Kyoto Protocol obligations while at the same time better manage dairy farm effluent, enhance on-farm and national energy security and increase milk production through better quality pastures.


2019 ◽  
Vol 20 (18) ◽  
pp. 4415 ◽  
Author(s):  
Anna Szafranek-Nakonieczna ◽  
Anna Pytlak ◽  
Jarosław Grządziel ◽  
Adam Kubaczyński ◽  
Artur Banach ◽  
...  

Methanogenesis occurs in many natural environments and is used in biotechnology for biogas production. The efficiency of methane production depends on the microbiome structure that determines interspecies electron transfer. In this research, the microbial community retrieved from mining subsidence reservoir sediment was used to establish enrichment cultures on media containing different carbon sources (tryptone, yeast extract, acetate, CO2/H2). The microbiome composition and methane production rate of the cultures were screened as a function of the substrate and transition stage. The relationships between the microorganisms involved in methane formation were the major focus of this study. Methanogenic consortia were identified by next generation sequencing (NGS) and functional genes connected with organic matter transformation were predicted using the PICRUSt approach and annotated in the KEGG. The methane production rate (exceeding 12.8 mg CH4 L−1 d−1) was highest in the culture grown with tryptone, yeast extract, and CO2/H2. The analysis of communities that developed on various carbon sources casts new light on the ecophysiology of the recently described bacterial phylum Caldiserica and methanogenic Archaea representing the genera Methanomassiliicoccus and Methanothrix. Furthermore, it is hypothesized that representatives of Caldiserica may support hydrogenotrophic methanogenesis.


2017 ◽  
Vol 68 (6) ◽  
pp. 1294-1297 ◽  
Author(s):  
Gabriela Alina Dumitrel ◽  
Adrian Eugen Cioabla ◽  
Ioana Ionel ◽  
Lucia Ana Varga

Anaerobic digestion processes of agricultural resources, as single substrates (wheat bran and barley) or as combination of substrates (75 % corn&25% corn cob � named MIX1 and 40 % corn & 40 % wheat&20 % sunflower husks � named MIX2), were performed, at a mesophilic temperature in a batch reactor, at pilot scale. The results proved that the higher quantity of biogas yield was achieved for barley, followed by MIX1, and finally MIX2. The same order was obtained when the total methane production was evaluated. The performances of digesters were mathematically evaluated by using the modified Gompertz equation. The kinetic parameters, such as the methane production potential (MP), the maximum methane production rate (Rm) and the extent of lag phase (l) were calculated, for each experimental case. The values of the performance indicators confirmed that all the models fitted well with the experimental data.


2010 ◽  
Vol 61 (4) ◽  
pp. 1019-1026 ◽  
Author(s):  
S. Heubeck ◽  
R. J. Craggs

New Zealand has over 1000 anaerobic waste stabilisation ponds treating wastewater from farms and industry. Traditional anaerobic ponds were not designed to optimise anaerobic digestion to produce biogas and are therefore uncovered, releasing biogas to the atmosphere, which can cause odour problems and contributes to GHG emissions. The biogas production and treatment performance of an anaerobic piggery pond retrofitted with a perimeter cover working under field conditions was monitored over a 14 month period. The cover design proved successful in capturing biogas, mitigating odour and GHG issues and coping with New Zealand weather conditions. High solids removal rates (73% and 86% for TS and VS respectively) were achieved. An annual average biogas methane production rate of 0.263 m3 CH4/kgVSadded was observed, which is similar to gas production rates of mesophilic farm waste digesters, and indicates that the prolonged hydraulic and solids retention times of covered anaerobic ponds can fully compensate for lower operating temperatures. These results suggest that covered anaerobic ponds treating agricultural wastes in New Zealand have great potential to reduce odour and GHG emissions and recover renewable energy, while producing an easy to handle effluent for land irrigation or further treatment.


2016 ◽  
Vol 89 ◽  
pp. 58-66 ◽  
Author(s):  
Alessandro Agostini ◽  
Ferdinando Battini ◽  
Monica Padella ◽  
Jacopo Giuntoli ◽  
David Baxter ◽  
...  

2021 ◽  
Author(s):  
Guoxiang Zheng ◽  
Stopira Yannick Benz Boboua ◽  
Chenyang Zhou ◽  
Jiachen Li ◽  
Weishuai Bi ◽  
...  

Abstract Biogas production in the cold regions of China is hindered by low temperatures, which led to slow lignocellulose biotransformation. Cold-adapted lignocellulose degrading microbial complex community LTF-27 was used to investigate the influence of hydrolysis on biogas production. After 5 days of hydrolysis at 15 ± 1°C, the hydrolysis conversion rate of the straw went up to 22.64%, and the concentration of acetic acid rose to 2,596.56 mg/L. The methane production rates of TS inoculated by LTF-27 reached 204.72 ml/g, which was higher than the biogas (161.34 ml/g), and the CK (121.19 ml/g), the methane production rate of VS increased by 26.88% and 68.92%, respectively. Parabacteroides, Lysinibacillus, and Citrobacter were the main organisms that were responsible for hydrolysis. While numerous other bacteria genera in the gas-producing phase, Macellibacteroides were the most commonly occurring one. Methanosarcina and Methanobacteriaceae contributed 86.25% and 11.80% of the total Archaea abundance during this phase. This study proves the psychrotrophic LTF-27's applicability in hydrolysis and biomass gas production in low temperatures.


Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5423
Author(s):  
Margarita Andreas Dareioti ◽  
Aikaterini Ioannis Vavouraki ◽  
Konstantina Tsigkou ◽  
Michael Kornaros

The growing interest in processes that involve biomass conversion to renewable energy, such as anaerobic digestion, has stimulated research in this field in order to assess the optimum conditions for biogas production from abundant feedstocks, like agro-industrial wastes. Anaerobic digestion is an attractive process for the decomposition of organic wastes via a complex microbial consortium and subsequent conversion of metabolic intermediates to hydrogen and methane. The present study focused on the exploitation of liquid cow manure (LCM) and cheese whey (CW) as noneasily and easily biodegradable sources, respectively, using continuous stirred-tank reactors for biogas production, and a comparison was presented between single- and two-stage anaerobic digestion systems. No significant differences were found concerning LCM treatment, in a two-stage system compared to a single one, concluding that LCM can be treated by implementing a single-stage process, as a recalcitrant substrate, with the greatest methane production rate of 0.67 L CH4/(LR·d) at an HRT of 16 d. On the other hand, using the easily biodegradable CW as a monosubstrate, the two-stage process was considered a better treatment system compared to a single one. During the single-stage process, operational problems were observed due to the limited buffering capacity of CW. However, the two-stage anaerobic digestion of CW produced a stable methane production rate of 0.68 L CH4/(LR·d) or 13.7 L CH4/Lfeed, while the total COD was removed by 76%.


2021 ◽  
Author(s):  
Aaron Wall ◽  
Jordan Goodrich ◽  
Anne Wecking ◽  
Jack Pronger ◽  
David Campbell ◽  
...  

<p>Agricultural greenhouse gas (GHG) emissions account for almost half of New Zealand’s total emissions, and therefore considerable attention has been given to identifying and testing mitigation options. At plot scale, plantain (Plantago lanceolate L.) in the pasture sward has been demonstrated to reduce nitrous oxide (N<sub>2</sub>O) emissions but has not been tested at paddock scale on an operating farm. Our aim was to test the efficacy of a pasture sward containing >30% plantain as a GHG mitigation option at paddock scale (2.5-3 ha) on a year-round rotationally grazed commercial dairy farm in the Waikato region of New Zealand. Utilising eddy covariance measurements of CO<sub>2</sub>, N<sub>2</sub>O and CH<sub>4</sub> coupled to farm management records, N<sub>2</sub>O, carbon (C) and GHG balances (sign convention: positive value = emission to the atmosphere) were calculated for two adjacent paddocks – a control paddock containing an existing ryegrass/clover sward (RC), and a paddock that underwent renovation with the establishment of a ryegrass/clover/plantain sward (RCP). Establishment of RCP was via spraying and direct drilling and occurred in March 2018 (autumn). For the establishment period between initial herbicide application and the first grazing of the new RCP sward 66 days later, N<sub>2</sub>O emissions were 2.58 kg N ha<sup>-1</sup> compared with 1.69 kg N ha<sup>-1</sup> for the RC paddock. During the same period, C losses from the RCP paddock were greater than from the RC paddock (2.40 t C ha<sup>-1</sup> for RCP and 1.29 t C ha<sup>-1</sup> for RC) primarily due to reduced photosynthetic inputs associated with the herbicide application. The GHG budget (including enteric methane emissions from feed grown and eaten in the paddock) during the 66 day establishment period was an emission of 6.56 t CO<sub>2</sub>-eq ha<sup>-1</sup> for RC and 9.85 t CO<sub>2</sub>-eq ha<sup>-1</sup> for RCP. Unfortunately, the RCP sward establishment was poor, and after one year, total pasture production was unexpectedly lower than RC. Additionally, plantain accounted for <7% of the total RCP dry matter production. N<sub>2</sub>O, C and GHG balances for RCP in the first year following (and including) establishment were 6.61 kg N ha<sup>-1</sup> y<sup>-1</sup>, 3.25 t C ha<sup>-1</sup> y<sup>-1</sup> and 21.40 t CO<sub>2</sub>-eq ha<sup>-1</sup> y<sup>-1</sup> respectively, while for RC they were 7.21 kg N ha<sup>-1</sup> y<sup>-1</sup>, 0.95 t C ha<sup>-1</sup> y<sup>-1</sup> and 13.29 t CO<sub>2</sub>-eq ha<sup>-1</sup> y<sup>-1</sup>. Due to the poor establishment of plantain, any N<sub>2</sub>O and GHG benefits of this species were unable to be initially concluded, but additional plantain was sown and measurements are ongoing. However, we did identify several relevant findings: any N<sub>2</sub>O/GHG benefits of plantain must firstly offset emissions (including C losses) associated with the establishment of the sward (>3 t CO<sub>2</sub>-eq ha<sup>-1</sup> in this study), and furthermore, there is a risk that should the establishment be poor, GHG emissions can be considerably greater (and pasture production lower) than an existing pasture.</p>


2000 ◽  
Vol 42 (10-11) ◽  
pp. 195-202 ◽  
Author(s):  
R. J. Craggs ◽  
C. C. Tanner ◽  
J. P. Sukias ◽  
R. J. Davies-Colley

Dairy farm waste stabilisation ponds are a major source of ammoniacal-N to surface waters in New Zealand. Ammoniacal-N is of particular concern in New Zealand where native aquatic invertebrates appear to be very sensitive to ammonia toxicity. This paper investigates improvement of ammoniacal-N nitrification in dairy farm facultative ponds with mechanical aeration and provision of biofilm attachment surfaces. Biofilm was grown on surfaces at different depths (0.1 m, 0.2 m and 0.6 m) under three mechanical aeration regimes (no aeration, night-only aeration and continuous aeration). Nitrification potential of biofilm was determined as the rate of ammoniacal-N removal in bioassays with ammoniacal-N spiked pond water or culture medium under controlled conditions (20°C, pH 7.0, constant stirring, DO 2–3 g m−3, dark). The nitrification potentials (0.30 g N m−2 biofilm d−1 to 2.17 g N m−2 biofilm d−1) of biofilm-coated surfaces were largely controlled by oxygen availability and consistency of supply in the pond. Nitrification potentials were high where oxygen availability was high, such as close to the pond surface where atmospheric re-aeration and algal photosynthesis were prevalent. Nitrification potentials of biofilms incubated at depth were enhanced by mechanical aeration, with higher values achieved under the continuous aeration regime and at more turbulent sites closer to the aerator.


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