Biogas production from anaerobic waste stabilisation ponds treating dairy and piggery wastewater in New Zealand

2007 ◽  
Vol 55 (11) ◽  
pp. 257-264 ◽  
Author(s):  
J.B.K. Park ◽  
R.J. Craggs
Keyword(s):  
New Zealand ◽  
Energy Recovery ◽  
Biogas Production ◽  
Ghg Emissions ◽  
Dairy Farm ◽  
Gas Production ◽  
Dairy Wastewater ◽  
Average Volume ◽  
Piggery Wastewater ◽  
Waste Stabilisation Ponds

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.

Biogas recovery from a temperate climate covered anaerobic pond

2010 ◽  
Vol 61 (4) ◽  
pp. 1019-1026 ◽  
Author(s):  
S. Heubeck ◽  
R. J. Craggs
Keyword(s):  
New Zealand ◽  
Biogas Production ◽  
Ghg Emissions ◽  
Weather Conditions ◽  
Gas Production ◽  
Temperate Climate ◽  
Waste Stabilisation Ponds ◽  
Solids Retention ◽  
Cover Design ◽  
And Coping

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.

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
Keyword(s):  
New Zealand ◽  
Methane Production ◽  
Biogas Production ◽  
Ghg Emissions ◽  
Dairy Farm ◽  
Pond Water ◽  
Visual Observation ◽  
Methane Production Rate ◽  
Surface Conversion

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.

Greenhouse gas and energy balance of dairy farms using unutilised pasture co-digested with effluent for biogas production

2008 ◽  
Vol 48 (2) ◽  
pp. 104 ◽  
Author(s):  
Mark Lieffering ◽  
Paul Newton ◽  
Jürgen H. Thiele
Keyword(s):  
New Zealand ◽  
Anaerobic Digestion ◽  
Greenhouse Gas ◽  
Milk Production ◽  
Kyoto Protocol ◽  
Biogas Production ◽  
Ghg Emissions ◽  
Dairy Farm ◽  
Dairy Farms ◽  
Management Tool

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.

Dairy farm wastewater treatment by an advanced pond system

2003 ◽  
Vol 48 (2) ◽  
pp. 291-297 ◽  
Author(s):  
R.J. Craggs ◽  
C.C. Tanner ◽  
J.P.S. Sukias ◽  
R.J. Davies-Colley
Keyword(s):  
New Zealand ◽  
Dairy Farm ◽  
High Rate ◽  
Great Promise ◽  
E Coli ◽  
Effluent Quality ◽  
Waste Stabilisation Ponds ◽  
Faecal Bacteria ◽  
Period Performance ◽  
Farm Wastewater

Waste stabilisation ponds (WSPs) have been used for the treatment of dairy farm wastewater in New Zealand since the 1970s. The conventional two pond WSP systems provide efficient removal of wastewater BOD5 and total suspended solids, but effluent concentrations of other pollutants including nutrients and faecal bacteria are now considered unsuitable for discharge to waterways. Advanced Pond Systems (APS) provide a potential solution. A pilot dairy farm APS consisting of an Anaerobic pond (the first pond of the conventional WSP system) followed by three ponds: a High Rate Pond (HRP), an Algae Settling Pond (ASP) and a Maturation Pond (which all replace the conventional WSP system facultative pond) was evaluated over a two year period. Performance was compared to that of the existing conventional dairy farm WSP system. APS system effluent quality was considerably higher than that of the conventional WSP system with respective median effluent concentrations of BOD5: 34 and 108 g m-3, TSS: 64 and 220 g m-3, NH4-N: 8 and 29 g m-3, DRP: 13 and 17 g m-3, and E. coli: 146 and 16195 MPN/100 ml. APS systems show great promise for upgrading conventional dairy farm WSPs in New Zealand.

scholarly journals Economics of GHG emissions mitigation via biogas production from Sorghum, maize and dairy farm manure digestion in the Po valley

2016 ◽  
Vol 89 ◽  
pp. 58-66 ◽  
Author(s):  
Alessandro Agostini ◽  
Ferdinando Battini ◽  
Monica Padella ◽  
Jacopo Giuntoli ◽  
David Baxter ◽  
...  
Keyword(s):  
Biogas Production ◽  
Ghg Emissions ◽  
Dairy Farm ◽  
Po Valley ◽  
Emissions Mitigation

Plantain as a GHG mitigation option: N2O, C and GHG balances from an intensively grazed New Zealand dairy pasture

2021 ◽  
Author(s):  
Aaron Wall ◽  
Jordan Goodrich ◽  
Anne Wecking ◽  
Jack Pronger ◽  
David Campbell ◽  
...  
Keyword(s):  
New Zealand ◽  
Ghg Emissions ◽  
Dairy Farm ◽  
First Year ◽  
Herbicide Application ◽  
Ghg Mitigation ◽  
Pasture Production ◽  
Mitigation Option ◽  
Sign Convention ◽  
One Year

<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>

Nitrification potential of attached biofilms in dairy farm waste stabilisation ponds

2000 ◽  
Vol 42 (10-11) ◽  
pp. 195-202 ◽  
Author(s):  
R. J. Craggs ◽  
C. C. Tanner ◽  
J. P. Sukias ◽  
R. J. Davies-Colley
Keyword(s):  
New Zealand ◽  
Dairy Farm ◽  
Pond Water ◽  
Oxygen Availability ◽  
Ammonia Toxicity ◽  
Waste Stabilisation Ponds ◽  
Nitrification Potential ◽  
N Removal ◽  
Mechanical Aeration ◽  
Farm Waste

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.

scholarly journals Treatment of Combined Dairy and Domestic Wastewater with Constructed Wetland System in Sicily (Italy). Pollutant Removal Efficiency and Effect of Vegetation

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1086
Author(s):  
Mario Licata ◽  
Roberto Ruggeri ◽  
Nicolò Iacuzzi ◽  
Giuseppe Virga ◽  
Davide Farruggia ◽  
...  
Keyword(s):  
Plant Growth ◽  
Organic Compounds ◽  
Removal Efficiency ◽  
Constructed Wetland ◽  
Organic Pollutant ◽  
Dairy Farm ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Dairy Wastewater ◽  
Giant Reed

Dairy wastewater (DWW) contains large amounts of mineral and organic compounds, which can accumulate in soil and water causing serious environmental pollution. A constructed wetland (CW) is a sustainable technology for the treatment of DWW in small-medium sized farms. This paper reports a two-year study on the performance of a pilot-scale horizontal subsurface flow system for DWW treatment in Sicily (Italy). The CW system covered a total surface area of 100 m2 and treated approximately 6 m3 per day of wastewater produced by a small dairy farm, subsequent to biological treatment. Removal efficiency (RE) of the system was calculated. The biomass production of two emergent macrophytes was determined and the effect of plant growth on organic pollutant RE was recorded. All DWW parameters showed significant differences between inlet and outlet. For BOD5 and COD, RE values were 76.00% and 62.00%, respectively. RE for total nitrogen (50.70%) was lower than that of organic compounds. RE levels of microbiological parameters were found to be higher than 80.00%. Giant reed produced greater biomass than umbrella sedge. A seasonal variation in RE of organic pollutants was recorded due to plant growth rate Our findings highlight the efficient use of a CW system for DWW treatment in dairy-cattle farms.

scholarly journals Effect of Mixing Regimes on Cow Manure Digestion in Impeller Mixed, Unmixed and Chinese Dome Digesters

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2540
Author(s):  
Abiodun O. Jegede ◽  
Grietje Zeeman ◽  
Harry Bruning
Keyword(s):  
Urban Areas ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Gas Production ◽  
Cow Manure ◽  
Volatile Solid ◽  
Treatment Efficiency ◽  
Ambient Temperatures ◽  
Ch4 Production ◽  
Mixing Regime

This study examines the effect of mixing on the performance of anaerobic digestion of cow manure in Chinese dome digesters (CDDs) at ambient temperatures (27–32 °C) in comparison with impeller mixed digesters (STRs) and unmixed digesters (UMDs) at the laboratory scale. The CDD is a type of household digester used in rural and pre-urban areas of developing countries for cooking. They are mixed by hydraulic variation during gas production and gas use. Six digesters (two of each type) were operated at two different influent total solids (TS) concentration, at a hydraulic retention time (HRT) of 30 days for 319 days. The STRs were mixed at 55 rpm, 10 min/hour; the unmixed digesters were not mixed, and the Chinese dome digesters were mixed once a day releasing the stored biogas under pressure. The reactors exhibited different specific biogas production and treatment efficiencies at steady state conditions. The STR 1 exhibited the highest methane (CH4) production and treatment efficiency (volatile solid (VS) reduction), followed by STR 2. The CDDs performed better (10% more methane) than the UMDs, but less (approx. 8%) compared to STRs. The mixing regime via hydraulic variation in the CDD was limited despite a higher volumetric biogas rate and therefore requires optimization.

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