World Leading Technology From New Zealand Odour Reduction Green Energy Improved Effluent Quality Carbon Credits Waste Solutions Ltd. Business Support Division 1st Floor, John Wickliffe House 265-269 Princes Street, Dunedin PO Box 997, Dunedin, New Zealand Ph + 64 3 477 2375 Fax + 64 3 479 2249 Email info@wastesolutions.co.nz www.wastesolutions.co.nz
Anaerobic Digestion Waste Solutions are specialists in applied anaerobic digestion processes which offer low-cost, energy efficient treatment options for animal wastes. An energy-rich biogas is produced and captured, driving the generation of heat and electricity as well as reducing odour. Systems can range from very simple covered pond designs, to advanced in-ground digester systems or above ground, tank based systems. Low Cost Systems Waste Solutions has over 30 years experience in designing and installing anaerobic treatment facilities with a special focus on inexpensive and highly efficient systems. Our designs have been successfully marketed internationally and we have completed highly innovative projects in Europe, North America, South East Asia, Australia, Fiji and New Zealand. Our wide range of experience allows site-specific recommendations taking into account the requirements of our clients, the environment and the budget available. All of our systems have not only the environment in mind but also your pocket. Each of our waste treatment facilities produce biogas which can then be used in a number of ways for revenue or operational cost reductions; ~ Odour Reduction / Elimination ~ Power Generation ~ Boiler Fuel ~ Carbon Credit Offset ~ Heating ~ Cooling Waste Solutions is part of the Downer EDI group of companies and we have designed facilities on all six continents. Waste Solutions treatment facility in Thailand Copyright Waste Solutions 2008 Page 2
Odour Control A major consideration in animal farming practices is odour control. Ponds treating pig effluent can produce up to 5,000 ppm hydrogen sulphide, and this potent-smelling gas is one of the main causes of the many public complaints about odour. A simple solution such as the covered pond option results in the reduction or total elimination of odour problems. Capturing of the biogas generated, followed by flaring or combustion in a boiler or genset results in the destruction of malodorous compounds. The higher efficiency treatment offered by Cigar and tank-based options results in a slightly improved effluent quality, further reducing odour concerns with effluent discharge. Manure Handling Anaerobic digestion options are affected by site specific variations such as manure handling, animal bedding and housing configuration. Therefore a site visit is required to develop the most suitable option for each situation. Examples of differences which affect reactor design are manure collection technique (dry scrape vs. flush systems), frequency, volume of water used, inclusion of bedding materials and proportion of manure collected. Green Energy Production The three treatment options allow the biogas generated to be captured. The gas can then be flared, used directly as a boiler fuel or cleaned and used for electricity production via a generator. Flaring results in odour destruction and reduced greenhouse gas emissions, and therefore potential carbon credits. Use as a boiler fuel provides hot water, and reduced costs in the form of fuel equivalents or electrical heating costs. The production of electricity is the most capital intensive option but offers reduced costs in offset electricity purchase, and the electricity generated can be used for any purpose. Due to the currently low cost of electricity and high cost of fuel, use of biogas as boiler fuel offers the greatest financial return, but electricity generation is the most versatile use of biogas, and is a more attractive option in larger systems due to economy of scale. Copyright Waste Solutions 2008 Page 3
Additional Benefits 1. The treated effluent (Green Water) generated by the reactor system chosen can be re-used as flush water in housing or yards, and a recycle stream is used to dilute solids in dry scrape systems to reduce water requirements. 2. Treatment by anaerobic digestion improves the nutrient value, resulting in digested effluent being a more valuable end product than untreated manure. The Nitrogen content is 40% higher and the Nitrogen / Phosphate ratio is increased. Nitrogen is also present in the more bio-available form, Ammonium. 3. Methane and carbon dioxide, the main components of biogas, are both greenhouse gases. In small scale situations where the biogas generated is too little to be economically used for boiler fuel or electricity generation, biogas flaring is a viable alternative allowing the potential to earn capital through carbon credits. When burnt in a flare, methane is converted into carbon dioxide, producing a gas stream which is 21 fold less hazardous to the environment than allowing unmanaged biogas to be vented from open ponds. Under the Kyoto Protocol, preventing the emission of carbon into the atmosphere can be financially beneficial, offering additional advantages to anaerobic digestion systems. Covered Ponds Many farms already use ponds to capture and treat manure flushed from barns. Open ponds function as a facultative anaerobic treatment system, breaking down organic matter in the manure and producing a reduced strength effluent. This system generates the potent greenhouse gases methane and carbon dioxide, which are released into the atmosphere. A low cost option for manure treatment in this situation is the improvement of pond hydraulics increasing the efficiency of anaerobic digestion, and covering of the pond to capture the biogas produced. This has a double benefit of capturing and reducing carbon and odour emissions to the benefit of the environment, as well as providing a source of energy for the farm in the form of a high energy content biogas which can be used directly in boilers for the production of hot water, or in generator engines for the production of electricity. ~ Moderately efficient in producing Biogas ~ Low Maintenance ~ Odour Reduction or Elimination ~ Robust ~ Moderate level of Waste treatment Copyright Waste Solutions 2008 Page 4
Cigar Cigar is Waste Solutions trademarked covered in ground anaerobic reactor design developed over two decades of working with agricultural wastes. Ideal in situations where space is not limited, this design offers a low capital cost option with high efficiency waste treatment and energy recovery. These systems are flexible and highly robust, providing a long term sustainable solution. The design optimizes biogas production and capture, improving the amount of energy that can be generated in relation to a covered pond. ~ Highly Efficient in Producing Biogas ~ Odour Reduction or Elimination ~ Biologically Flexible and Robust ~ Moderate Capital Cost ~ High level of Waste treatment Tank Systems Waste Solutions also design tank based options in wood or stainless steel for situations where a small footprint is critical. Tank based design is more costly than in ground options, however we offer a unique timber tank structure that offers significant cost reductions over similar steel based options. Tank systems optimize mixing, allowing similar treatment efficiency and slightly higher biogas yields to be obtained in a smaller reactor volume in comparison to a Cigar. As with the two previous options, the biogas is captured and can be used for heat and/or electricity production. ~ Highly Efficient in Producing Biogas ~ Higher Capital Cost ~ Odour Reduction and Elimination ~ High level of Waste treatment Copyright Waste Solutions 2008 Page 5
Specific Example - 400 Sow Unit Farm An example of the energy potential within the gas captured on a medium-sized pig farm of 400 sow units is given below. The numbers are based on 100% manure collection via flush with 30-50m3/day (excluding bedding materials), an average of 20 piglets per sow per year with a 28 day suckling period, 78 day weaning/growing period and 56 day finishing period. An indication of the money saved through avoided diesel or electricity purchase when all the biogas is used are given, as well as approximate capital costs (±30%) of the various options. In all cases a flare is included as standard. The simple payback period shown is calculated relative to offset expenses minus staff & electrical operational costs. Potential revenue due to carbon credits, fertilizer sales and electricity sales are not included, and would be associated with additional costs. Further avoided costs such as odour control measures are also not included. Manure volatile solids (VS) and gas generated on a 400 sow unit farm under standard conditions. Conversion to boiler fuel or electricity and associated savings. 1 Digester heating energy subtracted 2 Digester heating provided by waste genset heat Capital Costs for energy capturing systems and potential payback period. Copyright Waste Solutions 2008 Page 6
Specific Example - 2000 Sow Unit Farm The energy potential of the gas captured from a large-sized pig farm of 2,000 sow units is shown below. The data is generated using an example of 100% manure collection via flushing with 150-250m3/day (excluding bedding materials), an average of 20 piglets per sow per year with a 28 day suckling period, 78 day weaning/growing period and 56 day finishing period. The gas generated can be used in place of diesel in a boiler, or to generate electricity with a genset, and the potential expenses offset when using all the gas this way are shown below. In all cases a flare is included as standard, meaning all options will eliminate odour problems. The simple payback period shown is relative to capital costs (±30%) and incorporates offset expenses, staff & electrical operational costs. Potential revenue due to carbon credits, fertilizer and electricity sales and other avoided costs such as odour control are not included, and would be associated with additional costs. Manure volatile solids (VS) and gas generated on a 2000 sow unit farm under standard conditions. Conversion to boiler fuel or electricity and associated savings. 1 Digester heating energy subtracted 2 Digester heating provided by waste genset heat Capital Costs for energy capturing systems and potential payback period. Copyright Waste Solutions 2008 Page 7
Specific Example - Shared facility serving several farms (10,000 sow units) To save on the capital costs of a reactor system, a shared facility could be built to treat the manure from several local farms. An example of the energy potential generated from a combination of farms with a total of 10,000 sow units is given below. The figures are generated on an average of 20 piglets per sow per year with a 28 day suckling period, 78 day weaning/growing period and 56 day finishing period and up to 650m3/day flush water, but incorporate some volatile solids loss which would be expected during manure transport to the shared facility. The diesel equivalent of the biogas is shown, although it is unlikely that in a shared facility there would be sufficient use for the quantity of hot water produced onsite, making this option less viable. There is potential for biogas to be used for transport or be piped to each farm linked to the reactor for individual use (this option is not included in the financial calculations below). The payback period shown is calculated relative to capital costs (±30%) and offset expenses with staff and electrical operational costs subtracted. Additional offset costs such as associated with odour control, and potential revenue due to carbon credits, fertiliser and electricity sales are not included, and would be associated with additional costs. Conversion to boiler fuel or electricity and associated savings. 1 Digester heating energy subtracted 2 Digester heating provided by waste genset heat Capital Costs for energy capturing systems and potential payback period. Copyright Waste Solutions 2008 Page 8
Waste Energy Environment Waste Solutions Ltd. Business Support Division 1st Floor, John Wickliffe House 265-269 Princes Street, Dunedin PO Box 997, Dunedin, New Zealand Ph + 64 3 477 2375 Fax + 64 3 479 2249 Email info@wastesolutions.co.nz www.wastesolutions.co.nz