|Charles I.F.E. Pty. Ltd. is saving $435,000 per year
from a $2 million investment in a Total Waste Management
System for its Berrybank Farm. The System involves
generating electricity from biogas, conserving and
recycling water and collecting waste for sale as
fertiliser. Despite the large investment, most of which
went into the electricity generation equipment, the
technologies and methods used are simple and
straightforward. Many of the measures simply involve good
housekeeping, such as putting timers on pumps to ensure
water is not wasted if taps are left on.
Charles I.F.E. is finding that the old farming philosophy of wasting nothing makes good business sense. The waste from one part of a farm is the input to another. Along the way, the company has eliminated environmental problems such as odours and groundwater contamination. At the same time, it has dramatically reduced consumption of water, one of Australias most precious resources.
- Managing Director
- Charles I.F.E. Pty. Ltd.
- Berrybank Farm
- BALLARAT VIC 3352
- (035) 343 2344 ph
- (035) 343 2443 fx
Pigs are able to utilise only 50% of the feed they consume, therefore half of all the feed used is returned as waste. Charles I.F.E., the company that runs Berrybank Farm at Windemere in Victoria, considered this a poor return on investment, as well as a poor use of resources, and decided to seek ways to improve the efficiency of the operation. The company also wanted to relieve the pollution problems associated with the odorous waste from the piggery, and to find ways of reducing its consumption of 400,000 litres of bore water per day.
Berrybank Farm is home to 15,000 pigs with an estimated live weight of 800 tonnes. It produces a daily average of 275,000 litres of sewage effluent with an organic solids content of approximately 2%. This is roughly the same as the sewage output of a town with a population of about 50,000 people.
Berrybank Farm developed a sophisticated waste management system to recover all the waste from the pigs, and to treat it so that the various by-products can be used on the farm (as flush water, gas for electricity, and fertiliser), or sold at a profit. The waste management system is a seven-stage process - shown schematically in the diagram below - including automatic and continuous waste collection, grit removal, slurry thickening, primary digestion, secondary digestion, biogas purification and a co-generation thermic plant.
The farm modified the existing drainage around and under the piggery to recover the waste products, and installed automatic flushing valves and linked them to the main pumping station. The valves are solenoid-activated and enable remote-controlled flushing at various times of the day, working in a somewhat similar way to an automatic watering system in a domestic garden.
Meat and bone meal fed to the pigs contains granules of bone and this passes through the pig and into the effluent. The grit from these granules resides in the slurry and is removed by simple sedimentation. This is important, as the grit can damage the internal pump mechanisms.
The slurry is then pumped to the thickening plant, where the finer suspended solids are separated from the water. The clarified water is recycled, either as flush water in the piggery, put into storage, or applied directly to the land as fertiliser.
The thickening plant separation process is a combination of an existing screen and a newly developed flotation system. Flotation allows the separation of water from the smaller suspended particles; this is not always possible using other processes.
The primary and secondary digesters are where the anaerobic digestion takes place. Anaerobic digestion is a biological process very similar to the production of naturally occurring swamp gas, where bacteria break down rotting vegetation to produce gas. A digester simply provides the ideal conditions for the process to proceed at a faster, more controlled rate, by excluding air, thoroughly mixing the contents and maintaining optimum temperatures.
The biogas is then purged of potentially damaging sulphur by scrubbers, traps and a dehumidifier, before being pumped to the co-generation thermic plant, where it is converted into thermic heat and electricity. The plant currently produces 180 kW/hr of electricity for 16 hours per day (enough to power over 400 households), and has the potential to considerably boost this output.
Heat is used for the primary digester, while electricity not used on the farm is sold to large power producers. The farm's feed mill consumes 60% of the electricity generated during the day.
The solid and colloidal parts of the digested slurry are separated from the water by centrifuge. This reduces the bulk of the slurry by up to 90%. The end result is composted humus - a valuable fertiliser, currently under development trials for the domestic potting mix market. The separated water also has enough residual nutrients so as to be useful for hydroponics, acquaculture or possible phosphate production.
Berrybank began implementing the process, which was itself an innovation, in November 1989. It started producing electricity in 1991.
Each day the farm now recovers:
- approximately 7 tonnes of waste solids at 35% dry matter, used as fertiliser;
- 100,000 litres of recyclable water;
- 100,000 litres of mineralised water, used as fertiliser; and
- 1,700 cubic metres of biogas, able to run a co-generation electricity program with a daily output of 2,900 kW of electricity.
Annual estimated savings as a result of cleaner production are shown in the Table below.
Total annual savings
The capital cost of the Berrybank Farm project was approximately $2 million, over a two year period. Berrybank Farm estimates that the economic payback on its investment will take about six years, but considers the immediate environmental benefits to be enormous. As a result of cleaner production, Berrybank Farm has also achieved:
- 70% reduction in water usage
- improved stock conditions
- improved working conditions for staff
- elimination of odour
The cleaner production incentives for Berrybank Farm were both financial and environmental. Berrybank wanted to change its image in the community - from an environmental problem to a welcome industry that offered a good working environment.
The Cleaner Production Case Studies Directory is part of EnviroNET Australia.
- For more information contact:
- Environment Australia
Environment Protection Group
PO Box E305
KINGSTON ACT 2604