Company ProfileCase Study: Pig Breeding Farm—Rennes, Brittany, France
The Problem
The waste generated by a French pig breeding farm, home to 22,000 animals, was costing its owners L30,000 each year in disposal expenses. The farm generated 120 cubic meters/day of liquid slurry with an average COD of 80,000 mg/liter. Land spreading with some pre-aeration was used as a disposal method. During the winter months when land spreading was not an option, the waste was held in a 9000 cubic meter concrete lagoon.In addition to lowering their costs, the farm's owners hoped to find a way to eliminate the need for land spreading, which created foul odors. The emanation of ammonia from the slurry was also a serious issue as ammonia can be detrimental to the growth of piglets. For this reason, it was important to keep the waste slurry moving quickly through the channels beneath the pigpens. The owners also saw the potential for generating energy from the waste through the use of anaerobic digestion.
The EversTech Solution
After consulting with EversTech, the farm owners decided to install a total treatment system based on our ET Process, using anaerobic digestion followed by chemical flocculation, catalytic oxidation and sand filtration. Bio-augmentation was still in the early stages of development at this time and, therefore, was not used for this project.The EversTech team designed a turnkey package, including all necessary equipment, which was put in place by the EversTech installation team four months later. The gas generated by the ET Process was sufficient to power two 45 kilowatt/hour generators which provided power to the ventilation system within the piggery, and also providing 4,000 m3/day of biogas at 80% methane for on-site heating and plant requirements. The surplus was vented into the atmosphere. The biomass or sludge generated by the process was pressed into a 30% dry matter cake. The cake was then used as organic fertilizer which was easily stored during the winter months. The final effluent was of such quality that it was discharged into the lagoon which was then stocked with fish, creating a potential second business for the farm. (See pictures)
Financial Benefits
The net benefit to the farm is that waste disposal costs have been eliminated and electricity has been generated for use within the farm. The value of this is approximately £350,000 per year.
The cost benefits break down as follows:
Capital Costs—£400,000
Operating Costs—£50,000 (approx. £1/m3 treated)
Resource Recovery Net Benefit—£300,000/year
Waste Disposal Saving—£30,000/year
Total Benefit—£330,000
Net benefit for first 5 years of operation—£184,000
Net benefit per year after first 5 years, which capital has been depreciated = £184,000 + £96,000 = £280,000