For years, pigs have generally been regarded as dirty animals, kept in unclean areas and given unclean feed. As a result, Batswana who keep pigs have habitually fed them food that is nutritionally lacking. Piggery has evidently failed several times due to this belief.
This may change, following an initiative by the Department of Engineering at the Botswana College of Agriculture, working with the Ministry of Agriculture. Within the 100km radius of Gaborone, extension workers and piggery farmers are hard at work on a project that could change this mindset.
The three partners are in the closing stages of a three-phased community project to produce biogas from well fed pigs. The product has been tested elsewhere outside Botswana.
“The project is meant to burn methane from animal dung and produce biogas that can be used for cooking instead of letting it accumulate and be emitted into the atmosphere to cause global warming,” said Dr Ezekiel Chimbombi, senior lecturer in the Engineering Department.
Dr Chimbombi, who as the project’s Principal Investigator is team leader, said a model has been designed showing that the burning occurs in a ‘digester’ which is located inside a fermentation chamber ÔÇô a tank buried some metres under the ground. The burning is biologically done.
A collaborative effort between the three parties, the project aims to solve the problem of manure accumulation for farmers in the South East Agricultural Region.
Dr Chibombi said the project adopts a ‘participatory approach’ that involves farmers from the onset. Through their involvement at take-off point, farmers get to embrace and appreciate the project.
He says they started with a survey of piggery concentration in the South East agricultural region, and identification of piggeries with a critical waste management problem. They then trained farmers on sustainable piggery waste management, and biogas generation.
This year the technical team has done the specifics for construction of a mobile biogas plant. They have made it robust and rugged, so it can be hauled over different terrain without difficulty.
The field days for community education operations on waste management by the team covered places around Ramotswa, Molepolole and Mochudi and their surrounding areas.
“For phase One-mobilisation, operational specifics have been developed. Farmers who have definite need of manure management have been identified, selected and educated about biogas production from piggery manure and community participation is assured. Thirty farmers have shown interest, and because of specifics set up, fifteen have been ‘temporarily suspended’ while the MoA extension workers are helping them uplift their current operational condition,” explained Dr. Chimbombi.
He said the conditions they agreed to set up are as follows: The farmer must have a minimum of 15 sows; the farmer must have been in pig production for at least five conservative years, and still willing to continue; the types of feed used by the farmer must be approved by the project team and the staff of the piggery section if the MoA. This is to ensure that the farmer feeds only conventional acceptable pig feed for the entire course of the study; the selected farmer must be willing to host farmers when they are brought to his or her farm for biogas technology demonstrations and finally, equal opportunity is given to all farmers irrespective of gender.
Asked why farmers should have been in pig production for such a period to qualify, Dr Chimbombi explained that many people attempted piggery but abandoned it within a very short period of time.
“There was a time when getting loan for piggery production from Citizen Entrepreneurship Development Agency (CEDA) was much easier than any other farming venture. This was because Batswana consider pigs filthy animals. They keep them on unhealthy environments and underfeed them- something that leads to the enterprise’s underperformance. So some applied for it, got the money and started buying other things with the funds. Funds were abused. So commitment to the piggery business matters in this biogas technology project.”
On why the feed should also be that approved by the project team he said people have the tendency to feed pigs on low quality foods. They feed them on left over from schools, damaged or condemned goods from supermarkets and millers like Bolux Milling.
“What comes in during feeding is what comes out during excretion of the food. You will find that someone feeds his or her pigs on cabbage. Cabbage is 80 percent water and from the 20 percent non-water material there could only be 5 percent methane. Very little energy will come from this. Recommended feeds lead to more production of the required methane,” said Dr. Chimbombi.
Phase two of the project is actual generation of the energy from biogas. In this phase the college is now preparing to go into the field and build the prototype- the biogas plants. The sponsors of the project have paid for this prototype. After the farmers adopt the model, then those who will be interested will pay something. Although they are still designing the prototype and
The eloquent Chimbombi explained that he told farmers during training that they should treat biogas plant with vigilance. The process uses living macro organisms to ferment the dung mixture, which after fourteen days emits the biogas.
The use of soap and detergents like vim and others to clean the animals houses is not allowed as these are none life supporting. Water used to mix the dung should neither be very hot nor cold. It should be in temperature that will permit reaction of the organisms.
So how is the biogas plant made? Research has been done and an experimental design is being made which will have model similar to this: A tank (called digester), with capacity volume of 200 litres is buried on the ground. An alternative could be building a same sized brick made ‘tank’. A sloping trench is dug and a 50 mm pipe inserted there. This is a channel through which the thoroughly stirred mixture (or sludge) is deposited into the digester at the bottom. The digester top is covered with hard plastic cover-the type that makes jojo plastic tank. A space is created above the sludge for gas to collect and be transferred through a narrow tube. A little hole-enough to pass gas is pierced there at the top of the tank where a gas ferrying tube is inserted. The tube will then be connected to cooker or braai stand.
Feeding of the digester with sludge can be done twice per day. The dung dilution ratio of dung to water according to the plant’s experimental design shall be varied at three levels of 0.75: 1 and 1: 0.75 weight basis.
And finally phase three of the project ÔÇô communication of results and replication ÔÇô will be continuous collection of the dynamics of biogas generation using pig manure, the results of which shall be shared with all farmers and the entire scientific community.
Periodically, during the course of the project, field days and training courses shall be arranged for updating the farmers on biogas technology. A field booklet on waste management using biogas technology shall be produced and availed to farmers.
Started in 2012 the project was co-funded by the Botswana College of Agriculture and the United Nations Office for Project Services (UNOPS) through the Global Environment Facility-Small Grants Program (GEF-SGP). BCA funded with P136, 000 while UNOPS popped out US$ 31,000.
Dr Chimbombi expressed his gratitude over the fact that farmers have embraced the project and that the Department of Waste Management and Pollution Control (DWMPC) has shown interest in it as a government body.
What he foresees as a problem in the project is that of feeding. He has realised that even renowned farming entities sometimes feed pigs on chicken feeds; sighting shortage of pig feeds as the cause. This could lead to poor energy production.
