Converting Waste from Slaughter House to Energy for productive use

Focus areas: Mitigation; Adaptation
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Location: Dagoretti, Nairobi, Kenya
Established: November 2010

The abattoir cluster in Dagoretti, on the outskirts of Nairobi, Kenya, provides meat to the city and employment to over 5,000 people. Daily, over 400 animals are slaughtered here. Instructed by Kenya's National Environment Management Agency, the City Council of Nairobi was on the brink of closing down the cluster in mid-2009, as improper discharge of slaughter wastes was polluting the Nairobi River. The surroundings were stinking, emitting large quantities of methane, and the blood and the wash water were seeping into the ground water. Unreliable grid electricity forced the abattoirs to depend on diesel gensets. The trees in the once dense woods nearby have been cut down heavily for firewood and charcoal for cooking by the population around the abattoirs. Based on the request of the Ministry of Environment, Government of Kenya, UNEP requested UNIDO to find a solution to the problem. UNIDO implemented an innovative (low cost) solution and its Phase-1 was completed in 2010.

Goals and Objectives:
1. Establish a functional model to reduce GHG emissions from the slaughter wastes through anaerobic conversion of it into energy (Phase 1);
2. Use biogas for electricity generation (Phase 1);
3. Use biogas and recovered heat from generator exhaust to heat water for cleaning in the abattoir (reduce water consumption ), replacing firewood or charcoal. (Phase 1);
4. Demonstrate biogas as a viable alternative for cooking for the urban poor in place of scarce firewood and charcoal (phase 1);
5. Demonstrate Biogas bottling after cleaning it of CO2 and distribute as a cooking fuel to the urban poor (Phase 2);
6. Develop business opportunities to market the residue as an organic fertilizer rich in nutrients like nitrates, phosphates and potassium for local farming (Phase 2);
7. Replicate and upscale the model in the whole cluster (Phase 2);
8. Refurbishing abattoirs within the country to be environmentally clean and be self-sufficient in energy (Phase 3).

Mitigation / Adaptation

Power required for the abattoir operation is obtained by a biogas generator. Hot water required for cleaning the abattoir is done using biogas. Dumping slaughter house waste has reduced resulting in lower methane emissions to the atmosphere.

The activity was able to demonstrate that the abattoirs were unaware that they are: (a) dumping a valuable resource which was contributing to greenhouse gases (CH4 emissions); and (b) contributing to the contamination of ground water which was already in short supply due to the adverse impacts of climate change.

One tonne of animal waste produces over 100 cubic meters of biogas which has a concentration of 65% CH4 and 35 % CO2. The potency of Methane is about 21 times that of CO2 in trapping heat in the atmosphere. This would translate into approximately 1500 cm3 of greenhouse gases emitted from the dumpsite from around 15000 kg waste per day, over and above the emissions from previous dumping.

Benefits

Daily, over 300 cattle and 100 goats are slaughtered and delivered by the 4 abattoirs for a fee.

In addition to the population of 4,000 living within 1 km radius, the nearby Thogoto forest supports a floating population of nearly 10,000 - pastoralists bringing cattle, traders and others in slaughter services. Most of the 3,000 odd abattoir workers commute daily, mostly on foot from nearby areas.

40% of the abattoir area populace lives in the 2 km long Kware slum along the river Kabuthi.

Anaerobic digestion of slaughter waste would uplift the living conditions of the urban poor.

Biogas for cooking would ease the financial and social burden of these families and reduce deforestation and land degradation.

Electricity generated from biogas can provide employment to local youth and women, resulting in less pollution and environmental contamination and healthier life for the poor residents. Abattoirs have electricity, but as electric heating is costly, floor cleaning water is only warm. Hot water reduces the water required for cleaning. Total water use in all plants is 20,000 l/day. Daily amount of wastes generated from Dagoretti abattoirs is over 15 tonnes.

With the activity, the amount of wastes to be flushed out will be much less. Water can be heated by biogas burners or by heat recovery from generators and help in sustainable water use.

Potential for scaling-up and replication

More than 30 % of the 40 million Kenyans live in urban centres, where access to commercial energy services ranges from 20 % to 40 % only. Agriculture and horticulture being the main source of revenues, Kenya has enormous amounts of agro waste. This can be very beneficially used as feedstock in digesters to get biogas for cooking and generating electricity.

The two stage biogas digester technology is widely used for commercial power generation in Europe and USA. The design was adapted by UNIDO to meet local African requirements (ease of replication, up-scaling and maintenance) and can be implemented in any place where organic waste ( food waste, market waste, fish waste, slaughter house waste, agro waste, chicken or animal manure) is available.

In the functional model implemented in Nairobi, only a fraction of the waste of one abattoir was used. Based on the success of the model, the Government of Kenya has requested that the programme be upscaled to process all the waste generated in the cluster, as was already indicated in the feasibility report.

Scientists and Engineers from the Kenya Industrial Research and Development Institute (KIRDI) were involved in the implementation from the very beginning of the activity, which enabled UNIDO to transfer the know-how and skills to local technicians, so that the maintenance, replication and up-scaling process would be very smooth.