If one visited a skin and hides factory (tannery), all that would keep lingering in their mind is the intolerable smell and pollution.
Globally, tanneries are associated with stench, which comes from the hides and chromium, a cancerous chemical used in the factories to make leather waterproof and less susceptible to decomposition.
And, the situation is not different in Uganda. Almost all tanneries have been embroiled in endless battles with the National Environment Management Authority (NEMA) for polluting wetlands and lakes like Victoria.
About two tanneries are closed by NEMA over pollution every year. The latest was Noveltry Tannery in Masaka closed in June last year after its effluent burnt about three acres of papyrus in the Nabajjuzi wetland, a Ramsar site.
However, somewhere in Jinja municipality, Leather Industries of Uganda (LIU) has made a difference by treating and recycling its waste, giving a positive image to leather tanning.
“The stench in conventional tanneries is like that of poorly managed abattoirs. It starts controlling pollution and reducing costs.
How the plant works
According to Agaba, used chrome from the factory is pumped into a reactor where it is precipitated using a chemical called magnesium oxide. After about eight hours, the chrome is discharged into a regeneration tank from where it is pumped back into the factory for reuse.
Unlike other tanneries whose solid waste (hides and skin pieces) are disposed of together with waste water which causes stench, LIU also installed a machine that filters solid residues from the waste water.
A large amount of waste produced by most tanneries is discharged in natural water bodies directly or indirectly through two open drains without proper treatment.
The water is then polluted in such a degree that it becomes unsuitable for public use. In dry seasons when the rate of decomposition of the waste is higher, serious air pollution is caused by the intolerable horrible odour.
At LIU however, the waste which is free of chrome is let to flow through various sedimentation ponds where it is mixed with lime to solidify and dry. Later, the dry lime sludge is used as manure.
The factory also injected sh37m to construct a wide concrete drying bed for the solid residues including leather cuttings, trimmings and gross shavings. At the bed, the residues are mixed with saw dust which reduces the smell and expedites their drying.
Marabou Storks eat some of the skin pieces during the three-day drying process which reduces the quantity of residues and stench.
The remaining dry solid residues are then burnt to ash in a well-built incinerator, just to ensure that no effluent is released into the nearby Lake Victoria shores
true Marabou storks feed on solid waste residues left to dry at LIU’s concrete drying bed
Commercial benefits
Besides reducing the chemical pollution load to the effluent, Agaba also says the recycling plant has far-reaching economic benefits despite its initial cost being somewhat high.
“We bought it (the plant) at $50,000. But we saved lots of money when we started recycling chrome. It took us only one year to recoup our investment,” Agaba said, calling upon other tanneries to emulate the technology.
He explains that in a drum of 5000kgs of hides, they use 250kgs of chrome, only half of which is new and the other half is recycled chrome.
Since each kilo of chrome costs $1.2 (about sh3,000), the factory saves $150 (about sh385,89) per drum of 5,000kgs of hides simply through recycling chrome.
According to Agaba, annual savings amount to over $13,700 (about sh35.2m), courtesy of recycling chrome.
“Working in a friendly environment which does not smell also boosts the workers’ morale. We have started seeing this happening,” he adds.
To bolster their efforts to save the nearby Lake Victoria, LIU recently embarked on planting trees in all open areas around the factory. So far over 5,000 trees have been planted, which has improved the aesthetics and protected eco-system.
“At the onset, LIU’s technologies like recycling plants may appear expensive, but in the long -run it is cost-effective and helps to improve the company’s image and environmental compliance,” said Wasswa, who also works as a consultant with UCPS
