Eco-Efficient Dry Wool Scouring with total by-prod.. (Wooldryscouring (WDS..)
Eco-Efficient Dry Wool Scouring with total by-products recovery
(Wooldryscouring (WDS))
Start date: Sep 1, 2012,
End date: Feb 28, 2016
PROJECT
FINISHED
Background
Wool sheared from a sheep contains a high level of impurities â as much as 60% by weight. The major impurity is wool grease (lanolin), which is a waxy substance secreted by the animals to help them shed water from their coats. Lanolin has commercial uses in the cosmetics industry, for example in hand creams. The wool also contains varying amounts of dirt, dead skin, sweat residue, pesticide, and vegetable matter, often in the form of wool dust.
Before the wool can be used commercially, it must be cleaned using a hot aqueous scouring process. Depending on the properties required for the final product, this can involve a complicated process using detergents and alkali, which generates large quantities of wastewater with a high organic content. For every kg of clean wool produced by aqueous cleaning, some 17 litres of effluent, with a high Chemical Oxygen Demand (COD) value - 0.3-2.4 kg - is generated.
Wool scouring therefore has a high environmental impact. It consumes a large amount of water and energy and generates large quantities of highly polluted effluent. The wool wastewater requires several treatment stages before disposal, consuming additional resources.
The world production of wool in 2009 was 2.04 million tonnes (Source: FAO STAT-United Nations). The EU is the fourth largest wool producer in the world after Australia, China and New Zealand.
Objectives
The 'WDS' project aims to demonstrate an innovative process of âwool dry scouringâ based on closed-loop processing and total waste recovery. It hopes to demonstrate that it is possible to achieve quality improvements in the clean wool at the same time as reduced wastewater generation and increased recovery and valorisation of by-products.
The project aims to recover lanolin and wool dust from the raw wool product by means of solvent extraction and purification technologies in a prototype dry process. It is expected that this will improve the yield of recovered by-products from wool treatment in comparison with traditional processes and present a cleaner wool for the aqueous scouring process.
It is expected that the by-products can replace some synthetic materials, such as fertilisers or synthetic grease. Some of the less polluted effluent emerging from the scouring process will be used with the wool dust to create fertiliser.
Since it is working with a cleaner input material, the scouring process will require less water and energy and fewer chemical cleaning products to deliver a final wool material that is of better quality than from traditional processes. This aqueous scouring stage will also generate less polluted wastewater.
Expected results
Demonstration of the technical feasibility of an innovative environmentally friendly dry scouring technology for wool;
Recovery of all valuable grease components;
Reduced pollution loads in the waste streams from wool processing;
An 80-100% reduction in the use of cleaning chemicals such as detergents;
An 80-95% reduction in water consumption;
Reduced energy consumption;
Avoidance of complex and expensive wastewater treatments;
An improvement in the quality of the final wool quality in terms of whiteness, fibre openness and wool combing performance, providing a 5-25% increase in sale price;
Demonstration of the economic feasibility of the process, taking into account the financial benefits from the recovery of valuable by-products and a 40% reduction in costs from reduced resource consumption and wastewater treatment requirements; and
An improvement in the ability of the wider wool-scouring sector to meet EU environmental requirements.
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