Environmental Technologies and Eco-innovation in the Czech ...

For the aforementioned reasons, the quality of sludge stored in settling pits needs
to be examined before mining. Research on the coking properties of coal sludge blends
revealed that the sludge extracted from outdoor settling pits can be used in limited
quantities (approximately 10% of the reflotation product and 90% of coal) for the
production of coal suitable for coking without affecting other elements such as ash or
water content.
The reflotation technology is used in the Ostrava-Karviná District and helps with
the utilisation of settled coal sludge for the production of flotation concentrates.
These are then used to prepare coal suitable for coking or for use as fuel for making
energy.
8.5 | Mineral biotechnologies
Progressive technologies in waste management include mineral biotechnologies.
State-of-the-art knowledge in this field has moved from research activities to practical
applications. The area of utilisation of biotechnologies in waste management is still
being expanded to include new options.
Mineral biotechnologies include technological processes that use micro-organisms
or their metabolic products during the treatment or processing of waste materials.
Soil contaminated by crude oil products and pesticides can be decontaminated by biodegradation.
A bio-preparation of mixed bacterial cultures that help to accelerate
the decomposition of contaminants in waste is applied on a prepared material. Biodegradation
can be performed either at the place of contamination (in-situ) or after
the mining out or removal of contaminated media (ex-situ).
Bio-flotation has proven especially effective for the desulphurisation of fine-grain
coal from which it is possible to float out pyrite.
Bio-flocculation is one of the available methods for processing very fine
non-homogenous waste coal sludge. The principle of this process consists in the
agglomeration of ultra-fine mineral components by the actuation of bio-flocculants 9 .
The resulting flakes are separated from the suspension by sedimentation or filtration.
Through bio-flocculation, a significant proportion of very fine grains can be removed,
which has a positive effect on the speed, efficiency and reduction in the power intensity
of the filtration and sedimentation processes.
9 bio-flocculants – microorganisms producing slimy substances which form a protective layer of cells