6 July 2007, News release from EEC EUROPE LTD
The textile industry is very water intensive. Water is used for cleaning the raw material and for many flushing steps during the whole production. Produced waste water has to be cleaned from, fat, oil, colour and other chemicals, which are used during the several production steps.
The cleaning process is depending on the kind of waste water (not every plant uses the same way of production) and also on the amount of used water.
Also not all plants uses the same chemicals, especially companies with a special standard (environmental) try to keep water cleaned in all steps of production. So the concepts, to treat the water can differ from each other.
Water treatment with different kind of pollutants, is large-scale, because of the many cleaning and removing steps involved.
The diagram above shows a general overview over the several steps in water treatment in the textile industry.
This first step of treatment is to remove small particles from the process water. In this way the water will be cleaned from fibres, fluff and cotton flock. For these filters, drum screens- and fine filters are used.
Oil removal (if required)
If during the step of textile treatment, solvents like white spirit or others are used they have to be removed from the wastewater. Oil Separators and oil skimmers are used to remove the oil and the other organic solvents from the wastewater so to avoid the microorganisms from being killed.
This step is useful in order to mix and homogenise the wastewater. With this step, the pollution is better distributed. That makes it easier for microorganisms to treat the water. The result is a more effective biological treatmnt.
After homogenization, the solution has a pH of around 9 to 10. Neutralization of the water can be done by acid or air flow injector depending on the pH value.
Physical- chemical- treatment
If the concentration of dissolved solids is very high (sulfides, chromates, etc.) and/ or color is also in the water, the kind of treatment is various.
- Oxidation of sulfides
- Color-removal with flotation
The type of biological treatment depends on the concentration and kind of pollutant. Two biological steps are used:
M.B.B.R (Moving Bed Bio-Reactor) or M.BR. (Membrane Bio-Reactor) technologies
With the MBBR method the wastewater is treated biologically using the bacteria living in the biomass that is attached as a biofilm on the moving media. The principle is easy and very reliable and the bioreactor volumes smaller that the conventional methods. Depending on the volume and load of the wastewater the reactors (basins filled with bio-media) operate in aerobic environment (air is injected in the wastewater by means of a air-blower and diffusers) or in anoxic environment (without air, only mixing). The micro-organisms (bacteria) that grow and develop in these bioreactors assist the degradation of the organic load achieving BOD5 removal rates that reach 90 to 95%.
With the MBR method the biological treatment process takes place in smaller bioreactors than conventional activated sludge method due to high concentration of biomass in the reactor. The main feature of this method is the use of micro or filtration membranes which separate all the suspended solids in the mixed liquor thus giving very good clarity in the treated water (TSS less than 1 mg/l).
The excess sludge To dump the sludge, it has to be thickened. This can be done by different procedures, depending on the amount of sludge, which has to be dumped.
If it is necessary this last step of treatment will remove the color by oxidation, adsorption or other procedures.
High-Speed Bio Tech - packaged plants
With this kind of treatment plant, which utilizes the benefits of the MBBR technology we maximize the use of modular units to provide the client with a very small footprint solution.
There is some limitations to the number of these units that can work in parallel, but it is possible to treat from 400 m3/d to 1,600 m3/d flow to treatment using modular units as an example.
One Unit with underground Balance Tank feeding the biological plant
Two modular units working in parallel.
With this flexibility EEC Europe Ltd can offer solutions to treating wastewaters from the Textile Industry from small producing factories to the largest producing factories.
Once EEC Europe Ltd have the INFLUENT parameters of the wastewater for treatment together with the EFFLUENT parameters required by the end-user to meet local laid down standards, we can offer you the ideal solution.
Dennis Hunter CEnv
EEC EUROPE LTD