Developments in wastewater treatment methods
Waste water from the textile finishing industry commonly contains moderate concentrations (10-200 mg/l) of dye stuffs, contributing significantly to the pollution of aquatic ecosystems. Various physio-chemical and biological techniques can be employed to remove dyes from waste water. The technical and economic feasibility of each technique is determined by several factors such as dye type, waste water composition, operation costs and generated waste products.
The adsorption technique is superior to other techniques
with regard to simplicity of design, initial cost, ease of operation and
insensitivity to toxic substances. This technique uses activated carbon and
other suitable sorbents. Activated carbon remains the most effective and widely
used adsorbent for the decolourisation of waste water from textile industries.
Process of recycling in textile industry using biological
activated carbon treatment system
In this bio treatment method, naturally occurring micro
organism breakdown materials in the water such as Dissolved Organic Carbon
(DOC), Biochemical Oxygen Demand (BOD), turbidity, Total Suspended Solid and
nutrient levels and thus improve water quality. The Activated carbon filters
are used to provide a place on which these microorganisms grow. Because of the
low price of bio treatment, the combination with AC may reduce the overall
treatment cost. Finally the biologically activated carbon systems degrade the
industrial waste water in a fast and inexpensive way.
There are 2 types of biologically activated carbon systems
for waste water treatment in textile industries. In the first type, biological
activated carbon (BAC) filter uses granular activated carbon to reduce
dissolved organic matter and remove color (20 to 30 mg/L ozone for 0.5 to 1
hour). While in the second, biological activated carbon filter (BAC) uses
activated carbon in the form of flexible clothes to reduce dissolved organic
matter (20 to 30 mg/L ozone for 0.5 to 1 hour).
The two biological activated carbon treatment systems
successfully reduce the levels of BOD5, COD, DOC, TSS, Color and Turbidity in
the wastewater to within the specified guidelines in each trial that is
continuously providing high quality recycled water to the entire factory
requirements. The improvement of water quality by the two BAC filters under
different conditions is tabulated below (Table 1.). Biological oxidation within
GAC filters also can be efficient for the removal of inorganic such as ammonia.
Ammonia is a toxic chemical which promotes bio-growth and reacts with chlorine.
The combined removal of DOC and ammonia leads to a significant reduction of the
chlorine demand of the finished water. The amount of DOC removal and oxygen
consumption by the two BAC in warm temperature (25-34 oC) are much greater than
cold temperature (9-17 oC.)
Table (1): Removal Efficiency of Two of Biological Activated Carbon Systems.
| Parameter | BAC1 | BAC2 |
| Biochemical Oxygen Demand after 5 Days, BOD5(mg/L) | 75% to 88% | 81% to 92% |
| Chemical Oxygen Demand, COD(mg/L) | 68% to 81% | 63% to 87% |
| Dissolved Organic Carbon, DOC(mg/L) | 66% to 89% | 71% to 93% |
| Total Suspended Solid, TSS | 87% to 94% | 61% to 80% |
| Color(TCU) | More than 80% of the color | More than 81% of the color |
| Turbidity(NTU) | 75% to 88% | 68% to 81% |
Boyce supplies wide range of activated carbon with an
exceptionally high surface area and a high degree of micro porosity makes it
very suitable for these textile industries for the removal of dyes in efficient
way.
For More Details Visit Boyce Range of Activated carbon
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