End - of - Pipe Treatment
Effluent Treatment Plant
The textile industry consumes large quantities of water for
different processes and the effluent generated is discharged into various
receiving bodies like public sewers, lakes, ponds, rivers and nallahs etc. This
effluent is contaminated with dyes and chemicals. While some of these contaminants
are non-biodegradable others have high oxygen demand. This waste water destroys
the quality of water in which they are disposed thereby affecting the flora,
fauna and human life also.
In the recent times the textile finishing sector on one hand
has to pay substantial amount towards fresh water charges and effluent
treatment charges and on the other hand has to strive hard to meet more
stringent effluent regulations. The treatment options are based on the
concentrations of dyes, auxiliaries & chemicals, types of chemicals, and
also norms of pollution control board based on types of disposal.
It is now widely accepted by the dye house managements, on
environmental and economic grounds, that they must treat the effluent before
discharging into water bodies on a continuous basis. Therefore, it becomes
essential to opt for an efficient working effluent treatment plant. Various
methods of effluent treatment are known but in most of the methods, the
treatments costs are high.
Designing of effluent treatment plant is a complex work
because varying nature of effluent coming from various operations of textile processing and has variable characteristics. Hence it becomes necessary to consider the
following factors before the construction/designing of effluent treatment plant.
- Quantity or the profile of the effluent to be treated.
- End use of the water reclaimed.
- Pattern of hourly flow and daily flow of effluent.
- Characteristics of effluent from each drain.
- Characteristics of combined effluent from the drain.
- Possibility of segregation of widely varying effluents
and treating them separately.
- Treatment options available by pilot trials.
- The available outlets for removal of the dewatered
- Possibility of reuse of treated effluent.
Following are some of the more common methods of treatment followed
throughout the world:
By using various flocculation decolourisation of the effluent can be carried
out and it can be partially reused.
2. Various oxidation treatments like spurge pipes, surface aeration
ejectors, diffusers, helixors, and oxygen and also chemical oxidation
treatments can be employed for decolourisation of the effluent.
3. Fenton reagent used for waste water treatment is based on it's oxidizing
efficiency which is highest at pH ranging from 2 to 5, and molar H2O2
to Fe2+ ratio is about 1:1.
4. The combination of UV radiation and hydrogen peroxide (UV/H2O2
involves an oxidative degradation of the noxious substances.
5. Bagasse, the waste material generated in sugar mills has been us for the
removal of chromium nickel, copper and lead from aqueous solutions. Bagasse has
been pretreated with 0.1 N NaOH followed by 0.1 N CH3COOH for effective