REDUCTION OF EFFLUENT LOADING

The cost of effluent treatment is related to the volume of effluent and the concentration of chemicals contained in that effluent. The best ways to reduce effluent loading, and therefore, the best ways to ensure consent limits are not breached are:
Reduce water consumption to reduce the volume of effluent
Reduce chemical usage and increase dye fixation to reduce the total effluent loading
 Use low impact chemicals to minimise loading for COD, BOD, TSS etc
etp reduction
Where technical performance is similar, it is
commercially sensible to use products that are
easily removed from the effluent or have thelowest contribution to COD, BOD, TSS, etc. For
example, formic acid contributes less to COD than acetic acid and can be used in its place in many wet processing facilities. The use of controlled
dosing and pH measurement systems will also help to minimise the total amount of acid used.

Chemical choices should not be made on the basis of biodegradability alone. It would be irresponsible to use biodegradable products which are less effective or inconsistent in meeting the required standards, and therefore, lead to increased levels of re-dye and re-processing, with associated increased water and energy consumption.

Although colour in effluent is a largely cosmetic issue it can create an impression that effluent controls are substandard and therefore colour discharges should be avoided. Where ever possible use dyes and
processes that give high levels of fixation. This not only reduces colour in the effluent, but could also help to reduce the number of wash off stages, leading to lower water consumption, improved productivity and
lower costs. Bi-reactive dyes, for example have a higher affinity than average dyestuffs. As more dye adheres to the fabric, less dye is used, less auxiliary chemicals are used, less rinsing is required and the
amount of colour in the effluent is reduced.

Salt is used in large quantities for reactive dyeing of cotton and it passes through effluent treatment plants into water courses without being affected. It is recommended that steps are taken to minimise salt consumption via the use of low salt reactive dyes.

One of the most important and cost effective ways to reduce effluent loading is to improve the quality and consistency of the dyeing and finishing process. This reduces the amount of unnecessary re-dyeing and
re-processing, improves productivity, on time delivery and customer satisfaction.

A holistic approach to effluent management is zero discharge or water recycling. If the treated effluent is clean enough to use in factory processing then it should not be discharged. This can reduce the cost of
waste management, reduce water extraction costs and protect the local environment.

Additional best practices that can be used to improve the control and treatment of effluent include:
Maximise filtration of solid materials
Biological treatment is an energy intensive process but the use of AC blowers rather than DC blowers can reduce energy consumption
Carefully dose flocculants to minimise solid waste and consider non-chemical methods of colour removal such as ozone to reduce solid waste
Avoid the use of chlorine to remove colour

Facebook0Google+0LinkedIn0Twitter0Email
(Visited 179 times, 17 visits today)

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *


× four = 4

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>