ITC Paperboards &
Specialty Papers Division commissioned India's first Elemental Chlorine Free
(ECF) pulp bleaching line in 2002, followed by another line incorporating the Light
ECF process in 2007, at Unit Bhadrachalam.
Conventionally,
elemental chlorine is used in the bleaching process during paper manufacture. The by-products of this process include a
large number of organochlorine chemicals, which are toxic and adversely impact
the environment. Elemental chlorine bleaching releases enormous quantities of carcinogenic toxins, amongst
them dioxin and furans, into the environment. Dioxin,
a known carcinogen, will leave detectable residues in any product that has been
bleached with any type of chlorine bleach.
ECF uses chlorine
dioxide for the bleaching of wood pulp. It does not use elemental chlorine gas during the bleaching process and
limits the level of dioxins and furans in the pulp to less than 1 PPT (parts per
trillion). This produces healthier, non-contaminating and odour-free food grade
packaging material.
The
Bhadrachalam Unit started Ozone Bleaching, in 2007. The Unit manufactures and uses pulp made from the ozone
bleaching process known as the light ECF process. The use of ozone technology
significantly reduces the load of toxins in the effluent discharged, and results in a brighter, stronger product that is environmentally responsible. The BOD (Biochemical Oxygen Demand) level in the treated effluent is at
22 mg/l and the COD (Chemical Oxygen Demand) level is at 157 mg/l (as of 31st
March 2016). These are way below the National Standard Limits which are at 30
and 250 mg/l respectively.
The Ozone Bleaching technology has led to a reduction in
chlorine dioxide and hydrogen peroxide consumption, along with better pulp
quality, improved strength properties and reduction in AOX (Adsorbable Organic
Halides) generation.