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4.0 AUDIT FINDINGS
The findings presented below on watcr use and waste disposal practices at the JISICO facility are based
on information collected during the facility audit through interviews and discussions with JISICO
employees, observations madc during thc site visit, and data provided by JISICO both before and after
the site visit.
4.1 Water Usage and Balance
There is a water meter that records thc amount of water used from a groundwater well. The water well
serves the JISICO facility and two other industries, the National Chemical Industries (NO), that
manufactures sodium hypochlorite and other liquid bleaching detergents, and the National Steel Factory
(NSF), a rolling mill.
Also, there are three water meters, one each for the meltshop, NCr and NSF. Each of these three water
meters is installed on thc main scrvicc watcr linc fceding each of thesc facilities so there are records of
the amount of water used by cach facility. However, until recently, there was no water meter on the main
water pipe that supplied waler to the JISICO rolling mill.
In the past, the amount of water used by thc JISICO rolling mill was estimated as the difference between
the water well meter and thc 3 water meters for the three facilities. Recently, a meter has been installed
that measures the watcr uscd by the JISICO rolling mill. Tablc 1, Watcr Balance, presents a water
balance of the facility. figure I, Mcltshop Process and Water Balance Flow Diagram, and Figure 2,
Rolling Mill Process and Water Balance Flow Diagram, depict the process.operations that use water.
4.1.1 MeItshop 'Vater Use
Water is used in the meltshop operations in the following areas:
• Noncontact Cooling of the Furnace - Water is continuously recirculated from the cooling towers
to the furnace roof ring, slag doors, and transformers.
• Noncontact Cooling of the Copper Tuhe Mold - In the continuous casting opcration, noncontact
cooling watcr is continuously recirculated from the cold water pool of the cooling towers to the
copper mold, then back to the hot well and the cooling towers.
• Contact Cooling of the Steel Billet in Continuous Casting - ConUl,ct cooling water is sprayed,
using high pressure nozzles, onto the solidified steel as it exits the c'opper tube mold. As the
steel cools, the surface of the steel is oxidized by contact with the air and a skin of iron oxide
forms on the surface. The force of the water spray removes this iron oxide; thus this contact
cooling water contains iron oxide particles referred to as scale.
This contact cooling water contaminated with iron oxide is collected in a scale pit next to the
casting operation. 1llis wastewater is pumped to the meltshop's cooling water pretreatment
system. 1lle treated wastewater is returned to the cooling towers for reuse.
.,
• Noncontact Cooling of the Hydraulic Shears - The hydraulic shearing machines are water
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