Page 59 - Materials Chemistry, Second Edition

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Sustainable Industrial Design and Waste Management
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• Juice concentration: Purified juice is concentrated in a four stage
evaporator.
• Sugar crystallization: This is done in three stages. Water evaporation
with steam from the evaporators drives the crystallization.
• Sugar processes: The mixture of sugar and mother liquor (masse-
cuite or magma) are centrifuged to separate the sugar from the liquor.
The white sugar is then dried and bagged.

This process, however, was not environmentally friendly due to gas emission,
waste, energy, water and raw material losses, thus the company instituted
the cleaner production program to resolve these issues. The pollution problems
observed at the facility include:

• High BOD (biological oxygen demand) loadings in wastewater
discharge.
• High COD (chemical oxygen demand) loadings in the wastewater
discharge.
• High energy and water consumption.
• The use of harmful materials.
• Poor maintenance leading to excessive loss of raw materials as waste
and low production efficiency.

CP opportunity assessment/techniques implemented
The cleaner production techniques used to improve the operations within
the beet factory include:

• Chip and trash recovery system: Reactivating the existing system to
recover pieces of whole beets and tips of beet roots containing sugar lost
as wastes. This operation falls under the good housekeeping technique.
• Diffusion and juice purification: Controlling operation parameters
to optimize production processes such as knife filling, diffuser tem-
perature and stable operation conditions. This operation falls under
the better process control technique.
• Heat exchange and evaporation: Monitoring and controlling opera-
tion parameters like the venting of non-condensable gases from the
bottom of heaters and calandrias and controlling sugar end brix, to
optimize evaporation and speed up production. This also falls under
the better process control technique.
• Sugar end purity control: Modifying purity management steps of the
sugar, lowering the purity of liquor (molasses) and reviewing crys-
tallization management to optimize this operation; a process modi-
fication technique.
• Unknown losses: Improving maintenance on pump seals to stop leak-
ages and improving operation methods to provide steady state con-
dition; a good housekeeping technique.