One week after the start of the sugar processing campaign, the COD concentrations of the water exiting the cooling towers (CT) at a sugar refinery registered spikes of organic matter above the thresholds defined in the prefectural order (125 mg/l and 900 kg/d). Duplicate analyses were carried out as soon as these spikes were noticed, but the operator was unable to identify the source of the spikes. It wasn’t until the refinery’s equipment was dismantled for its annual inspection during the 2018 campaign that leaks were found on a displacement juice (‘meichage’) heater and a raw juice pre-extraction heater. These items of equipment are not easily accessible during campaigns.
The operator plans to make the following technical improvements:
- install a desugaring unit on the evaporators;
- repair the pre-extraction juice and meichage juice heat exchangers, and request a new heat exchanger;
- install a deflector in the falling film evaporator to reduce entrainment;
- repair all the poly-baffles in the evaporators;
- reduce batch evaporation levels;
- cover the condenser pans;
- create a cleaning line between the desugaring unit and the Kesner separator.
It also undertakes to implement the following measures:
- inspect the condition of all its desugaring units;
- test the water quality in the desugaring units;
- fit conductivity meters in the column’s legs to monitor for sugar entrainment in each one;
- audit each evaporator technician’s practices;
- inform evaporator technician’s of the importance of starting evaporation on Monday morning during campaigns to avoid overflows.
