At Samra WWTP, once the liquid sludge is digested, it is conveyed to 16 lined solar evaporation lagoons where it is first dewatered for a year before being transferred to the storage area by trucks. During the drying process, the sludge is mixed regularly in order to avoid crust formation and consequently to maximise evaporation.
Considering the dimensions and geometry of the lagoons, the only feasible way was to consider a machine able to operate in no less than 50cm of liquid sludge without affecting the sensitive ground structure (liner under 30cm of sand) of the lagoons.
Furthermore, during the transfer of the dried sludge, there was a need to push the sludge to the sides of the lagoons where an excavator located outside the lagoon would collect and load it in trucks.
The Bobcat T320 compact steel tracked loaders were tested and purchased for work on these two stages of the process.
The steel tracked loaders are an alternative to the conventional rubber tracked configurations of these machines, allowing them to work in difficult conditions such as the sludge beds that are unsuitable for rubber track work. During the operation, pushing by the T320 loaders causes bow waves which either deflect the muck from the loader or, when reversing, force it into crevices in the machine.
Bobcat said that other components help contribute to the increased track life of the loaders, including a sealed and lubricated chain; forged idlers and rollers and hardened shoes, resistant to bending and breaking. The sealed and lubricated chain has a 50% reduction in internal bushing wear, a quieter operation and lower fuel consumption than the sealed only chain. The lubrication also reduces resistance compared to the sealed only chain.
www.bobcat.com
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