If streaks of sludge are observed on the belt filter process when sludge and polymer feeds are off, what might be the cause?

The presence of streaks of sludge on the belt filter dewaterer, even when the sludge and polymer feeds are turned off, suggests that there might be an issue with the washing mechanism. Clogged washbox nozzles prevent water from effectively cleaning the belt and removing the sludge from previous processes. When nozzles are obstructed, water cannot wash the belt thoroughly, leading to the visibility of residual sludge streaks. A properly functioning wash system is crucial for maintaining a clean belt and ensuring optimal operation of the dewatering process.

In contrast, inadequate polymer dosage relates more directly to issues during the polymer conditioning phase rather than the presence of sludge streaks when feeds are off. High sludge density could contribute to dewatering challenges but wouldn’t be linked to the observed condition in the absence of feeds. Low water supply could affect overall operation but again would not be the specific cause of sludge streaks on a dewatered belt without operational feeds. It’s the clogging of washbox nozzles that directly correlates to the observed issue.