Commonly used polyelectrolytes (cationic) for sewage sludge conditioning prior to dewatering normally  do not inhibit water uptake of the dried sludge. The BOD/COD ratios of the conditioned sludges also  show that the biological degradability of the sludge is not adversely affected by the sludge conditioners. However, as suggested above. by Mr Thomas, a more effective way could be adding the PE's after digestion. Of course one may have to try your approach in case your primary is hydraulically overloaded.  however, please do carry out a lab scale study first with your PE and dosage to be doubly sure in view of Mr Romero's comments.

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Commonly used polyelectrolytes (cationic) for sewage sludge conditioning prior to dewatering normally  do not inhibit water uptake of the dried sludge.

The BOD/COD ratios of the conditioned sludges also  show that the biological degradability of the sludge is not adversely affected by the sludge conditioners. However, as suggested above. by Mr Thomas, a more effective way could be adding the PE's after digestion. Of course one may have to try your approach in case your primary is hydraulically overloaded.  however, please do carry out a lab scale study first with your PE and dosage to be doubly sure in view of Mr Romero's comments.