A series of belt filter press trials were performed to assess BFP technology as a method for dewatering digested biosolids which had been pretreated by the Cambi Thermal Hydrolysis Process (THP). The THP is a sludge pretreatment process which heats raw sludges to high temperature (150-165 °C ) using steam followed by mesophilic digestion. In this study, two different full scale THP sludges were dewatered on two belt filter presses supplied by two different manufacturers. The digested THP sludges had solids concentrations between about 5- 7%. The goal of the project was to evaluate the effect of solids loading rates and polymer dosing on cake solids and capture. The results showed the THP sludges dewatered well using BFPs, with cakes solids of 30% or higher easily achieved along with capture rates greater than 99%. This performance was achieved over a broad solids loading rate with 30% cake solids being achieved at loading rates of up to 1000 kg/m-hr. The study also showed that mixing of the polymer and sludge was a critical parameter for achieving good flocculation and dewatering.
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