This old digester was completely full of biosolids. Some of this waste had been in the digester for over 20 years and was heavily compacted in the bottom of the round concrete structure. Geotextile dewatering bags would be utilized to dewater the digester. Eight drying beds adjacent to the digester were cleaned out to accept the bags. A small building was set up to house the chemical mixing and injection equipment. A large submersible pump is fixed to the end of a hydraulic crane. This pump can be lowered down into the digester as the pumping process is completed. The pump has a side discharge so that it can be used to mix as well as pump. After cleaning out the beds, drainage mat was laid out over the clean sand. Two bags would be placed in each bed. The bags were our 30' x 100' bags. The digester was being filled with new septic waste as it was being pumped down so it took several months to pump it completely down and give it a much needed cleaning. To put the same amount of biosolids over the sand drying beds without the bags would have been impossible. The bags allowed the beds to hold many times more sludge than normal. The old digester is cleaned out and is now as good as new. The bags will be opened up and the solids either land applied or loaded out and hauled to the landfill.

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