Zimpro Sludge Heat Treatment System

Heat Treatment can be applied towards wet sludge in order to stabilize and condition it. This process has several advantages because the treated sludge can easily sent for dewatering steps since it now has softer gel structure with less water content in the solids. Heat treatment can also be used to coagulate and thicken the sludge so that later part it can be readily transported between one location to another. The high temperature involved in the process will also help to sterilize and prevent accelerated sludge degradation that usually leads to foul odor.

One of the commonly used sludge stabilization and conditioning method is the Zimpro system which uses wet air oxidation, that operates under elevated pressure condition. The concept behind the whole operation involves feeding the sludge to a reactor accompanied by compressed air and live steam injection. The partially oxidized outgoing sludge generated from this reactor will later undergo heat exchange with the incoming sludge feeding to the reactor in order to recover back the heat for energy efficiency purposes. Further processing steps that includes lime dewatering, centrifugal thickening or sand drying beds can be considered to be used later part. The advantages with using the system is that sludge undergoing the heat treatment process has low water content with the solids ranging as high as 40 to 50 percent depending on whether fine-tuning of the system and optimization has been carried out.

Setting up and maintaining the system require high cost and strict maintenance schedule, which is why the system is rarely used today. Furthermore, the ash and volatile residuals generated can be health hazardous with adverse environmental effect. However, with all the considerations put into account, it maybe economical to operate if it involves large volume waste capacity as in large treatment plants and installation. In fact, the system can only benefit if it is operated with a lot of focus put in towards maintenance especially prevention on formation of scales in pipelines and heat exchangers.

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