Lime Application Without Affecting Subsequent Biological Treatment Processes

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This is in connection with pre-dewatering application of lime to faecal sludge (FS) in a FS treatment plan, in which the treatment of the liquid following unplanted drying bed after the lime application is through biological mechanisms of anaerobic filter and horizontal flow wetland (HFW). It is evident that the application of lime, in the beginning, may affect the biological processes in the anaerobic filter and horizontal flow wetland. The FSM book (IWA, 2014) on this however says, “after the initial reaction following lime application regrowth of bacterial pathogens can occur over time”.

On this, is it know how long after lime application regrowth of pathogens may occur for the normal biological process to take place in the biological filter and the HFW.

Or alternatively, is there any dose or extent of lime application that can without inactivating all the microbial activity just make the sludge dewater-able in the drying bed without affecting the downward biological process in anaerobic filter and horizontal flow wetland significantly?

   This is in connection with an emergency FS treatment plant where the faecal sludge is quite fresh (about three months old) and there is lack of space to store the FS for a longer time to stabilize to make it dewater-able in the unplanted drying bed. Lime application is considered to stabilize the FS to make it dewaterable quickly. Thanks.

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