Thank you for your elaborate answer which is most helpful. The water for the reactors is coming from a common buffer tank where pH is balanced before being sent to the anaerobic system. Temperature is also controlled collectively. the F/M ratio is adapted according to the measured sludge content of each reactor. This is however with some delay. If there is one single measurement that is lower the feed is not changed since we notice a lot of variation in the measurements due to decent sampling issue's. Not all the strings in reactor constantly receive the same amount of water, via valves this varies. This causes difficulty’s in sampling where there might be a difference when you take a sample 10 minutes later. The feed is thus based on the average measurements. Changes are thus always with a delay. In brief, it is possible that we are trailing behind and constantly slightly overfeed this reactor. I was not aware that acidifiers make the sludge lighter nor the fact that it makes them less compact. We do have an external consultant that could do a microscopic analysis of the sludge to determine whether these are mostly acidifiers.   Thanks again for the valuable information.

Published January 31, 2020 13:44 by Marijn Alliet