The effects of using various types of carbonaceous substrate on UASB granules and on reactor performance

A set of 10 upflow sludge blanket digesters was examined as five pairs—one control and four test reactors—to assess the way in which selected types of carbonaceous substrate affected the performance of the reactors. The carbon sources were sucrose, acetate, casein, butanol and ice cream. The results show that the change of feed caused a deterioration in the performance of all the test digesters. The casein feed caused the greatest impact, with de-amination of the protein producing inhibitory levels of ammoniacal-nitrogen. The use of ice cream in the feed resulted in the surface of the sludge granules being covered with what was thought to be lipid material.