CN ash - a novel parameter predicting cake solids of dewatered digestates
Svennevik, OK, Beck, G, Rus, E, Westereng, B, Higgins, M, Solheim, OE, Nilsen, PJ, Horn, SJ
Water Research, 2019
Abstract
In this study, we showed that thermogravimetric analysis is a reliable prediction model for dewatered cake solids using digestates from 15 commercial full-scale plants. The tested digestates originated from different substrates, with and without the pre-AD thermal hydrolysis process (THP). Moreover, a novel combined physicochemical parameter (C/N ash) characterizing different digestate blends was identified by multiplying the C/N ratio with ash content of the dried solids.
Using samples from 22 full-scale wastewater, food waste and co-digestion plants, a linear relationship was found between C/N ash and predicted cake solids for digestates with and without pre-AD THP. Pre-AD THP improved predicted cake solids by increasing the amount of free water. However, solids characteristics like C/N ratio and ash content had a more profound influence on the predicted cake solids than pre-AD THP and type of dewatering device.
Finally, C/N ash was shown to have a linear relationship to cake solids and reported polymer dose from eight full-scale pre-AD THP plants. In conclusion, we identified the novel parameter C/N ash which can be used to predict dewatered cake solids regardless of dewatering device and sludge origin.
Download the full article or read it in Water Research.
Write your own success story
Seen what we've done for others? Let’s chat about how we can do the same for you. Get in touch with our team to learn how thermal hydrolysis can transform your plant, too.