1 research outputs found
Thermophilic and mesophilic temperature phase anaerobic codigestion (TPAcD) compared with single-stage co-digestion of sewage sludge and sugar beet pulp lixiviation
The performance of temperature phase anaerobic co-digestion (TPAcD) for sewage sludge and sugar beet
pulp lixiviation (using the process of exchanging the digesting substrate between spatially separated
thermophilic and mesophilic digesters) was tested and compared to both single-stage mesophilic and
thermophilic anaerobic co-digestion. Two Hydraulic Retention Times (HRT) were studied in the thermophilic stage of anaerobic digestion in two temperature phases, maintaining the optimum time of the
mesophilic stage at 10 days, obtained as such in single-stage anaerobic co-digestion. In this way, we
obtained the advantages of both temperature regimes.
Volatile solids removal efficiency from the TPAcD system depended on the sludge exchange rate, but
fell within the 72.6e64.6% range. This was higher than the value of 46.8% obtained with single-stage
thermophilic digestion and that of 40.5% obtained with mesophilic digestion. The specific methane
yield was 424e468 ml CH4 per gram of volatile solids removed, similar to that of single-stage mesophilic
anaerobic digestion. The increase in microbial activity inside the reactor was directly proportional to the
organic loading rate (OLR) (or inversely proportional to the HRT) and inversely proportional to the size of
the microbial population in single-stage anaerobic co-digestion systems