Anaerobic co-digestion of sewage sludge: Application to the macroalgae from the Venice lagoon

✍ Scribed by F. Cecchi; P. Pavan; J. Mata-Alvarez

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 796 KB
• Volume: 17
• Category: Article
• ISSN: 0921-3449
• DOI: 10.1016/0921-3449(96)88182-1

✦ Synopsis

Possibilities of co-digestion of sewage sludge (SS) with other organic wastes are examined in this paper. Anaerobic co-digestion of macroalgae of the Venice lagoon (A) with SS, in wastewater treatment plants is studied in detail. This approach can contribute to the solution of the final disposal of the 50 000 m3 of macrophytes harvested each season. These are mainly Ulva rigida and Gracilaria confervoides. In the experiments A and SS were mixed at different ratios (20-40% algae, TS basis) and fed to mesophilic (37'C) and thermophilic (WC) digesters which operated at ll-to 15-day hydraulic retention times and 1.7-4.4 kgTVS/ m3/day organic loading rates. It was concluded that the mesophilic co-digestion process is applicable with potentialities of around 30% of the present SS flow-rate. Thermophilic digestion is not possible, because of the inhibition of methanogens probably due to the activity of sulphate-reducers.