Toxicity of heavy metals to thermophilic anaerobic digestion

✍ Scribed by B. K. Ahring; P. Westermann

• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 588 KB
• Volume: 17
• Category: Article
• ISSN: 1432-0614
• DOI: 10.1007/bf00499505

✦ Synopsis

The effects of heavy metals on the thermophilic digestion of sewage sludge was studied in three semicontinuous digesters step-fed with cadmium, copper and nickel, respectively. The daily gas production, gas composition, the quantitative accumulation of volatile fatty acids, and the distribution of the heavy metals were measured. The fermentations were carried out at 58~ with a retention time of 10 days and an addition of 1.7 g volatile solids/1 of reactor volume per day. Nickel was found to be 2-3 times more water soluble than cadmium and copper when the digesters were fed raw sludge containing heavy metals. The three digesters all showed tendencies to acclimate to the heavy metals up to a certain level. 200 mg nickel/1 was completely inhibitory while the same response was observed for cadmium and copper at 300 rag/1.