Impact of iron salts dosing on anaerobic fermentation

journal article - other

English

In order to meet the strict demand on nutrient removal, iron-based coagulants are in frequent use for phosphorus reduction, especially in wastewater treatment plants with capacities above 30,000 pe. In these plants, the phosphorus concentration decreases by precipitation with iron salts, and stabilisation of the sludge is attained in anaerobic fermentors in the mesophilic temperature area. Reduction of total phosphorus (P1) concentration is achieved by sim-ultaneous or primary precipitation. The iron content in the sludge from the wastewater treatment plants is also increasing with the use of iron salts for pre-precipitation. Increased use of iron salts in waste water treatment plants started dis-cussions about the possible inhibi-tion impact of iron on anaerobic digestion, which initiated this project. The project was divided into three stages. In the first stage tests were carried out in small anaerobic reactors (SAFR) of 250 ml volume in order to find basic data. It was possible, in a short time, to determine stimulation or inhibition of iron con-centraton on biogas production. In the second stage of the project, tests in the pilot anaerobic models with a volume of 22 I were carried out, Anaerobic reactors were set up under standard conditions for stabilisation of primary and se-condary sludge in a ratio of 5:2. During the third stage. results will be verified on the up-flow anaerobic reactors with a capacity of 3.5 m3. This operation will verity the results from stages l and 2.

iron salts, anaerobic fermentation, biogas

HLAVÍNEK, P., PALČÍK, J., NOVÁK, P., SOJKA, J., FIALOVÁ, J.

1. 1. 1997

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