The impact of chemical phosphorus removal on the process of anaerobic sludge digestion

Abstract

The paper investigates the efficiency of the mixture of primary sludge and excess activated sludge in Vilnius WWTP with reference to the anaerobic digestion process. Sludge digestion was carried out under laboratory conditions using anaerobic sludge digestion model W8 (Armfield Ltd., UK). Laboratory analyses consist of two periods – the anaerobic digestion of the un-dosed and Fe-dosed sludge mixture. The results of digestion were processed using the methods of statistical analysis. The findings showed reduction in volatile solids approx. by 6% when dosing min FeCl₃·6H₂O and 15% when dosing max FeCl₃·6H₂O into feed sludge. Gas volume produced during the digestion of the un-dosed sludge was 90–160 ml/d and 60–125 ml/d in min Fe-dosed sludge and 45-95 ml/d. Also, correlation between VS loadings and biogas production was found. A rise in VS loading from 0,64 g/l/d to 1,01 g/l/d increased biogas production from 90 ml/d to 140–160 ml/d.

Article in Lithuanian.

Cheminio fosforo šalinimo įtaka anaerobiniam dumblo pūdymo procesui

Santrauka. Straipsnyje analizuojamas Vilniaus m. nuotekų valykloje susidariusio pirminio ir perteklinio dumblo mišinio anaerobinio pūdymo efektyvumas, nustatomos dumblo pūdymo parametrų priklausomybės. Tyrimai atlikti dviem etapais – pūdant nedozuotą dumblą ir dozuojant FeCl3·6H2O druskos minimalią ir maksimalią dozes. Buvo tiriama laboratorinėmis sąlygomis, naudojant anaerobinio dumblo pūdymo modelį W8 (Armfield Ltd, Didžioji Britanija). Tyrimų rezultatai apdoroti matematinės statistikos analizės metodais, pateiktos išvados.

Reikšminiai žodžiai: anaerobinis dumblo pūdymas, biodujos, cheminis fosforo šalinimas, geležies druska.

Keyword : anaerobic digestion, chemical phosphorus removal, biogas, iron salt