Pre-precipitation Followed by Biological Denitrification Supported by Addition of Biological or Thermal/Chemical Hydrolysis Products
Pilot scale experiences are reported for the process combination of pre-precipitation followed by biological nitrogen removal. Biological denitrification was supported by addition of hydrolysis products from hydrolysis of pre-precipitated primary sludge. Pre-precipitation was performed with PAX and with JKL, respectively. The biological nitrogen removal was performed based on the Bio-Denitro system. Hydrolysis products from biological sludge hydrolysis and from thermal/chemical sludge hydrolysis were applied in the experiments.
Both precipitation chemicals resulted in efficient reductions in COD, phosphorus, and suspended solids. JKL was more efficient for precipitation of phosphorus than PAX. Reduction in nitrogen was low for both chemicals. Due to the very different levels to which COD and nitrogen were reduced, the ratio of COD to nitrogen was reduced from 10–12 in the raw wastewater to 4.5–5.0 in the pre-precipitated wastewater.
Nitrogen reduction in the Bio-Denitro plant was studied with pre-precipitated wastewater alone and with pre-precipitated wastewater with addition of biological hydrolysate and various doses of thermal/chemical hydrolysate, respectively. Mean nitrogen reductions of 63% and 67% were found for the two chemicals with an influent of chemically precipitated wastewater alone. When biological hydrolysate was added, the mean nitrogen reduction was increased to 76%; with the addition of thermal/chemical hydrolysate, the mean reduction was 77%.
KeywordsBiomass Hydrolysis Fermentation Phosphorus Sludge
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- Bundgaard, E., Nielsen F.M.: Stability of Effluents from Biological Nutrient Removal Plants — Danish Long-Term Operating and Optimization Experiments. Presented at the WPCF 62nd. Annual Conference, San Francisco, 1989Google Scholar
- Eastman, J.A., Ferguson, J.: Solubilization of Particulate Organic Carbon During the Acid Phase of Anaerobic Digestion. J. WPCF 53 (3) (1981) 352–366Google Scholar
- Henze, M., Harremoes, P.: Chemical-Biological Nutrient Removal — The HYPRO Concept. In: Chemical Water and Wastewater Treatment, H.H. Hahn and R. Klute (eds.). Springer, Berlin Heidelberg New York 1990, pp. 499–510Google Scholar
- Jørgensen, P.E.: Biological Hydrolysis of Sludge from Primary Precipitation. In: Chemical Water and Wastewater Treatment, H.H. Hahn and R. Klute (eds.). Springer, Berlin Heidelberg New York 1990, pp. 511–520Google Scholar
- Karlsson, I., Smith, G.: Pre-precipitation Facilitates Nitrogen Removal Without Tank Expansion. Wat. Sci. Tech. 23 (1990) 811–818Google Scholar
- Kristensen, G.H., Jørgensen, P.E., Henze, M.: Characterization of Functional Microbial Groups and Substrate in Activated Sludge and Wastewater by AUR, NUR and OUR. IAWPRC Conf. on Interactions of Wastewater, Biomass and Reactor Configurations in Biological Treatment Plants. Copenhagen, August 21–23, 1991 (in press)Google Scholar
- Kristensen, G.H., Jørgensen, P.E., Strube, R., Henze M.: Combined Pre-precipitation, Biological Sludge Hydrolysis and Nitrogen Reduction — a Pilot Demonstration of Integrated Nutrient Removal. To be presented at the IAWPRC 16th Biennial Int. Conf. Washington, DC, May 24–30, 1992Google Scholar
- Smith, G., Göransson, J.: Generation of an Effective Internal Carbon Source for Den-itrification Through Thermal Hydrolysis of Pre-precipitated Sludge. Proceedings from the 6th IAWPRC Conf. on Design and Operation of Large Wastewater Treatment Plants. Prague, Czechoslovakia, Aug. 26–30, 1991Google Scholar
- Ødegaard, H., Fettig, J., Ratnaweera, H.: Coagulation with Prepolymerized Metal Salts. In: Chemical Water and Wastewater Treatment, H.H. Hahn and R. Klute (eds.). Springer, Berlin Heidelberg New York 1990, pp. 189–220Google Scholar