Aerobic treatment

Treatment of high saline wastewater with aerobic granular sludge
Keywords: Aerobic granular sludge, Wastewater treatment, High salinity

The aerobic granular sludge process (Nereda®) has been proven to be an efficient way for wastewater treatment, achieving simultaneous removal of organic carbon (COD), nitrogen and phosphorus. The outer layer of the granules consists of an aerobic part, in which nitrifying bacteria can grow and oxidize ammonium to nitrate. Due to an oxygen gradient throughout the granule the inner part has anoxic conditions, which favours denitrification of nitrate to nitrogen gas. Simultaneously, phosphorus gets removed by polyphosphate-accumulating organisms (PAO) through the aerobic/anaerobic cycles in the system.

This method for wastewater treatment has been implemented on full-scale, achieving good removal rates and effluent quality. However, salt intrusion into water systems can be detrimental for the process performance. The aim of this project is to assess the effect of high salinity on aerobic granular sludge in terms of biological removal efficiency (COD, ammonium and phosphorus), the microbial community within the granular sludge, and the physical strength of aerobic granules.

Figure 1: Lab-scale granular sludge bubble column setup

Figure 2: Aerobic granular sludge grown at high salinity in a lab-scale reactor

List of publications:

1. Pronk & J. P. Bassin & M. K. de Kreuk & R. Kleerebezem & M. C. M. van Loosdrecht. Evaluating the main and side effects of high salinity on aerobic granular sludge. Appl Microbiol Biotechnol (2014) 98:1339–1348

1. P. Bassin, M. Pronk, G. Muyzer, R. Kleerebezem, M. Dezotti, and M. C. M. van Loosdrecht. Effect of Elevated Salt Concentrations on the Aerobic Granular Sludge Process: Linking Microbial Activity with Microbial Community Structure Applied and Environmental Microbiology, Nov. 2011, p. 7942–7953

J.H.F. Pereboom. Strength Characteristics of Microbial Granules. Water Science & Technology (1997), Vol. 36, No. 6-7, pp. 141-148