BIOTECHNOLOGICAL PRODUCTS AND PROCESS ENGINEERING Advanced phosphorus recovery using a novel SBR system with granular sludge in simultaneous nitrification, denitrification and phosphorus removal process Yong-Ze Lu 1 & Hou-Feng Wang 1 & Thomas A. Kotsopoulos 2 & Raymond J. Zeng 1 Received: 4 November 2015 /Revised: 30 November 2015 /Accepted: 12 December 2015 # Springer-Verlag Berlin Heidelberg 2015 Abstract In this study, a novel process for phosphorus (P) recovery without excess sludge production from granular sludge in simultaneous nitrification-denitrification and P re- moval (SNDPR) system is presented. Aerobic microbial gran- ules were successfully cultivated in an alternating aerobic– anaerobic sequencing batch reactor (SBR) for removing P and nitrogen (N). Dense and stable granular sludge was creat- ed, and the SBR system showed good performance in terms of P and N removal. The removal efficiency was approximately 65.22 % for N, and P was completely removed under stable operating conditions. Afterward, new operating conditions were applied in order to enhance P recovering without excess sludge production. The initial SBR system was equipped with a batch reactor and a non-woven cloth filter, and 1.37 g of CH 3 COONa·3H 2 O was added to the batch reactor after mixing it with 1 L of sludge derived from the SBR reactor to enhance P release in the liquid fraction, this comprises the new system configuration. Under the new operating condi- tions, 93.19 % of the P contained in wastewater was released in the liquid fraction as concentrated orthophosphate from part of granular sludge. This amount of P could be efficiently re- covered in the form of struvite. Meanwhile, a deterioration of the denitrification efficiency was observed and the granules were disintegrated into smaller particles. The biomass concentration in the system increased firstly and then main- tained at 4.0 ± 0.15 gVSS/L afterward. These results indicate that this P recovery operating (PRO) mode is a promising method to recover P in a SNDPR system with granular sludge. In addition, new insights into the granule transformation when confronted with high chemical oxygen demand (COD) load were provided. Keywords Simultaneous nitrification . Denitrification and phosphorus removal . Granular sludge . External COD addition . No residual sludge wastage . Phosphorus recovery Introduction While phosphorus (P) is one of the most abundant elements in the Earth’ s crust (Liu et al. 2015), only a small percentage is in high concentration enough to be mined in an economically viable way. Today, about 22 Mt (P) from mined fossil phos- phate resources is added yearly to the world economy (Reijnders 2014) with increasing tendency. Approximately 90 % of all phosphate demand is for food production (Wu et al. 2015), primarily for the production of artificial fertilizers. Due to the increasing demand for food, P will become increas- ingly scarce and expensive (Cordell et al. 2011). The demand for P is growing globally, creating concerns about its future resource availability. Therefore, there is a need for sustainable solutions for P recycling/recovering. Wastewater contains P; by recovering P from domestic waste streams including waste- water, about 15–20 % of the total world demand for phosphate could be satisfied (Yuan et al. 2012). Enhanced biological P removal (EBPR) is a very common method of P removal from wastewater (Li et al. 2015). EBPR requires alternating aerobic (anoxic)/anaerobic conditions for P accumulation. During the aerobic or anoxic phase * Raymond J. Zeng rzeng@ustc.edu.cn 1 CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China 2 Department of Hydraulics, Soil Science and Agricultural Engineering, School of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece Appl Microbiol Biotechnol DOI 10.1007/s00253-015-7249-y