Enhanced Biological Nitrogen Removal In PVA-Gel Based MBBR - A Novel Option To Save Dal Lake. J. Singh*, K.M.Gani*, N.K.Singh*, V. Rose**, A.A. Kazmi* * Department of Civil Engineering, Indian Institute of Technology, Roorkee , India ( **Kuraray India Private Limited, New Delhi (India) – MATERIAL AND METHODS  The treatment scheme consists of an aerobic tank for nitrification and organic removal, anoxic tank for denitrification and an additional aerobic tank for removal of external BOD (Fig. 1).  The bio carriers in each tank were spherical PVA gel beads with 10% filling fraction. Methanol was used as external carbon source in anoxic tank and the whole treatment was followed by chemical coagulation using Poly-Aluminum Chloride (PAC).  The adopted treatment scheme was a copy of existing MBBRs with the addition an anoxic reactor.  The pilot plant was optimized at four temperatures (25, 20, 15 and 6 o C), in order to evaluate treatment performance at all temperatures of the region. The authors would like to express appreciation for the support of the sponsors: Kuraray India Pvt. Ltd. RESULTS & DISCUSSION INTRODUCTION  Dal Lake is situated in the heart of Srinagar, India at an altitude of 1583m. The lake as one of the leading tourist attraction of the country is under high anthropogenic stress of nutrients since more than three decades. It not only receives storm water but also treated effluent from the sewage treatment plants located on its periphery.  In order to control eutrophication and further degradation of the lake, the Jammu & Kashmir State High Court imposed stringent treated effluent requirement, emphasizing higher degree organics, TSS and mainly nutrient removal.  Since, existing sewage treatment plants are found to be incapable of nitrogen removal, a pilot plant study is conducted on the actual sewage for enhanced organic, suspended solids and nutrient removal, in order to further upgrade existing Moving Bed Biofilm Reactor (MBBR) based sewage treatment plants. CONCLUSIONS  The ammonia removal in four phases was 91%, 92%, 88% and 85%.  Total nitrogen removal was maximum (87%) at a temperature of 25 o C and HRT of 32 hours.  Phosphorus removal efficiency was 83-87% in all phases.  The sludge flocs exhibited the presence of heterotroph filamentous bacteria. (Fig. 3)  The ammonia removal in four phases was 91%, 92%, 88% and 85%.  Total nitrogen removal was maximum (87%) at a temperature of 25 o C and HRT of 32 hours.  Phosphorus removal efficiency was 83-87% in all phases.  The sludge flocs exhibited the presence of heterotroph filamentous bacteria. (Fig. 3)  PVA gel based MBBR was evaluated as an alternate option for upgradation of MBBRs around periphery of Dal lake.  The characteristics of the effluent were almost in accordance with the regulations prescribed by respective state authorities.  From the results, it is concluded that the treatment scheme is a noble option to save dal lake from stresses of organics and nutrients especially during winters. Fig. 1. Actual Set up of pilot plant Fig. 2. The flow sheet for the pilot scale Fig. 3. SEM micrographs of Sludge Table 1. Characteristics of influent and effluent of pilot plant in various phases Fig 4. Variations in COD, BOD, NH 4 -N and TSS during the pilot scale study IWA Specialist Conference on Sustainable Wastewater Treatment and Resource Recovery, October, Kathmandu, Nepal Poster No For more information please contact:- Khalid Muzamil Gani, Parameter Phase 1234 Inlet (mg/L)Outlet (mg/L)Inlet (mg/L)Outlet (mg/L)Inlet (mg/L)Outlet (mg/L)Inlet (mg/L)Outlet (mg/L) COD 238 ± ± ± ± ± ± ± ± 9.9 BOD 121 ± ± ± ± ± ± ± ± 0.84 TSS 98± ± ± 243± ± 88.22± ± 2064 ± 2.9 VSS 45 ± 215 ± ± 11.12± ± ± ± ± 0.5 TP 5.89 ± ± ± ± ± ± ± ± 0.16 NH 4 + -N ± ± ± ± ± ± ± ± 1.7 NO 3 -N 2.25 ± ± ± ± ± ± ± ± 0.6