Biological nutrient removal was studied and modeled for a submerged bench-scale membrane bioreactor (MBR). Of the five configurations studied, the configuration with mixed liquor recirculation to the anaerobic compartment and permeate recirculation to the anoxic compartment gave the best results with 92.3 % sCOD, 75.6% TN, 62.4% TP removal, and almost complete nitrification (97.7%) at 25 days SRT and 2 hrs anaerobic, 2 hrs anoxic and 8 hrs oxic HRTs. When recirculation rates were varied within the same configuration, the highest TP removal was 88.1% with 300%/100% (mixed liquor/permeate) recirculation while the highest TN removal (90.3%) was with 200%/300% recirculation. TN and TP concentrations as low as 4.2 ± 0.1 mg/L and 1.4 ± 0.2 mg/L were obtained, respectively. The Biowin® AS/AD model, calibrated against a set of experimental data, predicted the effluent TN, TP and NO3− -N concentrations of MBR for varying recirculation configurations. Varying the SRT in the MBR impacted nutrient removal with 77.9% TN and 70.3% TP removal for 25 days SRT, 80.6% TN and 75.5% TP removal for 50 days SRT, and 84.8% TN and 61.5% TP removal for 75 days SRT. Biowin® modeling showed that the anoxic heterotrophic yield, oxic endogenous decay rate, anoxic hydrolysis factor, anaerobic hydrolysis factor, and fermentation rate increased proportionally with SRT. The estimated microbial kinetic parameters from Biowin® modeling for various SRTs predicted the experimental effluent quality at an SRT of 35 days. Incorporation of anaerobic, anoxic, and oxic sequences with intermittent aeration into the cycles of a full-scale sequencing batch reactor system (SBR) resulted in improvement in biological nutrient removal for the treatment of municipal wastewater and wastewater from a salad dressing plant. The two modified SBR schemes tested provided excellent sCOD removal (93 - 98%), TN removal (84 -90%) and TP removal (86 - 88%) in comparison to the regular SBR scheme which gave 55% TN removal and 45% TP removal. Winter temperatures impacted TN and TP removal negatively but did not impact sCOD and NH3-N removal.

. A pilot-scale MBR plant was designed, commissioned and operated in parallel to the full-scale sequencing batch reactor (SBR) treatment system in Nova Scotia. Samples were collected from the effluent of both treatment processes over a 3-month period (June to August 2016) and were analyzed for biochemical oxygen demand (BOD), total suspended solids (TSS), chemical oxygen demand (COD), ammonia (NH3) and total phosphorus. It was found that the full-scale SBR plant was able to meet discharge regulations for all water quality parameters examined consistently except for total phosphorus. The pilot-scale MBR system was able to meet the discharge regulations for BOD and TSS consistently, and ammonia once stable operating conditions were met, but failed to meet the total phosphorus discharge water quality goals under the experimental set points and during the study period. A bench-scale coagulation study focusing on phosphorus removal was completed to complement the pilot MBR plant.

The sequencing batch reactor (SBR) is perhaps the most promising and viable of the proposed activated sludge modifications today for the removal of organic carbon and nutrients. In a relatively short period, it has become increasingly popular for the treatment of domestic and industrial wastewaters, as an effective biological treatment system due to its simplicity and flexibility of operation. Mechanism and Design of Sequencing Batch Reactors for Nutrient Removal has been prepared with the main objective to provide a unified design approach for SBR systems, primarily based on relevant process stoichiometry. Specific emphasis has been placed upon the fact that such a unified design approach is also by nature the determining factor for the selection of the most appropriate cyclic operation scheme, the sequence of necessary phases and filling patterns for the particular application. The proposed basis for design is developed and presented in a stepwise approach to cover both organic carbon and nutrient removal, domestic and industrial wastewaters, strong and specific wastes. The merits of model simulation as an integral complement of process design, along with performance evaluation of SBR models are also emphasized. Scientific and Technical Report No. 19

Simultaneous biological nutrient removal (SBNR) is the removal of nitrogen and/or phosphorus in excess of that required for biomass synthesis in biological wastewater treatment systems where there are no defined anaerobic and/or anoxic zones. The hypothesis is that one or more of three mechanisms is responsible within individual systems: variations in the bioreactor macroenvironment created by the mixing pattern, gradients within the floc microenvironment, and/or novel microorganism activity. Understanding of the mechanisms of SBNR can be expected to lead to improved efficiency and reliability in its application. Preliminary work documented SBNR in 7 full-scale OrbalTM closed loop bioreactors. A batch assay demonstrated that novel microorganism activity was of little importance in SBNR at the three plants tested. While the floc microenvironment likely plays an important role in nitrogen removal in such plants, it cannot explain phosphorus removal. A computational fluid dynamics (CFD) model was developed to elucidate the role of the bioreactor macroenvironment in SBNR. This is the first reported application of CFD to activated sludge biological wastewater treatment. Although the software and computational requirements limited model complexity, it still simulated the creation of dissolved oxygen gradients within the system, demonstrating that the anaerobic zones required for SBNR could occur.

During the last decade membrane bioreactor (MBR) technology has grown up to be state of the art in municipal wastewater treatment. Since 1999 the Erftverband has designed, tendered and commissioned three MBR for municipal wastewater treatment in Germany, with capacities from 3,000 to 45,000 m3/d. The Erftverband was one of the pioneers in the full scale application of the technology regularly hosted training and information workshops for plant designers and operators from all over the world. Operating Large Scale Membrane Bioreactors for Municipal Wastewater Treatment provides hands-on information on many aspects of MBR technology based on more than ten years of practical experience in the operation of MBR plants with hollow-fiber microfiltration units. It gives details on process configuration, investment and operation costs based on case studies and also in comparison to data from conventional activated sludge (CAS) treatment processes. The book contains the most recent research findings as Erftverband has been collaborating on many of the major European research projects dedicated to MBR technology. Actual process data from all treatment steps of the plants (mechanical pre-treatment, bioreactors, filtration, membrane cleaning) gives an insight into the long-term performance of the MBR plants and into the possible do’s and dont's of full scale applications and the potential for further process optimisation. It is a good source of practical advice on tendering and construction, plant management and operation. Operating Large Scale Membrane Bioreactors for Municipal Wastewater Treatment is essential reading for practitioners and researchers, providing information on many aspects of MBR technology, including actual process data, graphs and pictures that illustrate the challenges of MBR design and operation. Visit the IWA WaterWiki to read and share material related to this title: http://www.iwawaterwiki.org/xwiki/bin/view/Articles/MBROperation