Innovative Membrane Bioreactor Research Articles

In-situ biogas upgrading by bio-methanation with an innovative membrane bioreactor combining sludge filtration and H2 injection

A bioreactor using membrane technologies was used to demonstrate the feasibility of in-situ bio-methanation coupled to industrial wastewater treatment for biogas upgrading. High biogas productivity (1.7 Nm3Biogas/m3Bioreactor/day) with high CH4 content (97.9%) was reached. In-situ bio-methanation did not affect the COD removal efficiency of anerobic digestion (>94%). Process resilience has been tested for both substrate overload and H2 intermittence injection. Recovery of high CH4 content after 7 days without H2 injection occurred within few hours. Influence of microbial community has been studied showing that both hydrogenotrophic and homoacetogenic-acetoclastic pathways were involved.

From R&D to application: membrane bioreactor technology for water reclamation

PUB Singapore has been developing the membrane bioreactor (MBR) technology for water reclamation. The MBR technology has significant versatility and can be applied for production of industrial water or combined with reverse osmosis to produce NEWater. The MBR technology offers greater opportunity for process intensification and further enhancement to achieve water sustainability. Compared to conventional treatment, MBR is a 3-in-1 solution that combines bioreactor, secondary sedimentation tank and microfiltration/ultrafiltration in one single step. The advantages of MBR include process robustness, superior filtrate quality and compact footprint. Progressing from pilot studies and demonstration testing, the MBR technology is currently implemented at full-scale in Jurong and Changi Water Reclamation Plant. Moving forward, PUB continues to embark on R&D in developing innovative MBR systems for future application that includes the forthcoming Tuas Water Reclamation Plant as part of the Deep Tunnel Sewerage System Phase 2 project. This manuscript provides an overview of R&D initiatives for developing the MBR technology for water reclamation spanning more than a decade at PUB.

Methane hydroxylation by Methylosinus trichosporium OB3b: Monitoring the biocatalyst activity for methanol production optimization in an innovative membrane bioreactor

A quasi-total loss of the bacterial hydroxylating activity was identified to be responsible for methanol production stop. Different strategies acting on the reaction mixture were implemented to apprehend the biocatalyst behavior in view to extend methanol production. Activity monitoring showed first that sodium formate addition did not maintain the biocatalyst activity and even disrupted bacterial equilibrium when added into the reaction mixture with still active biocatalysts. Reaction medium renewals had no influence on methanol production and highlighted a limited hydroxylating potential of the biocatalyst while addition of fresh biocatalysts in the reaction mixture resulted in methanol consumption. Finally, performing hydroxylation directly in the native bacterial culture appeared as a way to enhance methanol production by both release of intracellular methanol accumulated in the cells during cultivation and effective production by methane hydroxylation.

Pilot demonstration of energy-efficient membrane bioreactor (MBR) using reciprocating submerged membrane.

Membrane bioreactor (MBR) is becoming popular for advanced wastewater treatment and water reuse. Air scouring to "shake" the membrane fibers is most suitable and applicable to maintain filtration without severe and rapidfouling. However, membrane fouling mitigating technologies are energy intensive. The goal of this research is to develop an alternative energy-saving MBR system to reduce energy consumption; a revolutionary system that will directly compete with air scouring technologies currently in the membrane water reuse market. The innovative MBR system, called reciprocation MBR (rMBR), prevents membrane fouling without the use of air scouring blowers. The mechanism featured is a mechanical reciprocating membrane frame that uses inertia to prevent fouling. Direct strong agitation of the fiber is also beneficial for the constant removal of solids built up on the membrane surface. The rMBR pilot consumes less energy than conventional coarse air scouring MBR systems. Specific energy consumption for membrane reciprocation for the pilot rMBR system was 0.072 kWh/m3 permeate produced at 40 LMH, which is 75% less than the conventional air scouring in an MBR system (0.29 kWh/m3). Reciprocation of the hollow-fiber membrane can overcome the hydrodynamic limitations of air scouring or cross-flow membrane systems with less energy consumption and/or higher energy efficiency.

An innovative membrane bioreactor for methane biohydroxylation

In this study, a membrane bioreactor (MBR) was developed for efficient, safe microbial methane hydroxylation with Methylosinus trichosporium OB3b. This innovative MBR, which couples a bioreactor with two gas/liquid macroporous membrane contactors supplying the two gaseous substrates (methane and oxygen) was operated in fed-batch mode. The feasibility and the reproducibility of this new biohydroxylation process were first demonstrated. The mass transfer within this MBR was twice that observed in a batch reactor in similar conditions. The productivity reached with this MBR was 75±25mgmethanol(gdrycell)−1h−1. Compared to the literature, this value is 35times higher than that obtained with the only other fed-batch membrane bioreactor reported, which was run with dense membranes, and is comparable to those obtained with bioreactors fed by bubble-spargers. However, in the latter case, an explosive gas mixture can be formed, a problem that is avoided with the MBR.

An innovative membrane bioreactor (MBR) system for simultaneous nitrogen and phosphorus removal

Membrane filtration was integrated with a post-denitrification process to form an innovative membrane bioreactor (MBR) system for effective organic degradation and nutrient (N and P) removal. The system comprised of an aerobic tank, an anoxic tank, an intermediate sedimentation tank, and a membrane filtration tank. The sedimentation tank functioned not only as a rough settler for sludge–water separation before membrane filtration but also as an anaerobic chamber for P release. While half of the influent flowed into the aerobic tank, the other half was fed into the anoxic tank to favor the proliferation of phosphorus accumulating organisms (PAOs). The experiment was conducted continuously for about 430 days. With a short overall treatment time of less than 10h for municipal wastewater, the MBR-based process could achieve the total organic carbon, total nitrogen, and total phosphorus removals of around 94%, 85%, and 87%, respectively. The growth and activity of PAOs in the MBR system were evidenced by the significant P release in the anaerobic chamber followed by the luxury P uptake in the membrane tank. With the DAPI and PAOmix probe staining, the increases of PAOs and polyhydroxybutyrate (PHB) in sludge during the experiment were well observed under the fluorescent microscope.

A real trial of an innovative membrane bioreactor for saline sewage treatment

We have recently developed non-woven membrane modules to be immersed in activated sludge bioreactor for treating saline sewage. To evaluate the feasibility and energy consumption of this technology, a pilot trial of up to 7 m3/day was conducted over 270 days at the Hong Kong University of Science and Technology (HKUST). This paper reports part of the data obtained from this pilot trial. The pilot plant produced steady and good quality effl uent. The average effluent total nitrogen (TN) was 7.7 mg N/L, total chemical oxygen demand (TCOD) 27 mg/L and total suspended solids (TSS) 15 mg/L, respectively. The maximum effective permeate flux was found to be up to 6 m/d, while the air-to-water volumetric ratio could be as low as 15. The transmembrane pressure (TMP) was maintained at 0.1 bars after each backwash with around 1% of the effluent. The backwash was conducted once in 48 hrs. The membrane modules worked well without clogging for 270 days until an accidental failure of power source, which lasted for 30 hr...

Planning, Design, and Startup of a Large, Innovative Membrane Bioreactor Facility

The planning, design, and startup of the Broad Run Water Reclamation Facility (WRF), a new 41,600-cubic-metres-per-day (m3/day) (11-million-gallon-per-day) facility owned and operated by Loudoun Water in Ashburn, Virginia, is discussed. Located in suburban area near Washington, DC, in the Dulles Area Watershed, and upstream of a drinking water supply in the Potomac River, the facility sets a new world-wide technology standard for environmental protection and water reclamation. The Broad Run WRF uses a membrane bioreactor (MBR), followed by granular activated carbon (GAC) treatment and ultraviolet (UV) disinfection and is the first large-scale application of this combination of treatment technologies in the world. The facility is designed to meet stringent discharge limits, including a total nitrogen (TN) limit of 4 milligrams per liter (mg/L), a total phosphorus (TP) limit of 0.1 mg/L, and a chemical oxygen demand (COD) limit of 10 mg/L. The MBR, operated in a 5-Stage Bardenpho configuration and modified to save aeration energy by recycling the highly oxygenated return activated sludge (RAS) of the MBR to the first aerobic stage, is also one of the application points of alum for phosphorus removal. The facility is one of the largest operating MBR installations in the United States.

An innovative membrane bioreactor and packed-bed biofilm reactor combined system for shortcut nitrification-denitrification

An innovative shortcut biological nitrogen removal system, consisting of an aerobic submerged membrane bioreactor (MBR) and an anaerobic packed-bed biofilm reactor (PBBR), was evaluated for treating high strength ammonium-bearing wastewater. The system was seeded with enriched ammonia-oxidizing bacteria (AOB) and operated without sludge purge with a decreased hydraulic retention time (HRT) through three phases. MBR was successful in both maintaining nitrite ratio over 0.95 and nitrification efficiency higher than 98% at HRT of 24 h, and PBBR showed satisfactory denitrification efficiency with very low effluent nitrite and nitrate concentration (both below 3 mg/L). By examining the nitrification activity of microorganism, it was found that the specific ammonium oxidization rate (SAOR) increased from 0.17 to 0.51 g N/(g VSS·d) and then decreased to 0.22 g N/(g VSS·d) at the last phase, which resulted from the accumulation of extracellular polymers substances (EPS) and inert matters enwrapping around the zoogloea. In contrast, the average specific nitrite oxidization rate (SNOR) is 0.002 g N/(g VSS·d), only 1% of SAOR. Because very little Nitrobactor has been detected by fluorescence in situ hybridization (FISH), it is confirmed that the stability of high nitrite accumulation in MBR is caused by a large amount of AOB.

IWAPIL — innovative wastewater treatment applications for isolated locations

Due to the likely toughening of environmental legislation in near future, many of the currently operating wastewater treatments are no longer acceptable and need to significantly increase their efficiency. Stricter regulations are found for especially sensitive areas, drinking water abstraction areas and bathing waters. The problem of meeting existing and forecasted more stringent new regulations affects especially small communities, hotels campsites in relative remote areas without access to sophisticated wastewater treatment plants. Since a couple of years southern European countries observe on the one hand high water demands during the summer season (tourism, agriculture, horticulture, etc.). On the other hand these countries are facing a water scarcity in an so far unknown dimension. The IWAPIL project offers an innovative membrane bioreactor (MBR) intended for use in remote communities, mountain hotels, campsites. This decentralised system with the size of a standard container is based on submerged membrane module and highly automated control which ensures low-maintenance costs and a extremely high quality effluent which can be even reused for irrigation or toilet flushing purposes, as it is totally germ free. The IWAPIL pilot plant was designed to treat the wastewater of 50 PE and was tested under practical conditions fro seven months by treatment of grey- and blackwater from two campsites in Spain and Italy, respectively. The purification efficiency was characterized by very high COB, BOD5 and Nitrogen removal rates in combination with an at the end five times higher treatment capacity than originally designed. The permeate quality allowed water re-use on site, e.g. for irrigation purposes. The poster presents of test results in the two locations. The results are accompanied by a economic comparison of the IWAPIL system with SBR technology that indicates a high economic potential of the IWAPIL technology as a concept for decentralised wastewater treatment and re-use in remote areas. The project was supported by the Co-operative Research Program in the Sixth Framework Programme of the European Community for research, technological development and demonstration activities (COOP-CT-2004-208144.

Simultaneous Nitrification and Denitrification with Anoxic Phosphorus Uptake in a Membrane Bioreactor System

The performance of an innovative membrane bioreactor (MBR) process using anoxic phosphorus uptake with nitrification and denitrification for the treatment of municipal wastewater with respect to operational performance and effluent quality is addressed in this paper. The system was operated at steady-state conditions with a synthetic acetate-based wastewater at a hydraulic retention time (HRT) of 12 hours and on degritted municipal wastewater at a total system HRT of 6 hours. The MBR system was able to achieve 99% biochemical oxygen demand (BOD), chemical oxygen demand (COD), and ammonia-nitrogen (NH4(+)-N); 98% total Kjeldahl nitrogen (TKN); and 97% phosphorus removal, producing effluent BOD, COD, NH4+-N, TKN, nitrate-nitrogen, nitrite-nitrogen, and phosphate-phosphorus of <3, 14, 0.2, 0.26, 5.8, 0.21, and <0.01 mg/L, respectively, at the 6-hour HRT. The comparison of the synthetic and municipal wastewater run is presented in this paper. Steady-state mass balance on municipal wastewater was performed to reveal some key features of the modified MBR system.