Stable operation of MBR under high permeate flux

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
H. Y. Liu ◽  
B. Freeman ◽  
S. Sunano ◽  
N. Munehiro ◽  
C. Bartels ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Municipal Wastewater ◽  
Critical Role ◽  
Specific Energy Consumption ◽  
Pilot Scale ◽  
Stable Operation ◽  
Municipal Wastewater Treatment ◽  
Permeate Flux ◽  
Operating Condition

Permeate flux plays a critical role on the stable operation of membrane bioreactor (MBR) system for municipal wastewater treatment. The current commercially available submerged MBR systems, Zenon, Kobota, and Huber, etc. maintained their permeate fluxes at about 20–30 LMH to minimize the fouling potential of the membranes. A pilot scale MBR plant using HYDRASub®/Sterapore SADF® PVDF membrane module was stably operated at flux as high as 35 LMH for about 1 year by optimizing the operating condition of MBR system. The applied high permeate flux also resulted in low specific energy consumption per unit product water. This paper introduced the performance of membrane operated at high flux and discussed the factors affecting the stable operation of MBR. By applying the operating condition to an actual MBR plant, the specific energy consumption could reach a very low level, about 0.46 kWh/m3.

Design and operating experiences of full-scale municipal membrane bioreactors in Japan

2014 ◽  
Vol 69 (5) ◽  
pp. 1088-1093 ◽  
Author(s):  
H. Itokawa ◽  
K. Tsuji ◽  
K. Yamashita ◽  
T. Hashimoto
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Specific Energy Consumption ◽  
Oxygen Demand ◽  
Cost Evaluation ◽  
Guidance System ◽  
Small Scale ◽  
Municipal Wastewater Treatment

In Japan, membrane bioreactor (MBRs) have been installed in 17 small-scale municipal wastewater treatment plants (WWTPs) in the past 8 years, together with two recently installed MBRs for larger-scale WWTPs. In this study, design and operating data were collected from 17 of them as part of a follow-up survey, and aspects including system design, biological treatment, membrane operation, problems and costs were overviewed. Because most of the MBRs were designed according to standardized guidance, system configuration of the plants was similar; pre-denitrification using the Modified Ludzack-Ettinger (MLE) process with membrane units submerged in aerobic tanks, following a fine screen and flow equalization tank. This led to effluent quality with biochemical oxygen demand and T-N of less than 3.5 and 7.4 mg/L, respectively, for nine plants on an annual average basis. It was a common practice in extremely under-loaded plants to operate the membrane systems intermittently. Frequency of recovery cleaning events was plant-specific, mostly ranging from 1 to 5 times/year. Cost evaluation revealed that specific construction costs for the small-scale MBRs were no more than for oxidation ditch plants. Although specific energy consumption values tended to be high in the under-loaded plants, the demonstration MBR, where several energy reducing measures had been incorporated, attained specific energy consumption of 0.39 kWh/m3 under full-capacity operation.

scholarly journals Benchmarking of energy consumption in municipal wastewater treatment plants – a survey of over 200 plants in Italy

2018 ◽  
Vol 77 (9) ◽  
pp. 2242-2252 ◽  
Author(s):  
M. Vaccari ◽  
P. Foladori ◽  
S. Nembrini ◽  
F. Vitali
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Municipal Wastewater ◽  
Energy Savings ◽  
Wastewater Treatment Plants ◽  
Specific Energy Consumption ◽  
Oxygen Demand ◽  
Energy Performance ◽  
High Energy ◽  
Municipal Wastewater Treatment

Abstract One of the largest surveys in Europe about energy consumption in Italian wastewater treatment plants (WWTPs) is presented, based on 241 WWTPs and a total population equivalent (PE) of more than 9,000,000 PE. The study contributes towards standardised resilient data and benchmarking and to identify potentials for energy savings. In the energy benchmark, three indicators were used: specific energy consumption expressed per population equivalents (kWh PE−1 year−1), per cubic meter (kWh/m3), and per unit of chemical oxygen demand (COD) removed (kWh/kgCOD). The indicator kWh/m3, even though widely applied, resulted in a biased benchmark, because highly influenced by stormwater and infiltrations. Plants with combined networks (often used in Europe) showed an apparent better energy performance. Conversely, the indicator kWh PE−1 year−1 resulted in a more meaningful definition of a benchmark. High energy efficiency was associated with: (i) large capacity of the plant, (ii) higher COD concentration in wastewater, (iii) separate sewer systems, (iv) capacity utilisation over 80%, and (v) high organic loads, but without overloading. The 25th percentile was proposed as a benchmark for four size classes: 23 kWh PE−1 y−1 for large plants > 100,000 PE; 42 kWh PE−1 y−1 for capacity 10,000 < PE < 100,000, 48 kWh PE−1 y−1 for capacity 2,000 < PE < 10,000 and 76 kWh PE−1 y−1 for small plants < 2,000 PE.

Energy Reduction and Optimisation in Membrane Bioreactor Systems

2010 ◽  
Vol 5 (4) ◽  
Author(s):  
Guihe Tao ◽  
Kiran Kekre ◽  
Maung Htun Oo ◽  
Bala Viswanath ◽  
Aliman MD Yusof ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Energy Efficient ◽  
Specific Energy Consumption ◽  
Pilot Scale ◽  
Energy Reduction ◽  
Energy Audit ◽  
Membrane Flux ◽  
Demonstration Plant ◽  
Set Up

One of the major components of MBR operating expenditure is energy consumption. This paper presents our six-year journey of energy reduction and optimization in MBR systems through various pilot and demonstration studies. Through comprehensive and systematic MBR optimisation studies, the specific energy consumption was reduced from 1.3 kWh m−3 to less than 0.8 kWh m−3 by increasing membrane flux and reducing aeration at 300 m3 per day pilot scale plants. Through energy audit, the key energy consumption components including process aeration, membrane scouring rate, SRT, MLSS level, MLSS recirculation, and energy efficient equipment selection were identified, and these were optimised one by one at 23,000 m3 per day municipal scale MBR demonstration plant after the baseline had been set up. The specific energy consumption was further reduced to 0.37 kWh m−3.

scholarly journals MECHANICAL PULPING.Effect of long fibre concentration on low consistency refining of mechanical pulp

2012 ◽  
Vol 27 (4) ◽  
pp. 702-706 ◽  
Author(s):  
Stefan Anderssou ◽  
Christer Sandberg ◽  
Per Engstrand
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Fibre Length ◽  
Pilot Scale ◽  
Process Conditions ◽  
Mechanical Pulp ◽  
Fibre Concentration ◽  
Fibre Network ◽  
Length Reduction

Abstract The aim of this study was to investigate the influence of lang fibre concentration on Ioadability and pulp properties during LC refming of mechanical pulp. Lang fibre concentration was adjusted to three different Ievels by screen fractionation of the pulp. The three pulps were refined in a single disc pilot scale LC refiner at simi1ar process conditions. Increased lang fibre concentration suppmied a larger refiner gap and resulted in less fibre . cutting at a given specific energy consumption. The higher lang fibre concentration probably contributed to a stronger fibre network that maintained a !arger refining gap at certain specific energy consumption. Increased long fibre concentration also enabled a higher tensile index increase in the LC refmer at certain fibre length reduction. The study supports a process combining LC refining with screen fractionation, where the lang fibre fraction is recycled to the refiner feed. This enables a . higher Ioadability and a more effective utilisation of the LC refiner. By using this technology, overall specific energy consumption can be reduced if a !arger share of the refining is performed in LC rather than HC refining.

Pressurised compressive chip pre-treatment of Norway spruce with a mill scale Impressafiner

2012 ◽  
Vol 27 (1) ◽  
pp. 56-62 ◽  
Author(s):  
Erik Nelsson ◽  
Christer Sandberg ◽  
Lars Hildén ◽  
Geoffrey Daniel
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Paper Mill ◽  
Pilot Scale ◽  
Thermomechanical Pulp ◽  
Extractive Content ◽  
Mill Scale ◽  
Pre Treatment ◽  
Longitudinal Fibre

Abstract Mill scale trials were performed to evaluate pressurised compressive chip pre-treatment with the Impressafiner installed in one of the thermomechanical pulp lines at Braviken paper mill (Holmen Paper AB). The aim of the study was to determine if earlier reported effects of the Impressafiner pre-treatment on spruce chips from pilot scale trials (i.e. energy reduction and extractives removal) could also be attained with the mill scale Impressafiner. The mill scale Impressafiner pre-treatment resulted in partial disintegration of chips into a material consisting of fragmented chips with cracks running along the longitudinal fibre axis. Splits or evidence for weaknesses were observed between the primary and secondary fibre walls of pre-treated chips. An increase in water uptake for pre-treated chips was also observed. The extractive content was reduced by up to 24% for pulps produced with pre-treated chips compared to pulps from untreated chips. Pulp produced from pre-treated chips had higher tensile- and tear indices, elongation and light scattering and lower freeness compared to pulps from untreated chips produced with the same total specific energy consumption. The total specific energy needed to reach a tensile index of 47 Nm/g was reduced by 120 kWh/bone dry ton (6%) with Impressafiner pre-treatment. A smaller refiner plate gap was needed to reach the same specific energy consumption for pre-treated chips compared to untreated chips.

scholarly journals Comparison of Nanofiltration with Reverse Osmosis in Reclaiming Tertiary Treated Municipal Wastewater for Irrigation Purposes

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 32
Author(s):  
MhdAmmar Hafiz ◽  
Alaa H. Hawari ◽  
Radwan Alfahel ◽  
Mohammad K. Hassan ◽  
Ali Altaee
Keyword(s):  
Energy Consumption ◽  
Reverse Osmosis ◽  
Specific Energy ◽  
Recovery Rate ◽  
Municipal Wastewater ◽  
Water Flux ◽  
Applied Pressure ◽  
Specific Energy Consumption ◽  
Water Recovery ◽  
Food And Agriculture

This study compares the performance of nanofiltration (NF) and reverse osmosis (RO) for the reclamation of ultrafiltered municipal wastewater for irrigation of food crops. RO and NF technologies were evaluated at different applied pressures; the performance of each technology was evaluated in terms of water flux, recovery rate, specific energy consumption and quality of permeate. It was found that the permeate from the reverse osmosis (RO) process complied with Food and Agriculture Organization (FAO) standards at pressures applied between 10 and 18 bar. At an applied pressure of 20 bar, the permeate quality did not comply with irrigation water standards in terms of chloride, sodium and calcium concentration. It was found that nanofiltration process was not suitable for the reclamation of wastewater as the concentration of chloride, sodium and calcium exceeded the allowable limits at all applied pressures. In the reverse osmosis process, the highest recovery rate was 36%, which was achieved at a pressure of 16 bar. The specific energy consumption at this applied pressure was 0.56 kWh/m3. The lowest specific energy of 0.46 kWh/m3 was achieved at an applied pressure of 12 bar with a water recovery rate of 32.7%.

scholarly journals INCREASING THE EFFICIENCY OF THE SYSTEMS OF COMPRESSOR-PUMPING AND REFRIGERATION UNITS SUPPLYING LIQUID CO2 AND NH3 TO THE UNIT FOR CARBAMIDE SYNTHESIS

2021 ◽  
pp. 23-32
Author(s):  
G.K. Lavrenchenko ◽  
B.H. Hrudka
Keyword(s):  
Carbon Dioxide ◽  
Energy Consumption ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Stable Operation ◽  
Urea Synthesis ◽  
Daily Production ◽  
Additional Absorption ◽  
Liquid Co2 ◽  
Refrigeration Machine

Carbon dioxide is used in large volumes to produce urea, a highly efficient nitrogen fertilizer. It is compressed in a multistage compressor to a pressure of 15 MPa and fed to the urea synthesis unit. The specific energy consumption for the compression of carbon dioxide by a compressor reaches 0.16 kWh/kg. It may be more profitable to use in the system of compressor-pumping and refrigeration units. They can be used to liquefy carbon dioxide and compress it to pressure 15 MPa before feeding it to the synthesis of urea. In the simplest scheme, an ammonia compression refrigeration machine (ACRM) is included in the system to improve efficiency. The specific energy consumption in such a system for the liquefaction and compression of CO2 is 0.118 kWh/kg. In case of replacement of the ACRM with an absorption refrigeration machine, unit costs can be reduced to 0.09 kWh/kg. These two systems can be used to increase urea production or to ensure stable operation of the units during the summer period of their operation. The analysis showed that further improvement of the technological scheme of the entire system will completely abandon the use of the compressor method of compression of CO2 to pressure 15 MPa before its supply to the urea synthesis unit. To do this, you need to include an additional absorption lithium bromide refrigeration machine in the system. In this scheme, the compressor-pumping unit will provide the simultaneous supply of liquid carbon dioxide and ammonia for the synthesis of urea with a pressure of 15 MPa. To increase the daily production of urea from 1400 to 2000 tons, it is necessary to increase the feed liquid CO2 in the amount of 62 t/hour and liquid NH3 — 47.5 t/hour. Bibl. 14, Fig. 3.

scholarly journals Specific energy consumption of vacuum filtration: Experimental evaluation using a pilot-scale horizontal belt filter

2019 ◽  
Vol 38 (4) ◽  
pp. 460-475 ◽  
Author(s):  
Manu Huttunen ◽  
Lauri Nygren ◽  
Teemu Kinnarinen ◽  
Bjarne Ekberg ◽  
Tuomo Lindh ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Experimental Evaluation ◽  
Specific Energy Consumption ◽  
Pilot Scale ◽  
Vacuum Filtration

Alternate anoxic/aerobic operation for nitrogen removal in a membrane bioreactor for municipal wastewater treatment

2011 ◽  
Vol 64 (8) ◽  
pp. 1730-1735 ◽  
Author(s):  
G. Guglielmi ◽  
G. Andreottola
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Municipal Wastewater Treatment ◽  
Biological Phosphorus Removal ◽  
The Impact

A large pilot-scale membrane bioreactor (MBR) with a conventional denitrification/nitrification scheme for municipal wastewater treatment has been run for one year under two different aeration strategies in the oxidation/nitrification compartment. During the first five months air supply was provided according to the dissolved-oxygen set-point and the system run as a conventional pre-denitrification MBR; then, an intermittent aeration strategy based on effluent ammonia nitrogen was adopted in the aerobic compartment in order to assess the impact on process performances in terms of N and P removal, energy consumption and sludge reduction. The experimental inferences show a significant improvement of the effluent quality as COD and total nitrogen, both due to a better utilization of the denitrification potential which is a function of the available electron donor (biodegradable COD) and electron acceptor (nitric nitrogen); particularly, nitrogen removal increased from 67% to 75%. At the same time, a more effective biological phosphorus removal was observed as a consequence of better selection of denitrifying phosphorus accumulating organisms (dPAO). The longer duration of anoxic phases also reflected in a lower excess sludge production (12% decrease) compared with the standard pre-denitrification operation and in a decrease of energy consumption for oxygen supply (about 50%).

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