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.

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.

Conduction Roaster for Accelerated Roasting of Peanut

2021 ◽  
Vol 58 (02) ◽  
pp. 112-123
Author(s):  
Rakesh Kumar Raigar ◽  
Hari Niwas Mishra
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Rotational Speed ◽  
Specific Energy Consumption ◽  
Quality Parameters ◽  
Operating Conditions ◽  
Moisture Loss ◽  
Optimum Operating ◽  
Small Scale ◽  
Roasting Temperature

Roasting is one of the thermo-mechanical operation in cereals and oilseeds processing. Low-capacity machine for mechanisation of roasting is necessary for small-scale processing. A conduction-type motorised rotary roaster (8 kg per batch) was designed and developed for roasting of peanuts. Performance of the roaster was evaluated in terms of moisture loss, scorched kernels, and specific energy consumption for accelerated roasting of peanut. The effects of different roasting conditions were studied to determine the optimum operating conditions of the roaster. Quality indices of peanuts as moisture loss (kg.kg-1), scorched kernel (%), and specific energy consumption (kWh.kg-1) were dependent on the operating conditions. The optimum value of moisture loss (0.041± 0.003 kg.kg-1), scorched kernel (0.93± 0.0.004 % ), and specific energy consumption (0.185 ± 0.005 kWh.kg-1) were obtained at roasting temperature of 170°C, roasting time of 15 min, and rotational speed of 20 rpm for roasting peanut. The roasting characteristics of peanut decreased linearly with increase in the temperature and time; and decrease in the rotational speed. The inferior quality parameters were observed at higher temperatures, speed and medium time of roasting. The study indicated optimum roasting temperature of peanut to be 170°C, and further increase in the process temperature had undesirable effects on roasted peanut quality due to high loss of moisture.

scholarly journals Improving and upgrading an existing activated sludge with a compact MBBR – disc filters parallel line for municipal wastewater treatment in touristic alpine areas

2020 ◽  
Vol 15 (2) ◽  
pp. 515-527
Author(s):  
L. Desa ◽  
P. Kängsepp ◽  
L. Quadri ◽  
G. Bellotti ◽  
K. Sørensen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Parallel Line ◽  
Ammonium Nitrogen ◽  
Biofilm Reactor ◽  
Municipal Wastewater Treatment ◽  
Yearly Average

Abstract Many wastewater treatment plants (WWTP) in touristic areas struggle to achieve the effluent requirements due to seasonal variations in population. In alpine areas, the climate also determines a low wastewater temperature, which implies long sludge retention time (SRT) needed for the growth of nitrifying biomass in conventional activated sludge (CAS). Moreover, combined sewers generate high flow and dilution. The present study shows how the treatment efficiency of an existing CAS plant with tertiary treatment can be upgraded by adding a compact line in parallel, consisting of a Moving Bed Biofilm Reactor (MBBR)-coagulation-flocculation-disc filtration. This allows the treatment of influent variations in the MBBR and a constant flow supply to the activated sludge. The performance of the new 2-step process was comparable to that of the improved existing one. Regardless significant variations in flow (10,000–25,000 m3/d) and total suspended solids (TSS) (50–300 mg/L after primary treatment) the effluent quality fulfilled the discharge requirements. Based on yearly average effluent data, TSS were 11 mg/L, chemical oxygen demand (COD) 27 mg/L and total phosphorus (TP) 0.8 mg/L. After the upgrade, ammonium nitrogen (NH4-N) dropped from 4.9 mg/L to 1.3 mg/L and the chemical consumption for phosphorus removal was reduced.

scholarly journals Initiating Biodegradation of Polyvinylpyrrolidone in an Aqueous Aerobic Environment: Technical Note / Zainicjowanie Biodegradacji Poliwinylopirolidonu W Środowisku Wodno-Tlenowym: Notatki Techniczne

2013 ◽  
Vol 20 (1) ◽  
pp. 199-208 ◽  
Author(s):  
Marketa Julinova ◽  
Jan Kupec ◽  
Roman Slavik ◽  
Maria Vaskova
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Waste Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Technical Note ◽  
Aerobic Biodegradation ◽  
Municipal Wastewater Treatment

Abstract A synthetic polymer, polyvinylpyrrolidone (PVP - E 1201) primarily finds applications in the pharmaceutical and food industries due to its resistance and zero toxicity to organisms. After ingestion, the substance passes through the organism unchanged. Consequently, it enters the systems of municipal wastewater treatment plants (WWTP) without decomposing biologically during the waste treatment process, nor does it attach (through sorption) to particles of activated sludge to any significant extent, therefore, it passes through the system of a WWTP, which may cause the substance to accumulate in the natural environment. For this reason the paper investigates the potential to initiate aerobic biodegradation of PVP in the presence of activated sludge from a municipal wastewater treatment plant. The following agents were selected as the initiators of the biodegradation process - co-substrates: acrylamide, N-acethylphenylalanine and 1-methyl-2-pyrrolidone, a substance with a similar structure to PVP monomer. The biodegradability of PVP in the presence of co-substrates was evaluated on the basis of biological oxygen demand (BOD) as determined via a MicroOxymax O2/CO2/CH4 respirometer. The total substrate concentration in the suspension equaled 400 mg·dm-3, with the ratio between PVP and the cosubstrate being 1:1, while the concentration of the dry activated sludge was 500 mg·dm-3. Even though there was no occurrence of a significant increase in the biodegradation of PVP alone in the presence of a co-substrate, acrylamide appeared to be the most effective type of co-substrate. Nevertheless, a recorded decrease in the slope of biodegradation curves over time may indicate that a process of primary decomposition was underway, which involves the production of metabolites that inhibit activated sludge microorganisms. The resulting products are not identified at this stage of experimentation.

Removal of hazardous substances in municipal wastewater treatment plants

2020 ◽  
Vol 81 (9) ◽  
pp. 2011-2022
Author(s):  
Vallo Kõrgmaa ◽  
Mailis Laht ◽  
Riin Rebane ◽  
Erki Lember ◽  
Karin Pachel ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Aquatic Environment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Hazardous Substances ◽  
Chemical Pollution ◽  
P Value ◽  
Municipal Wastewater Treatment ◽  
Municipal Wastewater Treatment Plants

Abstract Chemical pollution poses a threat to the aquatic environment and to human health. Wastewater treatment plants are the last defensive line between the aquatic environment and emissions of pollutants. This study focuses on identification of most relevant hazardous substances in Estonian municipal wastewater and their fate in the treatment process. During this study, seasonal wastewater and sewage sludge samples were collected from nine municipal wastewater treatment plants and analyzed for 282 hazardous substances, including EU (n = 45) and Estonian (n = 31) priority substances. Results of this study show that several substances that are subject to international restrictions (e.g. Stockholm Convention) are still present in untreated sewage. Wastewater treatment systems that had a greater level of complexity (TEC >5) were more successful in removing hazardous substances. Statistical analyses showed that removal efficiency of organic hazardous substances had significant (p-value <0.05) linear correlation with removal efficiencies of chemical oxygen demand (COD) and total suspended solids (TSS), but a monotonic relationship with operators' competency. This study showed that operators' competency had a strong influence on the stability of the wastewater treatment efficiency and removal of organic hazardous substances.

scholarly journals Electrocoagulation for spent coolant from machinery industry

2017 ◽  
Vol 8 (4) ◽  
pp. 497-506 ◽  
Author(s):  
W. Pantorlawn ◽  
T. Threrujirapapong ◽  
W. Khanitchaidecha ◽  
D. Channei ◽  
A. Nakaruk
Keyword(s):  
Energy Consumption ◽  
Current Density ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Industrial Wastes ◽  
Electrolysis Time ◽  
Current Densities ◽  
Sludge Production

Abstract Spent coolant is considered as one of the most polluting industrial wastes and causes environmental problems. It mostly contains high non-biodegradable organic carbon and oil contents; the biodegradability index was very low at 0.04, which is difficult to be effectively treated by common treatment systems. Electrocoagulation (EC) was proposed for a pre-treatment of coolant. The laboratory-scale of EC reactor was developed with Al electrodes and 10 mm of interelectrodes. The efficiency of the EC reactor on chemical oxygen demand (COD) removal was investigated at various current densities and electrolysis times. The highest current density of 50 mA/cm2 induced a short electrolysis time of 10 min to reach the steady state of approximately 65% COD removal. When lower current densities of 20–40 mA/cm2 were supplied to the EC reactor, COD removal efficiency of 65% can be achieved at longer electrolysis times. According to the specific energy consumption and sludge production, the optimal condition for spent coolant treatment was the current density of 20 mA/cm2 and electrolysis time of 30 min in which a COD removal of efficiency of 68% was obtained, 0.88 kWh/kg-COD of the specific energy consumption and 0.04 kg/kg-COD of the sludge production.

Carbon recovery from screenings for energy-efficient wastewater treatment

2017 ◽  
Vol 76 (12) ◽  
pp. 3299-3306
Author(s):  
M. Kaless ◽  
L. Palmowski ◽  
J. Pinnekamp
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Energy Content ◽  
Oxygen Demand ◽  
Weighted Average ◽  
Chemical Energy ◽  
Municipal Wastewater Treatment ◽  
Wastewater Treatment Process ◽  
Washing Water

Abstract The energy content of screenings from six municipal wastewater treatment plants (WWTPs) was examined. Hourly samples of separated screenings were taken over 24 hours at three of the plants to illustrate diurnal variations. To recover the chemical energy, which usually leaves the WWTP with the screenings, a screenings wash press was used to transfer organic matter from the solid into the liquid phase. The chemical energy of raw and compacted washed screenings as well as the chemical energy of washing water were determined by measuring the chemical oxygen demand (COD) for the six WWTPs. A mass weighted average of 1.35 gCOD/gdm (dm: dry matter) was found in the raw screenings of three WWTPs. The overall recovered energy from screenings was found to range from 0.27 to 0.62 gCOD/gdm. This washed-out COD found in the washing water could be sent for anaerobic digestion or to the wastewater treatment process as a carbon source for denitrification.

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