Process design for nitrogen removal using nitrifying biofilm and denitrifying suspended growth in a biofilm airlift suspension reactor

1997 ◽  
Vol 36 (1) ◽  
pp. 119-128 ◽  
Author(s):  
W. A. J. van Benthum ◽  
M. C. M. van Loosdrecht ◽  
J. J. Heijnen
Keyword(s):  
Nitrogen Removal ◽  
Process Design ◽  
Oxygen Depletion ◽  
Liquid Oxygen ◽  
Biofilm Growth ◽  
Reactor Configuration ◽  
Suspended Growth ◽  
Nitrogen Concentrations ◽  
Pre Treatment ◽  
Set Up

Operation of a Biofilm Airlift Suspension (BAS) reactor was possible with nitrifying biofilm growth and heterotrophic suspended growth, simultaneously converting ammonium and acetate. Control of the location of heterotrophic growth, either in suspension or in layers over the nitrifying biofilms, was established by manipulation of the hydraulic retention time. Two process configurations (based on the BAS reactor) are identified, for nitrogen removal from wastewater by integration of nitrification in biofilms and denitrification in suspension. The first set-up consists of a conventional nitrifying BAS reactor, coupled with a suspended biomass reactor (without biomass retention). The second process configuration is a single BAS reactor which is sequentially aerated and non-aerated, by cyclically recirculating the offgas. Process design schemes for these configurations are presented and the design aspects are evaluated. Three limiting processes are identified: gas-liquid oxygen transfer, the hydraulic capacity of the settler and the minimal time needed for oxygen depletion of the gas phase during offgas recirculation. It was found that the two-reactor configuration is mainly suitable for pre-treatment of concentrated ammonia containing wastewaters. The one-reactor configuration can be applied to obtain low nitrogen concentrations in the effluent.

Nitrogen removal using nitrifying biofilm growth and denitrifying suspended growth in a biofilm airlift suspension reactor coupled with a chemostat

1998 ◽  
Vol 32 (7) ◽  
pp. 2009-2018 ◽  
Author(s):  
W.A.J. van Benthum ◽  
B.P. Derissen ◽  
M.C.M. van Loosdrecht ◽  
J.J. Heijnen
Keyword(s):  
Nitrogen Removal ◽  
Biofilm Growth ◽  
Suspended Growth

Performance of fixed film media integrated in activated sludge reactors to enhance nitrogen removal

1994 ◽  
Vol 30 (11) ◽  
pp. 13-24 ◽  
Author(s):  
Dipankar Sen ◽  
Pramod Mitta ◽  
Clifford W. Randall
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Biofilm Growth ◽  
Ammonium N ◽  
Suspended Growth ◽  
Fixed Film ◽  
The Media ◽  
Aerobic Zone ◽  
Sponge Media ◽  
Aerobic Cell

Nitrification and denitrification were evaluated in multiple CSTR continuous flow fixed film systems at 12°C. Three systems were operated with three types of media installations and a fourth as a control without media. The media configurations evaluated included: (i) frame mounted fine pore sponge media supported on wires; (ii) free floating fine pore sponge media; and (iii) fixed location frame mounted rope media (ringlace). The pore size for sponge media was 14 pores per centimeter. Each system included a two-cell anaerobic zone with 17 percent of total volume, two-cell anoxic zone with 17 percent of total volume, and a three-cell aerobic zone with 64 percent of total volume. The multi-cell configuration was used to maximize kinetics of removal with suspended growth biomass and evaluate improvements in nitrogen removal beyond the levels achieved with suspended growth. At the optimum location (aerobic cells 1 and 2), the nitrification in cells containing free-floating sponges was 143 percent of the control at aerobic MCRTs of 3.1 and 3.4 days, with 35 percent media volume to cell volume. The nitrification with rope media was 136 percent of the control in middle third of the aerobic zone. Removals with ringlace were poorer in the first aerobic cell operating at higher COD levels, and in the third aerobic cell which did not contain sufficient biofilm growth at low levels of COD. Nitrification was 14 percent higher in Systems 1 and 2 with fixed and free floating sponges, respectively, and 8 percent higher in System 3 (ringlace) when all systems were spiked with 20 mg/L additional ammonium over a 24 hour period. Optimizing location of the media, with higher density of media at locations where adequate COD and ammonium-N are available for biofilm growth increase nitrification on media. Studies in full scale systems show that COD and ammonium-N concentrations at downstream locations in the activated sludge basin increase during peak flows and with step feed of wastewater. This helps increase biofilm growth and improve nitrification on the media downstream locations. Denitrification observed in the aerobic cells of the fixed film systems was in excess of the control. All aerobic cells were operated at D.O. levels in excess of 6.0 mg/L. The fraction of total denitrification under aerobic conditions was 0.0 in the control as compared to 0.14 to 0.24 with ringlace media and fixed sponge media, respectively, at an aerobic MCRT 3.1 days. Fraction aerobic denitrification in all systems increased with an increase in MCRT of suspended growth - to 0.21 in the control and 0.35 and 0.39 with ringlace and sponges, respectively, at aerobic MCRTs of 3.4 to 7.7 days.

Process design and equipment selection for optimized steam and power concepts – the “zero” process steam sugar factory

2020 ◽  
pp. 40-50
Author(s):  
Boris Morgenroth ◽  
Thomas Stark ◽  
Julian Pelster ◽  
Harjeet Singh Bola
Keyword(s):  
Process Design ◽  
Sugar Industry ◽  
Electrical Power ◽  
Power Requirement ◽  
Equipment Selection ◽  
Good Potential ◽  
Set Up ◽  
The Right ◽  
Key Aspects ◽  
Steam Drying

Optimization of process steam requirement in order to maximize sugar recovery and export power along with manpower optimization is a must for sugar factories to survive under difficult conditions and to earn additional revenues. The process steam demand of greenfield and revamped plants has been reduced to levels of 32–38% from originally more than 50% steam on cane in the case of the brownfield plants. In addition, significant improvement in the power requirement of the plants has been achieved. Bagasse drying offers a good potential to improve the power export. Different available concepts are compared with a focus on bagasse steam drying and low temperature bagasse drying. In order to set up an optimized highly efficient plant or to optimize an existing plant to achieve competitive benchmarks, good process design and the right equipment selection are very important. Experience has been gained with multiple stage or double effect crystallization in the beet sugar industry offering further steam optimization potential. Vapour recompression is also an option to substitute live steam by electrical power. This even provides options to reduce the steam demand from the power plant for the sugar process down to zero. Key aspects concerning the process design and equipment selection are described.

scholarly journals Long-term field fertilization experiment with energy willow (Salix sp.) − Elemental composition and chlorophyll fluorescence in the leaves

2018 ◽  
Vol 67 (1) ◽  
pp. 91-103
Author(s):  
László Simon ◽  
Marianna Makádi ◽  
György Vincze ◽  
Zsuzsanna Uri ◽  
Katalin Irinyiné Oláh ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Crop ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Fertilization Experiment ◽  
Nitrogen Concentrations ◽  
Set Up ◽  
Leaf Chlorophyll Fluorescence ◽  
Term Field

A small-plot long-term field fertilization experiment was set up in 2011 with willow (Salix triandra x Salix viminalis ’Inger’) grown as an energy crop in Nyíregyháza, Hungary. The brown forest soil was treated three times (in June 2011, May 2013, May 2016) with municipal biocompost (MBC), municipal sewage sludge compost (MSSC) or willow ash (WA), and twice (June 2011, May 2013) with rhyolite tuff (RT). In late May – early June 2016 urea (U) and sulphuric urea (SU) fertilizers were also applied to the soil as top-dressing (TD). These fertilizers and amendments were also applied to the soil in 2016 in the combinations; MBC+SU, RT+SU, WA+SU and MSSC+WA. All the treatments were repeated four times. In July 2016 the highest nitrogen concentrations in willow leaves were measured in the U (3.47 m/m%) and SU (3.01 m/m%) treatments, and these values were significantly higher than the control (2.46 m/m%). An excess of nitrogen considerably reduced the Zn uptake of the leaves, with values of 39.5 μg g-1 in the U treatment, 53.4 μg g-1 in the SU treatment, and 63.5 μg g-1 in the control. All other amendments or TDs, except for WA, enhanced the specific potassium concentrations in willow leaves compared to the control. No significant quantities of toxic elements (As, Ba, Cd, Pb) were transported from soil amendments or TDs to the willow leaves. In July 2016 the most intensive leaf chlorophyll fluorescence was observed in the MSSC and MSSC+WA treatments.

scholarly journals UVA-LED Technology’s Treatment Efficiency and Cost in a Competitive Trial Applied to the Photo-Fenton Treatment of Landfill Leachate

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1026
Author(s):  
Javier Tejera ◽  
Antonio Gascó ◽  
Daphne Hermosilla ◽  
Víctor Alonso-Gomez ◽  
Carlos Negro ◽  
...  
Keyword(s):  
Landfill Leachate ◽  
Mercury Vapor ◽  
Cod Removal ◽  
Treatment Efficiency ◽  
Alternative Source ◽  
Effluent Quality ◽  
Radiation Sources ◽  
Initial Ph ◽  
Pre Treatment ◽  
Set Up

The objective of this trial was to assess the application of UVA-LED technology as an alternative source of irradiation for photo-Fenton processes, aiming to reduce treatment costs and provide a feasible treatment for landfill leachate. An optimized combination of coagulation with ferric chloride followed by photo-Fenton treatment of landfill leachate was optimized. Three different radiation sources were tested, namely, two conventional high-pressure mercury-vapor immersion lamps (100 W and 450 W) and a custom-designed 8 W 365 nm UVA-LED lamp. The proposed treatment combination resulted in very efficient degradation of landfill leachate (COD removal = 90%). The coagulation pre-treatment removed about 70% of the COD and provided the necessary amount of iron for the subsequent photo-Fenton treatment, and it further favored this process by acidifying the solution to an optimum initial pH of 2.8. The 90% removal of color improved the penetration of radiation into the medium and by extension improved treatment efficiency. The faster the Fenton reactions were, as determined by the stoichiometric optimum set-up reaction condition of [H2O2]0/COD0 = 2.125, the better were the treatment results in terms of COD removal and biodegradability enhancement because the chances to scavenge oxidant agents were limited. The 100 W lamp was the least efficient one in terms of final effluent quality and operational cost figures. UVA-LED technology, assessed as the application of an 8 W 365 nm lamp, provided competitive results in terms of COD removal, biodegradability enhancement, and operational costs (35–55%) when compared to the performance of the 450 W conventional lamp.

Studies on the use of cultured cells in a bioassay for parathyroid hormone

1994 ◽  
Vol 143 (2) ◽  
pp. 261-268
Author(s):  
A E Armston ◽  
P J Wood
Keyword(s):  
Parathyroid Hormone ◽  
Cyclic Amp ◽  
Cell Line ◽  
Cultured Cells ◽  
Biologically Active ◽  
Kidney Cell Line ◽  
Opossum Kidney ◽  
Pre Treatment ◽  
Set Up ◽  
Insufficient Sensitivity

Abstract Measurement of parathyroid hormone (PTH) is important for diagnosing hyper- and hypoparathyroidism. The move to two-site immunometric assays that detect the whole molecule has improved the discrimination of these conditions but these assays may be too restrictive because some PTH fragments that are biologically active may not be detected. In addition, PTH-like peptide of malignancy, an important cause of malignancy-associated hypercalcaemia, is not detected by the two-site assays. Experiments were performed to set up a simple, robust and inexpensive bioassay for PTH, exploiting a kidney cell line and using cyclic AMP or an eluted stain assay as the end point. Of the 12 cell lines tested, an opossum kidney (WOK) cell line showed the most promise. Despite optimization of the procedure to include pre-treatment with dexamethasone, insulin and PTH, followed by incubation in the presence of 5′ -guanylimidodiphosphate, isobutyl-1-methylxanthine and forskolin, the WOK cells showed insufficient sensitivity for use in a cultured cell bioassay for PTH in human serum. In addition, the cells were less sensitive to PTH-like peptide precluding their use for an assay for this molecule. Journal of Endocrinology (1994) 143, 261–268

scholarly journals Practical guidance in the use of image-guided radiotherapy systems

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
A. Pastorino ◽  
L. Todisco ◽  
E. Cazzulo ◽  
L. Berretta ◽  
A. Orecchia ◽  
...  
Keyword(s):  
Electronic System ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
Pre Treatment ◽  
Portal Images ◽  
Set Up ◽  
Geographic Miss ◽  
Technical Solutions ◽  
Modern Image ◽  
Delivered Dose

From mega-voltage portal images acquired on an electronic system (EPID), technological research has developed 3D and recently 4D volumetric verification modalities, allowing a direct visualization of the target, a direct comparison with the planning-TC and an optimization of the treatment (reduction of set-up errors, verification of the need for re-planning), leading to the very modern Image Guided RadioTherapy (IGRT). IGRT allows different technical solutions through direct or indirect visualization of the tumor and the acquisition of pre-treatment verification images, allowing to identify, quantify and correct errors related to set-up and organ-tumor motion, obtaining a greater compliance of the delivered dose, decreasing the risk of "geographic miss" and toxicity to healthy tissues and reducing the margins from CTV to PTV for the implementation of "dose escalation" protocols.

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