Removal and recovery of phosphate and ammonium as struvite from supernatant in anaerobic digestion

2003 ◽  
Vol 48 (1) ◽  
pp. 171-178 ◽  
Author(s):  
M. Yoshino ◽  
M. Yao ◽  
H. Tsuno ◽  
I. Somiya
Keyword(s):  
Draft Tube ◽  
Molar Ratio ◽  
Design Parameters ◽  
Phosphorus Concentration ◽  
Tube Reactor ◽  
Basic Reaction ◽  
Efficiency Estimation ◽  
Tube Type ◽  
Near Future ◽  
Removal And Recovery

Removal of phosphorus and nitrogen is required to prevent eutrophication problems in lakes and enclosed coastal seas. And recovery of phosphorus from wastewater has been attracting attention because of lack in phosphorus resources in the near future. In this study, reaction kinetics and design parameters of struvite production are experimentally investigated by using basic reaction type and a draft-tube type reactors. Struvite production rate, which is a very important parameter in reactor design and efficiency estimation, is formulated in an equation consisting of a rate constant (k2), and magnesium, phosphate and ammonium concentrations. The value of k2 is shown to be increased with struvite concentration and mixing intensity in the reactor. The developed equation is applied to the results obtained from the draft-tube type reactor experiments and verified for its applicability. High struvite concentration of 10-25% is maintained in the draft-tube reactor experiments. 92% removal and recovery efficiency with effluent phosphorus concentration of 17 mg/L is achieved under the conditions of 4 minutes reaction time, pH of 8.5 and Mg/P molar ratio of 1.1.

Effect of draft tube diameter on nitrogen removal from domestic sewage in a draft tube type reactor

1998 ◽  
Vol 38 (1) ◽  
pp. 319-326
Author(s):  
Taku Fujiwara ◽  
Iso Somiya ◽  
Hiroshi Tsuno ◽  
Yoshio Okuno
Keyword(s):  
Flow Rate ◽  
Nitrogen Removal ◽  
Draft Tube ◽  
Domestic Sewage ◽  
Tube Diameter ◽  
Continuous Treatment ◽  
Anoxic Zone ◽  
Type Reactor ◽  
Tube Type ◽  
Volumetric Loading

The effect of the ratio of draft tube diameter to reactor diameter (Di/Do) on the efficiency of nitrogen removal from domestic sewage is discussed based on liquid-circulating flow rate and continuous treatment data. More than 2.5 minutes of circulation time in the annulus part, which is required to create an anoxic zone, could be maintained under operating conditions in which air flow rate per reactor volume was 2 m3/(m3 · hr) and Di/Do was 0.19. When Di/Do was set at 0.19, the average total organic carbon (TOC), total nitrogen (TN) and dissolved nitrogen (DN) removal efficiencies were 83.2%, 72.1% and 71.6%, respectively, which were higher than those when Di/Do was at 0.26 or 0.36. From these results, it is concluded that 0.19 is the best Di/Do for nitrogen removal in a draft-tube type reactor with an effective depth of 4.0m under the treatment condition in which the BOD volumetric loading rate is in the range 0.22 to 0.46 kgBOD/(m3 · day). More than 80% nitrification and denitrification efficiencies can be achieved simultaneously when both conditions, the aerobic zone ratio being more than 0.2, and the anoxic zone ratio being more than 0.3, are satisfied.

scholarly journals Research on the Computed Tomography Pebble Flow Detecting System for HTR-PM

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Xin Wan ◽  
Ximing Liu ◽  
Jichen Miao ◽  
Peng Cong ◽  
Yuai Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Helical Ct ◽  
Design Parameters ◽  
Three Dimensional Model ◽  
Safe Operation ◽  
Cross Sectional ◽  
Ct System ◽  
Near Future ◽  
Pebble Flow

Pebble dynamics is important for the safe operation of pebble-bed high temperature gas-cooled reactors and is a complicated problem of great concern. To investigate it more authentically, a computed tomography pebble flow detecting (CT-PFD) system has been constructed, in which a three-dimensional model is simulated according to the ratio of 1 : 5 with the core of HTR-PM. A multislice helical CT is utilized to acquire the reconstructed cross-sectional images of simulated pebbles, among which special tracer pebbles are designed to indicate pebble flow. Tracer pebbles can be recognized from many other background pebbles because of their heavy kernels that can be resolved in CT images. The detecting principle and design parameters of the system were demonstrated by a verification experiment on an existing CT system in this paper. Algorithms to automatically locate the three-dimensional coordinates of tracer pebbles and to rebuild the trajectory of each tracer pebble were presented and verified. The proposed pebble-detecting and tracking technique described in this paper will be implemented in the near future.

Hydrolysis of palm stearin oil by a thermostable lipase in a draft tube-type reactor

1995 ◽  
Vol 80 (4) ◽  
pp. 340-345 ◽  
Author(s):  
Masanobu Tanigaki ◽  
Masaru Sakata ◽  
Hitoshi Takaya ◽  
Koji Mimura
Keyword(s):  
Draft Tube ◽  
Palm Stearin ◽  
Thermostable Lipase ◽  
Type Reactor ◽  
Tube Type ◽  
Hydrolysis Of

Investigation of chemical-free nutrient removal and recovery from CO2-rich wastewater

2013 ◽  
Vol 67 (10) ◽  
pp. 2195-2201 ◽  
Author(s):  
Elsie M. Jordaan ◽  
Babak Rezania ◽  
Nazim Çiçek
Keyword(s):  
Extended Period ◽  
Reactor System ◽  
Molar Ratio ◽  
Reactor Operation ◽  
Ph Increase ◽  
Major Adjustment ◽  
Recycle Rate ◽  
Removal And Recovery ◽  
P Removal

The feasibility of a bench-scale system for removal and recovery of phosphorus (P) as struvite from CO2-rich wastewater was tested. A continuous 12 L reactor system combining a fluidized seedbed and aeration for pH increase was developed and tested using synthetic feed. For a 100 mL min−1 influent rate, an aeration and recycle rate combination of 7 L min−1 and 700 mL min−1 was sufficient for increasing and maintaining the reactor pH from 6.7 to between 7.6 and 8.0. Significant P removal was achieved in 6 h runs without a seedbed (91–92%), while neither the struvite nor sand seedbeds improved P removal (91–96%). Struvite was recovered in all runs, with additional calcium (Ca) precipitation in the seedbed runs. Reactor operation was possible for an extended period of time, up to 46 h without any major adjustment during long-term run. The average P removal was 88%, and precipitate collected after 24 h was found to be mainly struvite, while the final precipitate had a Ca: total phosphorus molar ratio of 0.56 and also contained calcite. This study has demonstrated the technical feasibility of an aerated crystallization reactor system for chemical-free struvite removal and recovery from CO2-rich wastewater such as stored livestock manure.

scholarly journals Closing the cycle: phosphorus removal and recovery from diluted e?uents using acid resistive membranes

2019 ◽  
Author(s):  
Matthias Wessling
Keyword(s):  
Calcium Phosphate ◽  
Phosphorus Removal ◽  
Acid Resistance ◽  
Phosphorus Recovery ◽  
Treated Wastewater ◽  
Phosphorus Concentration ◽  
Phosphorus Cycle ◽  
Permeate Flux ◽  
New Approach ◽  
Removal And Recovery

New regulations in many developed countries call for significant reduction in phosphorus concentration for effluents released to the environment. At the same time, recovery of phosphorus – a non-renewable resource used mainly as fertilizer – from anthropogenic waste is extensively studied and bolstered as a crucial component in maintaining future food security. Thus far, studies on phosphorus recovery mainly focused on concentrated streams; although diluted effluents such as treated wastewater often contain a significant portion of the phosphorus mass. Here we propose a new approach for the simultaneous removal and recovery of phosphorus from diluted effluents using a membrane characterized by high phosphate rejection and acid resistance. High P rejection allows for the concentration of phosphorus in the retentate until recoverable calcium-phosphate precipitants are formed, while acid resistance enables a simple and effective chemical cleaning of the membrane. Factors affecting the removal and recovery of phosphorus during filtration are studied here experimentally and through thermochemical modeling. CaCO3 precipitation in the retentate resulted in severe scaling, whereas calcium-phosphate precipitated mostly in the bulk, resulting in colloidal fouling which was manageable by maintaining sub-critical permeate flux. Selective Ca-P precipitation is feasible via pH adjustments, requiring very little acid addition as shown through thermochemical modeling. Calcium-phosphate deposits were easily removed from the feed channel using acid-cleaning, and the permeate flux was completely restored. Furthermore, phosphorus removal and recovery by nanofiltration was shown to require less operating expenses compared to a more conventional approach comprising P removal by ferric chloride addition and its subsequent recovery from incinerated sludge. Our results therefore demonstrate the potential of this new approach as a step forward towards closing the anthropogenic phosphorus cycle.

scholarly journals Analysis of design features based on the application of modular elements of maximum readiness

2021 ◽  
Vol 11 (2) ◽  
pp. 65-77
Author(s):  
Angelina O. Rybakova ◽  
Keyword(s):  
Life Cycle ◽  
Modular Design ◽  
Modular System ◽  
Design Parameters ◽  
Model Parameters ◽  
Modular Construction ◽  
Industrial Construction ◽  
Advantages And Disadvantages ◽  
Principles Of Design ◽  
Near Future

Introduction. In the middle of the 20th century, technological progress made it possible to enlarge the building elements of buildings as much as possible, which led to the development of new industrial construction systems and increased production rates. However, to date, the issue has not been completely resolved and remains relevant. Modular construction is not sufficiently widely spread today, but many design experts predict its widespread introduction in the near future. The factor that decelerates the development of modular construction is the lack of theoretical foundations in the field of modular design, as well as significant differences from traditional design approach. Materials and methods. The purpose of this work is to develop the theoretical fundamentals of modular design based on the study of regulatory documents, Russian and foreign sources of research works, as well as the implemented projects. The task is to determine the fundamental features of modular elements of maximum readiness: principles of modular design, parameters of a modular element, advantages and disadvantages of a modular system, features of the design processes. Results. The theoretical basis of modular design includes basic concepts, principles and features; the conceptual design process is described using the case of development of an information model; parameters of modular elements of maximum readiness are presented, and the influence of modular items on the life cycle of a construction facility is analyzed. Conclusions. The presented system of principles of design based on modular elements of maximum readiness and parameters of modular elements allow us to systematize the established theoretical aspects of modularity, which make it possible to make modular buildings. The author formulates a new approach to design, which affects the entire life cycle and serves as the basis for new areas of engineering activities and scientific research.

Biodiesel Production from Kapok (Ceiba pentandra) Seed Oil using Naturally Alkaline Catalyst as an Effort of Green Energy and Technology

2013 ◽  
Vol 2 (3) ◽  
pp. 169-173 ◽  
Author(s):  
N.A. Handayani ◽  
H. Santosa ◽  
M. Sofyan ◽  
I. Tanjung ◽  
A. Chyntia ◽  
...  
Keyword(s):  
Seed Oil ◽  
Green Energy ◽  
Green Technology ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Alkaline Catalyst ◽  
Biodiesel Feedstock ◽  
Presidential Decree ◽  
Near Future

Nowadays, energy that used to serve all the needs of community, mainly generated from fossil (conventional energy). Terrace in energy consumption is not balanced with adequate fossil fuel reserves and will be totally depleted in the near future. Indonesian Government through a Presidential Decree No. 5 year 2006 mandates an increased capacity in renewable energy production from 5 percent to 15 percent in 2025. C. pentandra seed oil has feasibility as a sustainable biodiesel feedstock in Indonesia. The aim of this paper was to investigate biodiesel production from ceiba petandra seed oil using naturally potassium hydroxide catalyst. Research designs are based on factorial design with 2 levels and 3 independent variables (temperature, reaction time and molar ratio of methanol to oil). According to data calculation, the most influential single variable is molar ratio of methanol to oil. Characterization of biodiesel products meet all the qualifications standardized by SNI 04-7182-2006. Keywords: biodiesel, kapok seed oil, c. pentandra, green technology

Effect of liquid circulation in the draft-tube reactor on precipitation of calcium carbonate via carbonation

2009 ◽  
Vol 190 (3) ◽  
pp. 319-323 ◽  
Author(s):  
Donata Konopacka-Łyskawa ◽  
Zbigniew Cisiak ◽  
Bożenna Kawalec-Pietrenko
Keyword(s):  
Calcium Carbonate ◽  
Draft Tube ◽  
Liquid Circulation ◽  
Tube Reactor
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