scholarly journals Model assisted identification of N2O mitigation strategies for full-scale reject water treatment plants

2021 ◽  
Author(s):  
M. Beier ◽  
I. Feldkämper ◽  
A. Freyschmidt
Keyword(s):  
Water Treatment ◽  
High Strength ◽  
Full Scale ◽  
Mitigation Strategies ◽  
N2o Emissions ◽  
N2o Formation ◽  
Operational Conditions ◽  
Reject Water ◽  
Batch Tests ◽  
Measurement Campaigns

Abstract In a 3-year research project, a new approach to forecast biological N2O formation and emission at high-strength reject water treatment has been developed (ASM3/1_N2OISAH). It was calibrated by extensive batch-tests and finally evaluated by long-term measurement campaigns realized at three WWTPs with different process configurations for nitrogen removal of reject water. To enable a model application with common full-scale data, the nitritation connected supplementary processes are not depicted in the model. Instead, within the new model approach the N2O formation is linked to the NH4-N oxidation rate by defining specific formation factors [N2O-Nform/NH4-Nox], depending on three minor parameters, the concentrations of NO2 and O2 as well as the NH4 load. A comparison between the measured and the modeled N2O concentrations in the liquid and gas phase at the full-scale treatment plants prove the ability of the proposed modelling approach to represent the observed trends of N2O formation, emission and reduction using the standard parameter set of kinetics and formation factors. Thus, enabling a reliable estimation of the N2O emissions for different operational conditions. The measurements indicate that a formation of N2O by AOB cannot completely be avoided. However, a considerable reduction of the formed N2O was observed in an anoxic environment. Applying the model, operational settings and mitigation strategies can now be identified without extensive measurement campaigns. For further enhancement of the model, first results for kinetics of N2O reduction kinetics by denitrification processes were determined in laboratory-scale batch tests.

Testing and Analysis of Steel Strip Reinforcement for Pipeline External Rehabilitation

2010 ◽  
Author(s):  
David J. Miles ◽  
Tim J. M. Bond ◽  
Raymond N. Burke ◽  
Ruben van Schalkwijk
Keyword(s):  
Steel Strip ◽  
New Technology ◽  
High Strength ◽  
Full Scale ◽  
Operating Conditions ◽  
Operating Pressure ◽  
Batch Tests ◽  
Girth Welds ◽  
The Individual ◽  
Pipeline Design

A new technology for external rehabilitation of pipelines, known as XHab™, has been developed. This method involves wrapping multiple layers of ultra-high strength steel strip (UHSS) in a helical form continuously over an extended length of pipeline using a dedicated forming and wrapping machine. The reinforcement afforded by the strip can be used to bring a defective section of pipe (e.g. externally corroded or dented) back to its original allowable operating conditions, or even to increase the allowable operating pressure if the desired operating conditions exceed the original pipeline design limits. This paper describes the full scale burst testing and analysis of defective pipes which have been repaired using the XHab process. The full scale test sections are 30″ × 0.5″ API 5L X52 DSAW pipe and include the following specimens: • Bare pipe with no defects; • Bare pipe with single machined defect; • Wrapped pipe with single machined defect and designed reinforcement; • Wrapped pipe with single machined defect and insufficient reinforcement; • Wrapped pipe with interacting defect array and designed reinforcement. The above full scale burst tests are supplemented by FEA models using ABAQUS. The material models for the steel pipe, UHSS strip, defect patch material and strip adhesive are based on measured data from the batch tests and tuned against the control burst test results. The structural behavior in the individual metallic and non-metallic elements can therefore be examined more closely, particularly in the region of the defect and where the wrapped strip crosses seam and girth welds.

Dynamics of nitric oxide and nitrous oxide emission during full-scale reject water treatment

2008 ◽  
Vol 42 (3) ◽  
pp. 812-826 ◽  
Author(s):  
Marlies J. Kampschreur ◽  
Wouter R.L. van der Star ◽  
Hubert A. Wielders ◽  
Jan Willem Mulder ◽  
Mike S.M. Jetten ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Water Treatment ◽  
Full Scale ◽  
Nitrous Oxide Emission ◽  
Reject Water

Nitrous oxide formation during nitritation and nitrification of high-strength wastewater

2013 ◽  
Vol 67 (11) ◽  
pp. 2494-2502 ◽  
Author(s):  
Yvonne Schneider ◽  
Maike Beier ◽  
Karl-Heinz Rosenwinkel
Keyword(s):  
Nitrous Oxide ◽  
High Strength ◽  
Dominant Factor ◽  
Process Conditions ◽  
Stable Operation ◽  
Ammonium Oxidation ◽  
Formation Factor ◽  
N2o Formation ◽  
Operational Conditions ◽  
Oxidation Rates

The purpose of this study was to investigate the formation of nitrous oxide (N2O) in nitritation and nitrification under stable, comparable and not limiting conditions typical for treatment of high-strength wastewater. A laboratory-scale aerated chemostat was operated with reject water at different sludge retention times, achieving suppression of nitrate formation by wash-out of nitrite-oxidizing bacteria for nitritation. The N2O formation factor during stable nitritation was higher (2.90% N2O-N /NH4−-Nox) than during nitrification (0.74%). The positive correlation of N2O formation rates and ammonium oxidation rates was linear and thus did not contribute to changes of the N2O formation factor. The dominant factor for N2O formation during stable operation was high nitrite concentration, which was positively correlated with N2O formation rates. The highest formation factors were observed during a transition phase from nitrification to nitritation with unstable process conditions (4.81%) and during a short-term experiment with increased pH of 7 (10.28%). The results indicate that even with operational conditions that are regarded favourable for the process of nitritation N2O formation can be limited but not avoided.

Assessing the effects of intra-granule precipitation in a full-scale industrial anaerobic digester

2019 ◽  
Vol 79 (7) ◽  
pp. 1327-1337 ◽  
Author(s):  
H. Feldman ◽  
X. Flores-Alsina ◽  
P. Ramin ◽  
K. Kjellberg ◽  
U. Jeppsson ◽  
...  
Keyword(s):  
Energy Recovery ◽  
Granular Sludge ◽  
Full Scale ◽  
Scale Model ◽  
Ph Gradients ◽  
Operational Conditions ◽  
Reject Water ◽  
Biomass Activity ◽  
Multiple Mineral

Abstract In this paper, a multi-scale model is used to assess the multiple mineral precipitation potential in a full-scale anaerobic granular sludge system. Reactor behaviour is analysed under different operational conditions (addition/no addition of reject water from dewatering of lime-stabilized biomass) and periods of time (short/long term). Model predictions suggest that a higher contribution of reject water promotes the risk of intra-granule CaCO3 formation as a result of the increased quantity of calcium arriving with that stream combined with strong pH gradients within the biofilm. The distribution of these precipitates depends on: (i) reactor height; and (ii) granule size. The study also exposes the potential undesirable effects of the long-term addition of reject water (a decrease in energy recovery of 20% over a 100-day period), caused by loss in biomass activity (due to microbial displacement), and the reduced buffer capacity. This demonstrates how both short-term and long-term operational conditions may affect the formation of precipitates within anaerobic granules, and how it may influence methane production and consequently energy recovery.

Full-scale comparison of N2O emissions from SBR N/DN operation versus one-stage deammonification MBBR treating reject water – and optimization with pH set-point

2019 ◽  
Vol 79 (8) ◽  
pp. 1616-1625 ◽  
Author(s):  
L. Kanders ◽  
J-J. Yang ◽  
C. Baresel ◽  
J. Zambrano
Keyword(s):  
Nitrous Oxide ◽  
Wastewater Treatment Plants ◽  
Feeding Strategy ◽  
Batch Reactor ◽  
Full Scale ◽  
Biofilm Reactor ◽  
N2o Emissions ◽  
Set Point ◽  
Reject Water ◽  
Aeration Time

Abstract To be able to fulfill the Paris agreement regarding anthropogenic greenhouse gases, all potential emissions must be mitigated. Wastewater treatment plants should aim to eliminate emissions of the most potent greenhouse gas, nitrous oxide (N2O). In this study, these emissions were measured at a full-scale reject water treatment tank during two different operation modes: nitrification/denitrification (N/DN) operating as a sequencing batch reactor (SBR), and deammonification (nitritation/anammox) as a moving bed biofilm reactor (MBBR). The treatment process emitted significantly less nitrous oxide in deammonification mode 0.14–0.7%, compared to 10% of total nitrogen in N/DN mode. The decrease can be linked to the changed feeding strategy, the lower concentrations of nitrite, a lower load of ammonia oxidized, a shorter aeration time, the absence of non-optimized ethanol dosage or periodic lack of oxygen as well as the introduction of biofilm. Further, evaluation was done how the operational pH set point influenced the emissions in deammonification mode. Lower concentrations of nitrous oxide were measured in water phase at higher pH (7.5–7.6) than at lower pH (6.6–7.1). This is believed to be mainly because of the lower aeration ratio and increased complete denitrification at the higher pH set point.

Removal of sulphite-reducing clostridia spores by full-scale water treatment processes as a surrogate for protozoan (oo)cysts removal

2000 ◽  
Vol 41 (7) ◽  
pp. 165-171 ◽  
Author(s):  
W. A. Hijnen ◽  
J. Willemsen-Zwaagstra ◽  
P. Hiemstra ◽  
G. J. Medema ◽  
D. van der Kooij
Keyword(s):  
Water Treatment ◽  
Removal Efficiency ◽  
Water Quality Monitoring ◽  
Full Scale ◽  
Process Conditions ◽  
Safe Drinking Water ◽  
Unit Process ◽  
Treatment Processes ◽  
Scale Unit ◽  
Micro Organisms

At eight full-scale water treatment plants in the Netherlands the removal of spores of sulphite-reducing clostridia (SSRC) was determined. By sampling and processing large volumes of water (1 up to 500 litres) SSRC were detected after each stage of the treatment. This enabled the assessment of the removal efficiency of the full-scale unit processes for persistent micro-organisms. A comparison with literature data on the removal of Cryptosporidium and Giardia by the same type of processes revealed that SSRC can be considered as a potential surrogate. The average Decimal Elimination Capacity (DEC) of the overall treatment plants ranged from 1.3–4.3 log. The observed actual log removal of SSRC by the unit processes and the overall treatment at one of the studied locations showed that the level of variation in removal efficiency was approximately 2 log. Moreover, from the actual log removal values it was observed that a low SSRC removal by one unit process is partly compensated by a higher removal by subsequent unit processes at this location. SSRC can be used for identification of the process conditions that cause variation in micro-organism removal which may lead to process optimization. Further research is necessary to determine the optimal use of SSRC in water quality monitoring for the production of microbiologically safe drinking water.

scholarly journals The Effect of Diet and Farm Management on N2O Emissions from Dairy Farms Estimated from Farm Data

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 654
Author(s):  
Simona Menardo ◽  
Giacomo Lanza ◽  
Werner Berg
Keyword(s):  
Diet Composition ◽  
Predictive Power ◽  
Emission Inventory ◽  
Dairy Farms ◽  
Farm Management ◽  
Mitigation Strategies ◽  
N2o Emissions ◽  
Intergovernmental Panel ◽  
Manure Storage ◽  
Animal Diet

The N2O emissions of 21 dairy farms in Germany were evaluated to determine the feasibility of an estimation of emissions from farm data and the effects of the farm management, along with possible mitigation strategies. Emissions due to the application of different fertilisers, manure storage and grazing were calculated based on equations from the IPCC (Intergovernmental Panel of Climate Change) and German emission inventory. The dependence of the N2O emissions on fertiliser type and quantity, cultivated crops and diet composition was assessed via correlation analysis and linear regression. The N2O emissions ranged between 0.11 and 0.29 kg CO2eq per kilogram energy-corrected milk, with on average 60% resulting from fertilisation and less than 30% from fertiliser storage and field applications. The total emissions had a high dependence on the diet composition; in particular, on the grass/maize ratio and the protein content of the animal diet, as well as from the manure management. A linear model for the prediction of the N2O emissions based on the diet composition and the fertilisation reached a predictive power of R2 = 0.89. As a possible mitigation strategy, the substitution of slurry for solid manure would reduce N2O emissions by 40%. Feeding cows maize-based diets instead of grass-based diets could reduce them by 14%.

scholarly journals Optimising the performance of a lab-scale tidal flow reed bed system treating agricultural wastewater

2004 ◽  
Vol 50 (8) ◽  
pp. 65-72 ◽  
Author(s):  
Y.Q. Zhao ◽  
G. Sun ◽  
C. Lafferty ◽  
S.J. Allen
Keyword(s):  
Tidal Flow ◽  
High Strength ◽  
Pollutant Removal ◽  
Inorganic Pollutants ◽  
Operational Conditions ◽  
Agricultural Wastewater ◽  
Major Route ◽  
Reed Bed ◽  
Ammoniacal Nitrogen Removal

A gravel-based tidal flow reed bed system was operated with three different strategies in order to investigate its optimal performance for the treatment of a high strength agricultural wastewater. According to the three strategies, individual reed beds were saturated and unsaturated with the wastewater for different periods while reasonably stable hydraulic and organic loadings were maintained. Experimental results demonstrated that the system produced the highest pollutant removal efficiencies with a relatively short saturated period and long unsaturated period, highlighting the importance of oxygen transfer into reed bed matrices during the treatment. Significant removals of some major organic and inorganic pollutants were achieved under all three operational conditions. Nitrification was not the major route of ammoniacal-nitrogen removal when the system was under high organic loading. Due to the filtration of suspended solids and the accumulation of biomass, gradual clogging of the reed bed matrices took place, which caused concerns over the long-term efficiency of the tidal flow system.

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