scholarly journals Performance of Full-Scale Thermophilic Membrane Bioreactor and Assessment of the Effect of the Aqueous Residue on Mesophilic Biological Activity

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1754
Author(s):  
Maria Cristina Collivignarelli ◽  
Marco Carnevale Miino ◽  
Francesca Maria Caccamo ◽  
Marco Baldi ◽  
Alessandro Abbà
Keyword(s):  
Uptake Rate ◽  
High Strength ◽  
Acute Effect ◽  
Full Scale ◽  
A Value ◽  
Nitrogen Uptake Rate ◽  
High Concentrations ◽  
Input Load ◽  
Positive Effect ◽  
Sludge Production

To date, the management of high-strength wastewater represents a serious problem. This work aims to evaluate the performance on chemical pollutants and on sludge production of one of the two full-scale thermophilic membrane bioreactors (ThMBRs) currently operational in Italy, based on monitoring data of the last two and a half years. Removal yields on COD, N-NOx, non-ionic and anionic surfactants (TAS and MBAS), increased with the input load up to 81.9%, 97.6%, 94.7%, and 98.4%, respectively. In the period of stability, a very low value of sludge production (0.052 kgVS kgCOD−1) was observed. Oxygen uptake rate (OUR) tests allowed us to exclude the possibility that mesophilic biomass generally exhibited any acute inhibition following contact with the aqueous residues (ARs), except for substrates that presented high concentrations of perfluoro alkyl substances (PFAS), cyanides and chlorides. In one case, nitrifying activity was partially inhibited by high chlorides and PFAS concentration, while in another the substrate determined a positive effect, stimulating the phenomenon of nitrification. Nitrogen uptake rate (NUR) tests highlighted the feasibility of reusing the organic carbon contained in the substrate as a source in denitrification, obtaining a value comparable with that obtained using the reference solution with methanol. Therefore, respirometric tests proved to be a valid tool to assess the acute effect of AR of ThMBR on the activity of mesophilic biomass in the case of recirculation.

Anaerobic treatment of municipal wastewater using the UASB-technology

2007 ◽  
Vol 56 (10) ◽  
pp. 37-44 ◽  
Author(s):  
I. Urban ◽  
D. Weichgrebe ◽  
K.-H. Rosenwinkel
Keyword(s):  
Co2 Emission ◽  
Municipal Wastewater ◽  
Clean Energy ◽  
Anaerobic Treatment ◽  
Relevant Effect ◽  
Different Temperatures ◽  
High Concentrations ◽  
New Applications ◽  
Uasb Reactors ◽  
Positive Effect

The anaerobic treatment of municipal wastewater enables new applications for the reuse of wastewater. The effluent could be used for irrigation as the included nutrients are not affected by the treatment. Much more interesting now are renewable energies and the retrenchment of CO2 emission. With the anaerobic treatment of municipal wastewater, not only can the CO2 emission be reduced but “clean” energy supply can be gained by biogas. Most important for the sustainability of this process is the gathering of methane from the liquid effluent of the reactor, because the negative climate-relevant effect from the degassing methane is much higher than the positive effect from saving CO2 emission. In this study, UASB reactors were used with a flocculent sludge blanket for the biodegradation of the carbon fraction in the wastewater with different temperatures and concentrations. It could be shown that the positive effect is much higher for municipal wastewater with high concentrations in hot climates.

Use of DNVGL-RP-C203 for Determining the Fatigue Capacity of Connectors

2021 ◽  
Author(s):  
Anthony Muff ◽  
Anders Wormsen ◽  
Torfinn Hørte ◽  
Arne Fjeldstad ◽  
Per Osen ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Experimental Testing ◽  
High Strength ◽  
Element Model ◽  
Fatigue Analysis ◽  
Full Scale ◽  
The Finite Element Model

Abstract Guidance for determining a S-N based fatigue capacity (safe life design) for preloaded connectors is included in Section 5.4 of the 2019 edition of DNVGL-RP-C203 (C203-2019). This section includes guidance on the finite element model representation, finite element based fatigue analysis and determination of the connector design fatigue capacity by use of one of the following methods: Method 1 by FEA based fatigue analysis, Method 2 by FEA based fatigue analysis and experimental testing and Method 3 by full-scale connector fatigue testing. The FEA based fatigue analysis makes use of Appendix D.2 in C203-2019 (“S-N curves for high strength steel applications for subsea”). Practical use of Section 5.4 is illustrated with a case study of a fatigue tested wellhead profile connector segment test. Further developments of Section 5.4 of C203-2019 are proposed. This included acceptance criteria for use of a segment test to validate the FEA based fatigue analysis of a full-scale preloaded connector.

PENGARUH STRES KERJA TERHADAP TURNOVER INTENTION PADA KARYAWAN PT INTERNUSA JAYA SEJAHTERA MERAUKE

2018 ◽  
Vol 13 (1) ◽  
pp. 59
Author(s):  
Samrotu Sa’adah ◽  
Arif Partono Praseti
Keyword(s):  
Linear Regression ◽  
Work Stress ◽  
Turnover Intention ◽  
Descriptive Analysis ◽  
Linear Regression Analysis ◽  
Coefficient Of Determination ◽  
A Value ◽  
Employee Turnover Intention ◽  
Analysis Technique ◽  
Positive Effect

This study aims to examine the effect of work stress on employee turnover intention at PT Internusa Jaya Sejahtera Merauke, Papua. This study obtained data from questionnaires distributed to 117 employees of PT Internusa Jaya Sejahtera. The questionnaire used has 14 point statements and uses a 6 point Likert scale. The technique used in this research is descriptive analysis technique used to analyze the level of work stress and turnover intention level on employees. Simple linear regression analysis is also used to determine the effect between work stress variables and turnover intention variables. The results showed that work stress had a significant positive effect on turnover intention on employees of PT Internusa Jaya Sejahtera. The coefficient of determination in this study has a value of 0.571 which means that the level of job stress to turnover intention of 57.1%.Keywords : work stress, turnover intention, linear regression ABSTRAK Penelitian ini bertujuan untuk meneliti pengaruh stres kerja terhadap turnover intention pada karyawan di PT Internusa Jaya Sejahtera Merauke, Papua. Peneltian ini memperoleh data dari hasil penyebaran kuesioner kepada 117 karyawan PT Internusa Jaya Sejahtera. Kuesioner yang digunakan memiliki 14 butir pernyataan dan menggunakan skala Likert 6 poin. Teknik yang digunakan pada penelitian kali ini adalah teknik analisis deskriptif yang digunakan untuk menganalisis tingkat stres kerja dan tingkat turnover intention pada karyawan. Analisis regresi linier sederhana juga digunakan unntuk mengetahui pengaruh antara variabel stres kerja dan variabel turnover intention. Hasil penelitian menunjukkan bahwa stres kerja berpengaruh signifikan positif terhadap turnover intention pada karyawan PT Internusa Jaya Sejahtera. Koefisien determinasi pada penelitian ini memiliki nilai 0.571 yang memiliki arti bahwa tingkat stres kerja terhadap turnover intention sebesar 57,1%.Kata kunci : stres kerja, turnover intention, regresi linier.

Nitrogen removal from digester supernatant via nitrite - SBR or SHARON?

2003 ◽  
Vol 48 (8) ◽  
pp. 9-18 ◽  
Author(s):  
C. Fux ◽  
K. Lange ◽  
A. Faessler ◽  
P. Huber ◽  
B. Grueniger ◽  
...  
Keyword(s):  
Municipal Wastewater ◽  
Flow Reactor ◽  
Batch Reactor ◽  
Treatment Plant ◽  
Full Scale ◽  
Municipal Wastewater Treatment ◽  
Nitrite Oxidation ◽  
High Concentrations ◽  
Nitrite Nitrate ◽  
Sharon Process

Separate biological elimination of nitrogen from the digester supernatant of a municipal wastewater treatment plant (WWTP) was investigated in pilot and full-scale plants. Denitrification mainly via nitrite was achieved in a sequencing batch reactor (SBR) and a continuous flow reactor (CSTR or SHARON). Suppression of nitrite oxidation in the SBR was feasible at short aerobic/anaerobic intervals allowing for immediate denitrification of the produced nitrite. Nitrate production could also be stopped by exposing the biomass to anaerobic conditions for 11 days. Temporarily high concentrations (up to 80 gNH3-Nm-3) of free ammonia could not be considered as the major reason for inhibiting nitrite oxidation. In a full-scale SBR plant 90% of the nitrogen load was denitrified in a total hydraulic retention time (HRT) of 1.6 days and with a sludge age between 15 and 20 days. Ethanol and methanol were used for denitrification. The specific average substrate consumption was 2.2 gCODdosedg-1Nremoved with an effective biomass yield of 0.2 gCODbiomassg-1CODdosed. No dosing with base was required. In the SHARON process full nitrogen elimination was achieved only with a total HRT greater than 4 days at 29°C. The overall costs were estimated at €1.4 kg-1Nremoved for the SBR and €1.63 kg-1Nremoved in SHARON mode, respectively. The SHARON process is simple in operation (CSTR) but the tank volume has to be significantly greater than in SBR.

scholarly journals Application of the C-S-H Phase Nucleating Agents to Improve the Performance of Sustainable Concrete Composites Containing Fly Ash for Use in the Precast Concrete Industry

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6514
Author(s):  
Grzegorz Ludwik Golewski ◽  
Bartosz Szostak
Keyword(s):  
Fly Ash ◽  
Industrial Waste ◽  
Precast Concrete ◽  
High Strength ◽  
Nucleating Agents ◽  
Negative Effects ◽  
Sustainable Concrete ◽  
Wide Range ◽  
Time Periods ◽  
Positive Effect

Siliceous fly ash (FA) is the main additive to currently produced concretes. The utilization of this industrial waste carries an evident pro-ecological factor. In addition, such actions have a positive effect on the structure and mechanical parameters of mature concrete. Unfortunately, the problem of using FA as a Portland cement replacement is that it significantly reduces the performance of concretes in the early stages of their curing. This limits the possibility of using this type of concrete, e.g., in prefabrication, where it is required to obtain high-strength composites after short periods of curing. In order to minimize these negative effects, this research was undertaken to increase the early strength of concretes with FA through the application of a specifically formulated chemical nano-admixture (NA) in the form of seeds of the C-S-H phase. The NA was used to accelerate the strength growth in concretes. Therefore, this paper presents results of tests of modified concretes both with the addition of FA and with innovative NA. The analyses were carried out based on the results of the macroscopic and microstructural tests in five time periods, i.e., after 4, 8, 12, 24 and 72 h. The results of tests carried out with the use of NA clearly indicate the possibility of using FA in a wide range of management areas in sustainable concrete prefabrication.

scholarly journals Numerical Study of a Single-Point Mooring Gravity Fish Cage With Different Deformation-Suppression Methods

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Hui Cheng ◽  
Karl Gunnar Aarsæther ◽  
Lin Li ◽  
Muk Chen Ong
Keyword(s):  
Current Velocity ◽  
Numerical Study ◽  
Single Point ◽  
Local Environment ◽  
Full Scale ◽  
Tension Force ◽  
Wave Loads ◽  
Practical Advice ◽  
Rigid Frame ◽  
Positive Effect

Abstract Compared with the multipoint mooring fish cage, the single-point mooring (SPM) fish cage can spread out the fish wastes and uneaten feeds in a larger area, and it can also prevent the local environment from being overwhelmed. Thus, it has attracted much attention recently. In this research, different deformation-suppression methods are applied to the SPM system with a typical Norwegian fish cage aiming to increase the cultivation volume under the action of current and/or wave loads. A well-validated software, fhsim, is used to conduct the full-scale numerical study. The effects of the three deformation-suppression methods, i.e., (i) adding the lower bridles, (ii) adding the frontal rigid frame and (iii) adding the trawl doors, are analyzed under pure current and combined wave–current conditions. The results indicate that all the three deformation-suppression methods can improve the cultivation volume at least by 32% compared to the original SPM fish cage when the current velocity is larger than 0.5 m/s. In addition, moving the conjunction point close to the bottom ring can bring a positive effect on the cultivation volume maintaining with an only small increment in the tension force. This study can provide practical advice and useful guides for the SPM fish cage design.

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