Impact of microwave radiation on nitrogen removal and quantity of nitrifiers in biofilmA paper submitted to the Journal of Environmental Engineering and Science.

2010 ◽  
Vol 37 (4) ◽  
pp. 661-666 ◽  
Author(s):  
Marcin Zieliński ◽  
Magdalena Zielińska
Keyword(s):  
Microwave Radiation ◽  
Nitrogen Removal ◽  
Oxygen Demand ◽  
Environmental Engineering ◽  
Control Group ◽  
Nitrogen Compounds ◽  
Ammonia Oxidizing Bacteria ◽  
Organic Loading ◽  
Trickling Filters ◽  
The Impact

The aim of this study was to determine the impact of microwave radiation on the efficiency of nitrification and on the percentage of ammonia-oxidizing bacteria in biofilm and to study the possibility of the occurrence of nonthermal effects caused by the interaction of microwaves and biofilm. Eight trickling filters with a biofilm were used in the experiment: four were exposed to microwave radiation, and four were heated with warm air as a control group. Microwave radiation at a frequency of 2.45 GHz was applied at an intensity of 18 W (0.01 W·cm–3of the reactor packing), which increased the biofilm temperature by 6 °C compared with the ambient temperature. The hydraulic loading averaged 0.30 m3·m–2·h–1, and the organic loading equalled 1.93 g chemical oxygen demand (COD)·m–2·d–1. Microwave radiation had an effect on the concentration of nitrogen compounds in the biofilm, and microwave heating triggered alterations within the biofilm that increased the efficiency of both nitrification and denitrification and the percentage of ammonia-oxidizing bacteria.

Spatial distribution of ammonia-oxidizing bacteria in the biofilm and suspended growth biomass of the full- and partial-bed biological aerated filtersA paper submitted to the Journal of Environmental Engineering and Science.

2009 ◽  
Vol 36 (11) ◽  
pp. 1859-1866 ◽  
Author(s):  
S. Fatihah ◽  
T. Donnelly
Keyword(s):  
Spatial Distribution ◽  
Nitrogen Removal ◽  
Environmental Engineering ◽  
Ammonia Oxidizing Bacteria ◽  
Removal Process ◽  
Suspended Growth

The extent of comparable nitrogen removal in the full- and partial-bed biological aerated reactors needs further microbiological evidence, specifically the existence of ammonia-oxidizing bacteria (AOB). The nitrogen removal process in such systems is typically initiated by chemoliautotrophic ammonia-oxidizing bacteria converting ammonia to nitrite and traces of oxidized nitrogen gases. The formation of a dense biofilm as a result of higher turbulence would account for the higher number of AOB cells enumerated in the biofilm samples from the partial-bed reactor (4.3 × 105 ± 1.9 × 105No. of AOB cells/mL sample) as compared with those from the full-bed reactor (1.5 × 105 ± 8.0 × 104No. of AOB cells/mL sample).

scholarly journals Nitrogen Removal Efficiency for Pharmaceutical Wastewater with a Single-Stage Anaerobic Ammonium Oxidation Process

2020 ◽  
Vol 17 (21) ◽  
pp. 7972
Author(s):  
Lushen Zuo ◽  
Hong Yao ◽  
Huayu Li ◽  
Liru Fan ◽  
Fangxu Jia
Keyword(s):  
Nitrogen Removal ◽  
Oxygen Demand ◽  
Single Stage ◽  
Anaerobic Ammonium Oxidation ◽  
Ammonium Concentration ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Pharmaceutical Wastewater ◽  
High Concentrations

A single-stage anaerobic ammonium oxidation (ANAMMOX) process with an integrated biofilm–activated sludge system was carried out in a laboratory-scale flow-through reactor (volume = 57.6 L) to treat pharmaceutical wastewater containing chlortetracycline. Partial nitrification was successfully achieved after 48 days of treatment with a nitrite accumulation of 70%. The activity of ammonia oxidizing bacteria (AOB) decreased when the chemical oxygen demand (COD) concentration of the influent was 3000 mg/L. When switching to the single-stage ANAMMOX operation, (T = 32–34 °C, DO = 0.4–0.8 mg/L, pH = 8.0–8.5), the total nitrogen (TN) removal loading rate and efficiency were 1.0 kg/m3/d and 75.2%, respectively, when the ammonium concentration of the influent was 287 ± 146 mg/L for 73 days. The findings of this study imply that single-stage ANAMMOX can achieve high nitrogen removal rates and effectively treat pharmaceutical wastewater with high concentrations of COD (1000 mg/L) and ammonium.

scholarly journals Integration of the Process for Production of Ethyl Acetate by an Enhanced Extraction Process

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1425
Author(s):  
Wojciech Piotrowski ◽  
Robert Kubica
Keyword(s):  
Ethyl Acetate ◽  
Extraction Efficiency ◽  
Raw Materials ◽  
Oxygen Demand ◽  
Extraction Process ◽  
Process Models ◽  
Technological Solution ◽  
Organic Loading ◽  
Product Separation ◽  
The Impact

The paper presents a study on the performance of a conventional plant-producing ethyl acetate from ethanol and acetic acid. Process models were compiled in the simulator Chemcad 7. The impact of key parameters on the performance of individual installation nodes was examined by sensitivity analysis. Three installation approaches are presented and compared: two classic with different heat duties and an improved one. An improved technological solution, with a closed circulation of the extractant as well as the azeotrope subcooling for better extraction is demonstrated. The energy and mass balance of the installation were developed. The proposed enhancement of a technology with significantly reduced consumption of the fresh extractant also offers a deep recovery of the raw materials, i.e., ethyl acetate and ethanol from wastewater. We assumed that the same energy consumption relative to the classic strategy consumption of ethanol was reduced from 0.531 to 0.524 t/tproduct (−1.2%), fresh process water from 2.18 to 1.42 t/tproduct (−34.9%), and wastewater 2.36 to 1.61 t/tproduct (−31.8%). By this, the wastewater total organic loading (TOL), as well as chemical oxygen demand were nine times reduced. The major advantage is achieved through subcooling of azeotrope, which improves extraction efficiency, making the organic phase enriched with ethyl acetate. Therefore, the performance of the product separation node and the whole system are improved.

Bioelectrochemically-assisted nitrogen removal in osmotic membrane bioreactor

2020 ◽  
Author(s):  
You Wu ◽  
Yun Cai ◽  
Yu-Xiang Lu ◽  
Li-Min Zhang ◽  
Xiao-Li Yang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Operation Mode ◽  
Oxygen Demand ◽  
Denitrifying Bacteria ◽  
Future Research ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrite Oxidizing Bacteria

Abstract Nitrogen removal in osmosis membrane bioreactor (OMBR) is important to its applications but remains a challenge. In this study, a bioelectrochemically-assisted (BEA) operation was integrated into the feed side of OMBRs to enhance nitrogen removal, and sodium acetate was served as a draw solute and supplementary carbon source for the growth of denitrifying bacteria due to reversed-solute. The effects of operation mode and influent ammonium (NH4+) concentration were systematically examined. Compared to a conventional OMBR, the integrated BEA-OMBR achieved higher total nitrogen removal efficiency of 98.13%, and chemical oxygen demand removal efficiency of 95.83% with the influent NH4+-N concentration of 39 mg L−1. The sequencing analyses revealed that ammonia-oxidizing bacteria (0–0.04%), nitrite-oxidizing bacteria (0–0.16%), and denitrifying bacteria (1.98–8.65%) were in abundance of the microbial community in the feed/anode side of integrated BEA-OMBR, and thus BEA operation increased the diversity of the microbial community in OMBR. Future research will focus on improving nitrogen removal from a high ammonium strength wastewater by looping anolyte effluent to the cathode. These findings have demonstrated that BEA operation can be an effective approach to improve nitrogen removal in OMBRs toward sustainable wastewater treatment.

Effect of analgesics on the antibiotic resistance of ammonia-oxidizing organismsA paper submitted to the Journal of Environmental Engineering and Science.

2009 ◽  
Vol 36 (9) ◽  
pp. 1558-1566 ◽  
Author(s):  
Prapurna Koney ◽  
Audra Morse
Keyword(s):  
Antibiotic Resistance ◽  
Salicylic Acid ◽  
Nalidixic Acid ◽  
Environmental Engineering ◽  
Ammonia Oxidizing Bacteria ◽  
Plate Method ◽  
Ciprofloxacin Resistance ◽  
Reclamation System ◽  
The Impact ◽  
Environmental Microbes

The present study was conducted to determine the effect of analgesics (aspirin and salicylic acid) on heterotrophic organisms and ammonia-oxidizing bacteria (AOB) resistance to antibiotics (amoxicillin, ciprofloxacin, and nalidixic acid) using the spread plate method. The bacteria were cultured from a biological graywater reclamation system. The results indicate an increase in ciprofloxacin resistance of AOB at concentrations of 0.5 and 1 mmol/L salicylic acid and aspirin. An increase in resistance of heterotrophic organisms and AOB in the presence of salicylic acid and aspirin was observed at 0.064 and 0.107 mmol/L of nalidixic acid. However, the effect of salicylic acid and aspirin on amoxicillin resistance of heterotrophic organisms and AOB was minimal. This study is important because it focuses on the antibiotic resistance of the less studied environmental microbes by considering the impact of compounds other than antibiotics to induce antibiotic resistance.

An alternate oxic-anoxic process automatically controlled. Theory and practice in a real treatment plant network

2004 ◽  
Vol 48 (11-12) ◽  
pp. 337-344 ◽  
Author(s):  
P. Battistoni ◽  
R. Boccadoro ◽  
D. Bolzonella ◽  
M. Marinelli
Keyword(s):  
Flow Rate ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Control Device ◽  
Theory And Practice ◽  
Process Efficiency ◽  
Plant Management ◽  
Operational Parameters ◽  
The Impact

A simple mathematical model of an alternate oxic-anoxic process has been elaborated. It enables us to optimise the cycle time on the basis of maximum nitrates concentration in the effluent and the desired nitrogen removal performance. At the same time the model can be employed to verify the impact of the variations of flow rate and influent characteristics as well as the operational parameters of the process. Actually, the model confirms the process efficiency but its feasibility in real plants needs a local or remote process control. To verify these theoretical conclusions a real wastewater plant (700 PE) has been upgraded in an alternate oxic-anoxic process. It was implemented with software able to elaborate the data of dissolved oxygen concentration and oxidation reduction potential. Moreover, the evaluation of the flexing points was performed to manage mixer and blowers. A one-year experience of plant management allowed us to obtain very high nitrogen removal. However, the performances were different during wet or dry weather periods. The statistical analysis of probe signals evaluation confirmed the capability of the control device to detect the flexing points during the anoxic phase (70-94%). On the other hand, the capability of detecting the DO signal was lower, in particular when the oxygen demand was similar to the amount of supplied oxygen. The hourly variations of flow rate and mass loading determines different conditions for starting the anoxic phase: over aeration, over loading and the equivalence of oxygen demand and supply, are the main factors determining the blowers stopping.

The impact of organic carbon on the performance of a high rate nitrifying trickling filter designed to pre-treat potable water

2010 ◽  
Vol 61 (7) ◽  
pp. 1875-1883 ◽  
Author(s):  
Ben van den Akker ◽  
Mike Holmes ◽  
Nancy Cromar ◽  
Howard Fallowfield
Keyword(s):  
Organic Carbon ◽  
Potable Water ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
High Rate ◽  
Organic Load ◽  
Trickling Filters ◽  
Filter Performance ◽  
Carbon Load ◽  
The Impact

The application of nitrifying trickling filters (NTFs) to potable water treatment is less well understood than their application to wastewater treatment, particularly regarding the effect of low ammonia substrate concentrations and organic carbon loading on filter performance. A large pilot-scale NTF was operated under conditions that simulated the raw water quality of poorly protected catchments typically found in SE Asia, with the objective of reducing the ammonia driven chlorine demand during disinfection. The efficacy of a high rate NTF to remove low concentrations of ammonia (0.5–5.0 mg NH4-N L−1) in the presence of high organic carbon (1–12 mg soluble biochemical oxygen demand (sBOD5) L−1) was investigated. Results demonstrated that 90 to 100% of nitrification was maintained only when the carbon load was less than 0.7 g sBOD5 m−2 d−1 (<4 mg sBOD5 L−1). Once the organic load was increased beyond 0.75 to 2.1 g sBOD5 m−2 d−1 (4.5–12.1 mg sBOD5 L−1), a linear decline in nitrification from 70 to 15% was observed within a timeframe of 8 to 10 d. The impact of high organic loads on the distribution of nitrification down the NTF was also investigated. Results confirmed that carbon loads greater than 0.95 g sBOD5 m−2 d−1 (>5.5 mg sBOD5 L−1), severely suppressed nitrification throughout the entire filter bed.

Information and Communication Technology and Cultural Change

2012 ◽  
Vol 43 (4) ◽  
pp. 222-231 ◽  
Author(s):  
Nina Hansen ◽  
Tom Postmes ◽  
Nikita van der Vinne ◽  
Wendy van Thiel
Keyword(s):  
Cultural Values ◽  
Information And Communication Technology ◽  
Communication Technology ◽  
Cultural Change ◽  
Control Group ◽  
Self Construal ◽  
Information And Communication ◽  
The Impact ◽  
Ict For Development ◽  
Practical Implications

This paper studies whether and how information and communication technology (ICT) changes self-construal and cultural values in a developing country. Ethiopian children were given laptops in the context of an ICT for development scheme. We compared children who used laptops (n = 69) with a control group without laptops (n = 76) and a second control group of children whose laptop had broken down (n = 24). Results confirmed that after 1 year of laptop usage, the children’s self-concept had become more independent and children endorsed individualist values more strongly. Interestingly, the impact of laptop usage on cultural values was mediated by self-construal (moderated mediation). Importantly, modernization did not “crowd out” traditional culture: ICT usage was not associated with a reduction in traditional expressions (interdependent self-construal, collectivist values). Theoretical and practical implications are discussed.

A Newspaper’s Effect on the Strength of Automatic Associations in Memory

2012 ◽  
Vol 24 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Florian Arendt
Keyword(s):  
Treatment Group ◽  
Term Effect ◽  
Control Group ◽  
Implicit Measure ◽  
Short Term ◽  
Short Term Treatment ◽  
Short Term Effect ◽  
Automatic Associations ◽  
Foreign Nationality ◽  
The Impact

A test was done to see if reading a newspaper which consistently overrepresents foreigners as criminals strengthens the automatic association between foreign country and criminal in memory (i.e., implicit cultivation). Further, an investigation was done to find out if reading articles from the same newspaper produces a short-term effect on the same measure and if (1) emotionalization of the newspaper texts, (2) emotional reactions of the reader (indicated by arousal), and (3) attributed text credibility moderate the short-term treatment effect. Eighty-five participants were assigned to one of three experimental conditions. Participants in the control group received short factual crime texts, where the nationality of the offender was not mentioned. Participants in the factual treatment group received the same texts, but the foreign nationality was mentioned. Participants in the emotionalized treatment group received emotionalized articles (i.e., texts which are high in vividness and frequency) covering the same crimes, with the foreign nationality mentioned. Supporting empirical evidence for implicit cultivation and a short-term effect was found. However, only emotionalized articles produced a short-term effect on the strength of the automatic association, indicating that newspaper texts must have a minimum of stimulus intensity to overcome an effect threshold. There were no moderating effects of arousal or credibility pertaining to the impact on the implicit measure. However, credibility moderated the short-term effect on a first-order judgment (i.e., estimated frequency of foreigners of all criminals). This indicates that a newspaper’s effect on the strength of automatic associations is relatively independent from processes of propositional reasoning.

Impact of an educative program on dialysis patients’ knowledge and mental health: controlled before and after program

2018 ◽  
Vol 10 (2) ◽  
pp. 20204
Author(s):  
Laetitia Idier ◽  
Aurélie Untas ◽  
Nicole Rascle ◽  
Michèle Koleck ◽  
Maider Aguirrezabal ◽  
...  
Keyword(s):  
Mental Health ◽  
Depressive Symptoms ◽  
Vascular Access ◽  
Educational Program ◽  
Psychological State ◽  
Control Group ◽  
Dialysis Patients ◽  
Emotional Change ◽  
The Impact ◽  
Experimental Group

Introduction:Psychological impact of Therapeutic Patient Education (TPE) for dialysis patients is rarely evaluated since the focus of many studies is on medical variables (i.e., adherence).Objectives:The aims of this study were: 1) to estimate the impact of a TPE program on knowledge, depression and anxiety, 2) to examine change in knowledge as a mediator of the effects of a TPE program on mental health.Method:This study was conducted in three hemodialysis units and comprised two groups: an experimental group with education and a control group with routine care. The program was based of 5 educative sessions. Knowledge, depressive and anxious symptoms were assessed with self-reported outcomes measured before and 3 months after the program.Results:The sample comprised 125 patients. Knowledge about vascular access and nutrition (p < 0.01) and depressive symptoms increased in the experimental group (p < 0.01). Analysis of mediation showed that changes in knowledge about vascular access were a significant mediator of the effects of the program on depressive symptoms (F = 4.90;p = 0.01).Discussion:Knowledge acquired during an educational program could lead to an emotional change. Improving knowledge often leads to an awareness of the risks that can modify the psychological state of patients by reminding them of their vulnerability. This study shows that it is required to be attentive to the way of transmitting knowledge. It’s necessary adapting this transmission to the needs of patients and promoting the acquisition of psychosocial competence too.Conclusion:This study shows that knowledge acquired during an educational program can lead to an emotional change in the short term. A long-term follow-up of the population should be interesting to observe these emotional effects.

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