Search results for "removal"

An advanced control strategy for biological nutrient removal in continuous systems based on pH and ORP sensors

2012

[EN] A fuzzy logic-based control system that uses low-cost sensors for controlling and optimizing the biological nitrogen removal in continuous systems has been developed. The novelty of this control system is the use of several pH, ORP, and dissolved oxygen (DO) sensors instead of on-line nitrogen sensors/analyzers. The nitrogen control system was developed and implemented in a UCT pilot plant fed with wastewater from a full-scale plant. The developed nitrification controller allows the effluent ammonium concentration to be maintained below the effluent criteria discharge with the minimum energy consumption. The denitrification process controller allows the energy consumption derived from …

Mathematical modelling of greenhouse gas emissions from membrane bioreactors: A comprehensive comparison of two mathematical models.

2018

Abstract This paper compares two mathematical models (Model I and Model II) to predict greenhouse gases emission from a University Cape Town (UCT) – membrane bioreactor (MBR) plant. Model I considers N 2 O production only during denitrification. Model II takes into account the ammonia-oxidizing bacteria (AOB) formation pathways for N 2 O. Both models were calibrated adopting real data. Model comparison was performed in terms of (i) sensitivity analysis (ii) best fit and (iii) model prediction uncertainty. On average 6% of factors of Model I and 9% of Model II resulted to be important. In terms of best fit, Model II had a better capability of reproducing the measured data. The average effici…

The effect of the solids and hydraulic retention time on moving bed membrane bioreactor performance

2018

Abstract The aim of the present paper was to investigate the effect of solids (SRT) and hydraulic (HRT) retention time on Integrated Fixed Film Activated Sludge (IFAS) University of Cape Town (UCT) membrane Bioreactor (MBR). In particular, three different pairs of SRT and HRT values were analysed, namely, Phase I 56 d/30 h, Phase II 31 d/15 h and Phase III 7 d/13 h. The short-term effect of these three SRT/HRT conditions was assessed by analysing several system performance indicators: organic carbon and biological nutrient (nitrogen and phosphorus) removal, biomass respiratory activity, activated sludge filtration properties and membrane fouling. The results showed that the decrease of SRT/…

Comparison of Two Mathematical Models for Greenhouse Gas Emission from Membrane Bioreactors

2017

In this study two mathematical models (Model I and Model II), able to predict the nitrous oxide (N2O) and carbon dioxide (CO2) emission from an University Cape Town (UCT) – membrane bioreactor (MBR) plant, have been compared. Model I considers the N2O production only during the denitrification. Model II takes into account the two ammonia-oxidizing bacteria (AOB) formation pathways for N2O. Both models were calibrated adopting real data. Results highlight that Model II had a better capability of reproducing the measured data especially in terms of N2O model outputs. Indeed, the average efficiency related to the N2O model outputs was equal to 0.3 and 0.38 for Model I and Model II respectively.

Diimidazolium-based supramolecular ionogels for dye removal from wastewaters

Synthesis, Characterization, and Study, of New Nanostructured Materials

Dense drug-eluting biodegradable Fe-Ag nanocomposites

2021

Abstract Biodegradable metals in orthopedics are aimed to eliminate secondary the surgical intervention for implant removal, and thus improve patient compliance, reduce surgery costs and the risk of infections. In addition, biodegradable implants could be loaded with different drugs to prevent the growth of pathogens and the development of bone infections, kill remaining cancer cells after tumor resection or stimulate bone regeneration. However, drugs undergo thermal decomposition under the conditions of conventional metal fabrication processes. In this work, we describe the fabrication of a dense drug-eluting biodegradable Fe-Ag nanocomposite containing 10 vol% of Ag and loaded with the an…

Cactus pear (O. ficus-indica (L.) Mill.) fruit production: Ecophysiology, orchard and fresh-cut fruit management

2015

Cactus pear (Opuntia ficus-indica L. Mill.) is cultivated in wide range of environments with the consequence of large differences in crop potential, orchard systems and management. These differences may be related to temperature and rainfall range (water availability) but also to the day/night length and, of course, to soil characteristics. This leads to considerable variability in the field and in fruit quality. Crop value much depends in crop variability in terms of fruit size, which is the major factor for fruit price in Europe. The increase of crop value very much depends on regular cultural practices such as irrigation and fruit thinning, but it is also dependent on plant crop yield an…

Combined effects of electric toothbrushing and dentifrice on artificial stain removal : an in vitro study

2018

This in vitro study aimed to clarify the combined effect of electric toothbrushing and dentifrice on the removal of artificial stain. Twenty-five bovine incisors were cut at the cervix and the crown was embedded in auto-cured acrylic resin. Specimens were abraded using #240 SiC paper to obtain a flat enamel surface, and 20 specimens were treated with 10% citric acid / 3% ferric chloride solution followed by 1% tannic acid solution to produce surface staining. They were divided into four groups: 1) brushing with an electric toothbrush and whitening dentifrice (group S+B); 2) brushing with an electric toothbrush and fluoride dentifrice (group S+C); 3) brushing with an electric toothbrush and …

Dentist´s knowledge, attitudes and determining factors of the conservative approach in teeth with reversible pulpitis and deep caries lesions

2018

Background The aim of this study was to investigate dentists` knowledge, attitudes and factors regarding the conservative approach in the management of deep caries lesions (DCLs) in teeth with reversible pulpitis. Material and methods 187 dentists were contacted directly or by mail, and 125 (67%) were finally included in the study. Dentists were requested to answer an open/discursive questionnaire about the routine approach to the diagnosis and treatment of DCLs, including knowledge-related attitudinal items. Results Total caries excavation was the preferred treatment option for more than 80% of dentists in case of DCL with reversible pulpitis. Only a small percentage (8%) chose partial car…