Search results for "removal"

Phosphorus recovery by struvite crystallization in WWTPs: Influence of the sludge treatment line operation

2010

Phosphorus recovery by struvite (MgNH(4)PO(4).6H(2)O) crystallization is one of the most widely recommended technologies for treating sludge digester liquors especially in wastewater treatments plants (WWTP) with enhanced biological phosphorus removal (EBPR). In this paper, phosphorus recovery by struvite crystallization is assessed using the rejected liquors resulting from four different operational strategies of the sludge treatment line. Phosphorus precipitation and recovery efficiencies of between 80-90% and 70-85%, respectively, were achieved in the four experiments. The precipitates formed were mainly struvite, followed by amorphous calcium phosphate and, in some experiments, by calci…

Thrombosis, fracture, and percutaneous removal of a patent foramen ovale closure device 1 month after successful deployment

2010

Several different devices have been developed for the percutaneous closure of interatrial defects and patent foramen ovale. Although the implantation of these devices is both safe and effective, a number of complications, both in the early and the late follow-up, may occur. We describe a case of device fracture manifested early (1 month after implantation) with the formation of massive thrombosis on the right atrial disc. The patient was treated with anticoagulants and the device was percutaneously retrieved. Our images allowed early noninvasive therapy and emphasize the need for echocardiographic follow-up early after implantation. © 2010 Wiley-Liss, Inc.

Perkutane Entfernung eines intraperitonealen Fremdkörpers

1993

Cytotoxicity and dentin composition alterations promoted by different chemomechanical caries removal agents : a preliminary in vitro study

2021

Background The use of chemomechanical agents for caries removal has been indicated as a non-invasive treatment option; however, their possible deleterious effects on the dental-pulp complex have been insufficiently studied. This study assessed the direct cytotoxicity of two chemomechanical caries removal agents (Brix 3000™ - BX and Papacarie Duo™ - PD) on pulp cells from deciduous teeth, as well as to assess the morphology and chemical compositions of the dentin surface after the application of these materials. Material and methods The cells were seeded (50,000 cells/cm²) in a culture medium (DMEM with 10% fetal bovine serum - FBS). After 24 hours, the BX and PD materials were added to 1:20…

Contralateral potentials in the suprasylvian gyrus evoked by pulvinar stimulation.

1974

AbstractIn encephale isole cats the transmission of the bioelectrical activity in the suprasylvian gyrus, evoked by contralateral pulvinar stimulation was explored. Through the excitability increase and decrease of the pulvinar (by strychnine or KCl, respectively), the surgical removal of the ipsilateral suprasylvian gyrus and the electrocoagulation of the posterior commissure it appeared that the transmission of the activity in the suprasylvian gyrus evoked by contralateral pulvinar stimulation occurs through both the callosal and the interthalamic pathway.

New insights in the metabolic behaviour of PAO under negligible poly-P reserves

2017

[EN] In a previous study the authors confirmed the ability of PAOs to perform GAO metabolism in short-term experiments. However, what happens when PAOs are exposed to poly-P shortage for an extended period of time? The answer to this question was the aim of this work from a macroscopic and microscopic point of view. Therefore, the poly-P was removed from a PAO enriched SBR and maintained without poly-P during five solid retention time. The PAOs were found to quickly change their metabolism to a clear GAO performance and remained without GAO colonization for the entire experimental period, even though GAO was present (around 5%) at the beginning of the experiment. Unlike the results obtained…

Kinetics of nitrogen removal in a MBR nutrient removal activated sludge system

2006

The application of membrane bioreactor (MBR) technology to biological nutrient removal (BNR) activated sludge (AS) systems is limited and uncertainty exists as to the impact of the conditions induced by the membranes on the biologically mediated processes of nutrient removal. Two main conditions associated with MBRs are (1) high total suspended solids (TSS) concentrations (8–20 g/L) and (2) different selection pressures due to biomass retention not being based on settleability, compared with conventional systems with secondary settling tanks (SSTs). Recently, Ramphao et al. [1] concluded that incorporating membranes in BNR AS makes a profound difference to the design of the system. Previous…

Mixed microalgae culture for ammonium removal in the absence of phosphorus: Effect of phosphorus supplementation and process modeling

2014

Microalgal growth and ammonium removal in a P-free medium have been studied in two batch photobioreactors seeded with a mixed microalgal culture and operated for 46 days. A significant amount of ammonium (106 mg NH4-Nl(-1)) was removed in a P-free medium, showing that microalgal growth and phosphorus uptake are independent processes. The ammonium removal rate decreased during the experiment, partly due to a decrease in the cellular phosphorus content. After a single phosphate addition in the medium of one of the reactors, intracellular phosphorus content of the corresponding microalgal culture rapidly increased, and so did the ammonium removal rate. These results show how the amount of phos…

Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent

2012

This study investigated the removal of nitrogen and phosphorus from the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) by means of a lab-scale photobioreactor in which algae biomass was cultured in a semi-continuous mode for a period of 42 days. Solids retention time was 2 days and a stable pH value in the system was maintained by adding CO2. Nitrogen and phosphorus concentrations in the SAnMBR effluent fluctuated according to the operating performance of the bioreactor and the properties of its actual wastewater load. Despite these variations, the anaerobic effluent proved to be a suitable growth medium for microalgae (mean biomass productivity was 234 mgl(-1) d(-1)), achie…

Comparison of different removal techniques for selected pharmaceuticals

2015

[EN] Recently, there is an emergence of endocrine-disrupting compounds, pharmaceuticals, and personal care products (EDC/PPCPs) as important pollutants to remove from drinking water and reclaimed wastewater. In this work, the efficiency of removing pharmaceuticals (PCs) from model aqueous solutions and raw wastewater with ultrafiltration (UF), nanofiltration (NF), activated carbon adsorption (AC), biological methods (SBR) and oxidation with ClO2 was investigated. Some treatments have also been used as combined processes: UF + NF, UF +AC, SBR + ClO2. Ibuprofen, Acetaminophen, Diclofenac, Sulfamethoxazole, Clonazepam, and Diazepam were selected as model compounds. In order to evaluate their r…