Nitrogen removal in moving-bed biofilm reactor plants at low temperatures: experiences from Norway.

Cold and diluted wastewater is a major challenge for nitrogen removal at wastewater treatment plants. The moving-bed biofilm reactor (MBBR) process has proven suitable for nitrogen removal under these conditions and several full-scale plants have been in operation for more than 20 years. These plants are still performing well, even at above design loads.

Complete polyp resection with cold snare versus hot snare polypectomy for polyps of 4-9 mm: a randomized controlled trial.

Background: Endoscopic screening with polypectomy reduces the incidence of colorectal cancer (CRC). Incomplete polyp removal may attenuate the effect of screening. This randomized trial compared cold snare polypectomy (CSP) with hot snare polypectomy (HSP) in terms of complete polyp resection.

Integrated fixed-film activated sludge membrane bioreactors versus membrane bioreactors for nutrient removal: A comprehensive comparison.

This research elucidates the pollutants (nutrients and carbon) removal performance and nitrous oxide (NO) emissions of two pilot plants. Specifically, a University of Cape Town (UCT) Membrane Bioreactor (MBR) plant and an Integrated Fixed Film Activated Sludge (IFAS)-UCT-MBR plant were investigated. The plants were fed with real wastewater augmented with acetate and glycerol in order to control the influent carbon nitrogen ratio (C/N).

Nitrous oxide from moving bed based integrated fixed film activated sludge membrane bioreactors.

The present paper reports the results of a nitrous oxide (NO) production investigation in a moving bed based integrated fixed film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant designed in accordance with the University of Cape Town layout for biological phosphorous removal. Gaseous and liquid samples were collected in order to measure the gaseous as well as the dissolved concentration of NO. Furthermore, the gas flow rate from each reactor was measured and the gas flux was estimated.

Hybrid activated sludge/biofilm process for the treatment of municipal wastewater in a cold climate region: a case study.

A hybrid activated sludge/biofilm process was investigated for wastewater treatment in a cold climate region. This process, which contains both suspended biomass and biofilm, usually referred as IFAS process, is created by introducing plastic elements as biofilm carrier media into a conventional activated sludge reactor. In the present study, a hybrid process, composed of an activated sludge and a moving bed biofilm reactor was used.

Membrane filtration for particles removal after ozonation-biofiltration.

With the process combination Ozonation-Biofiltration-Membranefiltration (the OBM-process) an average removal of 63% for UV-absorbance (UV(254)), 79% for color, and 28% for DOC was obtained treating NOM containing surface water. In this paper, focus has been made on the removal of particles after the ozonation and biofiltration treatment steps, using a submerged hollow fiber ultrafiltration membrane reactor. For this purpose the membrane performed adequately.

Evaluation and testing of fine mesh sieve technologies for primary treatment of municipal wastewater.

Fine mesh sieve technologies were tested in full scale at several municipal wastewater treatment plants. A screening test was used to characterize wastewater and establish the design criteria for the sieves. To achieve high removal efficiencies it was crucial to operate the sieves with a filter mat.

Innovations in wastewater treatment: the moving bed biofilm process.

This paper describes the moving bed biofilm reactor (MBBR) and presents applications of wastewater treatment processes in which this reactor is used. The MBBR processes have been extensively used for BOD/COD-removal, as well as for nitrification and denitrification in municipal and industrial wastewater treatment. This paper focuses on the municipal applications.

Tracking particle size distributions in a moving bed biofilm membrane reactor for treatment of municipal wastewater.

A study has been conducted to investigate the effect of loading rates on membrane fouling in a moving bed biofilm membrane reactor process for municipal wastewater treatment, especially analysing the fate of submicron colloidal particles and their influence on membrane fouling. Two operating conditions defined as low and high organic loading rates were tested where the development and fate of the particulate material was characterised analysing the particle size distributions throughout the process. Analysis of the membrane performance showed higher fouling rates for the high-rate conditions.

High-rate wastewater treatment combining a moving bed biofilm reactor and enhanced particle separation.

Many cities around the world are looking for compact wastewater treatment alternatives since space for treatment plants is becoming scarce. In this paper development of a new compact, high-rate treatment concept with results from experiments in lab-scale and pilot-scale are presented. The idea behind the treatment concept is that coagulation/floc separation may be used to separate suspended and colloidal matter (resulting in > 70% organic matter removal in normal wastewater) while a high-rate biofilm process (based on Moving Bed biofilm reactors) may be used for removing low molecular weight, easily biodegradable, soluble organic matter.

Effect of organic loading rate on a wastewater treatment process combining moving bed biofilm and membrane reactors.

The effect of moving bed biofilm reactor (MBBR) loading rate on membrane fouling rate was studied in two parallel units combining MBBR and membrane reactor. Hollow fiber membranes with molecular weight cut-off of 30 kD were used. The HRTs of the MBBRs varied from 45 min to 4 h and the COD loading rates ranged from 4.

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water.

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes.

The effects of polymer characteristics on nano particle separation in humic substances removal by cationic polymer coagulation.

Removal of humic substances by coagulation involves nano- and microparticle transport processes. The objective of this paper has been to describe the effects of polymer characteristics on the initial coagulation of nano-sized humic substances and on the aggregates' ability to form larger flocs. The study offers a direct comparison of four different low molecular weight polycations, with charge densities ranging from 4.

Sludge minimization technologies--an overview.

The management of wastewater sludge from wastewater treatment plants represents one of the major challenges in wastewater treatment today. The cost of the sludge treatment amounts to more than the cost of the liquid in many cases. Therefore the focus on and interest in sludge minimization is steadily increasing.

A high-rate secondary treatment based on a moving bed bioreactor and multimedia filters for small wastewater treatment plants.

For small wastewater treatment plants (WWPTs), high-rate secondary treatment systems with good treatment efficiency and easy, stable, and robust operation are called for. In this paper an experimental study on a high rate secondary treatment based on moving bed biofilm reactor (MBBR) and multimedia filters is presented. A high rate MBBR converts easily biodegradable SCOD in short HRT (0.

Coarse media filtration--an alternative to settling in wastewater treatment.

In this paper coarse media filtration has been analysed as an alternative to the traditional settling in primary, secondary and tertiary treatment of wastewater. Various filter media configurations were evaluated for enhanced primary filtration. It was found that a dual media configuration based on Kaldnes biofilm media (1 and K2modified) were most suitable when taking both separation efficiency as well as filter run time into consideration.

Wastewater sludge as a resource: sludge disposal strategies and corresponding treatment technologies aimed at sustainable handling of wastewater sludge.

The paper discusses different strategies for the disposal of wastewater sludge, particularly the "use on land" strategy and the "productification" strategy. In the "use on land" strategy the new regulations in Europe call for stabilization as well as disinfection of sludge to be used on land. The paper discusses the design and operation experiences with stabilization/disinfection methods in Norway where such treatment has been compulsory since 1995.

Coarse media filtration for enhanced primary treatment of municipal wastewater.

In these experimental studies enhanced primary treatment in coarse media filters has been evaluated. The coarse media used in the filters have been plastic carriers normally used for moving bed bioreactors, a Kaldnes carrier K1 with density < 1 g/cm3 (K1L) and a bigger carrier K2, that was used both in a lighter, floating (K2L) version and a heavier, sinking one (K2H). The results demonstrated that media characteristics significantly influenced filter performance.

Aerobic moving bed biofilm reactor treating thermomechanical pulping whitewater under thermophilic conditions.

The continuously operated laboratory scale Kaldnes moving bed biofilm reactor (MBBR) was used for thermophilic (55 degrees C) aerobic treatment of TMP whitewater. In the MBBR, the biomass is grown on carrier elements that move along with the water in the reactor. Inoculation with mesophilic activated sludge gave 60-65% SCOD removal from the first day onwards.

The use of dissolved air flotation in municipal wastewater treatment.

Flotation can be used in municipal wastewater treatment plants in different ways. Since the pollutants in wastewater to such a large extent are associated with particles, a very substantial treatment efficiency can be reached at a very small space, by using flotation in a chemical (or enhanced primary) treatment scheme. This is demonstrated in this paper with reference to results from small, prefabricated chemical plants based on flotation, which are frequently used in Norway.

Biological phosphorus and nitrogen removal in a sequencing batch moving bed biofilm reactor.

Biological phosphorus and nitrogen removal in biofilm processes have a potential advantage compared to activated sludge processes, because of less vulnerability with respect to sludge loss and because biofilm processes, in general, are more compact with a smaller footprint. Experiments have been carried out in a moving bed biofilm reactor operated as a sequencing batch reactor (SBR), with simultaneous nitrification, phosphorus uptake and denitrification in the aerobic phase. In order to achieve good phosphorus and nitrogen removal, the length of the anaerobic period should be tuned to achieve near complete removal of easily biodegradable COD in the anaerobic period, and the length of the aerobic period should be long enough for complete nitrification.

Patient characteristics, MRI examination, and dopaminergic drug response in clinical possible Parkinson's disease.

Patients with parkinsonism can be classified as clinical definite, probable, possible, or unlikely Parkinson's disease (PD). Possible PD includes patients with PD according to conventional diagnostic criteria and with at least a moderate response to dopamine agonists. However, these patients have clinical features that may reduce the probability for idiopathic PD.

Diagnosis of brain metastases from a primary hemangiosarcoma of the spleen with magnetic resonance imaging.

Background: Primary malignant splenic neoplasms are rare tumors. Apart from involvement of the spleen by malignant lymphoma, hemangiosarcoma is the most common form of primary malignant neoplasm in the spleen. The diagnosis often is made at autopsy or after spontaneous splenic rupture.

MRI evaluation of the size and symmetry of the planum temporale in adolescents with developmental dyslexia.

MRI technique was used to examine the size and symmetry of the plana temporale in 19 dyslexic students in grade 8 and in carefully matched control subjects. The results demonstrated a high frequency of planum symmetry among the dyslexics (70%) whereas symmetry was observed in only 30% of the control subjects. It was not possible to demonstrate any clear association between symmetry/asymmetry of planum temporale and handedness.