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H Odegaard

Publications and source records attributed to H Odegaard.

17 recordsLinked to original sources
PubMed2005

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. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.

Biodegradation, Environmental↗
PubMed2005

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 4.1 to 26.6 g COD m(-2) d(-1). The trans-membrane pressure (TMP) was very sensitive to fluxes for the used membranes and the experiments were carried out at relatively low fluxes (3.3-5.6 l m(-2) h(-1)). Beside the test with the highest flux, there were no consistent differences in fouling rate between the low- and high-rate reactors. Also, the removal efficiencies were quite similar in both systems. The average COD removal efficiencies in the total process were 87% at 3-4 h HRT and 83% at 0.75-1 h HRT. At high loading rates, there was a shift in particle size distribution towards smaller particles in the MBBR effluents. However, 79-81% of the COD was in particles that were separated by membranes, explaining the relatively small differences in the removal efficiencies at different loading rates. The COD fractionation also indicated that the choice of membrane pore size within the range of 30 kD to 0.1 microm has very small effect on the COD removal in the MBBR/membrane process, especially with low-rate MBBRs.

Biofilms↗
PubMed2004

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. In this paper an overview is given for sludge minimization (sludge mass reduction) options. It is demonstrated that sludge minimization may be a result of reduced production of sludge and/or disintegration processes that may take place both in the wastewater treatment stage and in the sludge stage. Various sludge disintegration technologies for sludge minimization are discussed, including mechanical methods (focusing on stirred ball-mill, high-pressure homogenizer, ultrasonic disintegrator), chemical methods (focusing on the use of ozone), physical methods (focusing on thermal and thermal/chemical hydrolysis) and biological methods (focusing on enzymatic processes).

Biomass↗
PubMed2004

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 4.0 to 7.0 meq/g, as well as of a low and medium molecular weight cationic polyacrylamide with practically equal charge densities. The extent of coagulation of humic substances, determined as the percentage removal of humic substances after filtration through 0.1 microm, could, regardless of the polymer type, be explained by the amount of cationic charge equivalents added per mg TOC of humic substances. The optimal polymer dosage with respect to the extent of flocculation, determined as the percentage removal after filtration through 11 microm could not be explained by this, but the maximum extent of flocculation obtained with each polymer type increased with increasing polyelectrolyte charge density. However, the weak polycation chitosan showed a significantly higher maximum extent of flocculation than would be predicted from its charge density. Polyelectrolyte molecular weight did not show any significant effect on the coagulation of humic substances, nor did it increase the extent of floc separability at 11 microm.

Cations↗
PubMed2003

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 (0.5 h) directly after screening, then a Kaldnes-Filtralite-Sand (KFS) filter removes the particulate COD and detached biofilms at filtration rates of 10-20 m/h. The whole system gave effluent SS and COD less than 30 mg/L and 100 mg/L when total detention time is less than 1 h and small dosage of chemicals (iron and/or cationic polymer) is used. A new scenario of high rate secondary system with a primary Kaldnes coarse media filter in front of high rate MBBR and the KFS filter is proposed and discussed. This scenario with total HRT less than 2h is more suitable for high influent SS concentrations and may also be extended for nitrogen and phosphorous removal. Compared to conventional secondary treatment, the high rate secondary treatment will be using only 1/5-1/10 of the space, resulting in considerable savings for construction, energy and operation.

Biofilms↗
PubMed2003

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. SS removal efficiencies of around 75% were achieved in the dual Kaldnes primary filter at around 20 m/h without any chemical addition and around 85% at low dosage (1-2 mg/l) of a high MW cationic polymer FO4440SH. In the latter case COD was removed by around 70%. Further experiments were carried out on a multi-media Kaldnes-Filtralite-Sand (KFS) filter for enhanced primary treatment as well as for secondary filtration directly downstream of a high-rate moving bed biofilm reactor, resulting in an extremely compact secondary treatment process. The secondary KFS-filter gave SS-removal efficiencies around 90% (effluent SS < 15 mg/l) and filter run times of around 24 hrs at filtration rates of 10 m/h (sludge loading rates of around 1 kg/m2h) when a small dose (2 mg/l) of polymer was used. It is also demonstrated that the primary filter may also be utilised as a pre-denitrification reactor. A denitrification rate of 1.5 kg NO3-N(equiv.)/m3d was achieved when the filter was operated at a filtration rate of 5 m/h.

Carbon↗
PubMed2002

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. The dosing of a high MW and high charge cationic polymer was, however, found to have an even greater effect on treatment efficiency and especially on head loss development. Both filters were found to be feasible for enhanced primary treatment at high filtration rates (20-30 m/h) especially when dosing low dosages (1-3 mg/l) of polymer. The combination of two media into a dual media filter might take the advantages of both. Further experiments were carried out on a dual media filter consisting of lighter K1L media and heavier K2H media. It was indeed found that the K1L+K2H up-flow filter resulted in better performances in terms of water production when an optimised backwash procedure was taken into account.

Bioreactors↗
PubMed2002

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. In the "productification" strategy it is differentiated between the production of "bio-soils" and production of specific products (energy, nutrients, coagulants etc) and the "marketability" of these products is evaluated. An example of a sludge treatment concept aimed at recycling--the KREPRO process--is presented.

Conservation of Natural Resources↗
PubMed1996

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. The objective of this study was to clinically characterize patients with possible disease in a prevalence study of PD and to indicate the frequency of idiopathic PD in this group of patients. The diagnostic re-evaluation was based on detailed MRI examinations and investigations of dopaminergic drug response after several years of treatment. In a community-based prevalence study in Norway, comprising 245 PD patients, we found 36 patients (15%) with clinical possible PD. The patients with possible disease had significant and clinically important differences in demographic and disease characteristics compared to patients with definite and probable PD. Possible PD patients were older at disease onset, more disabled, and had more neurobehavioral disorders. MRI examinations of 14 of the 36 patients with possible PD in the prevalence study revealed significant group effects compared to an age-matched control group, with reduced pars compacta width and increased cortical atrophy. In individual patients, signal attenuation consistent with vascular lesions of the basal ganglia contributed to diagnostic reclassification. Dopaminergic drug withdrawal revealed no response in 4 of 12 examined patients. Two of the remaining eight patients had a clear short-duration drug response. Six patients had only a varying degree of long-duration response. The re-evaluation of diagnosis indicates that probably less than half of the patients with clinical possible PD have idiopathic disease. Patients with atypical features and diagnosed as possible PD should thus be excluded from studies with a presumed high specificity for idiopathic PD.

Aged↗
PubMed1993

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. The prognosis is usually poor, and widespread metastases soon occur. METHOD: Currently, no case of metastasis to the brain has been reported to the authors' knowledge. RESULTS: This case report describes a patient who, as the first sign of metastatic disease, had symptoms from brain metastases 3 months after splenectomy. CONCLUSION: Magnetic resonance imaging was diagnostic.

Aged↗
PubMed1990

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. Word-reading strategies among the dyslexics and control subjects were investigated with computerized tasks where accuracy and naming latency were recorded. All subjects with pure phonological deficits in reading had symmetrical plana temporale indicating a possible neuroanatomical basis for a characteristic symptom of linguistic processing deficiency in developmental dyslexia.

Adolescent↗
PubMed1989

Symptomatic hemidystonia of delayed onset. Magnetic resonance demonstration of pathology in the putamen and the caudate nucleus.

We present a case of symptomatic hemidystonia of delayed onset. The primary disease was a perinatal, presumed cerebrovascular infarction brought about by febrile illness with convulsions 12 weeks after partus. After many years without neurological symptoms, the hemidystonia started in adolescence, and became stationary after 4 years of mild progression. Magnetic resonance imaging revealed atrophy of the right striatum including the caudate nucleus and putamen. The symptoms responded moderately to treatment with benzhexol.

Adult↗
PubMed1989

Magnetic resonance imaging--a method of studying the size and asymmetry of the planum temporale.

The planum temporale is a triangular region on the upper surface of the temporal lobe. This area of the brain is important for language processing and shows a left-right asymmetry of size in most brains. Particular interest has been focused on the size and asymmetry of the planum temporale in brains of individuals with developmental dyslexia. Magnetic resonance imaging (MRI) is a method that produces excellent morphological details of organic structures. We have developed an MRI method of studying the size and asymmetry of the planum temporale in human brains. Because of considerable variation of anatomical landmarks in this cortical region of the brain, an evaluation of asymmetry is not possible in all brains. Furthermore, our experience with this method indicates that any indirect imaging technique of studying asymmetry of the planum temporale must be evaluated with caution. With this in mind, however, MRI may give valuable anatomical information about the planum temporale in individuals with anomalous language function.

Humans↗
PubMed1975

Fibrinolytic treatment of postoperative deep venous thrombosis.

Eleven patients with deep venous thrombosis were treated with streptokinase. Lysis of thrombi and prevention of pulmonay embolism were achieved in eight patients. Bleeding from the operative wound necessitated transfusions in seven patients. Fibrinolytic treatment of deep venous thrombosis lyses the floating portion of the thrombi. Protection against pulmonary embolism may be expected. The fibrinolytic effect of streptokinase is rapid; its value can be answered only by follow-up examinations.

Adult↗