Sludge bulking has been a problem ever since the activated sludge process was introduced for wastewater treatment. The problems were accentuated when low-loaded processes for nitrogen removal were introduced. Sludge bulking may appear in many forms and be caused by many different factors. Common in low-loaded processes are bulking caused by mass-appearance of filamentous bacteria. […]
Författare
ERIK SÄRNER och LARS KARLSSON
Nyckelord (Keyword)
Sludge bulking, filaments, selector, kinetic control, metabolic control, nitrogen remova
Årgång
1997
Nummer
3
Utgåva
Anaerobic biological treatment has proven to be a successful method for reducing Cr(VI) in a leachate from Vargön Alloys AB. Influent chromium concentrations ranged from 10-120 mg/L and satisfactory reduction was achieved in both laboratory and pilot plant studies, as long as sufficient amounts of electron donor were added. Glucose, acetic acid and sulfite evaporator […]
Författare
KAREN ANDERSSON and MARIA ROSEN
Nyckelord (Keyword)
hexavalent chromium, chromate reduction, biological treatment, biofilm process, suspended carriers, electron donor
Årgång
1997
Nummer
3
Utgåva
The objectives of this study were to investigate the possible effects of freeze/thaw-drying and drying as sludge dewatering methods on the organic matter, nitrogen, and phosphorus content in the sludge. The research work was carried out on three different levels. The effect of natural sludge dewatering on the overall status of the sludge was mainly […]
Författare
DANIEL HELLSTRÖM and ELISABETH KVARNSTRÖM
Nyckelord (Keyword)
natural sludge dewatering, combined freezing and drying, northern Sweden, organic matter, phosphorus, nitrogen, cold climate engineering
Årgång
1997
Nummer
3
Utgåva
The paper describes the use of wooden pipes, particularly drilled pine logs, as rural water conduits in Finland. The first documented case of such a system serving a single house is from Ilmajoki, Ostrobothnia from 1865. Later on, the system was expanded and the first joint system was completed in 1872. The latter scheme was […]
Författare
TAPIO S. KATKO
Nyckelord (Keyword)
water supply, wooden pipes, pipe drilling, water cooperatives, evolution, history, Finland.
Årgång
1997
Nummer
3
Utgåva
Activated sludge is a complex ecosystem consisting of bacteria, protozoa, yeast and virus. Because bacteria are such a large and important component of activated sludge floes, bacterial adhesion is a crucial mechanism of the flocculation. We have studied how electrostatical interactions influence floe stability and sedimentation in water with different ionic composition. Changes in floe […]
Författare
ANNA ZITA och MALTE HERMANSSON
Nyckelord (Keyword)
activated sludge, flocculation, bacterial adhesion, hydrophobicity.
Årgång
1997
Nummer
3
Utgåva
Segmented flow extraction has been applied to studies of the n-octanol/water partition of aquatic humus. This material is a heterogeneous mixture of compounds many of which have surfactant properties complicating the studies. The segmented flow extraction method is proved to be a simple and useful tool for screening the lipophilicity of humus thereby aiding in […]
Författare
YU-HUI ZHANG and LARS-GÖRAN DANIELSSON
Nyckelord (Keyword)
H-octanol, partition constant (coefficient), humic substance, humus, segmented flow extraction
Årgång
1997
Nummer
3
Utgåva
Lake and reservoir eutrophication is a complex process involving a variety of factors which are difficult to act upon simultaneously. The process is triggered off and perpetuated by nutriment inputs from the drainage basin. These may come into play at a later stage however, when the water body stratifies thermally in the summer, cau-sing phosphorus […]
Författare
ERIK GONAY and MICHEL LAFFORGUE
Nyckelord (Keyword)
Eutrophication, lake, aeration.
Årgång
1997
Nummer
3
Utgåva