Alla artiklar

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 […]

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 […]

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 […]

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. […]

The hardness of water, or rather the concentration of calcium and the alkalinity, has throughout the years been described with great diversity and imagination. The aim has always been to simplify the actual, nuanced and complex chemistry in question. The many assumptions and terms for these simplifications have in course of time become vague or […]

The Swedish company, VYRMETODER AB has developed a means of treating water in an artificial aquifer according to the VYREDOX method. The method is based on degassing and aeration of raw water which is then infiltrated into the artificial aquifer. The article informs about three VYRAKVI plants installed in the mountainous region in the north […]

There are wastewater treatment plants in Uppsala municipality with both high and low copper concentrations in the sludge, this is somewhat surprising as the raw water (groundwater) often is pumped up from the same esker (gravel ridge or glacial origin), the chemical composition or the water is expected to generate strong copper corrosion, as the […]

Hydraulic transients occur at rapid flow changes in pressurized water conveying pipelines. Normally such transients (waterhammer) are considered to be a problem as they might damage the pipeline due to strong pressure peaks, subatmospheric pressures or fatigue. However, normally occurring hydraulic transients have also a potential to be utilized in an advantageous manner. ’The idea […]

The cost for reduction of nitrogen in created ponds does not exceed 45 SEK per kilogram nitrogen. This result is based upon the costs for the creation of ponds with a total area of 27 hectares in southwest Scania 1992-1996, and results from nitrogen budget studies of one pond during three years. Three municipal wastewater […]

Mass-balance studies of nitrogen, phosphorus, and suspended matter have been carried out in a created pond. The pond is situated in the drainage basin of a farmland stream in Scania, southern Sweden. The investigation started shortly after the creation of the pond and has continued for three years. The aim of the study was to […]