Abstract: The present invention relates to a method for decreasing the contents of metals, metalloids, nitrate and nitrite, respectively, in raw water flowing through a basin (1), whereby water containing either oxygen, oxygen-releasing substances, naturally occurring micro-organisms and/or substrates therefore is intermittently introduced to the basin (1) through horizontally arranged infiltration/extraction means (2) above and below the injection pipes of raw water, and by alternating the withdrawal and infiltration of conditioned water between the horizontal means so that essentially a vertical flow of water is created between these means, thereby creating a reaction zone for purification of raw water before it reaches the central extraction well. The water to be purified is fed into the basin by horizontally arranged feeding pipes (5) and the extraction of purified water from said at least one extraction well (3) is such that a substantially negative pressure is created around said at least one extraction well (3).

Abstract: The present invention relates to a method for decreasing the contents of metals, metalloids, nitrate and nitrite, respectively, in raw water flowing through a basin (1), whereby water containing either oxygen, oxygen-releasing substances, naturally occurring micro-organisms and/or substrates therefore is intermittently introduced to the basin (1) through horizontally arranged infiltration/extraction means (2) above and below the injection pipes of raw water, and by alternating the withdrawal and infiltration of conditioned water between the horizontal means so that essentially a vertical flow of water is created between these means, thereby creating a reaction zone for purification of raw water before it reaches the central extraction well. The water to be purified is fed into the basin by horizontally arranged feeding pipes (5) and the extraction of purified water from said at least one extraction well (3) is such that a substantially negative pressure is created around said at least one extraction well (3).

Abstract: Processes for the removal of nitrogen compounds from a supply of raw water are disclosed, including an initial denitrification step followed by aeration to release cell-bound nitrogen in the form of ammonium ions from the bacteria produced in the denitrification step without converting the ammonium ions into nitrate or nitrite ions, and precipitating the ammonium ions from the water to produce a substantially nitrogen free supply of water. The precipitation preferably includes treating the water with magnesium and phosphate ions to precipitate the ammonium ions in the form of struvite.

Abstract: A lying rotatable drum for continuous biological decomposition which includes at least one transversal partition for dividing the container interior into chambers. The partition has opening to transmit liquid between the chambers. Guide means are also provided.

Abstract: A process for the purification of ground water is disclosed which comprises injecting conditioned water into a recharge well, simultaneously withdrawing water from an adjacent recharge well in order to create a purification zone therebetween, and withdrawing purified water from a supply well in an aquifer.

Abstract: The invention relates to a process for decreasing the content of nitrate in ground water, artificial ground water, that is infiltrated surface water, or surface water flowing through an aquifer or through a basin or a filter containing naturally occurring filter material. Water containing denitrification organisms and/or substrate therefore is introduced intermittently through a number of injection wells or injection pipes arranged around one or more extraction wells or extraction pipes for purified water. During each introduction of water containing denitrification organisms and/or substrate therefore said water is fed to only some of said injection wells or pipes and simultaneously water is drawn from nearby, adjacent or intervening injection wells or pipes for the purpose of creating a denitrification zone at a distance sufficiently far from the extraction well or extraction pipe.

Abstract: A process for precipitating heavy metals from wastewater containing sulfate ions by treatment of the water with sulfate reducing bacteria. Said bacteria will reduce the sulfate ions to hydrogen sulfide which in its turn will precipitate the metal ions in the form of metal sulfides. According to the invention the bacteria are cultured in one or more culturing vessels in the presence of a nutritive solution and a portion of the wastewater, and the resulting aqueous solution containing hydrogen sulfide produced by the bacteria is introduced into a precipitation vessel together with the remaining major portion of the wastewater.

Abstract: A process for the coulometric determination of the content of a component dissolved in water, e.g. oxygen gas in sea-water, and a coulometer cell for carrying out said process. The cell consists of an elongated, central measuring cell (1) and two auxiliary cells (2) which are directly connected to each end of the measuring cell (1). Electrolysis is performed simultaneously in the measuring cell (1) and the auxiliary cells (2) under such conditions that the concentration of the dissolved component will decrease at the same rate in all three cell elements.

Abstract: A procedure for separating and recovering marsh gas from bog mud. The marsh gas is separated from the mud by conducting the mud into a separating space carrying a pressure lower than the pressure prevailing in the bog, and from which said space the gas separating from the mud is conducted to a place of storage or of use.