Abstract: A water purifier capable of accomplishing water purification in a water area in which water purification is desired by merely dipping it in water without any additional operation. The water purifier includes a hollow cylindrical cell chamber member, a seal member arranged at each of both ends of the cell chamber member so as to pressedly seal the end, a terminal inserted through the seal member and electrically connected at one side thereof to each of the cells received in the cell chamber member, an annular tightening member threadedly fitted on each end of the cell chamber member to press the seal member into each end of the cell chamber member, an electrode plate connected to the other side of the terminal, and a water-permeable agent basket having a calcium fluoride agent and an iron salt agent received therein and releasably mounted on the tightening member through locking members so as to surround the electrode plate.

Abstract: A method enabling thorough purification of lacustrine water with simple operation in an energy-saving manner within a short period of time and being free from the possibility of secondary public nuisance, and further a filthy water purification boat for implementing said method. According to this invention, while operating filthy water purification boat having an electrolyzing device for calcium fluoride, DC current power source, and coagulant pouring device mounted thereon on lakes or marshes, the electrolyzing device is operated and coagulant is fed into a pipe having a coagulant pouring nozzle. Lacustrine water, while passed through electrodes, is fed with fluorine ion and coagulant, and polluting substances coagulate and turn into flocks of a large diameter.

Abstract: Methane is produced by fermentation of organic material, wherein the organic material is finely ground to an average particle size of less than 3 mm, mixed with a seed sludge containing bacteria which decomposes the organic material to methane, and the mixture maintained at a temperature which promotes the decomposition of the organic material to methane by the bacteria.

Abstract: To remove fluoride from raw water, whether the fluoride is in solution as an ion or in the form of a colloidally-dispersed salt, calcium ions are first introduced into the water. The resultant calcium fluoride is adsorbed on a floc during passage of electric current through the raw water. The floc may be formed from organic matter already present in the raw water or from diatomaceous earth floc in a separate operation, the diatomaceous earth floc then being added to the raw water. Adsorption on floc whether originating in organic matter or in diatomaceous earth is facilitated by the passage of electric current through the raw water and by the addition of a surfactant.