| 摘要 |
<p>1,234,106. Treatment of phosphorus-containing waste streams; osmosis; dialysis. DORROLIVER Inc. 31 May, 1968 [31 May, 1967], No. 26193/68. Heading B1X. The treatment of a phosphorus-containing waste stream (defined as a waste liquid, for example sewage or industrial waste, comprising a carrier liquid containing biodegradable waste material, i.e. material which may serve as nutrient for micro-organisms) by a process which comprises feeding the waste stream to a biological reactor as a nutrient supply for micro-organisms contained in the reactor whilst maintaining in the reactor conditions for sustaining the metabolic conversion of nutrients in the waste stream by the micro-organisms, withdrawing a micro-organism-containing stream of carrier liquid from the reactor, feeding the micro-organism-containing stream to one side of a selectively permeable membrane whilst maintaining a pressure drop across the membrane from the one side thereof to the opposite (effluent) side thereof so as to retain the micro-organisms on the one side of the membrane whilst allowing transport by reverse osmosis and/or by dialysis through the membrane of an effluent stream of carrier liquid, and removing the micro-organisms retained by the membrane from the one side thereof as a concentrate stream, is characterized in that calcium ions are added to the phosphorus-containing waste stream thereby to precipitate phosphorus as a phosphate which is retained on the one side of the membrane together with the micro-organisms. It is preferred that the calcium ions are added to the waste stream in the form of calcium oxide (lime) or calcium hydroxide and in a quantity which is sufficient to raise the pH of the waste stream to a value above 8.5 but below 10.0; more than 90 per cent for example 95 per cent or more, of the total (i.e. inorganic and organic) phosphorus present in the waste stream may be removed therefrom. The treatment of the waste stream may be effected in and by apparatus which is disclosed in Specification 1,209,769.</p> |
