Abstract: The present invention provides a method and an apparatus for treating boron-containing waste, which prevent clogging of a waste liquid line, achieve an increase in feeding of a waste liquid to a dryer, make in-drum mixing feasible, and increase the strength of a cement solidification product. A method for treating a boron-containing waste liquid comprises the step of adding an alkali metal element compound and an alkali earth metal element compound to the boron-containing waste liquid, and the step of then drying and powdering the boron-containing waste liquid, wherein the temperature of the boron-containing waste liquid during a period from addition of either the alkali metal element compound or the alkali earth metal element compound until the drying and powdering is maintained at not lower than the precipitation temperature of a compound containing boron and an alkali metal and a compound containing boron and an alkali earth metal.

Abstract: Raw material of algae cultivating medium molded body is manufactured by mixing a mixture containing inorganic material, curing material and algae cultivating nutriment, molding the mixture to molded bodies and curing the molded bodies. The molded bodies are manufactured such that the molded bodies are water floatable having a closed cavity inside the body, or containing density decreasing material for example. The manufacturing method enables to produce algae cultivating medium that can float on water in a large quantity. Industrial waste such as coal ashes and incineration ashes, sands and crushed shells can be used as the inorganic raw material of the medium. As the curing material which solidify the molded body, other than cement, algae cultivating nutriment such as phosphorus compounds can be used. Extrusion molding can favorably be applied for molding molded body. A cylindrically molded body can be sealed the both edges thereof to form a cavity portion inside thereof.