(DE3716851-A)      Waste dangerous to the environment in the form of solids, sludge or mixts. of solids, sludge or liq. waste with bonding agents such as cement are stored in underground cavities filled with water or brine by first forming a layer of a specific heavy liq. which is nonmiscible with the water or brine under the water or brine and then passing the waste through a tube into the water immiscible liq., the density of the waste being greater than that of the water immiscible liq.    ADVANTAGE -   The cavity is filled with waste and the water or brine removed without contact with the waste.    (4pp)    (DE3716851-C)      Waste dangerous to the environment in the form of solids, sludge or mixts. of solids, sludge or liq. waste with bonding agents such as cement are stored in underground cavities filled with water or brine by first forming a layer of a specific heavy liq. which is nonmiscible with the water or brine under the water or brine and then passing the waste through a tube into the water immiscible liq., the density of the waste being greater than that of the water immiscible liq.    ADVANTAGE -   The cavity is filled with waste and the water or brine removed without contact with the waste.    (EP291946-B)      A process for the introduction of environmentally hazardous, solid or sludge-like wastes and mixts.    (6) of solid, sludge-like or liq. wastes with binders into underground cavities (1) filled with water or brine soln., characterised in that a liq. of relatively high specific gravity immiscible with water or brine soln. is added to form a layer beneath the water or the brine soln. (2), in that the wastes or the mixts. (6) of waste and binders are introduced through a feed pipe (4) into the liq. (5) immiscible with water or brine soln., the density of the wastes or of the mixts. (6) of waste and binders having to be higher than that of the liquid (5) immiscible with water or brine soln. and in that the water displaced by filled with waste or the displaced salt brine (2) is removed upwards.    (4pp)    (US4976569-A)      Ecologically harmful waste is stored in a subterranean cavity having an opening to the surface, and is filled with water or brine. Process comprises (a) introducing an immiscible liq. which is heavier than water or brine into the cavity below water/brine to form layers; (b) inserting a conduit into the opening; (c) lowering the conduit until its lower end is into the liq. layer; (d) introducing waste into the liq., having density higher than that of the liq.; and as removing the water/brine displaced by the waste from the opening.    ADVANTAGE -   Chlorofluorocarbons can be used as water/brine immiscible liq.    (4pp)