The present invention is directed to a lamp assembly for use in a point-of-use water treatment system or other device. The lamp assembly includes a condensing element to condense mercury in a bulb within the arc path of opposing filaments when the bulb is de-energized. In one embodiment, the time required for the lamp assembly to produce light upon subsequent re-energization of the bulb is significantly reduced because the mercury is in the intermediate portion of the bulb, within the filament arc path.
Alum, used as a coagulant in water treatment, is recovered from clarifier sludge by adjusting the pH of the sludge downward to produce an aqueous clarifier sludge solution, and contacting the aqueous clarifier sludge solution with one side of a semi-permeable cation exchange membrane while contacting the other side of the membrane with an acidic sweep solution. By virtue of the Donnan co-ion exclusion phenomenon, aluminum ions, which are trivalent, pass readily through the membrane, in preference to divalent and monovalent cations, and consequently heavy metal carryover is relatively low. Organic matter carryover is substantially excluded, and consequently, the recovered alum can be reused without the potential for trihalomethane formation. The reactor is preferably in the form of a stack of spaced membranes, with the aqueous clarifier sludge solution and the acid sweep solution flowing through alternate spaces. The same process can be used for recovery of ferric iron coagulants.
A water treatment method uses a removable, disposable cartridge having an internal mesh structure. A disposable heater heats water fed to the cartridge. Precipitated solids collect on the mesh surface provided temperature and residence times are appropriately maintained. The heat breaks down the bicarbonate hardness of the water thereby depositing carbonates on the mesh surface and heavy metals will be codeposited due to the resultant change in pH. The cartridge has a head-space for collecting entrained gases such as volatile organic compounds, chlorine and air. Water sterility is achieved by heating the water over an appropriate period of time. Turbidity is removed within the cartridge due to settling induced by the low fluid velocity controlled by a controller and by a filter provided at the outlet of the cartridge. The filter will become blocked when bicarbonate hardness is carried over forcing a user to replace a spent cartridge. Heat economy and a cool treated water outlet stream are secured by use of a heat exchanger. Water is fed from the cartridge, through an intercooler and the heat exchanger to a storage tank. Water in the storage tank is kept out of contact with air by a movable barrier. Eventually, the. water is fed from the storage tank to a dispenser and can subsequently be used in a post-mix beverage dispenser. A visual display indicates the status of the water treatment system and a water release control system releases treated water from the water treatment system only after water in the system reaches a selected temperature and steam is released form the system so that the released water is potable.