Abstract: An aqueous scale inhibitor product is corrosive to the elongated feed lines of a geothermal well due to the length of such feed lines, extended residence time of the product therein, and/or the elevated internal temperatures reached therein, and such corrosivity of aqueous scale inhibitor products is reduced when the scale inhibitor actives are no more than about 10 weight percent of the aqueous solution, when the pH of such aqueous solution is raised to the range of from about 5.5, or 8, to about 12, when carbohydrazide is added to such product, and by combinations of such factors.

Abstract: The instant invention comprises a method of preventing ash deposition on equipment comprising adding a hemicellulose extract to phosphonate to form a mixture. The ratio hemicellulose extract to phosphonate in the mixture is preferably between 75 to 1 to 100 to 1. Once the mixture is formed, it is introduced to the equipment by injection into the spray water line. (Dosages of the mixture were based on the water flow). Alteratively, molasses maybe used in place of the hemicellulose extract to achieve comparable results by the instant method.

Abstract: A method of and a system for monitoring circulating water systems for conditions susceptible to deposition of a variety of scaling deposits. The invention includes presenting upset conditions at a surface area in the circulating water stream, or in a sidestream in a conduit connected to the main circulating water system, and closely monitoring either heat transfer rate or heat transfer resistance at the water contact surface adjacent the area of upset. When conditions for scaling are present, the upset conditions tend to cause formation of scale deposits at the upset area before the scaling occurs in the main circulating water stream, permitting countermeasures to be taken which inhibit scaling. In the specific case of boilers, heat exchangers or cooling towers, CaCO.sub.3 scaling is monitored at an area where the upset conditions are present, the upset conditions are an increase in the heat transfer rate. The solubility of CaCO.sub.

Abstract: The concentration of at least one metal species in an aqueous system is at least reduced in an aqueous system that contains at least one kind of chelating agent, by adding to such system a species or plurality of species of bacteria that have a low toxicity for the metal species, and establishing and maintaining a biomass in the system for a sufficent time period to reduce the metal concentration.

Abstract: A method of improving the SO.sub.2 scrubbing efficiency of flue gas desulfurization scrubbers which comprises conducting the scrubbing operation in such scrubbers in the presence of an oil-soluble surfactant.

Abstract: A carboxylic acid which has a pK.sub.a within the range of 2 to 7 and the ability to increase the effective alkalinity of fly ash for flue gas desulfurization. Carboxylic acid may be combined with adjuvants. Generally carboxylic acids with dispersant properties are preferred. Adjuvants which enhance the dispersant qualities of carboxylic acid are desirable.

Abstract: Gypsum scale inhibitors useful under wet flue gas desulfurization (FGD) scrubber temperature and pH conditions. The gypsum inhibitors advantageously prevent or minimize gypsum scale formation and crystal growth in mist eliminator wash water and in the scrubber internals. Specific inhibitors contemplated include copolymers of modified acrylic acid/acrylamide; acrylic acid/vinyl acetate; acrylic acid/maleic anhydride; acrylic acid/acrylate ester; and combinations thereof. In addition, gypsum scale inhibitors comprising phosphonate-polymer blends of hexamethylene diamine tetra (methylene phosphonic acid) salts and polymaleate, poly(acrylic acid/ethylacrylate), poly(acrylic acid/N-methoxypropyl acrylamide/acrylamide), poly(acrylic acid/N-propyl acrylamide/acrylamide), and combinations thereof are also contemplated.

Abstract: Sulfate-reducing bacteria present in industrial waste waters can be controlled by using hydrogen peroxide in combination with non-oxidizing organic biocides known to be effective against sulfate-reducing bacteria.

Abstract: Sulfate-reducing bacteria present in industrial waste waters can be controlled by using either the biocide glutaraldehyde or a blend of sodium dimethyldithiocarbamate and disodium ethylene bisdithiocarbamate.

Abstract: A method of preventing scale and deposit formation on the surfaces of mist eliminators in wet scrubber flue gas desulfurization systems which utilize intermittent wash cycles which comprises coating the surfaces of these mist eliminators with a thin coating of talc.

Abstract: Alkali metal nitrite controls sulfate-reducing bacteria and odors in flue gas desulfurization scrubber sludges.

Abstract: A deposit monitor comprising a constant head tank which empties into a graduated cylinder and a cylindrical drain fitted with an inner tube which defines an annular space. Water flowing through the constant head tank into the graduated cylinder, if it is deposit forming, will gradually plug the annular space and increase the liquid level in the second tank, thereby providing a simple method for determining whether or not scaling is occurring.