Abstract: Process for disposal of a waste ash by addition thereto of sodium salts, preferably sodium sulfur oxide salt Na.sub.2 SO.sub.x where x is 3 and/or 4, in an amount ranging from 5-85 weight percent (dry basis) and adjusting the water percentage to within the range of 6-35%, preferably 15-28%. The coefficient of permeability of the ash and sodium salt is reduced from 10.sup.2 cm/sec to the "impermeable" standard of 10.sup.-6 and below. The preferred mixes also call for a smectite clay additive present in the range of from 0.1% to 5%. A flocculant in amounts of 0.01% to 1% can be substituted for about 3-5% of the water content. A principal source of the Ma.sub.2 SO.sub.x is sodium FGD waste, preferably from the use of Nahcolite (a natural mineral form of sodium bicarbonate) as an SO.sub.x sorbent in the Nahcolite FGC process. The resulting co-disposal process simultaneously renders the highly soluble Na.sub.2 SO.sub.x (10.sup.

Abstract: Baghouse SO.sub.x /NO.sub.x pollution control process comprising injecting from 1 to 25% urea or ammonia along with dry, finely divided sodium bicarbonate or Nahcolite, a naturally occurring form of sodium bicarbonate. The process removes both SO.sub.x and NO.sub.x from the flue gases of utility and industrial plants, incinerators and the like by dry injection into a flue gas duct a sufficient distance upstream of a baghouse to collect spent reagent and additive. The sodium reagent reacts with the SO.sub.2 to form sodium sulfate and also removes NO.sub.x in the form of NO. The urea or ammonia additive prevents the conversion of NO to NO.sub.2 by the sodium reagent, and reduces the concentration of the NO.sub.2 in the exit flue gases to below the NO.sub.2 brown plume visibility threshold (about 30 ppm NO.sub.2, not corrected to 0% O.sub.2, depending on ambient conditions). The additive may be used wet (sprayed into the flue gases in a concentrated water solution) or dry.