Quality parameter_Phosphate (A)
Suspended solids (mg/L) 800-1200 pH (unit) 1-2
Ammonia (mg/L) Sulfate (mg/L) Chloride (mg/L) Total phosphate (mg/L) Fluoride (mg/L) Aluminum (mg/L) Iron (mg/L)
Radium 226 (picocuries/L)
450-500 4000 58 3-5M 6-8.5M 110 85 60-100
M=thousand. Source: Ref. 8.
ammonium phosphate; (c) phosphates and fluoride wastes from phosphate and superphosphate production; (d) acidic spillages from sulfuric acid and phosphoric acid production; (e) spent solutions from the regeneration of ion-exchange units; (f) phosphate, chromate, copper sulfate, and zinc wastes from cooling tower blowdown; (g) salts of metals such as iron, copper, manganese, molybdenum, and cobalt; (h) sludge discharged from clarifiers and backwash water from sand filters; and (i) scrubber wastes from gas purification processes.
Considerable variation, therefore, is observed in quantities and wastewater characteristics at different plants. According to a UNIDO report , the most important factors that contribute to excessive in-plant materials losses and, therefore, probable subsequent pollution are the age of the facilities (low efficiency, poor process control), the state of maintenance and repair (especially of control equipment), variations in feedstock and difficulties in adjusting processes to cope, and an operational management philosophy such as consideration for pollution control and prevention of materials loss. Because of process cooling requirements, fertilizer manufacturing facilities may have an overall large water demand, with the wastewater effluent discharge largely dependent on the extent of in-plant recirculation . Facilities designed on
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