Identification and Control of Calcium and Solids Fouling in a Packed Tower Steam Stripper

Wastewater from a solid dosage pharmaceutical manufacturing plant and research activities are combined and processed through an onsite wastewater pre-treatment system. The system consists of pH control and packed tower steam stripping. Solids accumulation and scale formation within the conveyance and treatment system adversely impacts performance. A comprehensive sampling program of the wastewater conveyance and treatment system was conducted to identify and determine the source of the fouling. Standard analytical analysis and Computer Controlled Scanning Electron Microscopy (CCSEM) were employed for scale and source identification. USEPA's MINEQL+ chemical speciation model and Watercycle™ (scaling and corrosion model) were utilized to better understand the fate of calcium within the wastewater treatment and conveyance system. Bench scale tests were used to determine the appropriate chemistry for cleaning the fouled media within the treatment system. Results of the modeling and bench scale tests indicated citric and sulfamic acid were effective in cleaning fouled media and is an effective calcium scaling control agent.