Wastewater Characterization and Process Reliability for Potable Wastewater Reclamation

This research effort was initiated to quantify water quality criteria of importance in evaluating the performance of a wastewater treatment facility producing a product water potentially available for potable reuse. Additionally, the reliability of individual unit processes was evaluated and the effects of process instability on product water-quality were investigated. The sequence of unit processes used in the study to treat municipal wastewater consisted of screening, degritting, primary clarification, biological treatment with completely-mixed activated sludge, high-pH lime coagulation, single-stage recarbonation with liquid carbon dioxide, gravity filtration, and two-stage activated carbon adsorption. Flows through the pilot plant ranged from 9.6 liters per second (152 gpm) for the activated sludge influent to 1.1 liters per second (18 gpm) for the product water. Twenty-four-hour composite samples were collected daily for routing analyses; weekly composite samples were used for metals determinations. The final product water complied with the quality criteria of the National Interim Primary Drinking Water Regulations in all respects. Significant process instabilities had little effect on product water quality due to the redundant nature of the treatment system employed