Variation in Raw Wastes (slight to extreme)............ | (0-6 pts. range) |
Variations do not exceed those normally or typically expected.......... | 0 |
Recurring deviations or excessive variations of 100 to 200 percent in strength and/or flow.................................... | 2 |
Recurring deviations or excessive variations of more than 200 percent in strength and/ or flow................................. | 4 |
Raw wastes subject to toxic waste discharges........................ | 6 |
Pretreatment |
Screening, comminution.................... | 3 |
Grit removal.............................. | 3 |
Plant pumping of main flow................ | 3 |
Standby power supply...................... | 2 |
Flow Equalization.......................... | 2 |
Primary Treatment |
Primary clarifiers........................ | 5 |
Combined sedimentation/ digestion............................... | 5 |
Chemical addition (except chlorine, enzymes)...................... | 4 |
Secondary Treatment |
Trickling filter w/sec. clarifiers.............................. | 10 |
Activated sludge w/sec. clarifiers (including ext. aeration and oxidation ditches................................. | 15 |
Stabilization ponds without aeration................................ | 5 |
Aerated lagoon............................ | 8 |
Chemical Stabilization.................... | 5 |
Advanced Waste Treatment |
Polishing pond............................ | 2 |
Chemical/physical - without secondary.................................. | 15 |
Chemical/physical - following secondary............................... | 10 |
Biological or chemical/ biological.............................. | 12 |
Ion exchange.............................. | 10 |
Reverse osmosis, electrodialysis......................... | 15 |
Chemical recovery, carbon regeneration............................ | 4 |
Additional Treatment Processes |
Dissolved air flotation units............. | 5 |
Chemical/physical odor control............ | 4 |
Influent/effluent pump stations........... | 3 |
Wastewater pump stations.................. | 3 |
Solids Handling |
Thickening................................ | 5 |
Anaerobic digestion....................... | 10 |
Aerobic digestion......................... | 6 |
Evaporative sludge drying................. | 2 |
Mechanical dewatering..................... | 8 |
Solids reduction (incineration, wet oxidation).......................... | 12 |
Disinfection |
Chlorination or comparable................ | 5 |
On-site generation of disinfectant........ | 5 |
Ultraviolet disinfection.................. | 10 |
Ozonation................................. | 10 |