DESIGN ALTERNATIVES
Six design alternatives were evaluated for feasability, constraints, and client requests. The table below displays the alteratives evaluated, a general evaluation, and whether or not the alternative was pursued further.
| Design Alternative | Evaluation | Reject/Pursue |
|---|---|---|
| Replace Existing Softener Column | Current system indicates improper performace. Does not definitively solve the problem. | Rejected |
| Coagulation/Flocculation | Requires ADEQ permitting. Full-time monitoring required. Must handle sludge disposal. | Rejected |
| Dilution | Dilution is not the solution to pollution. Requires unecessary volumes of water. | Rejected |
| Reverse Osmosis | Does not require ADEQ permit. Recovered water can be reused onsite. Reject water can be evaporated with solids disposed of in landfill. | Pursued |
| Increased Blowdown Schedule | Requires chemicals that strip the inside of the boiler. Requires additional volumes of water. | Rejected |
Reverse Osmosis
The RO process is where water high in TDS or conductivity is forced through a semipermeable membrane in the direction opposite to that of natural osmosis, as shown in figure on the right. This process requires a large amount of pressure to oppose natural osmosis and produces TDS concentrated water as a byproduct. Fine pores in the membrane allow water to pass through but not any contaminants. The large membrane is wrapped around a center core which collects all of the permeate water that has passed through the membrane. The treated permeate water and the rejected concentrate water are then able to be collecetd individually. This system is the most viable for reuse of the water onsite because the water is treated to an acceptable level to be discharged or reused onsite.
