Which is a limitation of softening?

• A. Increased hardness of water
• B. Ultimate disposal of process wastes
• C. No change in operating costs
• D. Lower pH as a result of softening

Answer: (B)

The key thing softening has to account for is how to handle the waste produced during the process. In ion-exchange softening, resin regeneration creates a highly concentrated salt brine that must be disposed of under strict environmental rules, often with pretreatment and permits. This waste stream can drive substantial ongoing disposal costs and limit viable disposal options. In lime‑soda softening, large amounts of sludge and spent lime must be managed and disposed of properly, adding handling, dewatering, and disposal costs. These waste-disposal challenges are a fundamental practical limitation of softening. By contrast, softening reduces hardness (so increased hardness isn’t a limitation), does involve operating-cost changes (not “no change”), and typically raises pH rather than lowers it, so that option doesn’t fit as a limitation.