I have some experience in ...

I have some experience in lime use at a Kraft pulp mill that also had a water treatment plant using milk of lime during the winter months for softening. 

Regarding quality, the purchased lime we received would vary in quality fairly significantly. We would get layering of high quality and low quality product in our storage silos that caused many issues in keeping the process stable as the supervisory controls and field testing could not adjust the process quickly enough to account for the variation. The physical quality also varied significantly (high quality pebbled lime to powdery and highly reactive crushed lime to low grade undercooked material often containing inert aggregate) which caused many issues in the feed systems; screw conveyor pile ups, erratic solids production in the slakers, and blower system pluggages.

Regarding handling, lime dust gets everywhere. Initial leaks may be localized to a small spot but if there is air movement that dust is travelling and it makes area housekeeping a relative nightmare. Field operators have to wear extensive PPE to stay safe around it and they are never too eager to work around it. Handling systems are difficult to maintain with bag filters fighting pluggages constantly, switching valves wearing out quickly, rotary feeder packing wearing out quickly, transfer lines having holes worn in them at the elbows, silos bridging, rappers on silos needing regular maintenance, and screw conveyors jamming up. We received lime via truck b-trains so unloading in a clean and timely manner was also an issue at times if the system wasn't functioning near top condition. 

Past the slaking stage, there were always safety issues with the heat generated from the reaction. Pumping the lime slurry was also a harsh duty for the pumps and lines requiring regular pipe cleaning and replacement of worn components.

Specific to the water treatment plant, the milk of lime would vary in strength due to the issues mentioned above so maintaining the reaction well pH at 11 or higher was always challenging. The sludge blanket was also difficult to maintain at a constant level due to the erratic quality. A lack of consistent sludge blanket in the clarifier would always result in solids carryover to the gravity filters which would require increased backwash frequency.