When a vacuum degasser misses the dissolved-oxygen target despite clean packing, inspect air ingress through manways, flanges, seals, drains, and vacuum equipment. Total pressure alone may not reveal the problem if the vacuum pump compensates for leakage. Oxygen partial pressure, vacuum-system load, liquid distribution, water temperature, and analyzer accuracy should be reviewed together.

When surfactants enter a wastewater air stripper, stable foam can increase liquid holdup, raise pressure drop, reduce operating range, overload the demister, and disturb mass transfer. Water chemistry, upstream source control, airflow, packing openness, anti-foam effects, and pretreatment should be reviewed before replacing packing or increasing blower capacity.

When a scrubber meets its gas-removal target but the downstream fan corrodes, investigate mist carryover, demister velocity, wall bypass, drainage, packing entrainment, downstream condensation, and deposit chemistry. Gas-phase removal efficiency and liquid-droplet control are separate performance requirements.

When an HF scrubber uses calcium-containing hard water, fluoride absorption can create a precipitation and scaling risk even if the packing material itself is fully compatible. Makeup-water hardness, local chemistry, evaporation, blowdown, distributor opening size, packing openness, demister deposits, and scale analysis should be reviewed together.

In ammonia-water packed absorbers, strong absorption can create a temperature bulge that reduces ammonia solubility and limits further removal. Bed height, water rate, inlet temperature, heat of absorption, intercooling, liquid properties, hydraulic loading, and cooling-failure scenarios should be evaluated as one integrated duty.