Water Treatment Equipment & Technologies Flashcards

What is 'scale inhibition' in the context of polyphosphate feeders used in residential water treatment?

Answer: Sequestering hardness minerals to prevent them from precipitating as scale deposits

Polyphosphates sequester (bind to) calcium and magnesium ions, keeping them in solution and preventing them from crystallizing into scale on pipes, heaters, and fixtures.

In a point-of-entry (POE) chlorination system for a private well, which chemical is most commonly fed by a peristaltic pump?

Answer: Sodium hypochlorite (liquid bleach) solution

Sodium hypochlorite (liquid bleach) solution is the standard chemical fed by peristaltic chemical feed pumps for residential well chlorination because it is stable, affordable, and easy to handle.

What does 'TFC' stand for in the context of RO membranes, and what is the key material used?

Answer: Thin Film Composite; polyamide film bonded to a polysulfone support

TFC stands for Thin Film Composite, featuring a very thin polyamide active layer bonded to a polysulfone support layer, offering high rejection rates and better chlorine tolerance than cellulose acetate.

Which water treatment technology uses a strong-acid cation resin in the hydrogen (H⁺) form and a strong-base anion resin in the hydroxide (OH⁻) form to produce high-purity water?

Answer: Mixed-bed deionization

Mixed-bed deionization combines H⁺-form cation resin and OH⁻-form anion resin in a single vessel; cations exchange for H⁺ and anions exchange for OH⁻, which combine to form pure water.

What operational problem does 'iron fouling' cause to an ion exchange softener resin, and how is it typically treated?

Answer: Iron coats exchange sites, reducing capacity; treated with iron-out or resin cleaner during regeneration

Iron deposits on resin beads block cation exchange sites and reduce softening capacity; periodic treatment with a resin cleaner (iron-out/citric acid product) during regeneration restores performance.

A customer reports that their RO system produces water very slowly and the storage tank takes many hours to fill. The FIRST diagnostic step should be to check:

Answer: The inlet water pressure and the condition of the pre-filters

Low production rate is most commonly caused by inadequate inlet pressure or clogged pre-filters starving the RO membrane, making these the first items to inspect before examining the membrane or drain components.

What is the purpose of the 'drain flow restrictor' (DFR) in a residential reverse osmosis system?

Answer: To create back-pressure on the concentrate side, increasing the pressure differential across the membrane

The DFR restricts concentrate (reject) flow, building up pressure on the feed side of the membrane to maintain the operating pressure differential needed for adequate RO rejection and production.