Drinking Water I

Municipal drinking water cimponents

a source, a water treatment plant, a water distribution network

Drinking water sources

lake and reservoirs, rivers, groundwater, seawater

Main goals

removal/inactivation of pathogens and provisions, improve aesthetics, removal of harmful chemicals, reduce corrosiveness of water

Safe Drinking Water Act

government regulates water system, establishes maximum levels for both chemicals and microbial contaminants

Primary standards

mandated thresholds for the purpose of protecting public health

Maximum contaminant level

states the allowable concentration in treated water

Treatment Technique (TT)

specifies which treatment to practice

Secondary Standards

suggested limits on contaminants which pose more aesthetic or distribution problems

Hardness

comprises the combined concentration of metal cations that can precipitate to form mineral scale

Natural organic matter (NOM)

large molecules derived from degradation of plant material (humic substances)

Alkalinity

reflects a water’s ability to resist change in pH, due to presence of buffering compounds

Coagulation

addition of dissolved cations to neutralize negative surface charges on solid particle

Flocculation

the formation of loose aggregates of destabilized solids via mixing-induced collisions