Water & WW Treatment: Noteset 7 - Water Treatment: Sources, Treatment Intakes

Drinking Water Sources

Natural lakes, impounding reservoirs, rivers, deep/shallow groundwater wells

NJ Reservoirs

Spruce Run and Round Valley

Watershed

The land area that collects and drains precipitation into a common water body such as a river, lake or reservoir. Considered the first stage of treatment as land use affects raw water quality

Water Budget

Describes the balance of water entering, stored in, and leaving a watershed. Includes precipitation, evapotranspiration, runoff, infiltration. Determines water availability and planning.

Why is surface water quality more variable than groundwater?

It’s exposed to runoff, weather events, and seasonal changes.

How does seasonal lake stratification affect water quality?

Summer stratification can degrade quality; fall/spring turnover improves oxygenation and reduces stagnation.

What does eutrophication indicate?

High nutrient levels → increased algal growth → more treatment needed

How does geology affect groundwater quality?

Different formations contribute different dissolved constituents (e.g., limestone = hardness, shale = Fe/Mn, sand = arsenic)

Deep vs shallow wells — treatment differences?

Deep = stable, usually just disinfection. Shallow = more variable, may need softening, Fe/Mn removal, filtration.

What’s a typical groundwater treatment train for a deep well?

Disinfection only.

List the standard treatment train for lake/reservoir water.

Intake screen → mixing/coagulation → flocculation → settling → filtration → disinfection.

Why do rivers require extra treatment steps compared to lakes?

Higher variability and sediment loads

Difference between coagulation and flocculation?

Coagulation = add chemicals & rapidly mix to destabilize particles.

Flocculation = slow mixing to let particles collide and form larger flocs for removal.

What’s the purpose of coagulation/flocculation?

To clump fine particles into larger flocs that can settle or be filtered out.

What’s the role of filtration?

Removes remaining particles, turbidity, microorganisms before disinfection.

What is the purpose of a water intake structure?

Connect source to treatment plant; handle variable flows and protect water quality.

Submerged vs exposed intakes — key difference?

Submerged = less visible, harder to maintain; exposed = easy to maintain but more vulnerable.

What are collector wells and why are they used?

Structures that use bank filtration through aquifers to naturally improve water quality before treatment.

Dug vs drilled wells — main differences?

Dug = shallow, vulnerable to contamination; Drilled = deeper, access confined aquifers, more protected.

Surface vs groundwater treatment — main difference?

Surface → more variable, needs full treatment train. Groundwater → more stable, often simpler (just disinfection or minor adjustments).

What is the main goal of intake design?

Ensure reliable, clean raw water delivery to treatment plant with minimal disruptions.