envirothon aquatics pollution + remediation

PPCPs

Pharmaceuticals and Personal Care Products

Not monitored and regulated

Includes makeup, prescriptions, shampoo and body wash bottles, etc.

Our Wastewater treatment is not designed to remove them

Can be toxic, and impact behaviors

PCBS

Polychlorinated biphenyls

Toxic and manmade

Disrupt endocrine system

Used in appliances such as fridges as well as paints and other household products

PCBs are now banned

PFAS

Poly and perfluoroalkyl

Made to resist heat, oil, water, stains, grease, etc.

Teflon, Food wrappers and household products

Still not much being done

Damage to liver & immune system

Microplastics

plastic pieces or fibers measuring less than 5 mm

-microbeads found in personal care products are almost always smaller than 1 mm.

Found in PPCPs and made of plastics such as PE, PP, PETs, and more

Specific examples: Toothpaste, cleansers/exfoliation products, etc.

Microplastic types

fibers & fragments (secondary), microbeads (primary)

-primary made at that size, secondary broken down

Cyanobacteria

Microscopic bacteria that live in basically all water bodies

Algal blooms

Rapid overgrowth of cyanobacteria or other algae

(Cyanobacteria is technically not algae)

Occur as a result of eutrophication

Algal bloom impacts

"Dead Zones" - low oxygen, bc when algae die, decomposition uses a lot of O

Toxic: many cyanobacteria produce toxins that are toxic to fish & humans

Aquatic Invasive Species (AIS)

a non-native species that outcompetes native species & harms the environment. They reproduce quickly, and have few/no native preadtors

-Can be spread through ships, boats, barges, aquaculture, aquatic recreation (fishing, hunting, boating, diving, etc.), water gardening, seaplanes, connected waterways, etc

Examples: zebra mussels, sea lamprey, Asian carp

Wastewater

Water from human use that may contain fecal waste along with other water from non-building usage

Also known as sewage

Usually rich with nutrients

May cause algal blooms if untreated

Steps of Wastewater Treatment

PRIMARY TREATMENT (removes solid materials)

Bar screen (M)

Grit chamber (M)

Primary clarifier (C)

SECONDARY (uses biological processes)

Aeration basin

Secondary clarifier

TERTIARY (chemicals)

disinfection

Bar screen

Removes large objects that may damage pumps and other equipment

Generally anything >1

Grit Chamber

Removes grit (larger particles) to help reduce abrasion of equipment

Slows down the water so they can sink and settle

Primary Clarifier

Water sits for 2-12 hrs. Flocculent & Coagulant is added so the material forms clumps & sinks

Most small particles are - charge (bc clays), add + coagulant (often Al3+)

Scum floats to top & sludge sinks to bottom, both are then scraped off

Removes around 60% of BOD

Aeration Basin

Oxygen is added and bacteria is allowed to grow and break down organic matter

Water will look brown due to bacteria

Removes around 85-95% of BOD

Secondary Clarifier

Essentially the same as the primary clarifier

Sludge from the primary clarifier tends to be denser

Sludge is taken away and then digested, can turn into CH4 for energy, fertilizer.

Disinfection

Either with Chlorine or UV light

Only done if humans will be in contact with the water (ie in the summer bc swimming)

Chlorine will be removed via aeration if it is added

Nutrient removal (disinfection)

Phosphorous: use magnetite Fe3O4 to bind with phosphate, and then use magnet to pull it out

Nitrogen: have anaerobic aeration basins and use anaerobic denitrifying bacteria

runoff process

1. Surface runoff (overland flow)

-Sheet flow → rills → gullies

2. Subsurface flow (throughflow)

3. Groundwater Flow

4. Baseflow

hydrograph factors

"Flashy" = higher peak, less lag time. Generally more dangerous

Catchment features

-Catchment size

-Soil Type (more impermeable = more flashy)

-Geology (steeper = more flashy)

-Vegetation Type and Cover (Less Vegetation = more flashy)

-Hydraulic Length (Distance from Outlet to most distant point)

-Drainage Density (total channel lengths/area of catchment)

3 types of groundwater contaminants

sinking, floating, soluble/compatible

sinking contaminants

Coal tar

DNAPL (Dense Non-Aqueous Phase Liquid)

floating contaminants

Petroleum

LNAPL (Light Non-Aqueous Phase Liquid)

soluble/compatible contaminants

Aluminium, cyanide, zinc

Overdraw

When you withdraw water from a groundwater aquifer faster than it can be replenished

Can lead to saltwater intrusion + subsidence

types of watershed alterations

Dams

Artificial Levees

Channel Straightening

Dikes

Dam uses

Creates a reservoir for human water supply

Flood control

Pollution control (often for mines)

Energy generation

dam impacts

Thermal pollution

Potential for dam to break and kill people

Causes downstream scour, channel deepening and erosion, bank armouring

Blocks sediment upstream so downstream sediment is not replenished

Blocks wildlife

Artificial Levee uses

Protect an area from flooding (generally a city)

Increase available land for inhabitation

Artificial Levee impacts

Makes floods downstream more flashy - more intense flooding downstream

Prevents nutrient recharge of surrounding soils from flooding