WATER QUALITY

Evaporation

Water heated up by the sun → changes from liquid to gas state + enters the atmosphere

Condensation

Water vapor in the atmosphere cools and returns to liquid state → forms clouds

Precipitation

Large enough water drops in clouds fall down as precipitation (rain, snow, hail, or sleet)

Transpiration

Groundwater absorbed by plants released/evaporated into atmosphere as water vapor

Surface water

Water on the surface of land that flows into other bodies of water

Sublimation

Solid (e.g. ice) changing directly into gas state. Happens mostly in cold, dry, and sunny conditions like on the side of a mountain.

Infiltration

Surface water soaking/infiltrating into ground → gradually moves downward through soil layers and porous rock (percolates) → becomes groundwater

Cohesion

water molecules’ strong attraction to itself due to H-bonding, causing surface tension + water droplets. “co” hesion like “co” operate

Adhesion

Water’s polarity causes it to be attracted to + stick to charged/polar surfaces. “ad”-hesion like “ad”-hesive

Capillary Action

In narrow spaces, water will cling to the walls (adhesion) and itself (cohesion) → it will overcome gravity and propel upwards above the water line

Density of Ice

Unusually, water has a lower density as a solid than as a liquid because it’s bonds as a solid are more stable, and form a crystalline structure that holds the water molecules farther apart from each other than as a liquid.

Potable Water

Safe for human consumption

Coagulation and flocculation

In potable water treatment, coagulents(lime, alum) added to clump small particles into larger ones called flocs through flocculation(gentle mixing)

Sedimentation

In potable water treatment, heavy flocs settle to the bottom of tanks

Filtration

In potable water treatment, water passes through sand, gravel, and sometimes charcoal to remove suspended particles and matter

Disinfection

In potable water treatment, a disinfectant(usually chlorine or UV light)is added to kill pathogens

Fluoride/pH adjustments:

An optional last step in potable water treatment, Fluoride may be added for dental health. pH may be adjusted for controlled erosion in pipes.

Effluent

Sewage

BOD

dissolves and suspended organic matter

Aeration tank

Used in secondary wastewater treatment to provide air to grow aerobic bacterial microorganisms that consume pollutants

Primary Wastewater Treatment

Uses sedimentation and filtration. Solids sink to the bottom of the primary clarifier while grease and oil rises to the surface. Once settled, sludge is scraped off bottom and oils are skimmed off top. Removes around half of the solids and ⅓ of the (dissolved and suspended organic matter) BOD

Secondary Wastewater Treatment

Removes up to 90% of dissolved and suspended organic matter(BOD) from effluent(sewage). Various techniques used, all include the use of bacteria that consume/break down organic contaminants:

Activated sludge process(ASP)

Most common technique for secondary wastewater treatment. Aeration of wastewater to promote aerobic bacteria growth to break down organic contaminants. Then moved to a clarifier where the sludge settles and is returned(returned activated sludge) to the aeration tank.

Sequencing batch reactors

Variation of activated sludge processes, where all processes happen in one tank, allowing for more control

Trickling filters

Wastewater sprayed over a bed of media covered with biofilms of microorganisms. As water trickles down, microbes consume organic matter.

Aerated Lagoons/stabilization ponds

Wastewater placed in large shallow basins. Air introduced mechanically to support growth of aerobic bacteria, which break down organic contaminants.

Moving Bed Biofilm Reactors(MBBR)

Thousands of small floating carriers with high surface area in an aeration tank to support bacterial growth which consume organic contaminants.

Tertiary wastewater treatment

Remaining wastewater cleansed of nutrients(Usually phosphate, nitrate), pathogens, and trace contaminants. Then it is returned to it’s water source.

Watersheds/Drainage Basin Systems:

Area of land where water from rain/snow/ice drains downhill into controlled river/lake/reservoir/ wetland, using a variety of techniques. Improves water quality, manages flood risks, controls erosion.

Detention/Retention Ponds:

Basins that temporarily store water(detention) or hold permanent water(retention) to settle pollutants and control flow rates

Rain barrels/cisterns

Barrels placed to collect roof runoff for non-potable uses

Rain gardens/Bioswales

Shallow, planted depressions that absorb and filter runoff from roofs or driveways. Prevents flooding and harmful runoff

Permeable Pavement

Permeable concrete/asphalt that can absorb water from runoff/rain, preventing flooding and harmful runoff.

Green roofs

Vegetative roofs that absorb rainwater to prevent flooding and harmful runoff

Riparian buffers

Vegetative “walls” along bodies of water to stabilize banks and filter pollutants

Non point source pollution

Pollution whose source spans a broad area, carried usually by runoff, and has no single source. Ex: runoff, soil erosion

Point Source Pollution

Pollution whose source is from a single, identifiable location. Ex: oil spills, wastewater treatment

Lentic ecosystems

Ponds, lakes, wetlands: Has significant vertical stratification (light penetration and temperature)

Benthic ecosystems

Composed of bottom layer and sediment surface. Most organisms are scavengers or decomposers. Critical for testing water quality because it contains macro invertebrates that are bio indicators.

Litoral ecosystems

Shallow, well-lit, close to shore. Rooted+shallow vegetation, wide variety of organisms. Roots anchor soil preventing excessive erosion, as well absorb excess nutrients, preventing excessive algae growth. Also contributes to high levels of dissolved oxygen.

Limnetic ecosystems

Open+well lighted, away from shore. Supports photosynthesis, part of euphotic zone. Dominated by free-floating organisms, mostly phytoplankton and zooplankton, some fish.

Profundal ecosystems

Deep aphotic zone. Where dead organic matter from above (detritus) is broken down → minerals plentiful. Temperature and Oxygen low. Usually does not mix with surface water due to temperature difference, only mixes a few times a year to increase oxygen levels.

Oligotrophic Lake

Deep, extremely clear water, low productivity(nutrient poor, low nitrogen and phosphorus). Low algae and plant levels, high oxygen levels. Many large fish

Mesotrophic Lake

Alright productivity, accumulated organic matter (occasional algal blooms), good fishery

Eutrophic Lake

Shallow, murky water, very productive, may experience oxygen depletion, rough fish common

Lotic ecosystems

Moving water: streams, rivers. Moves consistently in one direction. Headwater: 1^st through 3^rd order streams (80% of all waterways). 1^st order = no tributaries  → 2^nd order = two 1^st order streams etc. Cold and clear, little sediment/few mineral nutrients, narrow channel and rocky substrate (∴less erosion) → water flows swiftly. Mouth: where a river flows into larger body of water. Wider channel+silty substrate, higher turbidity + higher nutrient content. Riffles: rapid turbulent flow caused by rough shallow bottoms. Pools: slower smooth flow caused by smooth deep bottoms. Higher flow rate = higher DO

Primary succession

When organisms populate an area for the first time

Secondary succession

When organisms repopulat an area after a small disturbance. Ex: wildfire, earthquake, flood, drought, etc

Turbidity

How much light can pass through water (affected by suspended particles). Reduces sunlight, increases temp(particles absorb heat), harms organisms(ex: clog fish gills), carries pollutants and pathogens. Indicates soil erosion.

Bio accumulation

Build up of harmful chemicals within an organism

Biomagnification

The buildup of harmful chemicals within a food chain

Hypoxia

Too little oxygen. Results from nutrient pollution: runoff, sewage, etc. Anoxia: no oxygen at all.

Nitrates

NO₃ crucial for plant growth, but too much causes eutrophication (severe pollution).

Phosphates

Necessary for plant growth. Can also cause severe pollution (eutrophication) if there is too much. Often limiting nutrient(small amounts cause rapid plant growth). High lvls indicate runoff, sewage, or soil erosion.

Eutrophication

Too many nutrients in water→overgrowth of plants→decreases DO→creates “dead zones” + harms animals

Hardness

concentration of minerals in water

• Soft: <60mg/L (<3.5 gpg)

• Moderately hard: 60-120 mg/L (3.6-7.0 gpg)

• Hard: 120-180 mg/L (7.1-17.5 gpg)

• Very hard: >180 mg/L (>17.5 gpg)

Alkalinity

Capacity to neutralize acids, buffer

Meromitic lakes

Stratified (because of temperature, salinity, or glacial differences)

• Epilimnion: Upper, warmer, mixed layer

• Thermocline(or metalimnion): “boundary” of extreme temp difference

• Hypolimnion: Lower, colder, generally unmixed, layer

  • Upper (mixed) mixolimnion layer

Lower (unmixed) monimolimnion layer - often anoxic(little/no O)

Holomitic Lakes

Mixed completely (at least once a year, uniform temperature and density)

• Dimictic: mix twice a year (spring+fall)

• Monomictic: mix once a year (warm: mix in winter, cold: mix in summer)

• Polymictic: mix frequently/continuously due to wind

• Oligomictic: mix irregularly less than once a year

Sunlight (Photic/epipelagic) zone

<200m. Upper sunlit layer where photosynthesis occurs.

Twilight (Disphotic/mesopelagic) Zone

200-1,000m. Some sunlight, rapid temperature drop (thermocline).

Midnight (Aphotic/bathypelagic) Zone

1,000-4,000m. Darkness, cold, high pressure.

Abyssal (abyssopelagic) Zone

4,000-6,500m. Deep seafloor, very cold.

Hadal Zone(hadalpelagic) Zone

>6,500m. Ocean trenches, extreme pressure.

Shredders

Feed on coarse particulate organic matter(CPOM: Larger pieces of organic matter, ex: leafs) from terrestrial leaf litter inputs (allochthonous material). They shred organic matter with their mouthparts, and in doing so suspend smaller pieces into the water column.

Grazers/scrapers

Use rasping mouth parts to graze biofilm(usually algae) off rocks and submerged aquatic vegetation. Greatly affects algae, therefore can make a big impact on primary producers. Would dominate in a stream that lacks shade because the algae would grow significantly.

Collectors/gatherers

Scavenge stream or lakebed substrates for deposited fine particulate organic matter(FPOM: Small pieces of organic matter. 0.01-1mm) and dead organisms. Have a large effect on bioturbation(reworking of soil and sediment, is a primary driver of biodiversity) and resuspension of organic matter.

Filterers

Remove suspended fine particulate organic matter(FPOM: Small pieces of organic matter. 0.01-1mm) from the water column using a variety of filtering mechanisms. Expend less energy searching for food, instead rely on their velocity and upstream food supply.

Predators

Consume animal tissue, and therefore have a top down effect on the footweb. Large number signifies an environment able to support a strong food web.