geog 2136 lectures 23+24 chesapeake bay

waste water treatment protocol - preliminary

Fine screens remove large materials like garbage

Physical removal of solid material

Screening removes sand, stones and other large non-biodegradeable particles

Aeration done for grit removal

waste water treatment protocol - primary treatment

Sedimentation settles out remaining particulate matter into a mudlike sediment called sludge

Buoyant materials are skimmed

Treated wastewater continues to secondary treatment

what percent of pollutants are removed primary treatment?

30 to 40%

waste water treatment protocol - secondary treatment

biological treatment

microbes treat and remove organic materials

air pumped in and aerobic (oxygen-requiring) bacteria break down organic matter

final sedimentation tank more sludge (living and dead microorganisms get removed)

sludge does into a digester, when anaerobic bacteria break down organic matter in the sludge

does secondary treatment remove all nutrients, heavy metals, or organic pollutants?

no, but around 90% are removed after this stage

can water that has undergone secondary treatment be released?

yes (according to the EPA), and it is done during large flows

waste water treatment protocol - tertiary treatment

advanced treatment to reduce concentration of selected pollutants identified in effluent, primary nutrients

nitrification and de-nitrification, cleaned by bacteria, removes nutrients, organic pollutants, etc.
Wastewater is filtered and disinfected with chlorine, and discharged into the Potomac

Tertiary treated water is cleaner than the Potomac river itself

residuals

come out of the water treatment process. they are called bio-solids— safe organic product used mainly by farmers for fertilizers.

what do farmers do with bio-solids?

they make fertilizer, or make digester gas to power the plant

blue plains wastewater treatment plant

clean water act (1972)

federal law to reduce water pollution to achieve “fishable” and “swimmable” waters by controlling and reducing pollution from factories/treatment plants. EPA is in charge of enforcing

do the Anacostia and Potomac meet the requirements of the CWA?

-Anacostia: does not meet these requirements (hoping to by 2025)

-Potomac: many areas do not meet these requirements, but much cleaner than the 1960s

what is the largest estuary in the US

Chesapeake bay

chesapeake bay

watershed, 64,000 sq miles between 6 states + dc. approx 15m people live in the watershed

is the chesapeake bay polluted?

very severely, on EPA’s “impaired waters” list

what resources does the chesapeake bay provide?

fisheries (migrant and resident species), blue crab (largest producer in country), oysters (overharvesting), and migrating waterfowl

what is the major water pollutant in the chesapeake bay?

nutrients, primarily nitrogen (phosphorous).

what is eutrophication?

influx of nitrogen

what does eutrophication cause?

explosive growth of algae (algae blooms), which clouds water and blocks out light, consumes oxygen when decomposing, and leads to dead zones with no oxygen that can no longer support aquatic life

why does eutrophication cause problems for oxygen levels?

low dissolved oxygen results in hypoxia, which can impair growth and reproduction, and stress living resources, leaving them vulnerable to disease. additionally, water with no oxygen (anoxic) will kill most aquatic animals (“dead zones”)

healthy vs. unhealthy water quality

healthy: bay grasses, balanced algae growth, adequate oxygen

unhealthy: algal blooms, algae decomposition, no oxygen, reduced bay grasses

what do underwater grasses provide?

shelter for fish and crabs, food for migrating water fowl, adds oxygen to the water, absorbs nutrients

how do algae blooms prevent underwater grasses from growing?

they block sunlight

has the Chesapeake bay experienced a loss in grasses?

yes. Once grew in abundance-covering an estimated 200,000 acres-along the shallows and shoreline…

where does the majority of nutrient pollution come from?

human pollution

what are the sources of nutrients

natural sources such as decaying organic matter. majority comes from human pollution through sewage treatment plants, large-scale animal operations, agriculture, air pollution (vehicle exhaust), smoke stacks from industry.

WHAT is the number one source of nitrogen pollution to the Chesapeake bay?

AGRICULTURAL RUNOFF. contributes to 40% of the nitrogen and 50% of the phosphorus.

what has reduced the amount of nitrogen delivered to the chesapeake bay?

riparian buffers, cover crops, and rotational grazing

agriculture impacts in maryland

lManure and waste from chicken production plays a big role in agricultural nitrogen loads to the Bay. chickens outnumber people 1000 to 1

agriculture impacts in shenandoah and potomac

Large-scale poultry operations produce more waste than hog, cattle, or dairy farms. up to 150 percent more of the nutrient pollution generated by human waste in the same area

where is the majority of urban growth occuring?

major tributaries (susquehanna and the potomac). clearing open land for development hastens the “funnel” effect; amount of acreage cleared is rising faster than population. goal is to direct growth into more compact forms of development to slow loss of open land.

how many plants discharge into the chesapeake bay watershed?

472

what does advances in sewage treatment technology help with?

major reductions in nitrogen flowing from plants (2nd largest source). this entails improving pipe/pumping station infrastructure, which eliminates leakage and helps efficiency

how does cleared off land change runoff patterns (as opposed to old-growth woodland)?

it runs off very differently — the chesapeake bay watershed has changed from filter to funnel

what are the goals in the chesapeake bay?

reduce pollution from farmland, urban runoff, sewage treatment plants, and other sources to restore bay’s natural defenses

what are the bay’s natural defenses?

forestlands, wetlands, oysters, and underwater grasses

when was the first chesapeake bay agreement?

1983

chesapeake 2000

new agreement for partners of the Chesapeake Bay Program to guide restoration/protection of the bay to improve water quality

commitments for bay and river water quality

Water Clarity – light for underwater Bay grasses

Chlorophyll a – base of the Bay food chain

Dissolved Oxygen – for fish, crabs and oysters

cooperative clean-up plans

allow more flexible cleanup plans, however if the Bay does not get removed from the impaired waters list a regulatory clean-up plan will be required

chesapeake clean water blueprint regulatory agreement

Put the bay on a pollution diet & Make the Bay “fishable, swimmable” by 2025

For the first time, the states have each committed to two-year incremental milestones of pollution reduction. EPA will impose consequences for failure.

how does the pollution diet for the Bay work?

Science-based, enforceable limits on the amount of pollution entering in order to remove the Bay from the federal "dirty waters" list. 25% less nitrogen, 24% less phosphorous, 20% less sediment

What are the four steps of the Blue Plains wastewater treatment process?

Preliminary - Screening; Primary - Sedimentation (sludge removal); Secondary - Biological treatment; Tertiary - Nitrification and Denitrification.

What pollutants are the primary contributors to Chesapeake Bay degradation?

Nitrogen and phosphorus are the main pollutants.

What is eutrophication?

Eutrophication is nutrient enrichment (from nitrogen and phosphorus) that causes algal blooms, hypoxia (low oxygen), and ecological harm.

Name three major sources of pollution to the Chesapeake Bay.

Agriculture (including manure and poultry litter), sewage/wastewater treatment plants (point sources), and urban runoff/urban growth (non-point sources).

What is the Chesapeake Clean Water Blueprint and when was it established?

A regulatory Total Maximum Daily Load (TMDL) agreement established in 2010 to reduce pollution to the Bay by 2025.

Which three states account for roughly 90% of pollution to the Chesapeake Bay?

Maryland, Virginia, and PA

Which state was reported as off-track for meeting its Bay pollution goals?

Pennsylvania has been reported as off-track and has faced litigation.

How much have nitrogen and phosphorus loads from wastewater changed since 1985?

Nitrogen reduced by about 57% and phosphorus reduced by about 75% since 1985.

How much nutrient reduction have improvements at the ten largest wastewater plants prevented?

They prevented about 240 million pounds of nitrogen and 48 million pounds of phosphorus.

What portion of nutrients entering the Bay is attributed to manure and poultry litter?

Manure and poultry litter account for almost 50% of the nutrients entering the Bay.

What conservation practices have farmers adopted to reduce nutrient runoff?

Planting cover crops, creating riparian buffers, streamside fencing, improved manure application and storage, and regenerative agriculture practices.

What is a forest buffer and why is it important for the Bay?

A vegetated strip (usually trees and shrubs) along waterways that filters runoff, traps sediment, and absorbs nutrients before they reach streams and the Bay.

What is the reported forest buffer shortfall in the presentation?

Behind by 152,245 acres or 12,448 miles of buffer; states need to add about 2,075 miles per year between 2020 and 2025 to meet targets.

What is the Conowingo Dam issue and why does it matter for the Bay?

The reservoir is ~92% full of sediment, so it no longer effectively traps sediment and phosphorus; that means more sediment and nutrients flow downstream to the Bay.

Historically, how much phosphorus and sediment did Conowingo trap annually?

On average it trapped about 3.5 million pounds of phosphorus and about 4 billion pounds of sediment per year.

What was the 'Day Zero' crisis in Cape Town?

A severe water shortage (late 2017 predicted 'Day Zero' when taps would be turned off) caused by an extended drought beginning in 2014 and low reservoir levels.

What is the Working for Water (WfW) program and when was it launched?

A South African multi-departmental public works program launched in 1995 to remove invasive alien plants, improve water yield, and provide employment (targeting marginalized groups).

List the main goals of the Working for Water program.

Improve ecological integrity; enhance water security; restore productive potential of land; promote sustainable use of natural resources; invest in marginalized sectors (women, youth, disabled).

What is 'fynbos' and why is it ecologically important?

Fynbos is the vegetation type of the Cape Floral Kingdom, one of six global floral kingdoms. very species-rich with over 7,700 plant species and ~70% endemism.

what does fynbos vegetation look like?

hard, tough and leathery leaved or small leaved

Name common invasive species that threaten the fynbos.

Hakea species, Australian wattles (Acacia), and pine trees

How do invasive plants affect water runoff and streamflow?

Invasives (especially tall, woody species like pines and eucalyptus) increase evapotranspiration and can substantially reduce mean annual runoff and low flows models predict up to 30→74% runoff loss over decades if not cleared.

By how much can clearing invasives increase streamflow?

Clearing can increase streamflow by about 8,000-12,000 liters per hectare per day in winter rainfall regions and up to 34,000 L/ha/day in summer rainfall regions.

Invasives in water

ET alien plant is much > indigenous plant (up to 200% more reduction)
Groundwater storage: hallow coastal sand dune aquifers, storage increases in response to the clearing of woody alien vegetation. Shallow and deep groundwater aquifers can be accessed by woody invasive trees

What impacts do invasives have on fire risk and erosion?

Many invasives increase fire frequency and intensity, which raises erosion, causes loss of topsoil, and worsens sedimentation of rivers and dams.

What are the three control phases for invasive removal?

Initial control (drastic reduction), follow-up control (seedlings, resprouts), and maintenance control (annual or periodic control to keep numbers low).

What are common methods of invasive plant removal?

Controlled burns, biological control (introducing natural enemies), mechanical removal (chainsaws, cutting), and chemical control (herbicides).

what are the advantages/disadvantages of controlled burn?

Advantages: Inexpensive, Rapid

Disadvantages: Spread, Reproduction

What are advantages/disadvantages of biological control for invasives?

Advantages: Environmentally friendly, target-specific, self-perpetuating, cost-effective, and avoids large soil disturbance/allows gradual killing of invasives/recovery of native species

Disadvantages: works slowly (at least five years).

What are disadvantages of mechanical/chemical invasive removal?

Labor-intensive, time-consuming, can be costly, and may disturb soils if not managed carefully.

What social benefits does WfW provide to participants?

Employment income (reducing poverty), skills training for longer-term work, health improvements, and fostering responsible citizenship.

How large is the WfW program and what demographics does it serve?

Over 350 projects across nine provinces, employing ~32,000 people with a budget of about $66 million; ~54% of workers are women and ~26% are youth.

What are proposed future steps to improve South Africa’s water security mentioned in the presentation?

Increase water use efficiency (agriculture), collect rainwater, raise public awareness/education, consider desalination (expensive), and increase storage capacity or transfer water from upstream dams.

What role do point-source and non-point-source pollution play in Bay cleanup?

Point sources (e.g., wastewater plants) have shown major reductions; non-point sources (agriculture, urban runoff) remain challenging and are the largest contributors.

Why was Pennsylvania specially mentioned in relation to the Chesapeake cleanup?

Pennsylvania remains off-track to meet TMDL goals and has been subject to lawsuits (e.g., by Chesapeake Bay Foundation) about inadequate pollution reductions.

What improvements in the wastewater sector were highlighted in June 2016?

The wastewater sector met nutrient goals of the 'pollution diet' a decade early, with substantial nutrient reductions from major plants.

How do forest buffers and riparian zones affect nutrient and sediment transport?

They trap sediment, uptake nutrients (Nitrogen and Phosphorus), stabilize banks (reducing erosion), and provide habitat buffers reduce the loads that reach streams and the Bay.

What is a Total Maximum Daily Load (TMDL)?

A regulatory limit on the amount of a pollutant (e.g., nitrogen, phosphorus, sediment) that a waterbody can receive and still meet water quality standards; used as part of the Clean Water Blueprint.