EHST Exam 4 (Water Pollution)

When human settlements were small and spread out _____.

water contamination was not a major concern

Effluent

liquid waste or sewage discharged into a river or the sea.

It’s estimated that most of the world’s drainage basins are polluted with?

1. Toxic chemicals

2. Human & Animal Waste

3. Heavy Metals

4. Pesticides

5. Silt and Fertilizers

Municipalities

incorporated area within a county, like a city or town, that provides services like water, sewer, and police

Point Sources

Enter waterways at well defined locations (e.g. pipes, ditches, outfalls)

About how many traditional point sources are in the U.S?

100,000

What are the 2 major categories of point sources?

Sewage treatment plants and industrial discharges

Nonpoint Sources

pollution that enters from multiple, diffuse sources

Non point sources are responsible for states not meeting _____.

water quality goals

NPS (Non point sources) are just a new terminology of?

runoff and erosion

When are bodies of water considered impaired?

When a pollutant elevates to a level where the water can no longer meet its intended use

Agriculture, a leading source of water pollution, affects _____% of the nations water quality?

50-70%

How much more do concentrated animal feeding operations (CAFOs) contribute to nutrient pollution than point sources?

5-6x

How many hog lagoons are in Eastern North Carolina?

about 3,800

What are the most common pollutants from CAFOs?

• Nutrients

• Nitrogen & Phosphorus

• Bacteria

• Heavy metals

• BOD

• Antibiotics

Construction activities are responsible for what sources of pollution?

sediment (10-20 times more than agricultural lands); 500 tons of sediment per acre per year

Urban street runoff is a leading pollutant source because?

pollutants accumulate on impervious surfaces between storms and flow into US bays, estuaries, and lakes

Only ________ mines are NPS.

abandoned

Acid mine drainage drops the PH of the water, making it ____.

uninhabitable for aquatic life

NPS can occur from fallout of airborne pollutants such as?

acid rain

Areas impacted heavily by atmospheric deposition include?

• The Great Lakes (PCBs & toxicants)

• Chesapeake Bay ( 33% nitrogen; eutrophication)

• Oceans (hydrocarbons)

What is the goal of wastewater treatment?

improve wastewater enough that the discharged water doesn’t disrupt aquatic and human life

Wastewater treatment relies on?

Killing pathogenic organisms and removing organic waste

Most common method of rural wastewater treatment?

Septic System

Municipal sewage treatment systems focus on?

removing pathogenic organisms

____% of the U.S population is served by municipal sewer treatment systems.

70-75%

Municipal sewage treatment systems can support urban areas because?

They can handle large volumes of wastewater, meaning they can handle dense population growth

Even though municipal sewage treatment systems are more manageable in rural areas, they are also more ____.

expensive

Raw Sewage

anything flushed or that inadvertently enters sewer system

Primary Treatment

mechanical/physical process of sedimentation and settling of suspended solids; lowering of biological oxygen demand

Secondary Treatment

Tertiary Treatment

There is an increased resistance to chlorination of wastewater because?

• Chlorine is ineffective against viruses

• It’s damaging to aquatic habitats

Chlorination is effective at?

• reducing disease outbreaks associated with using contaminated water supplies.

• enhances self-purification of natural waterways

Due to the issues with chlorination, treatment facilities have started using?

• membrane filtration

• ozonation

• UV light (radiation kills the microbes)

Biosolids (sludge) has _______ since the Clean Water Act.

doubled

Treatment facilities handle sludge by?

• composting / making fertilizer

• heat drying

• eliminating pathogens

Onsite wastewater treatment systems are most common in _____ areas.

rural

How much of the U.S. population is in a non-sewered area?

25-30%

Septic tank

anaerobic environment, settling tank; watertight containers made of concrete or fiberglass with a minimum capacity of 750 gal

Effluent distribution device

distribute effluent to trenches

Drainfield trench

wastewater stored until it infiltrates the soil

Soil

beneath trench is aerobic, filters large pollutants, most important component for pollutant treatment

Setback distances

required from septic system components to wells, surface waters, property lines and other areas of interest

Malfunctioning septic systems can endanger environmental and public health because?

Wastewater containing elevated nutrients, pathogens, and BOD causes eutrophication and may spread illness

Septic systems pose a threat to groundwater levels when?

they are near drain field trenches

Industrial wastewaters contain broad ranges of pollutants such as:

• Conventional Pollutants (organic wastes (high BOD), suspended solids, acids, oil and grease, etc.)

• Toxic Pollutants (heavy metals, PCBs, benzene, chloroform, cyanide, arsenic, 2,4-D, and other pesticides)

• Nonconventional Pollutants (nitrogen, phosphorus, iron, tin, aluminum, chloride, and ammonia)

Direct Discharge

waste flows directly into receiving stream or lake

 National Pollutant Discharge Elimination System (NPDES) permit

sets allowable amounts of pollutants in their effluent; violation of permits can result in civil or criminal penalties

Indirect discharge

Wastes are sent to the municipal sewage treatment plant before entering a waterway

Industrial dischargers have pretreatment programs to?

mitigate damages done to sewer plants

___% of regulated toxics entering municipal sewer plants come from residences

15%

By plants uptaking nutrients and water runoff and pollution transportation are?

reduced

Stilling Basin

Dissipates energy and allows sediment (especially sand and larger silt) to settle; Stores water for 24 – 48 hours

Rain Gardens

• Inlet → where water enters rain garden via swale, pipe, etc.

• Mulch → provides organic matter for plant growth, binds pollutants, carbon source for denitrification, looks nice

• Plants → uptake nutrients and water, look nice, wildlife habitat, stabilize soil

• Forebay → for larger gardens, dissipate energy, settle out some sediment,

• Outlet → can be structure or overflow, where excess water exits

• Bowl → water storage area of rain garden

Permeable Pavements

Pavement that allows water to infiltrate through its surface, reducing runoff; not effective if surfaces aren’t kept clean

Wetponds

• Inlet → where water enters wetpond via pipe, swale, etc.

• Forebay → permanent deep pool of water at inlet, dissipates energy, collects solids

• Berm → baffles flow, dissipates energy 

• Aquatic shelf → vegetated, gently sloping bank for nutrient uptake, denitrification, bank stabilization, sediment retention, aquatic habitat

• Micropool- open water area (shallower than deep pool), storage, aquatic habitat 

• Outlet- where water exits the pond

Storm Water Wetlands

• Inlet → where water enters wetland via swale, pipe, sheet flow

• Deep pool → permanent deep pools of water

  • Forebay – at inlet, dissipates energy, collects solids

  • Non-forebay – always contain water, habitat for floating and submerged plant zones and aquatic life (Gambusia), pollutant storage

• Shallow water → low marsh, inundated by permanent pool to a depth of 3 – 6 inches, occasional drying during droughts, top of shallow water is top of permanent pool elevation

• Shallow land → high marsh, provides temporary storage volume, top of shallow land is top of temporary pool elevation, wet only after rain events, rooted plant zone

• Upland → never wet, not required in design, but provides aesthetics

• Outlet → drawdown placed at top of shallow water elevation; this allows water in the shallow land to slowly drawdown.

Controlled Drainage

utilizes water control structures such as a flashboard riser to adjust (raise or lower) drainage outlet elevation; reduces nutrients, pesticides, and sediment transport

Nutrient management

using science to guide agricultural practices; factors to determine the best fertilizer and application; mitigate offsite transport of fertilizers

Asiatic cholera

sudden onset of violent, profuse, watery diarrhea and vomiting rapidly dehydrating victims and killing ~50% of those affected

Microbial Waterborne Diseases help highlight?

the necessity for wastewater (and water) treatment

The most pressing environmental health problem in the developing world is?

Contamination of waterways

The most notorious bacterial enteric diseases are?

Typhoid fever and cholera

Typhoid and paratyphoid

headache, muscle pains, high fever, and constipation alternating with diarrhea (paratyphoid symptoms less severe)

Cholera, dysentery, and salmonellosis

severe diarrhea and vomiting, dysentery diarrhea may be bloody

The most common viruses associated with water pollution are?

Noroviruses, hepatitis A, poliomyelitis, and rotavirus

Giardiasis

caused by Giardia lamblia; is an inhabitant of intestines of many vertebrate animals

Cryptosporidium

a parasitic pathogen that causes diarrheal outbreaks – commonly associated with swimming pools and other recreational waters

Amoebic dysentery

parasitic protozoan afflicting ~500 mil people globally

Sedimentation

 incoming raw water settles for 24 hours in a tank for heavy sediment to settle out.

Coagulation

Alum (hydrated aluminum sulfate) is added to water to precipitate out smaller solids in the form of flocs

Filtration

Through beds of sand, crushed anthracite coal, or diatomaceous earth (reduces concentration of remaining solids).

Disinfection

Chlorine is most used; most important method for killing pathogens in water

Synthetic Organic Pollutants (SOCs)

Consist of vast array of pesticides, industrial solvents, cleaning fluids, etc.

Trihalomethanes (THMs)

Disinfection by-products initiated a controversy over drinking water disinfection.

Lead is dangerous as a result of it being?

Ingested or inhalation

By-product of fertilizer, feedlot runoff, seepage from septic systems, or airborne fallout of nitrogen compounds emitted by industry or motor vehicles.

Inorganic nitrate

What occurs during eutrophication?

algal growth leads to eventual decomposition of organic matter and lower dissolved oxygen in water, killing fish

Salt waters are ______ limited

nitrogen

Fresh waters are _________ limited

phosphorus

Safe Drinking Water Act

A federal program to protect drinking water quality in the United States that’s governed by the provisions of the Safe Drinking Water Act (SDWA). 

EPA establishes a maximum contaiminants level (MCLs) for how many biological chemicals?

80