Water & Wastewater

Hydrologic Cycle

Five Transfer Mechanisms:

1. Evaporation: from water and soil

2. Transpiration: by plants

3. Transport: of water vapor in the atmosphere

4. Precipitation: rain, snow, etc.

5. Runoff: flows back to bodies of water

Uses of water

Categories & examples

- Domestic: drinking, cooking, bathing, hygiene, laundry, toilets

- Industrial: manufacturing (e.g., 10 gallons to refine 1 gallon of gas, 1,400 gallons for one burger meal)

- Agricultural: irrigation (69% of global use)

- Other: Recreation, mining, fire-fighting, electricity, sewage disposal

Well water

- Drilled wells: most modern and accepted type; drilled using a rotary bit, suitable for deep water access

- Other types (mostly outdated or limited): dug, driven, bored, jetted

Groundwater

Contamination sources (3 major categories):

1. Septic system - leaks, improper construction

2. Waste storage/disposal - landfills, underground storage tanks

3. Non-point source pollution- fertilizers, animal waste, urban runoff, leaking septic tanks, etc.

Septic systems

Soil suitability:

- Evaluated through permeability tests and soil profile

- Considerations: depth to water table, mottling, rock, slope, proximity to streams/well

Modern acceptable system:

- Septic tank -> Distribution box -> Leach (disposal) field

- Leach fields filter and treat effluent via aerobic soil digestion

Contaminants from septics:

- Human waste, cleaning products, food waste, pet waste, etc.

- Can introduce bacteria (cholera), viruses (hepatitis), protozoa (Giardia), and chemicals (TCE, nitrate) into groundwater

Causes of illness relaed to wastewater & exposures

Routes of exposure:

- Ingestion, dermal contact, inhalation, ocular exposure

- Can cause irritation, infection, or death

- Includes bacterial, viral, protozoan, parasitic, and chemical causes

Waterborne pathogens

Giardiasis

- Agent: Giardia lamblia

- Transmission: fecal-oral; contaminated water; hand-to-mouth

- Reservoirs: humans, beavers

- Symptoms: chronic diarrhea, cramps, bloating, fatigue

- Prevention: protect water supply, sewage control

- Treatment: rehydration, Flagyl

Cryptosporidiosis

- Agent: Cryptosporidium parvum

- Transmission: fecal-oral, waterborne, person-to-person

- Reservoirs: humans, cattle

- Symptoms: diarrhea, cramps, weight loss

- Prevention: boil water, hygiene

- Treatment: rehydration

Cholera

- Agent: Vibrio Cholerae

- Transmission: water/food contaminated with feces or vomitus

- Reservoir: humans

- Symptoms: watery stool, vomiting, dehydration, kidney failure

- Prevention: safe water, chlorination, sanitation

- Treatment: rehydration, antibiotics

Sewage Treatment

1. Preliminary- screens & grit chambers remove large solids

2. Primary- sedimentation; solids settle, some organic load removed

3. Secondary- trickling filters or activated sludge remove 90-95% organic load

4. Tertiary- advanced treatment; removes nitrogen, phosphorus, carbon compounds

5. Disinfection- chlorine or UV kills pathogens

6. Final disposal- treated water is released; sludge is incinerated, landfilled, or used as fetilizer

Safe Drinking water act

- Passd in 1974; major updates in 1986 and 1996

- First national protection of public drinking water

Primary standards (health-related):

- Pathogens: coliforms, Giardia, Crypto

- Chemicals: lead, mercury, arsenic, benzene

- Disinfectants and by-products: chlorine, THMs

- Radionuclides: uranium, radium

Secondary standards (aesthetic/maintenance)

- Iron, manganese, copper, aluminum

- Fluoride, total dissolves solids, corrosivity