Module 6: Water Supply and Waste Treatment

1
Module 6 Water Supply and Waste Treatment
2
Issues

• Natural water
• Domestic water
• Sewage

3
Occurrence of Freshwater in the Arctic

• Glaciers and ice caps hold much of Arctics
  freshwater (Greenlands ice cap contains 10 of
  worlds freshwater)
• Glaciers and accumulated snow in mountain feed
  Arctic rivers
• Many wetlands, ponds, and lakes
• Groundwater is scarce in permafrost areas

4
(No Transcript)
5
(No Transcript)
6
Freshwater Cycle
7
Key Characteristics of Arctic Freshwater

• Drastic cycles in lakes and rivers each year
• Thick or solid ice in winter ? high water flow in
  spring (can be destructive)
• In areas dominated by vegetation, freshwater
  carries high concentrations of dissolved organic
  carbon (DOC)
• E.g. humic and fulvic acids (colour the water)
• Supports an array of flora and fauna in sediment
  and water column (bacteria, protists, algae,
  micro-invertebrates)
• Essential habitat for freshwater fish (few in
  Arctic), anadromous fish, waterfowl, mammals
• Part of the freshwater food web that recycles
  carbon, nitrogen, phosphorous, and other nutrients

8
Overview

• Impacts on aquatic receiving environment
• Import of nutrients to marine environment
• Import of toxicants to marine environment
• Barrier to fish migration

9
(No Transcript)
10
Mackenzie River Delta
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
Concepts

• Acid rain
• Rainfall with a pH of less than 7.0 (in practical
  terms, lt5.0).
• Rain Sulphur Dioxide
• Same as acid deposition
• Effects are a function of the pH buffering
  capacity of the environment.

15
Concepts

• Nutrients
• As a pollutant, any element or compound, such as
  phosphorous or nitrogen, that fuels abnormally
  high organic growth in aquatic systems (i.e.
  eutrophication).
• As a fertilizer, any element or compound,
  principally P, N, K, S, that are limited in
  availability, hence influence plant growth (e.g.
  algae) in water
• Note Can be used to precipitate pollutants in
  algae through long-term sedimentation.

16
Concepts

• Effluents
• The sewage or industrial liquid waste that is
  released into natural water by sewage treatment
  plants or structures to treat industrial water
  (including mine water)
• Receiving waters
• A river, lake, ocean, etc., into which waste
  water or treated effluent is discharged

17
Drinking Water in the North

• Issues
• Wells for extracting ground water is not an
  option
• Underground water lines in permafrost require
  insulation installation of such infrastructure
  is a challenge
• Reservoirs are above ground and insulated
• Quality drinking water is generally available

18
Sanitation of Water

• Inadequate sanitation may lead to
• Gastrointestinal illness
• Hepatitis A
• Bronchitis
• Meningitis
• Other bacterial infection
• Skin and eye diseases
• Note lack of running water has consequences in
  terms of poor hygiene

19
(No Transcript)
20
(No Transcript)
21
Concepts

• Drinking Water
• Water intended for human consumption but which
  has other household uses

22
Best Practices

• Prevention of the contamination of water sources
  (lakes, rivers, streams, and groundwater sources)
• Treatment of water
• Proper maintenance of water distribution systems
• Regular monitoring of drinking water
• Public education and awareness (especially for
  in house water distribution)

23
(No Transcript)
24
(No Transcript)
25
Waste Water

• Sewage
• Liquid waste from toilets, baths and showers,
  kitchens, that is disposed via sewers, trucking,
  or on site treatment systems
• Industrial Waste Water
• Waste water from industries of mines. Generally
  involves some on site processing

26
Treatment Stages

• Primary Mechanical treatment to reduce coarse
  solids, sand and dirt, oils and grease
• Note Ideal as pre-treatment or for treating
  surface water (e.g. street water)
• Note Involves screening, sedimentation, skimming

27
Treatment Stages

• Secondary Treatments designed to degrade
  biological content of sewage (e.g. human waste,
  food waste) through aerobic biological processes
• Note Require aeration for bacterial and
  protozoan activities to degrade organic compounds
• Note Effluent water and sludge are by-products

28
Treatment Stages

• Tertiary Advanced stages of treatment to raise
  the effluent quality to the standard required
  before it is discharged to the receiving
  environment
• Potential steps Filtration, polishing, ponding
  (lagoons, wetlands), nutrient removal,
  disinfection.
• Note Industrial contaminants remain an issue.

29
(No Transcript)
30
Primary Sewage Treatment
31
Common Options for Secondary Sewage Treatment
Treatment Process Description Key Features
Activated Sludge Process (ASP) Oxygen is mechanically supplied to bacteria which feed on organic material and provide treatment Sophisticated process many mechanical electrical parts, needs careful control of operator provides high degree of treatment.
Aerated lagoons Like lagoons but with mechanical aeration Not very common oxygen requirement mostly from aeration and hence more complicated and higher operational and maintenance costs.
Land Treatment (soil aquifer treatment SAT) Sewage is supplied in controlled conditions to the soil Soil matrix has quite a high capacity for treatment of normal domestic sewage, as long as capacity is not exceeded. Some pollutants, such as P, are not easily removed.
32
(No Transcript)
33
Issues for Arctic Environments

• Small communities cannot support extensive sewage
  treatments
• Storage tanks and transfer sites (closed to
  houses) are sources of contamination
• Overland treatment of raw sewage is often the
  only approach to treat sewage
• Nutrient loading and sewage-based contaminants
  are key issues
• Leaching into the marine environment

34
Arviat, Nunavut
35
Arviat, Nunavut