Water, Sanitation, and Solid Waste in the Urban Environment

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Water, Sanitation, and Solid Waste in the Urban
Environment

• Kara L. Nelson
• Civil and Environmental Engineering
• U.C. Berkeley
• Environmental Leadership Program
• Tuesday, July 13, 2004

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Outline

• 900-1000 Roundtable discussion
• 1000-1030 Solid waste in the urban environment
  Problems and action-based solutions
• 1030-1045 Break
• 1045-1215 Water and sanitation in the urban
  environment Problems and action-based solutions
• 1230-130 Lunch
• 145-300 Appropriate technologies for water and
  wastewater treatment

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Solid waste problems in the urban environment

• I. Inadequate collection and disposal ? risk to
  public and environmental health
• II. Increasing quantities of waste generated ?
  unsustainable use of resources

4
Water problems in the urban environment

• I. Water pollution ? poor water QUALITY
• II. Water consumption ? insufficient water
  QUANTITY
• III. Land use changes ? decrease QUANTITY and
  QUALITY

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Roundtable Discussion

• What is the current situation with urban
  water/sanitation/solid waste where you live/work?
• How are urban water/sanitation/solid waste
  problems related to your work/experience?

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Solid waste problems in the urban environment

• I. Inadequate collection and disposal ? risk to
  public and environmental health
• II. Increasing quantities of waste generated ?
  unsustainable use of resources

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Inadequate collection and disposal - Problems

• Public health
• Formal and informal workers (collectors, sorters)
  exposed to waste
• Garbage piles create reservoirs for insects and
  rodents that carry diseases
• Open burning of garbage contributes to
  respiratory illness
• Environmental health
• Contamination of water, soil, air (metals,
  toxins, nutrients)
• Blockage of water flow in drainages ? floods ?
  erosion
• Attraction of vultures
• Deterioration of aesthetic value of landscapes

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Inadequate collection and disposal - Solutions

• Implement effective collection of solid waste
• Separate collection of hazardous waste
• Provide safe environment for collection and
  sorting
• Landfill design
• Impermeable liner (protects groundwater)
• Leachate and gas collection
• Cover new fill at end of day (prevents wastes
  from blowing away and discourages vectors)

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Increasing quantities of waste generated -
Problems

• Environmental health
• Increased emissions of pollution (air, water and
  soil)
• Increased emissions of greenhouse gases
• Faster depletion of non-renewable resources
• etc.
• Public health

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Increasing quantities of waste generated -
Solutions

• Consumer-based
• Participate in recycling and composting
• Buy products with less packaging and recycled
  content
• Producer-based
• Manufacture products so that they may be recycled
  or reused
• Reuse or recycle materials during production
• Use only non-toxic materials in production

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Increasing quantities of waste generated
Solutions cont.

• Policy approaches
• Consumer (e.g. differential pricing of waste,
  recycling, compost)
• Industry (e.g. mandatory take-back)
• Government (e.g. diversion targets)

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For more information

• Swiss Federal Institute for Environmental Science
  and Technology (EAWAG) Department of Water and
  Sanitation in Developing Countries (SANDEC) Solid
  Waste Management (SWM) homepage
  www.sandec.ch/SolidWaste/SWM-Home.htm

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Water problems in the urban environment

• I. Water pollution ? poor water QUALITY
• II. Water consumption ? insufficient water
  QUANTITY
• III. Land use changes ? decrease QUANTITY and
  QUALITY

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Impacts of urban water problems

• Water QUALITY
• Loss of aquatic habitat
• Contamination of drinking and bathing water
• Water QUANTITY
• Loss of aquatic habitat
• Subsidence of land surface
• Insufficient water for drinking and hygiene

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Water Pollution
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Water Pollution - Pathogens

• Types of waterborne pathogens
• Viruses Hepatitis A, Enterovirus
• Bacteria Cholera, Salmonella
• Protozoa Entamoeba, Cryptosporidium
• Helminths (worms) Ascaris, Schistosomiasis
• Public health impact
• 4 billion cases of diarrhea/yr
• 5 million deaths/yr due to diarrheal disease
• Improved drinking water, sanitation, and hygiene
  would reduce diarrheal disease by 25-33

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Water Pollution Other types

• Types of water pollution (besides pathogens)
• Organic matter (BOD Biochemical Oxygen Demand)
• Nutrients (Nitrogen and Phosphorus)
• Pesticides
• Metals
• Sediment
• Environmental impact Loss of aquatic habitat
• Low dissolved oxygen (from BOD, N, P)
• Toxicity
• Public health impact contamination of drinking
  and bathing water with pathogens

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Environmental Health and Public Health Are
Intimately Connected!

• Both can be protected by minimizing water
  pollution
• Top priority is provision of adequate COLLECTION
  and TREATMENT of human fecal waste

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Water Pollution - Sources

• Human feces
• Direct deposit in environment
• Leaky latrine pits or septic tanks
• Discharge of untreated or inadequately treated
  wastewater
• Graywater (washwater from kitchen, bathroom,
  etc.)
• Industrial discharges
• Stormwater runoff (non-point source pollution)
• Solid waste

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Water quality in USA
Source USEPA National Water Quality Inventory
2000 Report
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Water quality in USA
Source USEPA National Water Quality Inventory
2000 Report
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Source WHO and UNICEF Global Water Supply and
Sanitation Assessment 2000 Report
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Source WHO and UNICEF Global Water Supply and
Sanitation Assessment 2000 Report
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Source WHO and UNICEF Global Water Supply and
Sanitation Assessment 2000 Report
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Source WHO and UNICEF Global Water Supply and
Sanitation Assessment 2000 Report
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Water Pollution - Solutions

• Provide collection, treatment, and disposal of
  fecal waste and greywater for all households via
• Latrine or flush toilet and septic tank at each
  household
• Community sewer system AND treatment plant
• Require industries to collect and treat
  wastewater BEFORE it enters sewer system
• Reduce the non-point sources of pollution, or
  collect and treat stormwater runoff
• Collect solid waste and recycle, compost, or
  landfill

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Assessment of Water Quality

• Environmental health
• Temperature, pH, dissolved oxygen, turbidity,
  toxicity, biology
• Public health - Fecal indicator organisms
• Total coliform bacteria
• Fecal coliform bacteria
• E. coli

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Example Colilert Test for Total Coliform and
E. coli
Idexx Laboratories, Inc.
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Water and Sanitation Millennium Development Goal
(MDG)

• Eight MDGs adopted by 191 nations at UN
  Millennium Summit
• 1990 baseline
• Under goal seven
• By 2015, reduce by 50 the proportion of people
  without access to safe drinking water and basic
  sanitation

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Water Consumption
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Water Consumption - Environmental Impacts

• Depletion of groundwater resources
• Degradation of aquatic habitat (e.g., declining
  fish populations)
• Altered flow and temperature in rivers due to
  dams and reservoirs
• Loss of wetland habitat

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Water Consumption - Facts

• Largest use of freshwater is for agricultural
  irrigation
• Globally, about 2/3 of freshwater
• In some regions often more than 90 (e.g.,
  California, many developing countries)
• By 2025, 50 of global population may live in
  water-stressed regions (WRI)
• Per capita household consumption is higher in
  urban areas

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62 countries report per capita water use less
than 50 L/d (more than 1/3 of global population)
Source Gleick (2000) The Worlds Water
2000-2001
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Water Consumption - Solutions

• Conservation policies
• Metering of water use
• Equitable (incremental) price structure
• Conservation measures
• Household (Low-flow showerheads, toilets, washing
  machine, dishwasher) or waterless toilets
• Industrial
• Fix leaking water distribution systems (40 loss
  is typical)
• Wastewater reuse

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Wastewater Reuse (Reclamation, Recycling)

• Wastewater must be treated to protect public
  health and the environment
• Benefits
• Reduce consumption of freshwater
• Reduce water pollution (reduce discharge of
  wastewater)
• Examples
• Agricultural irrigation
• Landscape irrigation
• Industrial processes
• Aquifer recharge

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Recycled Water Service Area
12,000 acres irrigated with tertiary-treated
wastewater Crops include artichokes, lettuce,
broccoli, and strawberries
Monterey Bay
Monterey County, CA
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Wastewater Irrigation in Mezquital Valley, Mexico
(using untreated wastewater from Mexico City)
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Land Use Changes
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Land Use Changes Examples and Environmental
Impacts

• Increase in impervious surfaces
• Rainfall doesnt filter into soil
• Can cause both flooding and drought
• Washes pollution into surface waters
• Deforestation
• Can cause both flooding and drought
• Increased erosion, washes soil into surface
  waters
• Development in watersheds used for drinking water
• Contamination of drinking water
• May cause expensive treatment to be required

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Land Use Changes Solutions

• Preserve green space
• Use pervious surfaces for parking lots, roads,
  etc.
• Collect stormwater runoff in ponds and wetlands
  (retain and treat)
• Sustainable forestry management
• Manage development in watersheds used for
  drinking water (may be cheaper than treating!)

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Appropriate technology for water and wastewater
treatment
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Key Points

• Emphasis on SANITATION (adequate disposal of
  feces), WASTEWATER COLLECTION, and TREATMENT
• Protect the environment AND human health
• Reduce contact with human waste
• Lower cost of drinking water treatment
• Protect valuable natural resources
• Typical US approach may be inappropriate in other
  urban areas
• May not provide adequate removal or inactivation
  of pathogens
• Not developed using a risk-based approach (and
  therefore not necessarily cost-effective)

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West Point wastewater treatment plant, Seattle, WA
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Factors to consider in choosing an
approach/technology

• Decentralized (household or community) vs.
  Centralized (city)
• To sewer or not to sewer, that is the
  question
• Removal or inactivation of pathogens
• Energy use
• Costs construction and operation and
  maintenance
• Degree of operation and maintenance necessary
• Availability of replacement parts

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Sanitation
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Types of Sanitation

• Household vs. Community
• Dry vs. Water carriage (flush)
• In urban environment
• Most household sanitation should be dry
• If flush toilets are used, a community collection
  and treatment system is typically required

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Household Sanitation

• When to use
• Only option if households do not have piped water
• Too expensive or no room to install sewer system
• Political unwillingness to provide services (like
  sewer)
• Advantages
• More affordable
• Does not require large amounts of water to carry
  wastes
• Opportunities for microenterprise
• Challenges (mostly due to high density!)
• Contamination of nearby wells or
  rivers/lakes/beaches
• No room to build another pit once the first one
  fills up
• Must also provide for disposal of greywater (wash
  water)

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Household Sanitation Technologies

• VIP Latrines (empty and treat)
• Pour-flush toilets (empty and treat)
• Bucket collection (collect and treat)
• Urine-separating latrines (treat onsite and
  reuse)
• Flush toilet

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Squatting platform
For more info www.sanplat.com
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Ventilated Improved Pit (VIP) Latrine
For more info Mara, D. (1996). Low-cost Urban
Sanitation, John Wiley Sons, Chichester,
England.
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Pour-flush Latrine
Image from http//www.unep.or.jp/ietc/publication
s/freshwater/sb_summary/5.asp
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Bucket system in Shanghai, China
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Vacutug for emptying latrine pits
Vacutug demonstration in Kenya
For more info http//www.irc.nl/themes/sanitation
/smallpit.html
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Ecological Sanitation

• Recognize that urine and feces are valuable
  resources (nutrients and organic matter)
• Provide treatment to prevent the spread of
  pathogens

For more info Esrey, S. A., J. Gough, D.
Rapaport, R. Sawyer, M. Simpson-Hebert, J.
Vargas, and U. Winblad. (1998). Ecological
Sanitation, Swedish International Development
Cooperation Agency (SIDA), Stockholm.
(http//www.worldbank.org/watsan/topics/tech_sanit
ation.htmleconsan)
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Urine-Separating Latrines (aka Ecological Dry
Toilets)
For more info http//www.laneta.apc.org/esac/dryt
oilet.htm http//www.lboro.ac.uk/well/resources/we
ll-studies/full-reports-pdf/task0324.pdf
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Double vault system
From Esrey et al. (1998)
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Ecological dry toilet (Huajuapan, Mexico)
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Ecological dry toilet (San Juan Amecac, Mexico)
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Dry toilet microenterprise
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The Flush Toilet Dilemna
Most likely there is not enough room for the soil
absorption system ? Wastewater must be collected
and treated offsite Flush toilets should not be
installed unless a sewer system AND wastewater
treatment plant are also constructed!
From http//ohioline.osu.edu/aex-fact/0743.html
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Septic tanks
Bad (leaky)
Good (waterproof)
For more info about on-site wastewater treatment
http//www.nesc.wvu.edu/nsfc/
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From Mara, D., (1996). Low-cost Sewerage. John
Wiley Sons, Chichester, England.
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Wastewater Collection and Treatment

• Collection (Sewer system)
• Conventional
• Simplified sewerage
• Treatment
• Objectives
• Options

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Small-diameter, shallow depth sewerage
Best for transporting settled wastewater (like
septic tank effluent), but can also be designed
for raw wastewater
For more info Mara, D., (1996). Low-cost
Sewerage. John Wiley Sons, Chichester, England.
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Wastewater Treatment Objectives

• Remove sediment
• Remove organic matter (BOD)
• Remove nutrients (N and P)
• Remove or inactivate pathogens

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Levels of Wastewater Treatment

• Level Objective
  _
  
  
• Pre-treatment Remove sand, grit, large objects
• Primary Remove suspended particles by
  sedimentation (BOD, N, P, and some pathogens)
• Secondary Remove dissolved BOD, N, and P by
  biological degradation (bacteria)
• Tertiary Additional treatment, specific to
  situation (nutrients, organics, colloids)
• Disinfection Inactivate pathogens

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Wastewater Treatment Technologies

• Wastewater Stabilization Ponds (WSP) The best
  option if land is available
• Typical US treatment plant (very expensive!)
• Sedimentation ? Activated Sludge ? Secondary
  Clarification ? Disinfection
• Anaerobic sludge digestion
• Other alternatives
• Advanced primary treatment (sedimentation with
  coagulation)
• Trickling filter instead of activated sludge
• Oxidation ditch instead of activated sludge
• Promising technologies
• Upflow Anaerobic Sludge Digester (UASB)
• Membrane Bioreactor (MBR)

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Wastewater Stabilization Pond System
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Wastewater Stabilization Pond in Xalostoc, Mexico
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Wastewater Stabilization Pond (Primary,
Secondary, some Tertiary treatment, and
Disinfection)
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Sedimentation Basin (Primary Treatment)
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Activated Sludge (Secondary Treatment)
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Secondary Clarifier (Secondary Treatment)
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Secondary Clarifier
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Sludge Digestion
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Drinking Water
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Drinking Water Treatment Objectives

• Pristine source (rare in urban environment!)
• Disinfection recommended but not necessary
• Examples Groundwater (wells), Spring, Rainwater
• Contaminated source (fecal pollution)
• Removal of particles recommended and disinfection
  necessary
• Examples River, Lake, Contaminated well or
  spring
• May need additional treatment for other
  contaminants, such as
• Arsenic (Bangladesh) physicochemical treatment
  necessary
• Nitrate babies should not drink (blue baby
  syndrome)

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Drinking Water Treatment Technologies

• Removal of particles and some pathogens
• Sedimentation community or household
• Filtration
• Slow sand filter - community
• Biosand filter household
• Inactivation of pathogens
• Chlorination community or household
• UV community or household
• SODIS - household

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Sedimentation
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Slow Sand Filtration
Drained slow sand filter in foreground Operating
slow sand filter in background
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Household Filtration
The Biosand filter (www.cawst.org)
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Chlorination

• Most common type of disinfection
• Risks vs. benefits
• Disinfection by-products linked to cancer
• Risk of cancer MUCH lower than risk of pathogens
• Hypochlorite can be manufactured locally

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Ultraviolet (UV) Disinfection Community system
For more info www.waterhealth.com
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Ultraviolet (UV) Disinfection Household system
UV Tube installed in Patzcuaro, Mexico
For more info email nelson_at_ce.berkeley.edu
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Solar Disinfection (SODIS)
For more info www.sodis.ch
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For more information

• Water Supply and Sanitation Collaborative Council
  (WSSCC), www.wsscc.org
• IRC International Water and Sanitation Center,
  www.irc.nl
• The Sanitation connection, www.sanicon.net