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Appropriate (and Inappropriate)Technology for SewagePollution Control in anInternational Context
Randal Samstag, P.E.
Carollo Engineers
How Big is the Problem?
Less than 10 percent of the population in theCaribbean Basin and South America is servedby adequate sewage pollution control
This is typical for much of the developing world
Singapore and Japan are the only countries inAsia with near complete coverage of thepopulation with adequate sanitation
South Africa has extensive sewage treatment,but much of the rest of Africa has little or none
Some progress is being made, but in generalthings are not improving very fast
A Typical Sewage Outfall in India
The Ganga at Varanasi
The Ganga
Inappropriate Sewage PollutionControl at Varanasi
Ganga Action Plan(GAP) funded sewagepump stations andactivated sludgetreatment plant upstream
Unreliable power supplyhas led to completefailure of the pumpstations and treatmentplant and raw sewagepollution of tube wells
Advanced Integrated Pond System(AIPS) Proposed for Varanasi
Site downstream ofVaranasi
Low or no-powersecondary treatmentsystem
Effluent coupled withirrigation and/orinfiltration
Disadvantage: Relativelylarge land area (but asite has been identified)
The Yangtse at Chengdu
River Disposal in Chengdu
Washing Vegetables in Kanding
The River inKanding
Excreta Management in SichuanProvince
Sacred Sanitation at Dzogchen
Sanitation in Kham
Modern Sewage Treatment inSingapore
Rooftop Gardens at theMiwakashima WWTP in Tokyo
A TypicalSewage
PollutionControl Solution
in Venezuela
Venezuela’s First ActivatedSludge Plant
An MSBR WWTP onMargarita Island
Lagoon Treatment underConstruction in Valencia
MSBR Treatment for Valencia,Venezuela
The Beetham Lagoons in Portof Spain, Trinidad
Trickling Filter Effluent InTrinidad
A Trickling Filter WWTP inTrinidad with No Effluent
An Extended Aeration ActivatedSludge Plant in Trinidad with No
Influent
A Lagoon Plant in St. Luciawith Almost No Influent
A HotelWetlands
WWTP onSt. Lucia
Disinfectionby UV at aHotel in St.
Lucia
Disinfection by “Natural UV”in Venezuela
UASB Reactor in Ecuador
Decision Tree for Appropriate WastewaterCollection
Decision Tree for AppropriateTreatment
Example Comparison ofProcess Costs
$0.00
$20.00
$40.00
$60.00
$80.00
$100.00
$120.00
$140.00
Base MLE MLE with Fine
Pore Aeration
Primary, MLE Chemically
Enhanced
Primaries, MLE
MLE Anaerobic
Digestion
UASB, MLE
Project Costs ($ Million) Present Worth of O&M Cost ($ Million)
Example Comparison ofGreenhouse Gas Emissions
-2,000
-1,000
0
1,000
2,000
3,000
4,000
MLE - No Primaries MLE - Fine PoreAeration
MLE - Primaries MLE - ChemicallyEnhanced Primary
Treatment
MLE - AnaerobicDigestion
MLE - UASB
Me
tric
To
ns
of
CO
2e
Chemicals Handling
Solids Handling
Chemical Production
Electricity Emissions including T&D Loss
Renewable Energy Production (Offsets)
Is Water Carriage the Problem?
Water carriage is convenient and a symbol ofdevelopment
But there would be no water pollution (or muchless) without water carriage!
It is not justified in every context
In many contexts ventilated pit latrines orcomposting toilets are more appropriate
The sociology is as important as the sanitaryengineering in selecting appropriate technology
What is Preventing Sewage PollutionControl in the Developing World?
The biggest obstacle is urbanization without economicdevelopment
Followed by lack of institutional development
Technical development is way down the list of obstacles
The pessimist’s view: Truly widespread sewagepollution control will only come with economicdevelopment
The optimist’s view: We don’t have to repeat themistakes of the developed world. Appropriatetechnology can help us sidestep them.
For More Information UNEP, Appropriate Technology for Sewage Pollution
Control in the Wider Caribbean Region, . . .(http://www.cep.unep.org/pubs/Techreports/tr40en/index.html)
Randal W Samstag Carollo Engineers
1218 Third Avenue Suite 1600 Seattle 98101
206-684-6532
Questions?
