LOADING

A STUDY ON RISKS AND OPPORTUNITIES RELATED TO

SEWAGE IRRIGATION

Presented by: Zeeshan Shahid (Pakistan)

BS –Chemical Engineering (4th Semester)

COMSATS Institute of Information Technology, Lahore, Pakistan

Presentation Outline

• Introduction To Sewage

• Sewage Use In Agriculture

• Opportunities In Sewage Irrigation

• Risks In Sewage Irrigation

• Conclusion

INTRODUCTION TO SEWAGE

What is Sewage? Sewage as a source of

Environmental Pollution

What is Sewage

• Wastewater produced as a result of industrial and domestic activities

• Mainly liquid waste but also contains solids

• Rich in pollutants

Sewage as a source of Environmental Pollution

Organic matter Pathogens Nutrients Toxic contaminants Dissolved minerals

• Pollutants in wastewater may be classified into:

• Generation of huge volumes of sewage

Sewage as a source of Environmental Pollution

• A major source of environmental pollution

• Sewage must be treated before its disposal

SEWAGE USE IN AGRICULTURE

• Water stress and scarcity due to over-exploitation of freshwater resources

• Freshwater is becoming insufficient for agricultural purposes

• To fulfill agricultural requirements of water, sewage is being used

• Use of raw sewage instead of treated sewage for raising crops

SEWAGE USE IN AGRICULTURE

OPPORTUNITIES IN SEWAGE IRRIGATION Fresh Water Scarcity and

Drought

Eliminating the Need for Artificial Fertilizers

Year Round Access to Farmers

Coping with Poverty

Fresh Water Scarcity and Drought

• Rapidly increasing freshwater scarcity in many arid and semi-arid countries

• Causing a major conflict between urban and agricultural demands for water

• These problems can be resolved by the use of wastewater in agriculture

Eliminating the Need for Artificial Fertilizers

• Wastewater contains large amounts of essential plant nutrients such as nitrogen, phosphorous and potassium

• Using treated wastewater in agriculture can decrease the need for expensive chemical fertilizers

0

10

20

30

40

50

60

70

80

90

Strong

Medium

Weak

Phosphorous PotassiumNitrogen

Chart showing the levels of the plant nutrients of strong, medium and weak domestic wastewaters [1]

Co

nce

ntr

atio

n (

mg

/L)

Year Round Access to Farmers

• In Pakistan 90% of the 116,590 million gallons of sewage produced per day from large industrial-urban centers is disposed off into irrigation system without any treatment

• Hence, major vicinity of the cities can be fertilized

Coping with Poverty

• Dependence of South Asian countries like India and Pakistan on agriculture

• Water shortage creates unemployment hence affecting people involved in the field of agriculture

• Irrigation using sewage as a viable alternative

RISKS IN SEWAGE IRRIGATION

Risks, Associated with the Consumption of the Products of the Irrigated Field

Risks, Associated with the Personnel, Operating the Field

Risks, Associated with Groundwater Contamination

Risks, Associated with the Consumption of the Products of the

Irrigated Field

• Untreated city effluent contains full spectrum of pathogens

• Irrigation continues up to the harvest day due to the short growing cycle of most vegetables

• Some pathogens can survive for several weeks when discharged into fields and find their way into the consumers’ homes

Pathogen Class Diseases

Bacteria

Bacillary dysentery

Typhoid fever, Cholera

A variety of gastroenteric diseases

Viruses

Infectious hepatitis

Acute gastroenteritis

Poliomyelitis

''flu-like" symptoms

Protozoa

Amebiasis (amoebic dysentery)

Giardiasis (gastroenteritis)

Cryptosporidiosis (gastroenteritis)

Balantidiasis (gastroenteritis)

Helminths

Ascariasis (roundworm infection)

Taeniasis (tapeworm infection)

Ancylostomiasis (hookworm infection)

Trichuriasis (whipworm infection)

Table showing the classes of Pathogens associated with raw sewage [2]

• Transmission of heavy metals and trace elements through food crops into human is a more dangerous consequence of raw sewage

• The risk is especially prevalent where waste water from manufacturing industries is used

Risks, Associated with the Consumption of the Products of the Irrigated Field

Element Concentration (mg/L)

Aluminum 0.3-3

Arsenic 0-0.2

Barium 0-0.2

Boron 0.5-3

Cadmium 0.01-0.2

Chromium 0.1-0.3

Cobalt -

Copper 0.01-0.5

Iron 0.5-6.5

Lead 0-1

Manganese 0.0002-0.003

Nickel 0.05-0.5

Zinc 0.01-2.1

Table showing typical concentrations of Elements in Untreated Sewage[3]

Risks, Associated with the Personnel, Operating the Field

• The pathogens can also harm the health of agricultural workers

• High risk of skin irritations and itching among farmers

• Farmers exposed to untreated sewage effluent appear to suffer worse irritations

Risks, Associated with Groundwater Contamination

• Salts and trace elements from sewage water used for irrigation purposes concentrate in the deep percolation water and can pollute groundwater

• Exposure to this contaminated water can cause various diseases including diarrhea, skin irritation, respiratory problems etc

CONCLUSION

• Sewage water opens a new window of opportunities to find solution to various mankind problems

• Sewage use for irrigation purposes has been beneficial in providing round the year access to water

• It has played an important role in short term eradication of poverty

CONCLUSION

CONCLUSION

• However risks associated with the use of sewage water are considerably high and alarming

• The presence of heavy metals and pathogens in sewage may create numerous health problems for future generations

• Sustainability considerations should take into account three pillars of sustainability i.e., economy, environment and society

ACKNOWLEDGEMENTSI would like to thank my teacher, Mr. Asim Laeeq who is currently doing his PhD in Belgium, for his motivation to write for S3Regina.

Then I would like to thank my cousin, Salman Saeed and my friend, Ali Waqas, who helped me with presentation processing. Finally I am thankful to my cousin, Dr. Rizwan Saeed, for providing me reference books.

References

[1] Pescod, M, B. Wastewater treatment and use in agriculture, FAO irrigation and drainage paper 47, 1992

[2] Committee on the Use of Treated Municipal Wastewater Effluents and Sludge in the Production of Crops for Human Consumption, National Research Council., Use of Reclaimed Water and Sludge in Food Crop Production, 1996

[3] Chang, A, C., Pan, G., Page, A, L., and Asano, T. Developing Human Health-related Chemical Guidelines for Reclaimed Waster and Sewage Sludge Applications in Agriculture, WHO 2001

THANK YOU