Can anyone give scientific evidence that sewage sludge is harmful?


In our near by sludge treatment plant the sludge is spread over the land . Is this harmful? Is there any scientific evidence or study carried out indicating that this is harmful??



Vishakha Rajput
Tia, in many countries treated domestic sewage sludge are used beneficially in agriculture, composting and land rehabilitation and there's an abundance of evidence for this. Depending where you are there must be disposal guidelines for municipal sewage sludge. A specific answer can be given if you can mention the country you are living in.
Engr. Mansoor Ahmed PhD. Scholar
Dear Tia A,

There are several Studies conducted on using the Domestic Sludge as Soil Conditioner or by adding some NPK (Nitrogen, Phosphorous and Potassium) to give it complete Fertilizer Qualities. Many part of the world it is being used after some basic treatments:

A few excerpts are for your consideration as follows;

A Joint Study/Research Conducted by:
Nuclear Institute of Agriculture (NIA), Tandojam, Sindh, Pakistan
National Centre of Excellence, University of Sindh, Jamshoro, Sindh Pakistan,
Department of Botany, University of Karachi, Karachi, Pakistan.

"The high nutrients and organic matter contents of sewage sludge make it an excellent fertilizer to enhance soil fertility and crop production. However, presence of metals is a major problem for such a utilization of sludge. It may be concluded that application of sewage sludge was good for improving crop yield but it was also a source of metals. Therefore monitoring of metals, in soils as well as in plant parts, should always be carried out in case of continuous use of sewage sludge." [Reference: Pak. J. Bot., 39(7): 2511-2517, 2007.]

By USEPA, please read Fertilizers Made From Domestic Septage and Sewage Sludge (Biosolids) on the following link:

Another Detailed Link

And Another Link

I hope this details are sufficient for your satisfaction.

Thank you,
Best regards,
Engr. Mansoor Ahmed - PhD. Scholar Environmental Engineering
M. Engg., M.Sc., B. Engg., Post Graduate Certified PMP, Advanced PMP
Chief Executive - Associate Professor
ABAMET Environmental Technologies Pakistan - AETP
Global Environmental Engineering Technologies - GEET
Karachi, Pakistan
Tel : +92 21 3705 9951
Cell: +92 333 2444781
Skype: dr.mansoorahmed
Email; ;
Tia A
Thanks Gary and Felcia. The sludge which is spread on our land is from municipal sludge treatment plant.
Gary Chandler
The risk is enormous. Prion disease is always deadly. There is no cure. There is no way to neutralize deadly prions in sewage. Prions migrate, mutate and multiply.

People with Creutzfeldt Jakobs disease, Alzheimers and other prion diseases are infected with deadly prions. They proceed to contaminate their environment with their bodily fluids (urine, feces, saliva, blood, etc). If just one person with prion disease has used your sewage system, the system is permanently contaminated. Everything discharged from that plant is contaminated. Watersheds that receive the biosolids are contaminated. Every time that it rains on the biosolds, water runoff can spread prions to groundwater. Rain and irrigation can spread prions via surface water runoff--into creeks, ponds, streams, lakes, rivers and oceans.

Cattle and other animals that graze on land with biosolids will uptake soil as they graze, which exposes them to prion disease (better known as Mad Cow disease). Therefore, biosolids threaten food and water supplies.

See my posts on prion diseases at (go into the archives and find "Pandora's Lunchbox" for citations and further detail. Contact me and I will add perspective.
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