Toxic Sludge is Good for Farmland

Kelly Lavery and Ella Haley Athabasca University

kellylavery@hotmail.comellah@athabascau.ca

Sustainable recycling of sewage sludge?

• Point 7a of the Earth Charter – “Ensure that residual waste can be assimilated by the ecological system”(1).

• Municipalities and industry call land application of sewage sludge ‘recycling’

• However, according to the US Federal Clean Water Act, sewage sludge is a pollutant(2).

What are biosolids?

• The term “biosolids” is industry’s term for sewage sludge.

• The term “biosolids” is not in the federal US sewage regulations Part 503 or the Canadian Federal Fertilizer Act.

Halifax’s situation

• In the late 19th century, sewers replaced outhouses. • Halifax Regional Municipality (HRM) discharges its

sewage directly into the Halifax Harbour with little treatment.

• Raw sewage destroys the aquatic environment • The Habour Solutions Project involves the construction

of three new wastewater treatment plants to treat sewage waste.

Adding Toxins to sewage sludge

• N-Viro is a US multinational corporation that processes sewage sludge for municipalities and industrial customers (1).

• N-Viro will mix Halifax’s sewage sludge with cement kiln dust or lime and dry the mixture.

• N-Viro plans to sell this sewage sludge mixture as Class A fertilizer.

Contaminants in sewage sludge

• 4 key categories of contaminants: pathogens, heavy metals, chemicals, pharmaceuticals

• Waste water treatment plants are not designed to remove heavy metals or toxic chemicals. They don’t do a very thorough job of eliminating pathogens either.

• In Canada, only 11 heavy metals are regulated: lead, mercury, copper, molybdenum, nickel, zinc, cadmium, arsenic, selenium, chromium and cobalt.

• Land applied sewage sludge is regulated province by province.

Nova Scotia RegulationsMaximum Acceptable Metal Concentrations Biosolids

(mg/kg of dry weight)

Metal EQ Quality Class A/BArsenic 13 75Cadmium 3 20Chromium 210 1060Cobalt 34 150Copper 400 760Mercury 0.8 5Molybdenum 5 20Nickel 62 180Lead 150 500

Nova Scotia RegulationsMaximum Acceptable Metal Concentrations Biosolids

(mg/kg of dry weight)

Metal EQ Quality Class A/B

Selenium 2 14

Zinc 700 1850

Ontario’s Standards are Slacker

Metal Maximum ConcentrationMg/kg solids

Typical ConcentrationMg/kg solids

Arsenic 170 4.3

CadmiumCobaltChromiumCopper

3434028001700

3.46.580550

Ontario’s Slacker Regulations

Metal

MercuryMolybdenumNickelLeadSeleniumZinc

Maximum ConcentrationMg/kg solids11944201100344200

Typical ConcentrationMg/kg solids1.46.512482.7506

Processing sewage sludge

• sewage treatment plants reduce pathogens to a certain extent.

• E.coli can survive the treatment process and gets reactivated in soil (1).

Nova Scotia’s regulations for “biosolids”

• If the material is given away, the NS Dept of Env’t and Labour analyze soil samples to determine levels of pathogens and heavy metals.

• If the material is sold, the Canadian Food Inspection Agency randomly checks to see that the label is accurate.

Pathogens in sewage sludge

• “Exceptional quality (EQ) and class A biosolids” can contain a certain level of fecal coliform or salmonella.

• The accepted level of fecal coliform increases by 2000 times in “Class B biosolids.”

• What about all the other pathogens?

Industry PR

• The word “biosolid” was created by a PR firm for the sewage sludge industry(1)

• Industry and US EPA government officials have minimized the risk of sewage sludge

• Industry hired scientists are also being used to defend the safety of sewage sludge.

Dumping Sludge on Farmland is a cheap, quick fix

• US and Canadian municipalities have a history of dumping sewage sludge into waterways.

• To stop ocean dumping key US environmental groups supported the land application of sewage sludge.

Lack of Independent science

• Whistleblower Dr. David Lewis is a internationally known senior research scientist. Lewis used to work for the EPA until he started researching the health complaints and deaths associated with sewage sludge exposure.

Clip from Sludge Diet

• Dr. David Lewis

Precautionary Principle

• If we suspect that a practice or policy is an environmental health risk, than it is better to err on the side of caution in order to protect public health and the environment.

Reverse Onus

• The onus to prove that sewage sludge is safe for farmland should fall on government officials, and industries that are dumping contaminants down the sewer.

Safer sewage disposal

• Separating residential waste from industrial waste would make treating sewage waste much easier.

• Composting toilets

Environmental Justice Health Movements

• Sludge Watch-Maureen Reilly

• Farmers groups: Ottawa Citizens Against Pollution by Sewage, NS Federation of Agriculture, National Farmers Union

• The Concerned Citizens of RR#1 Truro

Policy Implications for Sustainability

• Activist scientists, environmental health justice groups and some policy makers are questioning the dumping of sewage sludge on farmland.

• Several European countries (Switzerland, Sweden) have banned the application of sewage sludge on farmland.

How does your community dispose of sewage sludge?

• Think about it the next time your flush the toilet