The District of Sechelt, B.C. is pursuing a unique pilot project that will use recovered sewage solids to remove traces of pharmaceutical drugs, recreational drugs and hormones from post-treatment wastewater.
Such a system could be used to treat the province’s wastewater before it is discharged into surface water systems used for drinking water by downstream communities. Many municipalities outside the Lower Mainland discharge treated wastewater into rivers and a handful — such as Vernon and Oliver — already use it for irrigation on golf courses and hay fields.
The U.S. Geological Survey recently reported that pharmaceuticals persist for several months in irrigated soils, which Sechelt Mayor John Henderson fears could hinder consumer acceptance of foods grown with reclaimed water. Plus, trace chemicals from treated municipal wastewater are known to disrupt the reproductive systems of fish.
Sechelt is hoping to divert its wastewater for use in agriculture and Henderson hopes the pilot will help answer the “last objection” from people concerned about the introduction of trace amounts of drugs and other contaminants into the food system.
The Sunshine Coast community plans to make charcoal for filtration from wood waste, paper and solids recovered from sewage by heating it to at least 500 C, which destroys pathogens and contaminants and leaves behind a powerful filtration medium not unlike activated charcoal, according to Sechelt’s water treatment project coordinator Paul Nash.
The product — called biochar — will then be used to remove drugs, hormones and other contaminants dangerous to humans and other living creatures from treated wastewater.
A treatment facility that uses biochar made from sewage solids to filter drugs and hormones from water would the first of its kind in the world, said Henderson.
“If we succeed, we will have a way to remove pharmaceuticals from both effluent and biosolids using waste as a resource,” said Henderson.
Up to 35 per cent of drinking water samples taken across the country and analyzed for an as-yet unpublished survey show trace amounts of drugs and their byproducts, according to University of Waterloo researcher Mark Servos.
“This is part of a major study being undertaken by Health Canada and we looked at about 60 samples collected from across the country,” said Servos.
Samples that tested positive for medications — including psychiatric and heart medications, anti-inflammatories and veterinary drugs — were typically from sources downstream from municipal wastewater treatment facilities.
Communities that obtain drinking water from rivers and lakes downstream from treatment facilities are most at risk of consuming these compounds, though in amounts so small they are measured in parts per billion or trillion, he said.
The analysis focused on 16 medications and compounds associated with certain drugs — selected from a potential roster of thousands of drugs — as a baseline snapshot to gauge the concentration of drugs in a variety of water sources.
“These kinds of compounds are commonly found in surface waters all over the world,” he said. “We would have been surprised if we hadn’t found some of these drugs.”
Studies of municipal wastewater consistently turn up trace amounts of over-the-counter and prescription medications, some of which are persistent in the environment. Ibuprofen and naproxen were detected in wastewater from Vancouver as early as 1986 and several subsequent studies have found detectable levels of cocaine, methamphetamine, ecstasy (MDMA) and more than 100 prescription drugs, including many widely used antidepressants, in Canadian drinking water sources.
A recent review of scientific literature on pharmaceutical micro-pollutants and endocrine-disrupting contaminants warned that hormonal contraceptives may bioaccumulate in organisms when introduced to the environment and adversely affect hormonal systems.
“The threat to human health from consuming these compounds in such small amounts is extremely minimal,” said Servos.
What is less clear is the effect of consuming trace amounts of drugs in combination because dozens of common pharmaceuticals may be present in a drinking water source.
“You can never say that the risk is zero, but because (drugs) can appear in so many combinations, the truth is that we just don’t know,” said Servos. “That’s the precautionary principle.
“After (the Walkerton, Ont. E. coli outbreak) we were told that when we have a suspicion we should explore it fully,” he said. “People expect their drinking water to be pristine.”
Sechelt recently commissioned a new three-stage water treatment facility that processes and disinfects wastewater to a high standard suitable for use by industry, agriculture and park irrigation, while producing compost from solid waste.
“Our new plant can already clean up most of (the pharmaceuticals), but we thought, ‘why not clean up all of it?’” said Nash.
“We wanted to put this system into the original specifications for the water treatment centre, but there is no off-the-shelf technology to do this,” he said. “We have to invent a way to do this.”
Biochar — which can be cheaply manufactured from waste materials — has shown great promise as a filter medium that is longer lasting than activated charcoal, according to Nash.
The pilot project recently received a $169,000 grant from the Federation of Canadian Municipalities’ Green Municipal Fund, which will cover half the cost of development.
Drinking water screened for pharmaceuticals
A University of Waterloo study commissioned by Health Canada is screening drinking water samples from across Canada for a shortlist of common pharmaceuticals.
Atenolol :: Beta blocker
Atorvastatin :: Lipid regulator
Carbamazepine :: Anti-epileptic
Diclofenac :: Anti-inflammatory
Fluoxetine (Prozac):: Anti-depressant
Gemfibrozil :: Lipid regulator
Ibuprofen :: Anti-inflammatory
Lincomycin :: Veterinary antibiotic
Monensin :: Veterinary antibiotic
Naproxen :: Anti-inflammatory
Norfluoxetine :: Metabolite
Sulfamethoxazole :: Antibiotic
Triclocarban :: Antibacterial
Triclosan :: Antibacterial
Trimethoprim :: Antibiotic
Venlafaxin :: Anti-depressant