Secondary Treatment of Wastewater: is it Good Enough?


Hi everyone, hope you all enjoyed a great semi-rainy weekend! I spent the weekend working alone at two Farmers’ Markets, Saturday in Errington and Sunday in Cedar. Despite the less-than-ideal weather, I was amazed at how many people dropped by, and leaving the kids’ activities in the car meant I was able to focus more on having some in-depth conversations with interested people. And boy, did I have some good conversations! I talked with one man for almost an hour about various conservation issues we’re working on. He supported the expansion of the Trans Mountain pipeline for economic reasons (but thought we should refine the oil here instead of sending it overseas to be refined, thereby further increasing our economy). His opinion was that there are many more immediate things to be worried about in the Georgia Strait. His primary concern, which we spent most of our time talking about, was sewage treatment.

Canada has always been way behind in their sewage treatment regulations. It was only last

Iona WWTP in Richmond (Photo by Georgia Strait Alliance)

year that the Federal Government finally made it mandatory to upgrade sewage treatment to the secondary level in Canada (except for small northern communities). Before that, many plants were only employing primary wastewater treatment, and were as a result likely in violation of the Fisheries Act’s section which does not allow the discharge of deleterious (dangerous) substances into fish bearing waters. Wastewater, the stuff that is dumped down our toilets, sinks, and bathtubs as well as the water that drains out of our washing machines, dishwashers, and storm drains, now needs to be treated at the secondary level before it is reintroduced to the environment. Plants have been given until 2020, 2030, or 2040 to make the necessary upgrades to their systems, depending on the facility’s risk (high, medium, or low, respectively). All wastewater treatment plants (WWTPs) perform preliminary wastewater treatment or screening, or removing the “lumps.” In most plants today, the wastewater is left to settle, so heavy things will sink and can be removed, while liquids such as cooking oils (which are less dense than water) will rest on top and can be skimmed off. This is primary treatment, and the collected “sludge” can be processed to extract energy that can be used to offset local fossil fuel use. For all WWTPs in Canada, secondary treatment is now a mandatory upgrade. This is done mostly by bacteria and other micro-organisms, which break down 85-90% of the dissolved and suspended solids, including most pathogens, toxic chemicals such as pesticides, and heavy metals. The bacteria are then removed with the sludge they produce and the wastewater is either released back to the environment or further treated. Tertiary treatment, only used in a few cities such as Calgary (which receives an A+ on the 2004 National Sewage Report Card), removes select substances such as ammonia, phosphorous, nitrogen, and heavy metals to a further degree using advanced filtration methods, UV sterilization, and reverse osmosis.

Photo by Georgia Strait Alliance
As per the sewage treatment upgrades required for all WWTPs Canada-wide, the CRD (Victoria) and Lions Gate (in North Vancouver) WWTPs must be upgraded to perform secondary wastewater treatment by 2020, and the Iona plant (in Richmond) must perform these changes by 2030. Well that’s great, but why has it taken so long? It’s unfortunate that for decades BC lagged behind the rest of the provinces in moving its communities to secondary treatment. Though they showed leadership in ordering Victoria to treat its sewage in 2006, it’s the federal laws that have moved BC forward. In Saskatchewan, secondary treatment has been the law for all WWTPs since 2002. In fact, 94% of the sewered population in the Prairies and Ontario had secondary or tertiary treatment in 1999. Only 63% of BC’s population did at that time. Victoria remains the only treatment plant in Canada to not even perform primary wastewater treatment, but will thankfully be upgraded to secondary treatment in the near future. So why has it taken BC so long to upgrade their prehistoric WWTPs? During our conversation, we hypothesized that it may simply be because residents of the mid-country provinces can physically see the effects of insufficient wastewater treatment. Treated wastewater goes directly into Canada’s rivers and lakes, almost all of which are accessible. Meanwhile, British Columbia’s WWTPs dump their wastewater into the surrounding ocean and other large bodies of water, where a lot of the waste can sink to depths that only recreational divers can see, or can be carried off by oceanic currents and tides to less populated areas. Besides, the ocean is a vast body of water that couldn’t possibly be affected by something so small in comparison. Could it?
I don’t even have the heart to go into the details of what this sewage does to the environment and the organisms that have the misfortune of living near the outfalls. There are documents online such as the National Sewage Report Card from 2004 and TBuck Suzuki’s “Hidden Killer”that summarize these threats thoroughly. What I will say is that while secondary treatment removes most of the dangerous compounds in wastewater, it doesn’t remove all of the hormones, toxic chemicals (like pesticides), pathogens, and heavy metals. It also doesn’t remove all the organic nutrients like nitrogen and phosphorous, which can be a food source for photosynthetic micro-organisms and can cause massive algal blooms (creating an anoxic environment below it, a problem all its own). While it is a great minimum standard, an area as vulnerable as the Georgia Strait ecosystem deserves to be protected from these compounds, and WWTPs that dump their wastewater into this area should try to upgrade to tertiary treatment as soon as they can. All that estrogen from birth control pills that’s being flushed down toilets? It’s feminizing male fish. And BC’s resident Orca population is considered one of the most toxic animal populations on the planet because of all the hazardous substances (such as PCBs and mercury, both rather effectively removed by secondary treatment) they accumulate from the poisoned fish they eat. Sewage isn’t the only source of this contamination but it’s one we can stop. So even though we are making a change to improve the quality of the Strait’s water, we still can reach further to protect these waters.
It’s okay, here’s the silver lining! There are things you can do!
      – Stop or limit the use of toxic cleaning products in your house (from glass cleaner to laundry detergent to dishwasher soap), there are safer alternatives for your family and the environment.
      – Never flush old medications down the toilet, any pharmacy will take them and dispose of them properly free of charge.
      – Avoid getting oil, anti-freeze fluids, and soaps in storm drains.
      – Feminine hygiene products should never be flushed; really nothing except toilet paper and the obvious should go in your toilet. Besides, it could clog your pipes (ew.).
– Tell your friends and family about ways they can help do their part. If everyone made little changes to what went down their drains, we’d have a huge and positive result!
Have a look at the 2004 National Sewage Report Card and the Government of Canada’s new Wastewater Systems Effluent Regulations(careful, it’s wordy) for a ton of information about Canada’s sewage treatment methods. I hope you enjoyed my rant; hopefully Megan will write a happier blog post next week!
– Mikaela

Leave a Reply

Your email address will not be published.