Biosolids – the processed sludge Metro Vancouver recovers at its Annacis Island sewage treatment plant from what residents flush down the toilet – could soon be burned as a fuel in local cement plants.
That’s the tentative plan the regional district is pursuing as a “diversification” opportunity as it faces growing opposition to its conventional use of biosolids as a soil supplement, particularly on agricultural land.
Dried biosolids have two-thirds of the fuel value as coal, which it would replace if burned at the Lehigh cement plant in Delta or Lafarge in Richmond, according to Metro biosolids program manager Laurie Ford.
Both cement plants are eager because the fuel from human excrement would help reduce their greenhouse gas emissions, they wouldn’t pay the carbon tax that’s charged on coal and they may be able to tap a provincial low-carbon fuel program to cover their upgrade costs.
“Our understanding is the coal plants are definitely able to take it all and they’re very interested in taking as much as possible,” Ford said.
Metro Vancouver biosolids in the form used for soil improvement (left) and dried and processed for fuel (right). Contributed
If a final decision is made to proceed, the region would construct a $25-million plant to dry the biosolids into fuel pellets, using heat already captured from sewage at the Annacis treatment plant, supplemented by natural gas when necessary.
Ford says drying half of Metro’s annual biosolids for fuel would reduce the cement plants’ coal use by four per cent, cutting regional greenhouse gas emissions by 15,000 tonnes per year. The ash from burned biosolids would be mixed in to the cement.
The regional district is expected to call for bidders to develop a conceptual design.
Biosolids recovered at Annacis have been used for nearly 25 years to supplement soil in Metro’s regional parks, in local landscaping, to help with mine reclamation and to improve agricultural range soil in the Interior. The human manure is heat treated to kill pathogens.
Richmond Coun. Harold Steves said he would prefer to see as much of the region’s biosolids burned as fuel as possible and kept off agricultural land, where he fears there may be some risk of transmitting toxins up the food chain.
Ford said Metro would continue to produce some biosolids for use as a fertilizer or soil supplement, in part to ensure the region doesn’t become dependent solely on cement plants.
“That would be taking all of our eggs from one basket and putting them into another basket,” she said.
Biosolids production will rise significantly in the decades ahead as the Metro population grows and two older wastewater treatment plants – Iona and Lions Gate – are to be upgraded to secondary treatment.
Concern grows among Metro politicians over biosolid use on land
Fear of fertilizing with human waste unfounded: soil scientist
Some Metro Vancouver directors want an independent review of the safety of the biosolids the regional district sends away to fertilize Interior agricultural land.
“I think it’s an important question,” said Delta Mayor Lois Jackson.
She said she’s not sure whether to believe claims of opponents or advocates, but is uneasy enough to press for some sort of investigation.
“The chemicals that are being flushed include antibiotics and pills. I’m very concerned about putting these things on our crops.”
Biosolid opponents in the Nicola Valley fear their groundwater wells could become contaminated by metals and other chemicals present in sewage if the practice of spreading the material there continues.
Libby Dybikowski, a Merritt resident, argued in a letter to Metro directors that they should adopt the precautionary principle and cease biosolid shipments inland.
Plenty of chemicals get improperly dumped down sewers, Dybikowski noted, including dangerous acids from illegal drug labs, and she said there is “grave concern” biosolids are transporting those contaminants to inland watersheds.
Food processors including Dairyland and Saputo refuse to accept milk from cows fed hay grown where biosolids were spread, Dybikowski said.
Biosolids sent by Metro Vancouver for use on agricultural land must meet a Class A provincial standard ensuring the material is treated to kill dangerous bacteria and that tested chemicals are below permitted levels.
Metro utilities committee chair Darrell Mussatto defended the use on farmland of the region’s biosolids as a beneficial use of a nutrient-rich earth-like organic material.
He said Metro’s biosolids are not to be confused with the material deposited in the Nicola Valley, triggering protests and blockades earlier this year. That lower grade material came from the Okanagan.
Mussatto said Metro is supporting a call by Interior municipal leaders to bolster regulation of biosolid use and Jackson said the regional district could adopt its own higher standard, regardless of what happens at the provincial level.
University of Washington soil scientist Sally Brown said fears about contamination of food are unfounded.
“It’s a perception concern that has no basis in reality,” Brown said, calling it a “fabulous” way to recycle nutrients that otherwise damage habitat in rivers and oceans.
“Biosolids are really good for plants, really good for the soil,” she said, adding they are the most researched and tested soil amendment – getting far more scrutiny than livestock manure.
Brown said she believes fear about biosolids largely boils down to the fact “people are scared of their poo.”
As a result, she said, local governments that should take pride in their biosolids programs are keeping a low profile, or considering other uses.
“Metro Van has been a responsible player for a long time,” she added.
But Brown said the regional district’s proposed switch to drying biosolids as a fuel for cement producers would be “wasting” the resource.
She said biosolids help sequester carbon in the soil and avoid emissions from production of synthetic fertilizers, adding those benefits outweigh the carbon offsets Metro expects by burning biosolids as fuel instead of coal.
As for processors that won’t take food grown on biosolid-enhanced land, Brown dismisses the choice as corporate public relations.
“It’s a marketing call with no basis in science.”
PHOTOS: Metro Vancouver’s uses of biosolids
Aldergrove Lake Regional Park before (above) and after (below) landscaping with biosolids.
OK Ranch research plot with Metro biosolids applied 13 years ago on the left side and no biosolid use on the right side.
Granby mine tailings area reclamation before (above) and after (below) use of biosolids.