Sewer divers beat robots in human waste

By Ty Lim

When remotely operated robots meet their limit in the city’s sewers, it’s time for a human diver to delve into the complete darkness of Metro Vancouver’s toxic raw sewage.

In an age of human jobs conceding to the efficiency of robots, sewer divers are a rare exception where humans need to do the work. For several years now, Metro Vancouver has started to use humans rather than robots for some sewer inspections and repairs. 

The unflushables

Divers tasked with entering the cramped, pitch black sewers in Metro Vancouver wade through human waste and what Metro Vancouver calls “the unflushables.” Accompanied by a constant threat of toxic gas, parasites and bacteria, the “unflushables” further complicate the transient sewage cocktail. They include wipes, condoms, tampons, pills, hypodermic needles, cigarette butts, hair and giant blobs of fat.

Ravi Grewal, a lead senior engineer at Metro Vancouver, said during inspections, robots are limited in their visual capability. Robots cannot see or repair underwater defects as accurately as humans  — making a human sewer diver faster and cheaper.

“Sewer divers can … actually ascertain the defect much better,” he said.

Ryan Anderson, a former diver with 22 years of experience using both robots and human divers, now owns and runs Canpac Marine Services Inc., which occasionally deals with sewer diving.

Diving, like most trade work, is not a job devoid of risk, he explained.

“If you make it over 20 years in this business and you, yourself or someone you know closely hasn’t been injured or killed, it’s pretty rare,” Anderson said.

But Anderson refused to call his work dangerous, instead saying, “I consider it more ‘unforgiving’ if you make mistakes.” 

Equipment is critical in the sewer

Anderson explained that a sewer diver often needs a support team of up to five people. The sewer-bound diver is fitted with a fully sealed “vulcanized rubber suit,” attached to a dive helmet and air supply. The suit is put to the ultimate leak test when entering the subterranean network of sewer pipes where any opening could mean exposure to disease-ridden sewage. 

When the diver emerges from the sewer, Anderson said they must go through a critical three-phase cleaning process to avoid contamination or illness.

“Anything someone flushes down the toilet is going into those reservoirs,” Anderson said.

For now, humans must still go into sewers and do the work necessary, but robotic advancements will only advance and could one day replace sewer divers, according to Anderson.

“In 50 years, the way robotics are going, I’d be surprised if there are lots of manned diving operations going on.”