What To Do With 2000 Tonnes/Day of Fish Waste.
One of my favorite documentaries is ‘Jiro Dreams of Sushi’. I enjoyed it well before it became cliché to reference it for the entrepreneurial spirit it fostered amongst the startup crowd in the US. I watched the movie over a decade ago and, even then, one of the scenes that stuck with me was the one where Jiro (the protagonist) went to shop for the fresh fish he was going to serve to the guests who would come to his 10-seat restaurant that day. Yes, he personally shopped for the fish in his restaurant every single day. And he shopped at the Tsukiji fish market.
The Tsukiji fish market in Tokyo originally opened in the 15th century in the Nihonbashi area of Tokyo as a fish wholesaler. In the early 20th century, as Tokyo grew into a major metropolitan area, the fish market outgrew its Nihonbashi location. In 1935, the market was moved to its current location in Tsukiji (and has since been moved to a location twice its size in the Toyosu fish market, the largest fish market in the world). At the new, larger Tsukiji location, the fish market thrived and became one of the largest wholesale fish and seafood markets in the world. At its peak, over 2,000 tons of seafood worth over $14 million was sold daily at Tsukiji. The market is most famous for its pre-dawn tuna auctions, where large frozen tuna are auctioned off to the highest bidder.
Economically, the Tsukiji fish market has an enormous impact on Tokyo and Japan as a whole. It supplies seafood to over 65% of Japanese restaurants and stores. The freshest catches from across Japan (and the world) are brought to Tsukiji, supporting fishermen, transport businesses, seafood processors, and food distributors. Tourists also flock to the market, providing revenue from tourism. Culturally, the market is central to Tokyo life beyond just food. Residents of Tokyo shop at Tsukiji in the mornings for the freshest seafood for their families.
However, a market of this scale does have significant waste management challenges. A study by Tokyo Metropolitan government estimated that Tsukiji was discharging 280 tons of organic wastewater solids daily in the early 2000s. Unsurprisingly, this waste has high biological impact from the organic waste from fish guts, scales, blood etc. causing rapid depletion of oxygen in waterways if released untreated, harming aquatic life. To handle this Tsukiji has on-site water treatment facilities to remove solids and purify wastewater before discharge to the city sewer system but (despite best efforts) there is still illegal dumping damaging the waters.
But what if we could make some electricity from this fish waste? Apparently, we’ve tried. Scientists at Jadavpur University in Kolkata, in 2016, reported generating piezoelectricity using fish scales.
Piezoelectricity: electricity generated in response to mechanical stress
“They created flexible bio-piezoelectric nanogenerators (BPNG), where the fish scales, composed of self-assembled and ordered collagen nano-fibrils, served as a "self-poled piezoelectric active component". They showed that these nano-generators can produce electricity by harvesting energy from sound vibrations, wind flow and even repeated tapping with a finger.”
Imagine the amount of electricity that could be generated by using the fish scales from the 2k tonnes of fish waste created in Tsukiji daily!! All that waste cannot continue to just be waste and we have to become better at managing our waste and energy draw. As more small devices proliferate (sensors everywhere, micro hearing aids, etc) small scale power generation like piezo electricity generated from waste should be made a more viable option for us all. We have to evolve.
Jiro Ono lost the Michelin 3-star rating of his restaurant in 2019. Not because his quality dropped, he continued to buy his fish from Tsukiji, but because his 10-seat location became too exclusive. The demand became too much and rather than drop the quality, the chef chose to serve his customers at the level of commitment that he always wanted to maintain. As Tokyo continues to evolve in the 21st century, sustainable management of a vital facility like Tsukiji fish market will be important. The city, and many cities honestly, need to invest in modern (and sometimes novel) waste processing infrastructure for the market. Our future depends on it.