Early HistoryArchaeological excavations have confirmed that fallen garbage stayed permanently on the floors of Trojan and Roman homes - a practice that continued through the Middle Ages. Rather than clean debris, residents would re-cover their floors in clay, resulting in cities changing elevation over time. Troy raised more than five feet per century.
History has shown the devastating effect of poor waste management on human health: the Black Death wiped out a third of the population of Europe in the fourteenth century, and other epidemics, such as yellow fever and smallpox, spread through poor hygiene and cleanliness as well.
After hundreds of years, societies began to take notice. Many cities began adopting methods of garbage and waste management cycles, with differing results.
Post-WWIIUp until the end of WWII, solid waste collection relied heavily on the physical labour of individual collectors - often, at the expense of the collector's health. Men would physically transport individual solid waste containers from homes to dump in horse- or mule-drawn wagons, and then returned the containers to the residents. These wagons would transport the waste to open dumps to slowly degrade over time. In 1934, the U.S. Supreme Court banned ocean dumping (Canada didn’t follow suit until the seventies), and this lead to the popularity of in-home and commercial incinerators.
At the same time, smaller towns and cities were using “piggeries” to reduce waste. These were small pig farms, where pigs would consume a town’s food and mostly-edible garbage. Seventy-five pigs could consume two thousand pounds of waste in a day. But by the mid-1950s, popular opinion shifted. Many thought piggeries spread disease, and so most pigs were killed and piggeries disappeared.
Cities also moved to ban in-home incinerators for safety reasons. Instead, some focused their energy on building central incineration centers in downtown and accessible locations. Others used landfills as open-burning dumps. Still, waste would leak into groundwater, animal scavenging was common, and there were no controls for gas or environmental impact. Odours were a huge problem.
Municipalities began looking into regulated, sanitary landfills in order to deal with flies, rats, and the threat of polio. Waste management developed on a national scale.
Sanitary landfills and energy reclamationThe Air Quality Act of 1967 in the United States directly impacted the incineration movement in both the United States and Canada. Incinerators were capital-heavy investments, and new regulations meant millions of dollars for cities to comply with emission controls. Cities couldn’t keep up - within five years of the Act’s passing, hundreds of incinerators were shut down.
Cities started recovering reusable materials from solid waste in order to reduce the amount sent to landfills. Curbside separation was rare; instead, picking lines were used to manually separate reusable materials from waste at dump sites.
Early systems were fraught with operational difficulties. Monsanto originally developed pyrolysis systems for city waste management, and they suffered cost overruns and created poor quality fuel for decades after their introduction.
Instead, sanitary landfilling became standard for larger cities - although many smaller, more rural areas in Canada still have unsafe landfill and dump sites. At a sanitary landfill, waste is spread in thin layers by a compaction vehicle. Then a layer of clean soil is spread and compacted over the layer of refuse. This series of alternating layers builds until a mound created. As cities expand, sanitary landfills can be reclaimed for other uses, such as parks or golf courses.
Landfill gas is one of the main concerns for operating and maintaining sanitary landfills. A complex mix of methane, carbon dioxide, and other volatile compounds, landfill gas contributes to huge levels of air pollution and greenhouse gas emissions. Some cities are now using landfill gas to convert into power. Vertical wells collect and transport gas to enclosed flares, where excess hydrocarbons are burnt off and the gas can be converted into liquid or compressed natural gas.
Recycling movementSince 2007, over 34% of American and Canadian municipal solid waste is recycled or composted. Toronto has some of the highest rates of waste diversion in North America - more than 50% from household sources.
There are four primary methods of recycling: composting, physical reprocessing, energy recovery, and biological reprocessing. Composting is commonly used to recycle organic waste. Materials that aren’t compostable are either manually or mechanically removed, and the organic waste degrades into potassium, nitrogen, and phosphorus.
Physical reprocessing involved collecting commercial waste like grease from grease traps, oil filters, transformers and containers through recycling. Energy recovery is when commercial waste are thermally treated and the waste generates electricity and steam, then used in combustion fuel.Finally, biological reprocessing is when organic waste like mineral, plant and soil waste is composted, and the emitted methane is used to generate electricity.
These methods are often more expensive and time-consuming than landfills and dump sites. But the diverted refuse reduces the need for other higher-impact waste management methods.
The FutureCities, advocates, and businesses are split as to what the future of waste management looks like. Many cities are focusing their short-term energy on pressing residents to recycle and compost more, increasing diversion rates through fee structures and mandatory recycling penalties. Studies of recycling rates in the City of Toronto found that residents with larger garbage bins recycled less, and those with smaller receptacles recycled more. So they lowered fees for smaller garbage bins in 2015.
Still, diversion rates are less than half in many larger cities and within high-density housing. While the diversion rate for single-family homes in the GTA is around 68% - a high international average - apartment and condo rates hover at less than 30%. Some cities are responding by creating mandatory recycling and composting programs, which have been standard across the European Union since the ‘90s. Though some see it as not far enough: zero-waste advocacy is growing.