20th Century Landfills
Some of the biggest concerns about sanitary landfills continue to be their ability to prevent contamination of the local environment, whether it’s from vermin, odors, or contact with soil and water. In the early days of sanitary landfills (starting with the Fresno Municipal Sanitary Landfill, which opened in 1937), the focus was almost entirely on preventing problems like blowing trash and attracting vermin. The focus was indeed so narrow that a landfill was deemed “sanitary” if it was simply compacted and covered with soil on a daily basis.
These simple measures helped alleviate some of the more immediate and obvious problems traditionally associated with city dumps, but the designers and operators either did not recognize or address many additional long-term hazards associated with concentrating tons of mixed waste. In fact, it was originally assumed that water percolating through the soil, either from rainfall or as a result of organic decomposition, would be naturally filtered and rendered harmless before it reached aquifers or traveled into nearby soil. Unfortunately, that was not the case.
The proud opening of the nation’s first sanitary landfill in the late 1930s was in Fresno, California. Its operations were differentiated from old style city dumps by the new practice of compacting incoming waste and covering each day’s waste with a soil cover. Impermeable liners, leachate capture, and gas collection were simply not concerns in those years. It’s not surprising, then, that this historic site was declared a Superfund site. In addition to the tons of toxic waste that had accumulated over 50 years of operation, highly toxic leachate had migrated from the landfill to surrounding areas, including off site to several private, residential wells nearby.
It wasn’t until the 1980s that restrictions were put into place that provided surface and groundwater protection and restricted siting in floodplains or near endangered species’ habitats. The new restrictions also required controls for handling explosive gases, fire prevention, and mitigating bird hazards for nearby aircraft. In the early 1990s, more updates required active groundwater monitoring and provisions for both corrective action and long-term, post-closure management.
21st Century Landfills
In the first quarter of the 21st century, innovative technologies and approaches continue to be tested, with a new urgent focus on sustainability. Multi-layered protection of the local environment remains a high priority and long-lasting, dependable barriers that prevent incursion of landfill waste and leachate into nearby soil and water is a primary focus.