As the wreckage is cleared from the recent earthquake in Japan, Los Angeles' earthquake debris recycling program may provide some insight as to how to respond to natural disasters.
Materials from residences damaged by the January 1994, 6.7 magnitude Northridge, Calif., earthquake are being reused, in a cooperative effort between the Los Angeles County Sanitation Districts and the City of Los Angeles Integrated Solid Waste Management Department.
In January 1994 the county-owned Calabasas Landfill began accepting debris from damaged or destroyed homes, walls, fireplaces and other structures. As disposal tonnages rose, district engineers explored ways to recycle some of the materials.
Once the City of Los Angeles agreed to fund the recovery program through higher tipping fees, the districts launched a pilot program to collect, sort and reuse up to 500 tons of the 1,000 tons per day (tpd) of debris that were brought to the landfill for disposal. As of January 1995, more than 800 tpd were being sorted and processed; by last December, materials recovery reportedly had reached more than 90 percent (see chart).
At the landfill, earthquake debris loads are directed by Sanitation Districts weigh masters to the recycling point on the working deck. The local recycling contractor, Hayden Brothers Inc., hand-sorts the load to find large logs, stumps, metal items, large cardboard pieces and green wastes.
The remaining refuse is loaded into a processing line where dirt and other small items are mechanically separated and moved to the recycled-materials area for reuse. Remaining refuse drops onto a conveyor belt and is further hand-sorted to collect wood and metal. Large blocks of concrete and bricks are separated to be crushed into reusable aggregate material.
Green wastes are shredded and used as mulch and refuse cover at the landfill. Dirt recovered from the debris also is used as refuse cover, reducing the amount of dirt that must be obtained from other locations.
Large logs and lumber are sold to firms as firewood. Scrap lumber and wood products are shredded and sold as fuel to power cogeneration plants in southern California. Cardboard is sold to recyclers and metal items are transported to salvagers. Concrete aggregate is reused for road beds at the landfill.
Unfortunately, due to the wide availability of wood and metal products from the earthquake, the market is glutted with such materials. As a result, there has been a sharp drop in their prices per ton.
However, the Sanitation Districts, the City of Los Angeles and the recycling contractor are working to refine the process and increase efficiency as well as the total tonnage of materials recovered from debris cleanup.
By late November 1994, more than 15,000 tons of earthquake debris reportedly had been recovered for recycling and other uses. In addition, the project created more than 15 jobs to operate the sorting stations and the equipment.