How can glass be recycled/reused locally in rural communities?

Question

I live in a "remote" part of the USA, where it is prohibitively expensive to ship glass elsewhere for recycling. Because of the small population (the nearest city over 10k people is 110 miles away), recycling is a relatively new phenomenon here. Paper, cardboard, and some plastics are trucked to a larger city, but glass goes in the landfill because it is too expensive to transport.

A friend and I recently purchased a tool for scoring glass bottles so they break evenly for use as drinking glasses or art, but that's only a small-scale solution. Glass recycling won't get off the ground here unless there is a way to use large volumes of glass in a way that either 1) is profitable or 2) generates significant savings. So how can large volumes of intact, crushed, or melted glass bottles and jars be made useful, or at least profitable, enough to be worth the cost of recycling in a small town? Are there any communities that have done this successfully?

Note: By "large volumes" I mean the amount of glass containers consumed in towns of under 10,000 people.

Answer 1

I have seen broken glass (± 1" (~25 mm) square pieces) used effectively as the drainage backfill around a residential foundation. The owner reported that it worked very well.

An internet search shows other situations where the crushed glass is used as aggregate in construction, including some cases where the aesthetics are used to an advantage. See HowToPedia article, for example, which suggests the following uses:

Crush to sand size which removes sharp edges:

• use as bedding in place of sand
• use as aggregate instead of sand
• add to plaster for decorative shine

Crush to pebble size which removes sharp edges, use as decoration in concrete plaster.

For more, see Studies of Glass in Construction Applications, (CWC, Ref BP-GL4-01-01, Nov 96) which refers to the following (relatively old, now) studies:

Clean Washington Center ... glass as a construction aggregate.

Florida Institute of Technology ... Waste Glass and Waste-to-Energy Bottom Ash as Highway Fill Materials

Schmucker, Bruce O., and Buffalini, Rick J: Pulverized Glass and Landfill Liner Systems

University of Missouri - Rolla; Glasphalt Paving Handbook

Answer 2

This is one of those economics things. Small towns often have very cheap landfills. Glass in the landfill is not particularly harmful, it's just bulky.

The uses mentioned above glass is essentially competing with either gravel or sand. So it has to be roughly the same price.

If there is a reasonable dumping fee at the landfill then glass doesn't have to be cheaper than gravel, the avoidance of the dumping fee pays for crushing the glass. Then the use of it as aggregate is icing on the cake. That is Dumping Fee > (Crushing cost + price charged as aggregate) And price charged as aggregate < local market for aggregate. If you have $50/ton dumping fees this gets quite feasable.

The ideal use for glass is one that uses some characteristic other than it's bulk. The two obvious characateristics are it's color, and it's transparancy. One that occurs to me is to use it as an aggregate to make breeze blocks (Normally made of concrete 4" x 12 x 12 square, with various patterns of holes in them. About 3/4 of the block is holes.)

A suitable process might flash heat the surface of the crushed cullet, then mold them together. This bypasses the need to heat the entire mass of glass. Or there may be some suitable glue that could be used. In either case you would get breeze blocks that sparkled in the sun. With enough glass this might become an export from your town.