WHY COLOR SORT RECYCLED GLASS? JUST CLEAN IT!By
An article in the British environmental publication letsrecycle.com entitled “Infrastructure Needed to Meet Split Glass Targets” (http://www.letsrecycle.com/news/latest-news/glass/infrastructure-needed-to-meet-split-glass-targets) points out that the UK is proposing to raise its target for glass sent for re-melt, while lowering the percent of recycled glass used for aggregate (building and road making materials). The article explains that recyclers in the UK believe they will not be able to meet the re-melt targets because, as one industry representative stated, there is a “limited number of facilities in the UK capable of sorting glass [from the MRFs] according to color.” According to this recycler, there are only a “a couple” of UK companies with the ability to sort MRF glass. He concluded that it will be necessary to invest in the glass recycling infrastructure to reach the new government targets.
The goal of increasing cullet recovery from MRF glass for re-melt use is critical to waste reduction, but why not pursue it with the aim of achieving maximum recovery of cullet from the recycling stream with the highest level of efficiency and the lowest possible cost of capital investment? Green Mountain Glass, LLC (http://www.greenmountainglass.com), a company located in the US, has developed technology which eliminates the glass manufacturers’ perceived need to use only color-sorted cullet in order to make their products. Therefore, rather than spending their limited time and resources separating MRF glass into three different colors, recyclers need only clean the waste glass and deliver it to the glass makers. Color-sorting cullet in order to re-melt it would become a thing of the past.
The GMG technology was proven in full-scale plant tests conducted in the US several years ago. In those tests, Dr. Richard Lehman, GMG’s technical director and Chairman of the Ceramics Department at Rutgers University, showed how large quantities of multicolored, furnace-ready glass could be melted to produce a single colored amber beer bottle meeting the most rigorous glass manufacturing industry standards. For the past few years, GMG has refined and expanded its technology by developing the Batch Formulation System (BFS). The BFS combines the functions of an optical scanning device with a computer containing a set of algorithms which allow the glass furnace operator to “read” the cullet input to the glass batch as it makes its way to the furnace. It furthermore makes adjustments in the chemical make‑up of the batch—all in real time—such that the mixed‑color cullet renders a glass product to specification.
Rather than expanding the color-sorting capacity in their industry, the recyclers should devote their efforts to encouraging the glass manufacturers to adopt the GMG core technology and Batch Formulation System at their plants. The benefits of using more glass for re-melting in the UK has been acknowledged by the UK’s Department for Environment, Food and Rural Affairs (defra) for years (see defra’s, Consultation on recovery and recycling targets for packaging waste for 2013-2017, at http://www.defra.gov.uk/consult/files/packaging-consult-doc.pdf). Use of recycled glass in bottle production reduces raw material costs, requires less energy to melt and, most importantly, lowers carbon and noxious gas emissions at the glass plant. By increasing the national targets for re-melt glass, defra has put emphasis in the right place. It is up to the glass manufacturers — the ones who benefit most from the use of clean, recycled glass — to help the recyclers and the UK achieve those goals in the future.
Another fact worth mentioning is that color separation in the UK produces primarily flint (clear) cullet for jars and liquor bottles, and amber (brown) bottles for beer and ale. Although color-separated green cullet is also produced in this process at additional cost, most of that cullet is exported to EU countries where it is used to make wine bottles because there is very little green bottle production in the UK. The GMG technology would allow the manufacturers to use all the green cullet currently in the UK waste stream to make amber bottles, thus increasing overall the amount of glass re-melted in the country.
As a final thought, the UK has adopted a system to encourage waste recycling called the Packaging Waste Recovery Note (PRN). These Notes are generated when waste is recycled or recovered and are paid for by the manufacturers of the recycled product. The revenue generated by these Notes is invested back into the recycling system to help increase collection and recycling capacity. In the case of glass, the UK should consider reducing the cost of the PRN to those glass manufacturers that recycle using the BFS, since the use of the system at the glass plant reduces recyclers’ costs by eliminating the need to color-sort the cullet. The technology will also increase the amount of glass recycled as green cullet, currently collected but exported to foreign countries, is used to make amber bottles in the UK.