Two public agencies recently analyzed two key recycling challenges: end markets for glass and multi-family recycling collection. Although the agencies looked at specific regions, their findings are applicable to the wider recycling industry.

Multi-family data

Oregon’s regional Metro governing agency, which has jurisdiction in the greater Portland metropolitan area, tackled multi-family recycling and the factors that lead to contamination and other problems.

A Metro study looked at data from more than 4,000 multi-family service accounts and 20 local governments, as well as interviews with residents and a waste characterization study specific to the multi-family setting.

Property owners are required to make recycling service available to tenants, but what that means varies from site to site. Metro found multi-family access to commingled and glass recycling service is largely inadequate and is much different than single-family recycling access.

For instance, the median multi-family service volume was about 17 gallons of commingled recyclables per household per week. But single-family households enjoy collection of between 35 and 90 gallons per household per week, according to Metro’s analysis.

Service provision and collection frequency are also inconsistent among properties, the study found, as is the collection equipment that’s used. Recycling receptacles of all colors are used, and signage on the receptacles is sometimes outdated or confusing. This is particularly problematic, Metro said, due to the high rate of turnover in apartment buildings, leaving new residents unsure of where to place materials.

Contamination in the mixed recycling stream is high, Metro found. A seven-month waste characterization study revealed the multi-family commingled stream had a 21 percent contamination rate, with glass, non-recyclable paper and organics among the highest contaminants. That’s compared with 9 percent contamination in the single-family stream, according to the most recent figures.

Metro solid waste planner Sara Kirby attributed the higher multi-family contamination rate more to the discrepancies in service provision, rather than multi-family tenant behavior.

To address those shortcomings, which is Metro’s goal with this data, the project team came up with options that wouldn’t require any policy changes, and some that would. Without any new rulemaking, local governments could provide financial help or other assistance to sites with inadequate collection, and Metro could analyze those sites to monitor improvements.

With some policy action, governments could administer new requirements for per-unit service volume minimum standards for commingled and glass recycling collection, as well as garbage. Metro could also standardize receptacle appearance and collection frequency.

Glass opportunities

The Wisconsin Department of Natural Resources (DNR), meanwhile, took a look at the downstream uses for crushed container glass outside of new container manufacturing, spurred by the limited number of bottle-to-bottle plants in the state.

Container glass is generally covered by a landfill ban in Wisconsin, with the exception of residual glass that ends up with the waste stream during the sorting process.

Residual glass of a certain size and quality can be effectively used as daily cover in a landfill, according to the report, as can sorted container glass as long as it receives state approval. But there are other end uses for both outside the landfill setting. Glass can be used as a sandblast media right out of the materials recovery facility without any additional processing, the DNR determined.

It can also find a home as an alternative aggregate in asphalt pavement or as a base material in road construction, but in these uses, higher quality is required. Contaminants including labels and caps must be minimized to avoid impacting the road performance.

With a low hazard waste exemption from the DNR, the opportunities expand further. Glass can be used as part of a septic tank treatment system, as a drainage medium for utility trenches, a filter medium in water systems, an aggregate in wider construction use, a decorative material for landscaping, in glass sand production and more.

The DNR also completed a similar guidance resource focused on managing container glass in the MRF setting and properly utilizing recycled glass in a landfill.

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