Recycle Street Sand
Remnants of the harsh winter remain on the sandy sidewalks of Terre Haute. With so much sand left over, is it possible to reuse it for this upcoming winter? It is a question many cities across the United States and Canada have posed. The City of Terre Haute used approximately 2,500 tons of sand last winter. According to Terre Haute Street Department Director Brad Miller, each ton costs the city $7.40; so for the winter of 2013-14, it cost the city $18,500 to disperse sand. The Indiana Department of Transportation used 60,595 tons of sand this past winter compared with just 15,265 tons in the winter of 2012-13. Similarly, the state pays between $6 and $7 a ton.
“We looked into recycling the sand that we use but we found that the cost to sift and filter it was more expensive than it was worth. It makes it difficult to find a process that can filter the used sand for less than what a ton of new would cost,” Miller said.
It may sound simple to sweep up the sand and load it back into a truck to reuse it, but it is far more labor intensive than that. Street sweepings are not as clean as the virgin earth materials and should be handled with a certain degree of care. Sweepings can contain sand, salt, leaves, broken glass, small pieces of metal, litter and debris. Zinc and copper have surpassed lead as being the most common metals contained in road sediment. Sodium and compounds associated with asphalt and motor oils can also be found. A vehicular accident or spill can result in higher levels of these hazardous compounds.
Edmonton, Alberta, Canada
Imagine a pile of sand that weighs two and half times as much as the Titanic. That is approximately how much sand the City of Edmonton in the Alberta Providence of Canada removes from its streets each spring. Some years ago, director of roadway maintenance for the City of Edmonton, Bob Dunford, says regulations changed and they were no longer allowed to give it to people who wanted it for fill material, a practice that takes place in Vigo County.
“We dump on private sites where we have the owner’s permission. It’s usually someone who is trying to fill in low areas or ravines. At this time, and since I have been here, there has been no cost to the city,” Miller said.
Because of a change in its legislation, Edmonton would have to haul the debris to the landfill, which would incur an additional cost. Additionally, it nearest source of sand had already been depleted so it was trucking in sand from roughly 50 miles away, which came with additional fees.
In 2003, they started a pilot program where Edmonton is able to sweep up 70 percent of what they put out. Once the sand is collected, they then have to sift out any debris with a giant “gold pan.” They then wash the sand to make sure it meets or exceeds the specifications of new sand. Dunford says 80 percent of the collected sand can be reused for
Their recycled sand is 1 percent less expensive than purchasing new sand, but more importantly Dunford says they are saving on the disposal of a material that would just take up landfill space. “We are preserving a non-renewable source. There is not an infinite amount of it,” Dunford said.
Cedar Rapids, Iowa
Cedar Rapids, Iowa, was faced with a similar scenario when a local landfill was getting ready to be capped and closed. They were then charged a $35. administrative fee per ton to haul the material to another landfill, which became a significant cost. They pick up more than 3,000 tons a year. This forced the city to look at options to reduce its costs. Instantly, it started stockpiling the sand. After a few seasons it ended up with 6,000 to 8,000 tons of material. After punching some numbers, the City of Cedar Rapids made a $100,000 investment for a screen to filter the debris. Street Operations Superintendent Michael Duffy says any time you are trying to make the pitch to invest $100,000, it can be a hard sale. “It is money we would have normally spent to haul the material to the landfill, so it’s a pretty easy investment when the sorting machine paid for itself after one year.”
The collected sand has more uses than reapplying it the following year. Cedar Rapids uses it as fill material for structural projects. Using recycled sand to fill is allowed, but they must not be near waterways because of the high metal count in the fill. They also give a lot of the material to their county, which then uses it to sand-seal a road.
“What they do is put a liquid asphalt down on the gravel road and then they put the sand directly over the asphalt,” Duffy said. The sand sealing becomes a good dust-sealing method on its county roads. Additionally, they fill sand bags, which are used during flooding events.
Not all cities have found cause to recycle street sand. Earlier this year, Providence, R.I., Councilman Michael Correia proposed a resolution, asking the Public Works Department to recycle street-swept sand after the city ran out of sand over the long winter months. In Providence they pay to haul the sand to the landfill where it is then used as a top soil over the garbage. For them, the landfill charge is built in to their street sweeping contract. Councilman Correia’s resolution was found unfavorable because it would come at an additional cost to taxpayers.
“I would think with the way things are in struggling municipalities, maybe the merger of certain city services, where everybody could split the cost and share the benefits, could benefit all municipalities if we all work together,” Correia said.
In all, Correia thought recycling sand would have fit perfectly with the city’s push to increase recycling efforts. A silo vision may work for some communities, but when city, county and state agency costs are shared, Correia still holds out that greater productivity can happen.
Jane Santucci SI2016 Regional Coordinator, Terra Haute
Jane Santucci is an environmental freelance writer for the Tribune-Star. Santucci is a proud volunteer with TREES Inc. and Our Green Valley. She also sits on the Wabash Valley Goodwill Industries Board of Directors. Share your environmental stories and tips with her at JaneSantucci@yourgreenvalley.com.