BioCycle September 2005, Vol. 46, No. 9, p. 27
With over 400,000 tons/year of yard trimmings, wood and C&D debris coming through three sites, a California processor focuses equally on market and product development as efficient processing strategies.
Larry Trojak

IF maximizing the use of one’s incoming waste stream is any measure of a recycling firm’s success, few companies could hold a candle to the success enjoyed by Tierra Verde Industries (TVI). The Irvine, California-based processor takes in green waste, wood waste and C&D debris from neighboring municipalities and creates more than 20 products for a broad range of industries. In doing so, it will divert in excess of 400,000 tons of material from area landfills in 2005 alone.
Founded in 1997 as Green Waste Recycling, with one grinder and a couple of loaders, Tierra Verde today operates its primary location (there are three in total) in a 30-acre area south of Los Angeles, taking in green waste from waste management contract firms, gardeners, landscapers and residents in Orange County. Tierra Verde is able to assist municipal jurisdictions in meeting the 50 percent waste diversion goals set by the state of California.
“For smaller municipalities in the area, it is difficult, if not impossible, to make the capital investment in the equipment needed to recycle their green waste, let alone set up and maintain a recycling program,” says John Kazarian, Operations Manager at Tierra Verde. “More often than not, it’s a losing proposition. Because we create such a broad range of products, less than one percent of our incoming feedstock is landfilled. As a result, these municipalities are able to easily reach the diversion rates set by the California Integrated Waste Management Board and avoid the penalties that come from failure to do so.”
The firm has chosen to diversify both its markets and the products it takes to those markets. Today TVI’s product offering includes everything from compost to a number of mulches in a varied range of sizes and colors to nursery blends to chips for ground cover and more.
PROCESSING LINES
Green waste is, by far, the primary feedstock processed at Tierra Verde’s sites. Kazarian notes, however, that not all green waste at TVI is created (or treated) equal. Curbside material, for example, falls far short of meeting the company’s criteria for resale to its customers, though it too eventually serves a useful purpose.
“People tend to throw everything in with their curbside green waste and, because the collection trucks are all automated, we have no way of knowing what’s mixed in. We’ve found everything in there from propane tanks to boxes of bullets. That material is manually picked through, the undesirables are pulled out, and it is run through a Morbark Model 1300 tub grinder and used for alternate daily cover at area landfills. Much as we’d like to, we can’t get the curbside material clean enough to use it for our products.”
“Clean” green waste, on the other hand – the trees, bushes, plants, etc., received from area landclearing firms and others who drop off material at the Irvine site – is reduced to sizes ranging from 4 inch-minus down to 3/8-inch. That 3/8-inch product is the size most demanded by area nurseries that take ground material, blend it with equal parts sand and soil, and create what they call a box mix.
“That is undoubtedly the biggest-volume product we create,” says Kazarian. “However, we also send a sizeable volume of wood to area cogeneration plants to burn for energy. Those plants really like our product because it’s the cleanest they receive, but we have two things working against us. First, most of those plants have a huge list of suppliers so we’re not able to send them the volumes we would like. And second, because they are so far away, we are impacted by transportation costs. What’s important, though, is the fact that we’ve made a real effort to establish a number of varied markets so that if one goes down it doesn’t affect us too seriously.”
As with any recycling operation, virtually everything passing through TVI is size-reduced in some way. C & D waste, a relatively small, but growing, part of the incoming stream, is run through a double-deck CEC 6 X16 Screen-IT screen which feeds a picking station and can generate product from as fine as under 1-inch up to 6-inch and over. At the picking station, workers sort for wood, green waste, plastic and cardboard.
Wood, the overwhelming bulk of the material TVI addresses, is processed at several points on-site through one of five Morbark grinders the company owns. It also has a colorizing unit and a trommel.
COMPOST AND “GRUBBLE”
TVI rounds out its operation by offering two products – high quality compost and a proprietary material called Grubble – which, while demanding a bit more attention to detail, are nevertheless important parts of the company’s overall mix.
“Composting takes place on a nine-acre site adjacent to our main yard,” notes Kazarian. “At that site, preground material is windrowed and managed using a Scarab turner, resulting in a composted material which is high in nitrogen, potassium and phosphorous in about 110 days. A combination of sprinklers and a modified water truck are used to maintain moisture levels. To ensure product cleanliness, compost is checked every 5,000 yards by independent labs for heavy metals, salmonella, fecal coliform and other impurities which could render the product worthless. An independent laboratory also randomly comes in every three months to check the nutritional value of the material and sends us a report afterwards. We’re very proud of the quality of our compost products and want to make certain there is never an issue with it.”
Grubble, perhaps the company’s most unique product, is actually not a by-product of wood waste at all but instead uses scrap tires as its feedstock. “We are excited about this product, both because of its applicability and because it opens up still more new markets for us. We get preground scrap tires reduced to 1/2-inch size and free of any metal from the tire’s steel belts, and run it through a Morbark colorizing unit. The end product, which we call Grubble, is ideal for use as playground material, having achieved some of the industry’s highest ratings for playground safety.”
Kazarian adds that Grubble is finding other equally successful applications, including mixing it with a bonding agent and spraying it onto hillsides for use in weed abatement and erosion control. “We have an ongoing pilot program with Caltrans and the initial results have been impressive. It is proving to be easy-to-apply – it is sprayed on – effective, and durable, nonhazardous and FDA approved. The fact that it is offered in a range of colors is a big plus for us, but colorizing rubber can be challenging. It’s taken us more than a decade to come up with a binder that works well to colorize rubber. That formula, coupled with the effectiveness of our equipment, has helped us take a huge step in making this product available.”
According to Kazarian, any discussion about the level of TVI’s success would not be complete without stressing the importance safety plays in every facet of their day-to-day operation. “There is a lot of traffic moving in and out of this site every day, as well as a lot of equipment moving about and being operated all day long, so the potential for a mishap is always there. For that reason, our biggest single concern is the safety for our employees. We have regular safety meetings to let personnel know of any changes or to stress areas that we feel need emphasis. We are also not afraid to give warnings or time off without pay for safety violations. Our emphasis on safety, coupled with a good business plan, diversity in products and markets, and solid equipment performance have really been – and hopefully will continue to be – our recipe for success.”
Larry Trojak is with Trojak Communications in Ham Lake, Minnesota.