Tampa Firm Uses Grinder to Efficiently Rid Green Waste

Mon December 08, 2003 - Southeast Edition

The Tampa-St. Petersburg area, like most of Florida, is experiencing solid growth at a time when a large segment of the construction industry is feeling a downturn in business in other regions of the country.

Because nearly every new Florida development involves landclearing, it is the challenge of the developer to determine how to handle the processing and disposal of the resulting waste. Many hire a dedicated landclearing firm to come in and do both the clearing and the removal of the waste. Others have chosen to view the waste as a potential revenue source, incorporating a recycling function to their operational mix.

For Tampa, FL-based Kearney Development Corporation, neither approach seemed the right fit. The green waste issue seemed extremely simple, and Mike Montgomery, Kearney project manager, felt the solution should be as well.

“As a company, we do a fairly broad range of projects but tend to focus on three main areas: creation of housing subdivisions, building of malls and new road development,” said Montgomery. “Ideally, those jobs would involve us going in doing the work and getting out. However, here in Florida, there is always clearing involved and, like everyone else, we’ve had to find a way to handle the trees we take down. There’s been something of a learning curve in doing that, but we now have the solution we need in a Morbark 1400 tub grinder. Virtually anything we encounter in a clearing situation can be downsized, if necessary, fed into the tub, and ground into manageable mulch.”

Getting the material down to a manageable size is only part of the solution. The question of what to do with the material still remains. For that, Kearney Development relies on the most basic of methods — burying it on site.

“There are laws in place here and elsewhere that forbid the disposal of any organic material into the area of the building pad that will support the structure. It’s a good sound rule because organic material will eventually break down and create gaps beneath the pad, compromising the integrity of the structure it is supporting. However, the law does not preclude us from disposing of the material in other areas on site — to the rear part of the pad for example,” noted Montgomery. “So once the material is cut down, it is either run through a small mulcher we have in our fleet or, if it’s more sizeable material, sent through the Morbark tub grinder and then dumped into the ground and covered up. Another option is to put the material into a pond that has been created on site. In this area, if a contractor creates a pond on a site, there is a 99 percent chance that he needed fill to build up an area of the pad. That is an inexpensive and aesthetically pleasing way to make that happen. Once created, that pond is now an excellent disposal site for the mulch material.”

Montgomery said enforcement of the ban on organics under the actual structure is strict. “Prior to any construction, representatives from the state come out and do a density check to verify that there is no organic material in the area in question. The test will immediately identify any questionable areas of the fill.”

Looking Back

Kearney Development did not always use its tub grinder to process the green waste. In the past, the solution to its disposal needs was even more basic.

“Prior to this, and up until about the mid ’90s, any material we generated from the landclearing facet of the job was simply bulldozed into a trench on site and burned. It was not uncommon for us to have a hose pumping air into the ditch to more efficiently keep the material burning. All that changed. Because of prolonged dry conditions, burning became a safety issue. Permits became harder and harder to get; burning couldn’t start before nine in the morning or go past three in the afternoon. It became a real headache. That really prompted us to look for an alternative disposal method.”

When burning was removed from the equation, Kearney chose a series of horizontal grinders which, while reliable, simply did not give them the production and efficiency it needed.

“In this business, when we land a contract to begin work on a subdivision we generally have 180 days to get things done, so every day counts. We needed something that could do a wider range of material, including stumps, and do it fast to avoid holding back the operation. We really feel we have that now in the tub grinder.”

While Kearney’s tub grinder has met the company’s expectations, there are, nonetheless, limitations to what it can handle. In order to maintain efficiency, oversized pieces and stumps alike are now being downsized using a Morbark 60 talon debris shear mounted on a Cat 330 excavator.

“The shear was added to maximize the performance of the tub grinder,” said Montgomery. “Occasionally, we would find ourselves in situations in which the volume of stumps encountered could adversely impact our production. The stump shear will ensure that never happens.”