Polymer Injections Cut Water Usage in Half

Water conservation is a big deal in places like California. In fact, it's becoming a big deal in municipalities all across the country. Tom De Lany, co-owner of Fresno-based All Commercial Landscape Service Inc. (ACLS), has developed a new service that speaks directly to this issue.

ACLS was profiled in the October 2011 issue of Green Industry PRO. At that time, De Lany said his company's Certified Water Consulting division was helping create some competitive separation. Now, its new Aqua Cents service is helping create even more.

De Lany came up with the idea for Aqua Cents in summer 2010. "While doing installations for a developer, we were trying out this product called Stockosorb, a cross-linked polymer granule capable of retaining up to 400 times its weight in water," De Lany tells. "We used a belly-grind fertilizer spreader to apply the sponge-like granules, hand raked them into the soil, and then applied the sod on top."

These newly installed lawns required about 50% less water, according to De Lany, but were also knitting much better than lawns where the polymer granules weren't utilized. "The benefits were clear," De Lany says.

The only problem was that, due to economic conditions, ACLS was not installing many new lawns in 2010-2011. Thus, De Lany wanted to figure out a way to utilize these water-absorbing polymers in existing lawns. That would mean finding a way to inject them deep into the soil below the plant roots.

The polymer-injecting process is the key

"I had one of those middle-of-the-night ideas," De Lany relates. He contacted Andros Engineering, a well-known manufacturer of harvesting and irrigation equipment for the ag industry, based in Paso Robles, CA.

"The first thing we came up with was basically a pressure washer with a single probe," De Lany says. The probe had four orifices on the tip. "You cranked your foot on the machine's pedal to manually inject the granules into the ground. We used this for field tests at Fresno State. Results showed 38% water savings. So we knew we were onto something."

De Lany and his co-inventors at Andros Engineering also knew they had to make improvements in the way of productivity. Now onto the fourth generation of the machine, they definitely have. This latest machine is computer-driven, features four probes with eight orifices each, and injects at 3,000 pounds of pressure as compared to just 1,000.

The new machine also maintains its pressure throughout an entire injection. "Our first prototype would burst at 1,000 pounds, but trail off to around 200 in a micro-second," De Lany explains. "The new machine stays in the 2,500- to 3,000-pound range throughout the entire injection cycle. That leads to a consistent dispersion of polymer material roughly two to six inches below grade. That's important because you want to get an inch or more below the root zone in order to develop roots and get them down to the water bar."

How the Aqua Cents machine works

Tom Klippenstein of Andros Engineering is one of the co-inventors of the Aqua Cents machine. He provides a quick rundown of how the machine works.

From a system standpoint:

• The polymer granule/water slurry is stored in a large tank that stays with the transport vehicle.
• A “nurse” pump located at the tank pushes the polymer through a hose to the polymer-injector machine at low pressure.
• The polymer injector machine then pressurizes the slurry to extremely high pressure and sprays it out of probes below the turf laterally.
• The injection sequence is: probes are in the up position while the machine moves … with the machine stationary, the probes move down to a set depth … the highly pressurized polymer sprays out of the probes … the probes move to the up position and the cycle repeats.  
• A series of hydraulic valves control the movement of the machine and movement of the probes.
• A small computer takes inputs from both the operator and machine, and sequences the hydraulic valves.

From an operator standpoint: