Case Study: Farm pond sludge and algae remediation

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Courtesy of Avir Environmental LLC

Problem
A 1 ½ acre farm pond located in southeastern Wisconsin was experiencing a severe algae bloom due to high levels of fertilizer runoff from the surrounding farm fields located on the north and east sides of the pond. Farm field runoff drains into the north end of the pond via a 4-inch drainpipe. The pond is further fertilized by the year round population of 6-8 resident ducks and by migrating waterfowl in the spring and fall of the year.

The pond was created by placing an earthen dam in the gully of the surrounding farm fields. Average water depth is 4-5 feet deep with an 18-foot hole located in the center of the lake. The periphery of the pond averages only 18 to 24 inches in depth for the first 6-10 feet from the shoreline, thus contributing to algae problems. The pond also has a small shallow cove that is a maximum 2-foot in depth. Water levels in the pond are regulated by an overflow pipe at the southern end of the lake.

Treatment Objectives
The objectives were to treat the Rossi Pond with the use of Avir Natural Water products only. Use of algaecides or other related products was not considered for this project. The goal was to document the treatment results and confirm the effectiveness of the Avir products.

Treatment began on July 5th, 2000 and was considered completed on September 7th, 2000 after it was noted that all algae had dropped from the water column and water clarity improved by 48 plus inches.

Equipment Used
The Rossi Pond project utilized an Avir aeration system. The blower unit consisted of a ¾ HP Gast Rotary Vane blower capable of producing 10 PSI and 10 CFM of air. A 3 way manifold was used to allow individual control of each diffuser. An internal industrial strength fan helps cool the internal air temperature an additional 30°- 40°F.

Three Avir diffusers were utilized for this project. One unit was located at the southern end of the Rossi Pond in the 18-foot hole. The second was located in the northern third of the pond and the third unit was located at the opening of the cove.

All piping from the blower was done with ¾ inch PVC pipe and was buried underground to the waters edge. Piping extended to the general location of the diffuser. PVC to diffuser attachment was completed with ½ I.D. reinforced clear plastic pipe. Approximately, 3 CFM of air pass through each diffuser.

Chemistry Used
Two Avir Natural Water products were used for actual remediation of the Rossi Pond: Liquid Enzyme Water Clarifier and Dry Bacteria Water Clarifier in 8-ounce dissolvable pouches.

The Dry Bacteria were fed weekly at a rate of 3 pounds per acre-foot. The Liquid Enzymes were fed weekly at a rate of 1/2 gallon diluted with tap water and sprayed topically with a 5 HP Briggs and Stratton pump and a fire hose.

Treatment with the Liquid Enzyme product was limited to topical spraying of the algae during the first 6 weeks of application, thereafter Avir personnel treated with Liquid Enzymes in a variety of concentrations and spraying methods. This was to determine if better and/or faster results were possible with the Avir Technology. These treatment methods were performed until September 7th when the project was essentially completed. Since then the Rossi Pond is being maintained using 1½ gallons of Liquid Enzymes and 2 pounds of Dry Bacteria bi-monthly.

Avir Natural Water Liquid Enzymes Water Clarifier - View Product Detail PDF
Enzymes inhibit turbidity in a lake or pond by speeding the breakdown and removal of organic material and suspended solids from water. This natural cleansing stimulates a mature biota to achieve superior water quality. Available in 4x1 Gallon Box, 2x2.5 Gallon Box, 5 Gallon Pail or 55 Gallon Drum.

Avir Natural Water Dry Bacteria Water Clarifier - View Product Detail PDF
Dry Bacteria improve overall water clarity. This blend of microbes on a fortified grain carrier consumes excess nutrients, visible solids, and other unwanted growth in water. Available in bulk or . Available in 10 Lb. Pail Bulk, 10 Lb. Pail of ½-pound Pouches, 25 Lb. Pail Bulk or 25 Lb. Pail of ½-pound Pouches.

Results
An analysis of the Rossi Pond showed an algae mat that extended 3 to 4 feet from the shoreline. Thirty-six hours after treatment a site visit revealed that the algae mat turned from a vibrant green to a neutral tan in the areas that were sprayed. Two weeks after the initial treatment the entire algae mat had turned a neutral tan or light brown in color as the Avir Natural Water product worked its way into the water column and began to affect the entire column of algae.

Water clarity improved from 12 inches prior to treatment to approximately 24 inches in three weeks. It was further noted that the algae column began to sink in areas that were heavily sprayed with the Liquid Enzyme product.

No fish kill was observed during or after use of the Liquid Enzyme product.

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