SEBS for CLARIFYING IRRIGATION RESERVOIRS NATURALLY

Part of the controversy of utilizing reclaimed water for irrigation is the problems associated with storage. Odors, algae, and aquatic weeds can all become threats to the value of stored water for irrigation purposes. To take advantage of reclaimed water, we must also solve problems with its storage.

The primary solution for water storage problems has been chemicals — herbicides to control various types of aquatic plants and copper compounds to discourage algae. More recently, the emphasis has been on encouraging nature’s own solutions to the problem by keeping stored water circulating and dissolved oxygen at healthy levels for decomposition by organisms, such as bacteria. Lately, there has been a move toward enlisting the help of beneficial bacteria to correct overabundant algae. Some experts predict that beneficial bacteria represent one of the largest growth areas in the water management industry.

Use of bacteria to clarify ponds is not new. Old timers tossed bales of barley straw into ponds to clear up algae “right quick” through the release of bacteria. Today technology allows researchers to identify and select ideal strains of bacteria and package them for easy use by landscapers, golf course superintendents and farmers. As a result, ponds are naturally clarified by reducing algae, scum, sludge and foul odors without impact to the environment, workers, other aquatic plants, and wildlife for fish.

Most pond problems are due to algae bloom. Overabundant algae, are a sign of an unbalanced aquatic ecosystem. Nitrogen, phosphorus and other nutrients run into the water supply and provide a food source for algae. In natural settings, bacteria also compete for these nutrients and help keep algae in check.

To cure the problem, algaecides are commonly used. Algaecides are good solutions for the short term. The problem is that they cause plants to die rapidly. The plants decompose, break down into nutrient form, and supply a new food source for a new population of algae.

If algaecides are used continuously, they kill the beneficial bacteria in the water ecosystem that normally compete with the algae for nutrients. Over time a pond loses its ability to regulate its nutrient level, and you have an out -of-balance system that favors the overabundant growth of algae. To keep the algae in check, more algaecide applications become necessary and pond maintenance costs rise.

It is important to understand that beneficial bacteria are not algaecides. Bacteria do not kill algae. They out-compete algae for food causing the algae to starve.

Bacteria also digest floating organic matter reducing the total suspended solids that normally cloud water. And, they take the “stink” out of ponds. An excess of ammonia and sulfur causes pond odors. Since beneficial bacteria accelerate the natural nitrogen cycle. Ammonia is more quickly converted into nitrite, which eliminates the release of ammonia. Ponds with low dissolved oxygen levels give off a rotten egg smell due to excess in hydrogen sulfide. Some pond products contain bacteria selected for their ability to biodegrade hydrogen sulfide eliminating any sulfur-based odors.

Trial and error is necessary to find the product that work best and most economically for each operation. Aeration (or some other form of turbulation) is important. Bacteria are living organisms and need a ready supply of oxygen to thrive. Keep the water moving through surface agitation. Exposed ponds with good wind chop on the surface water are usually adequately aerated. Be aware of water temperature. Water temperatures of 40oF to 90°F, are ideal for bacterial survival.