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Algae infestations in ponds lakes and dams

Like other countries enjoying a temperate climate, South Africa has limited rainfall and lots of lovely hot sunshine. Whilst making for pleasant living, many of our shallow bodies of water – from garden ponds and wetlands to irrigation storage dams, reservoirs and lakes – become, by virtue of their stagnancy and meagre inflow, covered in algae. These small plants not only turn the water green, they have a disastrous effect on the environment causing vegetative decay and odour.

Why algae?

The reason for the proliferation of algae is largely due to the presence of above average concentrations of Nitrates (N) and Phosphates (P) in the water. Catalysed by warmth and long hours of sunshine (ideal for rapid photosynthesis), the algal spores 'bloom' and multiply, often at incredible speed, depleting the water of oxygen as they do so. Eventually they form a floating blanket that prevents the uptake of oxygen by the reduced water surface area.

As the pond becomes anaerobic the various populations of life forms die. Anaerobic bacteria begin to bloom causing sulphide gasses that further reduce the oxygen content of the water. Eventually the fine floating roots of the algae that started the cycle are also destroyed. The aquatic plants die off and putrefy causing a pungent stench.

For the limnological life forms to co-exist, N and P must be removed from the water to restore the natural balance.

Where do Nitrates and Phosphates come from?

Nitrates can usually be traced back to the farmer who uses mineral fertilizers – high in Nitrates for sturdy plant growth – to 'feed' his crops. However, at planting time the seedlings take up only a small percentage of the spread. The remainder gets 'leached' out of the soil and into watercourses by either irrigation or rain.

Phosphate also leaches, but to a far lesser extent as its chemical structure binds it to soil particles. It is often present in river water – especially streams into which municipal Wastewater Treatment Works discharge, or rural folk use for washing clothes. The most common source is laundry powders – sodium tri-polyphosphate is a detergent ubiquitous to washing powders.

The BIO-SYSTEMS solution

Scientists have devised many ways to remove these so called 'nutrients', but nobody has perfected an extraction technique without exerting undue stress on an already fragile environment and the financial resources of he who owns the body of water. The solution however is really very simple: treat the cause and not the effect. Both algae and microscopic bacteria thrive on N and P. As a result of their relative sizes, bacteria will out-compete algae by attacking it, multiplying faster (doubling their biomass every 20-30 minutes), devouring the nutrients as they grow.

Therefore, in order to 'clean up' a body of water a healthy population of avaricious bacteria is essential to metabolize these radicals back into the natural food chain. Under normal natural circumstances, the status quo is maintained, but what with man’s non-organic fertilizers and his 'washes whiter', the whole harmonious scenario is turned upside down. The problem does have a solution, however. To keep the equation equal and to make all fair, the latent population of bacteria that readily consume N and P needs to be boosted to match the increase in polluting nutrients. Our microbial blends ensure that the biodegradation of N and P is efficiently controlled. As a result, water will be cleaner, healthier and free from unpleasant odours.

    B504 is a dry microbial powder blend that reduces algae and sludge by metabolising excess Nitrates and Phosphates. It lowers pH, improves effluent, and reduces odours and ammonia. B504 can be used in fish farming lagoons, ornamental dams and lakes.
  2. ClearWater
    ClearWater is a liquid microbial product that metabolizes nitrates and phosphates in fish ponds and ornamental lakes.

Click on the BIO-SYSTEMS Product table for a complete list of products. Also see our Algae case history.

Clearing algae from golf course pond 

Clearing algae from a golf course pond

For comprehensive information on how BIO-SYSTEMS can assist agricultural effluent disposal, click on Animal slurries, Crop processing wastes, Mechanical and chemical wastes, Rural sewage treatment and Rural catering effluent.

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