ALGAE & CYANOBACTERIA
Table 1 (continued)
PRINCIPLE – MODE OF ACTION
Require specialized equipment designed to remove large amounts of cyanobacterial
scum floating on water surface. Only applicable for extremely large algal blooms and
a safe method of disposal is required.
Desiccation of algal material to reduce potential for future blooms. Benthic
cyanobacteria can resist desiccation and regrow after prolonged periods out of water.
Dredging of reservoir bottom to remove phosphorus laden sediment. Expensive
process requiring appropriate methods for sediment disposal.
Clear Pond Extreme
Bio World Algae Control
Clean-Flo (C-FLO- 6)
Ultrasound – Low energy
LG Sonic Algae Control
Ultrasound Algae Killer
Toscano Línea Electrónica S.L.
VoR Algae Controller XXL
There are a range of small units marketed in many countries and they all appear to
operate with the same design principles. In each case high frequency sound waves
(around 20 KHz) are pulsated through the water from a transducer suspended on
a surface float to distances of up to 100–200m. The algae control device emits
ultrasonic waves that “fan out” at approximately 120°–150° from the front of the
transducer. The claim is that this process of ultrasonication destroys the gas vesicles
in algae, killing them. Other manufacturer’s claim that the submerged ultrasonic
transducer is programmed to generate a frequency of ultrasonic waves that destroys
cellular function and structure.
The “Algae Hunter” and “Waterbloom Killer” are both novel algal control
technologies from Japan. They combine a pumped circulation device with ozone
injection and irradiation with ultrasound. The device can be moored in situ on the
lake surface with an intake at depth or surface that draws water containing algae
or cyanobacteria into a stream where it is irradiated with ultrasound frequencies at
two frequencies (50, 200 KHz) and passed through a “jetstream” circulator where an
ozone dose is injected as the water is pumped through.
A range of formulations that contain the aerobic bacteria (Bacillus subtilis), in
some cases combined with activated charcoal. Other formulations may also contain
enzymes. Manufacturers claim they rapidly deplete bio-available nitrogen and
phosphorus (nutrient removal and denitrification) limiting nuisance algal growth and
the introduced bacteria “digest” organic matter, cell matrices of other bacteria.
Range of techniques that influence algal growth by manipulation of the food web.
A number of aquatic organisms that negatively affect cyanobacteria by producing
chemicals that can act directly or indirectly on their growth.
(Ultrasonic Algaecide system
for surface algae)
(Ultrasonic Algaecide system)