Problems and Control of Algae in water supply

Algae in water supply.

1. ALGAE IN WATER SUPPLIES: PROBLEMS AND CONTROL ENBOKLANG CHYNE 18393007

2. WHAT ARE ALGAE? Algae are photoautotrophic cells that contain chlorophyll, have simple reproductive structures, and do not have true roots, stems or leaves. They have a clearly defined nucleus and are classified as Eucarya . P igment-bearing plants found in nature either submerged under water, free-floating, living under sub-aerial conditions They range from unicellular, or single celled, to fairly complex multicellular organisms. The size of average individual algal cells is approximately 0.0010 mm in diameter.

3. FORMS OF ALGAE: Algal growth occurs in three basic forms: Planktonic algae are single-celled, microscopic algae that float freely in the water, can turn the water into yellow , gray , brown or red . Filamentous algae are sometimes referred to as “thread algae” or “pond scum”. Filamentous algae occur as fine green threads that form floating mats, which are often moved around the pond by wind. Macrophytic algae resemble true plants in that they appear to have stems and leaves.

4. TYPES OF ALGAE: Diatoms: exist singly and sometimes form colony. Yellowish or Brownish and found in freshwater. Chlorophyta : commonly known as green algae. Found in water, moist soil or trees. Euglenophyta : found mostly in ponds when polluted by runoff from agricultural fields. Dinoflagellata : green or colorless . They are responsible for the phosphorescence visible at night in tropical sea. Chrysophyta : golden algae. Found in saline and fresh water. Phaeophyta : Brown algae. Mostly found in ocean. Rhodophyta : Red algae. Found in ocean, in warm temperate and tropical climates. Cyanobacteria: blue green algae. they may form filaments, sheets or even hollow balls. They contain chlorophyll A which give the cells a typical blue-green color . Unlike bacteria, they contain chlorophyll.

5. DEVELOPMENT OF ALGAL BLOOM: Algal Bloom is a rapid growth or accumulation of microscopic algae in water Bloom which are harmful to animals or the ecology via production of natural toxins are called Harmful Algal Bloom Blooming at a concentrations of millions of cells per milliliter or ten of thousands of cells per liter . They grow rapidly in stagnant waters when exposed to sunlight and temperatures above 4 degrees Celsius. Phosphates and nitrates in the water encourage their growth.

6. Algal growth is influenced mainly by water composition, temperature and light intensity. Sodium Carbonate acts as the catalyst for the growth of algae by providing dissolved Carbon Dioxide for enhanced photosynthesis in the presence of nutrients. Runoff from fertilized fields, lawns and pastures, septic tanks and leach fields accelerate nutrient loading and algal growth in the pond

7. PROBLEMS AND CAUSES: Increase water temperatures High nutrient concentrations Drought – less water, low flows Cause Oxygen depletion following the death and decay of an algal bloom Taste and odour problems in drinking water and sometimes accompanied by an earthy, pungent or musty smell Form dense growths that make fishing, swimming, and other recreational uses nearly impossible. Result in higher BOD requirements. Some algae, like red algae and blue-green algae, can produce toxins that damage the human nervous system and the liver Raise treatment costs for drinking water Filamentous algae can clog filters and pumps. Algae can lead to undesirable pH shifts in the course of their growth in a lake or reservoir, usually toward the alkaline side

8. ALGAE CONTROL Mats of filamentous algae may be removed with a rake, screen wire, or similar devices. However, this control method is very labour intensive and provides only temporary control. F ilamentous algae can be picked up by hand .

9. Reducing fertilizer usage (for lawns, gardens, and farms), and by eliminating residential, municipal, and agricultural wastewater discharge For water tank: Always use a completely opaque water storage tank Add 1/4 teaspoon of *bleach to every gallon of water you store Add 4 parts of *chlorine to every 1,000,000 parts water

10. Control Algae with the LG Sonic e-line It is environmentally friendly, cost effective. This technology uses ultrasound to inhibit algal growth. D esigned for applications such as large ponds and farm ponds, large water reservoir. Eliminate up to 90% of existing algae and prevent growing of new algae Chemical-free solution that is safe for fish and other aquatic life Requires little maintenance to prevent frequent site visits

11. Control Algae with the LG Sonic e-line Ultrasound are sound waves with frequencies higher than the upper audible limit of human hearing (22 kHz). At specific frequencies, these sound waves can be used to control algae growth. It create a sound layer in the top layer of the water. The sound layer has a direct impact on the buoyancy of the algae. The algae cells will sink to the bottom and are unable to photosynthesize and eventually die due to a lack of light . The sound waves can spread through the water column over hundreds of meters.

12. The ultrasound creates a sound layer in the top layer of the water. The ultrasound affects the buoyancy of the algae, fixing them in the water column. Due to a lack of sunlight and nutrients, the algae will die and sink to the bottom of the reservoir. The algae are degraded by the bacteria present

13. ULTRAVIOLET METHOD. The UV sterilizer utilizes a germicidal fluorescent lamp that produces light at a wavelength of approximately 254 nanometers (2537 Angstroms). As the light penetrates the algae, it mutates the DNA preventing growth/multiplication of the organism. UV light will only penetrate clear saltwater to a depth of 5mm. The longer the amount of time the water is being exposed to the UV light, the more killing power is available.

14. Aeration : Adding dissolved oxygen to your pond through aeration can help to reduce the occurrence of algae blooms by removing their food sources. Diffused aerators use compressors to inject air at the bottom of your pond, where it bubbles up to the surface By splashing the water in the air, the aeration device is not only adding valuable oxygen, it is also helping to vent gases such as carbon dioxide which is being produced in large amounts during the decomposition process .

15. Algae control by use of Barley straw bales : When Barley straw bales are submerged in the water storage, they start to degrade. When barley is decompose, it releases enzymes that will slightly change the pH of the water. Algal cells already present are not killed , but the growth of new cells is minimized. For the maximal effect, the straw bales should be replaced every 1.5 to 3 months. This system is mostly applied on a domestic scale like in small garden ponds in gardens.

16. Using Chemicals and All Natural Products together to eliminate algae Chemical intervention involves treating the water with a variety of additives, such as alum, lanthanum, phoslock . Using algaecide like copper algaecide Cutrine Plus works great and is EPA approved for use in drinking water reservoirs, irrigation conveyance systems. Copper sulfate , chlorine, potassium permanganate are also use. However, at certain levels, copper sulfate becomes toxic.

17. BIOLOGICAL CONTROL OF HARMFUL ALGAL BLOOMS: U se of biological control (biocontrol) agents such as the predatory bacteria (bacillus bacteria), viruses, grazing by zooplankton (like copepod) the following seven attributes that defined a good predatory bacterial agent: adaptability to variations in physical conditions; ability to search for or trap prey; capacity and ability to multiply; prey consumption; ability to survive low prey densities; wide host range and ability to respond to changes in the host. bacterial agents are considered more suitable than viruses as biocontrol agents because bacteria can survive on alternate food sources during non-bloom periods . grazing of the algae by zooplankton which in turn enhances predator biomass, controls algal growth and regenerates nutrients

18. Uses of Algae as Energy source, Fertilizer, Food and Pollution control: Algae can be used to make Biodiesel : Algae can be grown to produce biomass, which can be burned to produce heat and electricity and reduce CO2 emission. Food supplement : It contains an extensive fatty acid profile, including Omega 3 and Omega 6. It has an abundance of vitamins, minerals, and trace elements in naturally-occurring synergistic design . They are used as fertilizers , soil conditioners and are a source of livestock feed. Algae are used in Wastewater Treatment facilities , reducing the need for greater amounts of toxic chemicals than are already used

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