ALGAECIDES.pptx

Algaecides that kill algal blooms without effecting other aquatic animals.

1. West Bengal university of animal and fishery sciences Faculty of Fishery Sciences Submitted to Prof. T .J . Abraham Department of AAH Submitted by Shrija Majumder F/2021/30

2. Algaecides An Assignment on-

3. Table of contents 01 04 02 05 03 06 Introduction Types of Algaecides Algae Matters Methods of application General Effectiveness Considerations

4. INTRODUCTION Algaecide is a biocide used for killing and preventing the growth of algae, often defined in a loose sense that, beyond the biological definition, also includes cyanobacteria ("blue-green algae"). An algaecide may be used for controlled bodies of water (reservoirs, golf ponds, swimming pools), but may also be used on land for locations such as turfgrass.

5. Algae blooms can clog filters and otherwise increase treatment costs and efforts. Historically, copper sulfate and other algaecides have been used to destroy this excessive biomass before it enters the drinking water treatment plant. Other methods involving metals (Al, Fe, Cu, Ag, Ca), photosensitizers (hydrogen peroxide, cyanines , TiO2), herbicides, and chemicals derived from natural compounds have proven effective in managing harmful algal blooms (HABs) as well. Chemical methods have a higher likelihood of toxicity and non-target response than other available methods.

6. TYPES OF ALGAECIDES Natural Algaecides Natural Alagaecides Synthetic Alagaecides

7. Natural Algaecides Natural algaecides are allelopathic chemicals (i.e., chemicals that inhibit the growth of a plant that are naturally released by a different plant). The efficacy for natural algaecides is typically more gradual than other types of algaecides, allowing the system to accommodate increased oxygen demand associated with algal mortality upon application. E xample :- B arley straw .

8. Barely straw as natural algaecide

9. Synthetic Algaecides Copper has been a known biocide of marine and freshwater organisms for hundreds, even thousands, of years. Ex: copper sulphate, chelated copper compounds . Synthetic organic algaecides are absorbed by algae and contain “membrane active” chemicals that disrupt algae metabolism. Oxidizer algaecides kill algae by rupturing the cell membranes; however, oxidizers can also disrupt other cellular functions. Ex: sodium carbonate peroxyhydrate .

10. Synthetic Algaecide

11. Algae matters Algaecides are used to control many species of planktonic, filamentous, and branched algae. The most common causes of taste and odour problems in drinking water are due to algae byproducts . Cyanobacteria produce toxins as secondary metabolites. There are three primary classes of cyanotoxins:1) Hepatotoxins 2) Neurotoxins and 3) Dermatotoxins . Filter run times in water treatment facilities can be directly affected by the level of primary production in water bodies. The clogging of treatment plant filters increases the cost of treatment.

12. Extensive algal growth can affect water quality and aquatic habitats. Algal blooms may reduce water clarity. Algae blooms can reduce aesthetic appeal of reservoirs, lakes, and rivers. Continues,

13. Methods of Application Algaecides should be applied in a uniform manner. Surface application : Spraying a diluted mixture of algaecide from the shore or a boat evenly across the surface of the water. Subsurface application : In deeper water, the algaecide is applied through a weighted hose or other sub-surface delivery system to concentrate application where the greatest concentration of algae is present. Polymer application : A polymer may be added to certain algaecides to improve sinking and deposition and minimize loss (e.g., due to spraying). Aircraft application : Algaecide is applied as a spray from aircraft (e.g., plane or helicopter). Drip system application : For application of algaecide in irrigation conveyance systems and other moving water.

14. A lgaecides can be effective for controlling or reducing the growth of unwanted algae. A lgae are difficult to control long term. Algaecides will eliminate all algae or their spores. The efficacy of algaecides is short-lived in water. The efficacy of copper-containing algaecides can be impacted under certain environmental conditions. Copper is less effective in waters with high alkalinity and pH. General Effectiveness

15. Consideration Cell lysis: 1. Algaecides must be used with particular caution 2. Algaecides should be used when cell numbers are low. Chemicals and water quality standards: 1. Chemicals used for algaecides must not be applied in doses. 2. Chemicals in algaecides do not degrade, and once applied, may persist in water bodies indefinitely. Non-target organisms : Algaecides can be toxic to non-target organisms. Short- vs. long-term management : Algaecides are generally a short-term solution to a pending bloom.. Permitted algaecides : Only use U.S. EPA- and State-approved algaecides.

16. Water body characteristics : Determine current pH, alkalinity, and DOC. Drinking water supply treatment : Treatment should be triggered by changes in water quality. Monitoring: For all algaecides, monitor for effects on target and non-target organisms. Continues,

17. Effects of Chemical Algaecides Copper, silver compounds : Advantages : Extremely low price. Disadvantages: Toxicity against non-target species, accumulation in the environment and release of toxins from algal cells after treatment . Hydrogen peroxide : Advantages : Low price, low toxicity for non-target species, fast degradability, selective towards cyanobacteria. Disadvantages: Risky manipulation with concentrated hydrogen peroxide, fast degradability (short time of action), risk of release of toxins from algal cells after treatment.

18. Phthalocyanines: Advantages : High toxicity towards photoautotrophs, biodegradable. Disadvantages: Insufficient knowledge about toxicity towards fish and macrophytes, blue/green coloration, risk of release of toxins from algal cells after treatment. Titanium dioxide and other insoluble photosensitizers: Advantages : Toxicity towards photoautotrophs via ROS production. Disadvantages: Insoluble in water.

19. Herbicides (diuron, endothal l , atrazine, simazine and others): Advantages : Low price, toxicity towards photoautotrophs. Disadvantages: Toxicity against non-target species, accumulation in the environment, toxic residues, release of toxins from algal cells after the treatment. Chemicals derived from natural compounds: Advantages : Effective in low concentrations, biodegradable, natural products. Disadvantages: Preparation of extracts or isolation of alkaloids in high amounts. Unknown toxicity towards other non-target species, price for extraction/synthesis, risk of release of toxins from algal cells after treatment.

20. Thank You