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How can nitrobacter and nitrosomonas be developed into biological filters quicker?
Seed new filter with material from an older well-established biological filter.
What are cultures of bacteria often marketed as?
Water conditioners.
What is denitrification?
Conversion of nitrate into nitrogen gas or nitrous oxide.
What is usually the carbon source for denitrification?
Methanol, acetate, or fish wastes and uneaten foods.
What type of reaction is denitrification?
Reduction reactions, must be done in anaerobic environments.
What is dissimilarity nitrate reduction?
If the C/N ratio gets too high in a system, it causes a shift in metabolic pathways.
What are chemical filters?
Used to remove substances dissolved in water.
What is foam fractionation?
Use of bubbles for removal of solute.
What are foam fractionation units also called?
Protein skimmers.
What is carbon filtration?
Used to take out both polar and non-polar molecules.
What is water passed through in a carbon filter?
Activated carbon.
What does 'active' mean in carbon filters?
Many pores on the carbon, increases surface area for reactions.
How can activated carbon be produced?
Physical activation and chemical activation.
Why should carbon filters be downstream of biological filters?
Need to remove nutrients before they get to the carbon, or bacterial colonies will grow over the carbon and block absorption.
What is ion exchange?
Removes unwanted ions from a solution and replaces them with desirable ones.
What is resin in ion exchange?
When the resin is manufactured, a certain type of ion is bound to the material, resulting in ion exchange.
What are the most commonly used resins?
Zeolites or polystyrene sulfonate beads.
Where should exchange resins be placed in a system?
Downstream of foam fractionators or activated carbon filters.
What is disinfection?
Reducing harmful microorganisms from water.
How is UV radiation used in disinfection?
Electromagnetic waves disrupt unsaturated bonds of molecules; are not killed immediately but are unable to grow and reproduce.
What is a benefit of UV disinfection?
Cheap to operate and cannot overdose on UV.
What is ozone?
O3, an unstable, bluish gas, and a very strong oxidizing agent.
What should ozone be broken down into before going to a culture system?
O2.
How is O3 converted to O2?
UV radiation.
What is another benefit of ozone, other than disinfection?
Oxidizes many organic and inorganic substances; removes color and smells from water.
What is chlorination?
Use of chlorine to disinfect water.
What is Cl2 sold as?
Liquefied gas under pressure, calcium hypochlorite powder, sodium hypochlorite liquid.
What does chlorine in water form?
Hypochlorous acid.
At what pH is chlorination more effective?
Lower pHs.
What is chlorine demand?
Amount of chlorine needed to react with dissolved compounds and microbes in the water.
What are chloramines?
Formed from chlorine and ammonia.
At what pH do chloramines work more effectively?
Higher pHs.
What are three methods of dechlorinating water?
Pass water through activated carbon or ion-exchange resins, UV radiation, sodium thiosulfate.
What is sodium thiosulphate?
Reacts with chlorine and neutralizes it.
What is a gravity aerator?
Water is raised, then falls back into the pond after being broken into droplets or mist.
What is a diffuser aerator?
Injects air into the water.
What is a venturi diffuser?
Water is pumped at high speed and air is drawn in through a valve.
What is a U-tube diffuser?
Water is pumped into a U-shaped tube, simple diffuser at entrance.
What is a down-flow aerator?
Water forced downward in hood, oxygen is injected into it, creating bubbles.
What is a surface aerator?
Water is thrown up from the pond surface into the air.
What are types of surface aerators?
Nozzles, spray aerators, floating paddle wheels.
What is a turbine aerator?
Not so much to add oxygen; moves aerated water, especially for moving surface water below a pond thermocline.
What is a thermocline?
Rapid change in temperature with depth.
What is degassing?
Removal of supersaturated gases from water, usually N2.
What can supersaturated waters lead to?
Gas bubble disease.
What are three common degassing methods?
Vacuum, oxygen injection, packed column.
What are ways to control temperature?
Insulating tanks and pipes can help retain heat in colder climates and prevent heat gain in warmer climates.
What kind of heaters are used?
Immersion heaters or in-line heaters.
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