Biological Filtration

Question 1

describe biological filtration

Answer 1

organisms take up waste products in the form of dissolved solids, or break down the concentrated suspended matter obtained from mech or chem filtration.

Question 2

Describe the bacterial conversion process, name it, and what might need to be added to the water because of it.

Answer 2

converts ammonia to nitrite to nitrate. Nitrification. alkalinity and oxygen are consumed, so may need to buffer or add oxygen.

Question 3

what should you do if your nitrate is building up? and what is this process called?

Answer 3

1-remove DO (anaerobic)
2-inject anaerobic bacteria
3-provide carbon.
-Denitrification: conversion from nitrate to N2 gas

Question 4

Name 6 water quality factors that can affect the rate of both nitrification and . why?

Answer 4

• alkalinity (gets consumed)
• DO (reduces growth rates of nitrobactar)
• pH (optimum @ 7.2-7.8 for nitrobacter)
• T*C (high= high conversion rate)
• Ammonia (high concentrations = high conversion rate)
• Organics (Provide growth substrate for heterotrophic bacteria)

Question 5

two general types of waste extraction systems

Answer 5

passive (wastewater passes by static organisms)

active (media is moving thru wastewater stream)

Question 6

Activated sludge

Answer 6

a process where solid waste is somewhat digested by bacteria.

Question 7

Lagoons

Answer 7

large aerated depressions in the earth where wastewater is injected for a set time.

Question 8

fixed bed reactor

Answer 8

forces wastewater thru a stationary or fixed bed where bacteria adhere to the surface and strip dissolved material from the water as it passes by

Question 9

fluid bed reactor

Answer 9

reactor vessels where the media ‘floats’ or become fluidized. Upwelling system.

Question 10

rotating biological contractors (RBCs)

Answer 10

reactor vessels that contain a series of baffles that rotate slowly. bacteria attached to the surface of the baffles are slowly drawn thru the water.

Question 11

for aquaponics, as the production of fish increases, what else increases? what is necessary to do because of it?

Answer 11

accumulation of suspended and dissolved solids which increases the complexity of the operation. It is necessary to remove solids and undergo nitrogen conversion.

Question 12

what sort of filtration is used to convert ammonia to nitrate for aquaponic systems?

Answer 12

biofiltration

Question 13

for optimum aquaponic systems, what should the levels be for:
alkalinity, pH, DO?

Answer 13

alk: >100mg/L
pH 6-9
DO: close to saturation

Question 14

what are the two type of plant beds for aquaponics, and which one is preferred? why?

Answer 14

substrate, floating.

floating is preferred, b/c roots need constant aeration.

Question 15

name the order of elevation and components for a gravity fed aquaponics system

Answer 15

(highest) fish culture, clarifier, biofilter, plant bed, sump (lowest). sump pumps filtered water back to highest point, the fish.

Question 16

what are the most demanding components in an aquaponics system?

Answer 16

iron and carbon. must add carbon, but not a much sodium bicarbonate.

Question 17

what is an alternative to pesticides?

Answer 17

probiotics, UV