L14 Flashcards
Mycotoxins
toxic fungal metabolites that accumulate in cereal grains, nuts, and other foodstuffs, particularly in storage
aflatoxins
highly toxic and carcinogenic
affect human and livestock
turkey X disease in the 1960s - killed >100,000 turkeys (contaminated groundnuts from brazil)
aflatoxin short term symptoms
abnominal pain and diarrhoea
headache
convulsions
vomiting
aflatoxin long term symptoms
cancer
liver/kidney failure
brain damage
ergot poisoning
‘st. anthonys fire’ - severe joint pain, hallucinations, seizures
what is important to waste water treatment? (4)
- reduce organic content
- reduce suspended solids
- remove pathogenic microbes
- remove NH4 by conversion to NO3
BOD
amount of oxygen consumed by bacteria in the dark over a set time
BOD used for
to predict the effect of discharging waste and to determine effectiveness of treatment
primary settling tank produces what
primary sludge
microbes in the top 0.5m ______
oxidize organic compounds
microbes below the top 0.5m _____
oxidize NH4 to NO3 (nitrification)
if it is wet, it will be dilute so you should _____ the flow rate
increase - to keep carbon and nitrogen levels the same
if it is dry, you should ____ the flow rate
decrease - bc you’ll have a much higher concentration of carbon and nitrogens
wht is the diference between an activated sludge tank and a percolating filtration
- microbes in AST are not surface attached
- AST aerated by air diffusers at the base
- in AST microbes grow as flocs and oxidize organic compounds and NH4
- AST 10x faster than percolating filtration
- running costs higher and more sensitive to composition of incoming water compared to percolating filtration
organic matter
x
organic acids / esters and alcohols
y
acetic acid + H + CO2
z
CH4 + H2O
x - fermentative bacteria
y - acetogenic bacteria
z - methanogens
