Water Treatment Flashcards
Associate lead and mercury with their affect on the human body
Lead: impaired mental development Mercury: Brain and central nervous system damage, kidney failure
What are industrial sources of Cu, Pb, and Cr?
Cu: copper pipes, marine paintPb: Iron and steel production, lead paintsCr: Organic chemical industries, electroplating
Name a few classes of pesticides
Insecticides, Fungicides, Algaecides, Rodenticides
What are dioxins? Under what conditions are they produced?
Polychlorinated derivatives of organic substances. Incomplete oxidation when temperature is not high enough.
What is the most toxic dioxin?
TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin)
What are PCBs? What are some uses?
Polychlorinated biphenyl compounds. Transformers and capacitors.
What are some sources and effects of Nitrates on humans and the environment?
Waste water, fertilizer; eutrophication, methemoglobinemia, cancer.
What are some sources and an effect of Phosphate on the environment?
Waste water, detergent, fertilizer; eutrophication
What are the three main stages of Primary water treatment?
Filtration/screening, Settling/grit removal, Sedimentation
What is flocculation and what chemical is usually used to achieve this?
Making waste water alkaline and then adding Al2(SO4)3, which coagulates other smaller particles in the wastewater
What are the methods of Secondary water treatment?
Trickling filter, rotating biological contactors, and activate sludge
Describe the process of activated sludge treatment
Wastewater is moved to a tank where oxygen is supplied continuously. Activated sludge (containing bacteria) is added to stimulate decomposition of organic matter, which then settles out.
What is tertiary treatment?
Sand beds and activated charcoal may be used to filter water for fine particulate matter and organic compounds.
How are phosphates removed from wastewater?
Al2(SO4)3 can be added to precipitate (PO4)3-
How are nitrogen compounds and nitrates removed from wastewater?
Nitrogen compounds oxidized by bacteria to nitrates. Denitrifying bacteria then reduce nitrate (V) to N2.
