1 usage of water, 3 fresh water disinfection

After the chapter about water supply and demineralisation, you now learn somtething about special treatment methods for fresh water. Fresh water treatment is necessary to meet the values of drinking water quality. If water of municipal supply is applied, this is not neccessary. Taking water from wells, rivers etc. or applying water recovery systems, disinfection can be neccessary.

What are the main methods for disinfection of laundry water?
1. flocculation
2. membrane filtration
3. chlorination, peracetic acid, UV irradiation, ozone generation
What types of chemicals can be used for chlorination?
1. sodium chloride
2. gas, liquid sodium hypchlorite solution, solid calcium hypochlorite etc.
3. sulfur dichloride
What is the greatest disadvantage of chlorination?
1. expensive price
2. causes bad smell and taste
3. chlorination of organic compounds may cause generation of harmful compounds
What is PAA?
1. poison acetic acid
2. peracetic acid
3. private academic aid
What are the advantages of PAA ?
1. strong oxidizing potential, wide spectrum of antimicrobial activity
2. stable for a long time
3. mixture can be prepared at the producer's site
What is the main disadvantage of PAA?
1. it it not stable and need to be mixed onsite
2. it bioaccumulates
3. it has carcinogenic, mutagenic, toxigenic properties
What is UV irradiation?
1. united violet electromagnetic radiation
2. ultra violet electromagnetic radiation
3. ultra violin electromagnetic radiation
How is UV-irradiation used as a disinfectant for wastewater?
1. the waters are subjected to outside sun
2. the UV lamps are put in the tunnel washer
3. UV light is produced by lamps, submerged in a channel through which the wastewater flows
What are the advantages of ozone for wastewater disinfection?
1. may produce formaldehyde
2. reverts to oxygen without a trace
3. is chemically stable
What is a biofilm?
1. film about general biology
2. a film of microorganisms
3. photographic film made of bio materials