X. Operation and Maintenance A. Record-keeping for drinking water supply monitoring
Objectives - students should: n Justify the necessity for record- keeping of microbiological, chemical, and physical parameters of water in treatment and distribution systems.
Record-keeping n Conscientious record- keeping is very important to keep track of short- or long-term changes in water quality. n It may not be evident at the time that a problem is occurring. Records can identify problems after the fact.
Examples of types of records: n Microbiological analyses: changes may cause illness in consumers. n Chemical analyses:changes may cause taste, odor or health problems. n Physical analyses: changes may lead to decreased palatability.
Why keep microbiological analysis records? n Microbial changes can occur due to: –Surface runoff into water sources (e.g., animal or human wastes). –Improper disinfection. –Cross-contamination of distribution system –Problems with physical treatment process.
Why keep chemical analysis records? n Chemical changes can occur due to: –Malfunctions or mistakes of metering pumps or personnel (Cl, Fl, etc.) –Natural levels in different water sources (Fl, Ca, Mg, etc.) –Runoff (surface) or groundwater contamination (pesticides, VOC’s, etc).
Why keep physical analysis records? n Physical analyses can be used to monitor the palatability of water: –Turbidity - particulate contamination. –Color - clarity and some contaminants. –pH - may contribute to taste. –Floating debris indicates general surface water quality.
Summary: n It is essential to keep records of physical, chemical, and biological water quality for both internal and external monitoring of water quality. n Proper monitoring and record- keeping can identify problems after- the-fact and help to prevent future problems.
X. Operation and Maintenance B. Emergency water treatment alternatives and sources of potable water.
Objectives: n List, describe and give examples of alternative water treatment techniques for emergencies. n Distinguish among alternative sources of drinking water during emergency situations.
Emergency water treatment and supplies n Health departments should be notified when a water emergency occurs. n Health departments may need to notify residents of alternative water sources. n There are several alternative available treatments to provide drinking water.
Alternative water treatments n Boiling for 1-2 minutes will disinfect water (inactivate bacteria, viruses, etc.) –Sterilization requires heating to F. (121 0 C) for 15 minutes. n Aeration and/or adding a pinch of salt will improve water taste after heating.
Alternative water treatments (continued) n Chlorination will disinfect water that is not grossly polluted with organic matter. –Various forms of chlorine may be added to batches of water, or flowing water. n Iodine can also be used to disinfect water (8 drops/quart for 30 minutes).
Alternative water treatments (continued) n Emergency filtration of water can be used to improve water quality. –Filter pumps can produce small quantities of potable water. –Slow sand filters can be improvised quickly, but must be monitored closely.
Alternative sources of potable water n Bottled water can be purchased at supermarkets. n Bulk water may be supplied by municipalities from safe sources. n Milk processing plants or beverage- bottling plants can produce water. n Even swimming pools can be an emergency source of drinking water
Summary: n Alternative emergency water treatments include boiling, filtering, and chemical disinfection. n Alternative emergency water sources include bottled water, other drink production facilities, and even swimming pools.