30-percent solution of hydrochloric acid. If clogging is by soot, oil, or dust from improperly filtered air, remove the diffusers and burn off the extraneous material in a furnace.

Porous ceramic tubes. Tubes may be removed and cleaned by soaking in acids or by burning (as described for porous plate diffusers).

Porous Saran-Wound Tube Diffusers

These diffusers should be inspected and cleaned semiannually as necessary. This material cannot be subjected to strong acids or heat. It must be scrubbed with a brush and soap or detergent.

Injection Nozzles

Injection nozzles should be inspected and cleaned semiannually as necessary. Diffuser nozzles on header lines may become clogged from deposits inside from iron oxide particles, or on the outside from organic growths. Clogging from the inside may require removal of the individual nozzles for cleaning. Chlorine gas injection into the air line header between inspections will hold down organic growths. At inspection periods, if growths are present, scrub them off with a brush and detergent solution to which hypochloride has been added.

SPRAY NOZZLE AERATORS

The maintenance procedures for spray nozzle aerators is as follows:

At weekly intervals, check the nozzles for clogging, and clean when necessary. Remove the nozzles only when necessary. Check for adequate spread.

Quarterly, check air line manifolds, remove caps and clean out sediment; check for joint leaks. Check pipe supports, replace or repair, and paint as necessary.

When spray fences exist, repair and paint them annually.

BLOWERS AND ACCESSORY EQUIPMENT

The procedures for injection aeration is as follows: Daily, lubricate the blower or compressor under the manufacturer's instructions. Check output pressures.

Weekly, inspect the air filters; clean, repair, or replace them as necessary.

Annually, open the blower or compressor and inspect for internal erosion or deterioration; repair as necessary.

Paint exterior surfaces. Maintenance operation frequencies and the schedule of inspections for aeration equipment are shown in appendix III, table G.

Q21. Waterfall-type of aerators use what type of action to areate water?

Q22. What reaction will occur when water is poured into sulfuric or chromic acid?

Q23. Chlorine gas injection into the air line header of injection nozzles will reduce what condition?

SAFETY AND EMERGENCIES

LEARNING OBJECTIVE: Recognize and understand basic safety procedures for use, handling, and storage of water treatment chemicals. Understand first aid for chlorine gas.

The operation of water treatment plants is a hazardous occupation, with dangers from noxious gases and vapors, physical injury, and infections. Work should be carried on only under the supervision of an experienced workman or operator who is trained in first aid and is familiar with the hazards of the work.

CHLORINATION

Specific precautions in handling ammonia, chlorine, and chlorine-yielding compounds were shown in an earlier chapter on water treatment plants. A number of chlorination safety precautions are given below.

Provide self-generating oxygen-breathing apparatus or self-contained oxygen-breathing apparatus designed to cope with chlorine.

Maintain only the supply of chlorine in any chlorinator room that will do for normal daily demands. Store the main supply in a detached noncombustible building or in a fireproof room which is vented only to the outside and which is separated from the main part of the building. Keep the chlorinator and chlorine storage. buildings or rooms locked to prevent the entrance of unauthorized personnel and restrict these areas from any other use.