MIXERS

Mixing basins, whether baffled or mechanically stirred (rapid or flash), require attention and cleaning semiannually. The maintenance requirements are as follows:

1. After draining, wash down the walls with a hose and flush the sediment to the drain. Repair spalled spots on walls or bottom as necessary.

2. Check the valves or sluice gates for corrosion and ease of operation; clean and lubricate; paint valves as necessary.

FLOCCULATOR BASINS

The following maintenance procedures apply to flocculator basins:

Monthly, during operation, check paddle rotation to assure that all flocculators are operating. Lower a light pole (bamboo fishing rod) into the water until the paddles strike the pole, revealing paddle operation. Broken shafts or chains may cause the paddles to become inoperative.

Semiannually, drain and clean the basin, walls, and floor; inspect the flocculator mechanism, drive, bearings, gears, and other mechanical parts; clean and lubricate. Especially check underwater bearings for silt penetration. Replace scored bearings. Paint mechanism parts where necessary.

SEDIMENTATION BASINS

All types of settling basins require the same basic maintenance, such as lubricating, cleaning, flushing, and painting. Basins, which have mechanical devices, should be maintained under the manufacturer's instructions.

Revolving-Sludge Collector Basins

Specific maintenance procedures for revolving-sludge collector basins should agree with the manufacturer's instructions. The procedures described here are the minimum.

Regular lubrication is required where the basin is in continuous operation. Intermittent operation affects the lubrication schedule, making it possible to increase the interval between lubrication periods. When operating periods are intermittent and infrequent, the mechanism should be operated briefly between operating periods and lubricated. Devices subject to wide seasonal temperature changes must have seasonal changes in lubricant grades, especially where summer grade oils thicken below freezing and reduce the flow capability. Daily or weekly lubrication of operating units is a part of operator inspection. The choice of lubricant and its frequency of application are established by the manufacturer or by local command.

Other devices found in the equipment require attention on a regular basis. Some examples of these devices and required care are as follows:

1. The speed reducer should be inspected weekly to ensure that the oil is at the proper level, is free of water and grit, and has the right body. When a reducer runs hot during its operation, the oil level may be too high or too low. (Where the reducer is out of service for a long time, make certain it is filled above the level of the seals to prevent the seals from drying out. Be sure it is tagged to reflect this condition. The reducer must be drained to proper level before being placed back in service.) Replace oil whenever necessary.

2. The drive head should be lubricated daily, but not too much.

3. The worm gear oil level should be checked at least weekly, and the water drained from the housing monthly.

4. The turntable bearings should be lubricated monthly and the oil changed twice yearly.

5. Lubrication procedures for chains depend on the design of the chain and chain guard. Inspect monthly and add oil as necessary; drain off the accumulated oil as necessary; and change the oil twice yearly.

6. Ball bearings and thrust bearings are lubricated annually. They should be inspected monthly for wear and proper lubrication.

7. Center bearings, shaft bearings, bushings, and so on, are lubricated under the manufacturer's instructions.

Tank equipment requires annual inspection. The steps for this inspection are as follow:

1. Check bolts and tighten nuts to maintain original alignments and adjustments.