Waste Water Treatment Plants

Lubrication Engineers lubricants have found ready acceptance in wastewater plants of all kinds. The ability to operate under difficult environmental conditions, and deal with the corrosive and hostile chemistry of sewage treatment makes them very useful. Also the absence of any toxic ingredients or additives is an important feature.

Proper maintenance of the equipment in wastewater disposal has become more important and more complex. There have been many new technical developments and a great deal of modern equipment put into use. This advancement demands more highly trained people and a much better knowledge of maintenance, lubricants and their application. Lubrication is the lifeblood of any mechanical system, but even more so in wastewater treatment equipment, as it is constantly in contact with harsh contaminants such as acid, moisture, and dirt.

Anti-friction and plain bearings operate under shock loads, high speeds, temperature extremes and contaminants. These bearings are exposed to chemical corrosion, dirt and moisture. They are widely found in motors pumps, U-joints and shafts, exhaust fan bearings, countershafts, turntable reservoirs, grit washers, disintegrators, grinders and rakes, conveyors, furnace step bearing reservoirs, scum burners, heat exchangers, ash hopper doors, ash elevators, ash screw conveyors, primary clarifiers, and blowers. Lubrication Engineers recommend:

For various other applications such as air compressors, pumps, hydraulics and turbines Lubrication Engineers recommend:

For gear reducers in pump/lift stations, wet wells, bar/drum screens, sludge, sewage, sump, slurry, scum, and circulating and chemical feed pumps, grinders, sludge thickeners, centrifuges, flocculators, collectors, skimmers, digestors, conveyors, grit collectors and removers, incinerators, ash elevators, aerators, and worm gear cases and turntable oil reservoirs in primary and secondary clarifiers we recommend:

For grease fittings found in valves and sluice gates, on bar screens and drum screens, collector/skimmers, tank and scale rollers, and chassis points on grounds keeping equipment we recommend:

For chains and chain drives, Lubrication Engineers recommends:

For miscellaneous applications such as standby generators and grounds keeping equipment, we recommend:

In the following, through a wastewater treatment plant process, it becomes apparent that the "unit group" of electric motor-gear reducer-coupling-then pump, blower, etc. is repeated over and over, with minor differences Incorporating either couplings and chain or belt drives, and interspersed with equipment of various configurations. Other major groups would be air generation, engines for power and heat generation and miscellaneous equipment.

Electric motors will range in all sizes from fractional horsepower to several hundred horsepower. They may be grease or oil lubricated. A top quality stable, high melting point grease should be selected. Typical might be an NLGI 2 complex grease, with rust and oxidation inhibitors and extreme pressure characteristics. It should be water resistant. The oil should be a turbine grade with rust and oxidation inhibitors and anti-wear additives. Certain gearboxes will require the same type oil and the same grade can possibly be used on electric motors and thus reduce the number of lubricants.

Gear Reducers are used in conjunction with electric motors all over the wastewater plant. Most of them will call for an SAE 90 mild EP lubricant. Many are subject to water contamination so the best quality should be selected, one that will not emulsify with water and can be drained off. Some gear manufacturers prefer turbine grade (non EP) oils with only rust and oxidation (R & 0) inhibitors. The possibility of changing these units to gear oil should be investigated in order to use a single product for all enclosed gears.

Chain Drives are efficient, economical and versatile. They can be lubricated by hand, drip, bath or spray. The American Sprocket Chain Manufacturers Association recommends oil for chain lubrication. Such oils as the turbine oils and gear oils mentioned before are appropriate. It is important that the pin bushing be lubricated so penetrating, creeping qualities are desirable in a chain lubricant. The oil should be rust and oxidation inhibited and have good anti-wear qualities. In certain applications, grease may be used and/or solvent cutback greases that can be sprayed on the chain.

For some of the gearboxes and chain drives, there may be grease-lubricated points as well as the many conveyors, pumps and couplings that require a tougher grease than the grease for electric motors. This grease should be a good multi-purpose, extreme pressure, and waterproof grease with a high melting point.Pumps may be rotary, piston or turbine type and are usually grease lubricated except the turbine types, which are drip oil lubricated at the lower bearings and greased at the top. The multipurpose grease should be used for its sealing ability and impact resistance. Turbine pumps use a turbine grade oil with rust and oxidation resistance.

Air Compressors are numerous in any large treatment plant. There are banks of them to supply air to the sludge aeration areas, and individual units scattered throughout the various needs. There are different types in use; rotary units which use a light oil and piston units which use a heavier oil. Both oils should be of the same turbine quality level, incorporating rust and oxidation inhibitors and anti-wear characteristics. The careful selection of these oils cannot be emphasized too much. They should be long lasting with low deposit tendencies. Rotary blower type air units may use grease or oil. The grease should be the tough, multipurpose material, while the oil should be of turbine quality or engine oil.

Engines are found in many wastewater treatment plants and are used to drive air compressors and generators and sometimes serve as a source of heat. They may be a gas, diesel or dual fuel engines. Gas or dual fuel engines are usually chosen to utilize the methane generated in the sludge digestion process. A top quality engine oil will non'nally be used for these engines, but certain gas engines require a low ash oil. It should be of the same quality level. There are certain branded oils on the market with special additives, and inhibitors which far outperfon'n conventional oils. These should be investigated for economics and energy savings.Large internal combustion engines are found at many wastewater treatment plants. They are used to produce electricity for the power needs of the entire plant, or as standby power should the electric power supplied by the municipal facility fail.

The power generated is used to drive blowers for aeration, or compressors, pumps and other mechanical equipment such as sludge collectors, digester stirrers, power operated valves and sometimes serve as a source of co-generation of heat. They may be of gas, diesel fuel or dual-fuel engines. Gas or dual-fuel engines are usually chosen in order to utilize the methane gas generated in the sludge digestion process at the plant.

Most or all of the methane produced is drawn from the digesters and compressed into storage tanks. Any excess methane gas is either sold to surrounding communities, industries or if not utilized, is "flared off".

Electricity is generally the most convenient source of power, especially for operating small units distributed around the plant. In fact, most of these are made for electric operation. Because of this, many plants use their sludge gases to power the engines driving generators. Some of these engines may serve only in case of failures of the municipal supply, or to reduce the excessive demand for electricity during peak loads. It is desirable that the engine efficiently deliver the horsepower needed. Therefore, a conscientious preventive maintenance program should be established for this equipment.

Whether or not to convert the gas to power and choosing the type and capacity of the engine to be employed is entirely an economic consideration. Conversion of sludge gas to standby power can fulfill a major need in most plants. The type of engine generally operating on sludge is the high compression, dual-fuel diesel which can operate over the entire range from minimum ignition fuel oil requirements and gas, to 100% fuel oil with no gas. Supercharged engines, with automatic throttling of air supply to maintain more constant air to gas ratio, appear to be the engines of choice under conditions of partial load, frequently found in engine generator sets.Sewage plant designers have found that dual-fuel engines provide a degree of versatility in that such engines may operate on fuel oil and gas combinations when sufficient quantities of gas are not produced to operate the engine. But regardless of the type of fuel, a top quality engine oil will non'nally be used for most engines. Those certain gas engines requiring a low ash oil should be supplied with the same quality level.

There are certain brands of low ash oils on the market, but the majority of all requirements can be met with our 8800 MONOLEC® ULTRA Engine Oil , or 8420 - 8450 MONOLEC® GFS Engine Oil. All these products are compounded from the very finest mid-continent 100% paraffinic base oils and special additives and inhibitors which generally far out-perform convention oils. The wastewater treatment plant operator should investigate these high quality oils for their economics and energy savings.