Waste water pumps

Unalloyed cast iron (grey cast iron) exhibits similar behaviour to unalloyed steel in waste water treatment plants. Waste water pumps made of grey cast iron (GG 22, GG 25, 0.6025) have a rough surface that is an ideal substrate for adhesive biofilms that can cause biocorrosion. Biocorrosion cannot be completely excluded on polished cast parts containing spheroidal graphite and silicon as well as on high-alloy CrNiMo cast pumps. The corrosion properties of hard chromium-molybdenum cast iron G-X 250 CrMo 15 3 (cf. G-X 300 CrMo 15 3, 0.9635) are comparable to those of unalloyed cast iron however, the former is a superior material for immersion... 

Waste water pumps made of grey cast iron (EN-GJL-250, 0.6025) have surface roughnesses between 12 and 50 pm (Ra, arithmetic mean roughness) and are thus ideal substrates for adhesive biofilms. Biocorrosion is accelerated on these materials, in contrast to polishable spherical graphite cast iron and cast ferrosilicon. Bronze pumps have improved mean roughness values of approx. 10 pm Ra, and pumps made of cast high-alloy CrNiMo can be polished to values of 5 pm Ra. However, the formation of cavities with a risk of biocorrosion cannot be excluded in this case [14]. 

Wear-resistant material for waste water pumps) (in German)... 

Chemically inactive These are made from a variety of materials that include wound yarn, felt, flannel, cotton waste, wood pump, mineral wool, asbestos and diatomaceous earth. The solid particles are trapped and retained within the medium. Certain types will remove water, as well as large and small particles of solids in a range down to 10 microns. Ceramics are sometimes employed for depth filtration, as also are special sintered metals. 

The need for good chemical resistance is no longer as great as it used to be. Under current waste water rules, most powerful chemicals may no longer be disposed of in a sink. Grood resistance, however, will be needed in cases where sinks do not drain to the sewer but to a waste holding tank which is pumped out by a waste disposal service. 

A cascaded system uses both centralized and individual heat pumps. A central heat pump removes low temperature heat from the primary source and adds it to the distribution water, which is sent to individual buildings. Heat pumps in the buildings then use this distribution water as a secondary heat source. This system is used when the primary source water is too corrosive, such as salt water, or contaminated, such as waste water. 

Sewage and wastewater heat sources are usually not much colder than the buildings from which they come. A cascaded ICES can remove heat from waste water and transfer it to the distribution system which then acts as a secondary heat source for heat pumps in individual buildings. Waste heat is often lost into the environment by industrial facilities in the form of hot water. This hot water can be used directly by the heat pumps in a centralized ICES. 

The rule should be adopted that any vacuum desiccator which does not fully keep its vacuum over night (test with a gauge) should be discarded. Thus it is sufficient to evacuate once and to leave over night. To continue suction at the pump for hours is to waste water. 

Another possibility to clean the waste gases of the tanks consists in placing a small scmbber with 500 m3/h on each tank (Fig. 10). This implement is compact and the air concentration is left out. As far as costs are concerned, there is no difference as all units, such as water pump, fan and control, must be provided for three times. 

The chemical Industry requires vacuum pumps which are highly reliable and which do not produce waste materials such as contaminated waste oil or waste water. If this can be done, the operating costs of such a vacuum pump are low in view of the measures otherwise required for protecting the environment (disposal of waste oil and water, for example). For operation of the simple and rugged ALL-ex pump from LEYBOLD there are no restrictions as to the vapor flow or the pressure range during continuous operation. The ALL-ex may be operated within the entire pressure range from 5 to 1000 mbar without restrictions. 

Pumps are used for many purposes. Additional examples include gasoline pumps used to pump the gasoline from a holding tank into your car, water pumps to transfer drinking water from a reservoir to your house or business, and industrial pumps used to move industrial fluids such as chemicals or waste products from one tank to another inside a plant. A car also uses pumps to pump fuel from the gas tank to the engine and to pump coolant from the radiator to the engine block. 

Waste water treatment. Supercritical CO2 has been put to use in a variety of industrial waste treatment applications. Clean Harbors Environmental Services, Inc., has used SCCO2 in Baltimore since 1989 to treat wastewater from chemical and pharmaceutical manufacturers. In the process the wastewater is pumped into the top of a 32-ft-high, 2-ft-diameter column, while the CO2 is pumped in from the bottom and percolates up. As the CO2 trowels up it dissolves the organics. CO2 contaminated with organics is at the top of the column, and clean water is at the bottom. The contaminants are incinerated off-site after separation from the CO2 which is recycled. 

In a dispersed gas system, a fine dispersion of gas bubbles is mechanically created in the waste water by means of an impeller or with a combination centrifugal pump and eductor. 

The most frequent operational problems in waste water ozonation systems are foaming and the formation and precipitation of calcium oxalate, calcium carbonates and ferrous hydroxide (Fe(OH)3) which may easily clog the reactor, piping and valves and also damage the pumps. 

Figure 24. Scheme of multilamp immersion-type photochemical installation for the photocatalyzed oxidative degradation of industrial waste water [12]. A Bypass circuit. B Reactor circuit. 1 Gas-liquid mixture and injection. 2 Reservoir. 3 Pump (ceramics). 4 Water pump. 5 Heating circuit. 6 Cooling circuit, hv Medium pressure mercury lamps (Pyrex). T Thermometers. 

A liquid will boil at a lower temperature when the external pressure is reduced, e.g. by using a water pump. The variation of boiling point with external pressure can be demonstrated with a volatile liquid, such as methanol it is advisable to introduce some form of cold trap to reduce the amount of vapour entering the waste. An alternative is to allow boiling water to cool and so stop boiling, and then reduce the pressure it will start to boil again at a temperature below 100 °C. ... 

Acid waste waters from silicone production enter neutraliser 9, a concrete container with two agitators, lined with acid-resistant tile from epoxy resin. Here the waste waters are neutralised with lime milk, which is automatically sent from reservoirs 6 with pumps 8. The pumps automatically switch off when pH in the neutraliser is 8-10 and switch on when pH is below 5. Neutral waste waters continuously self-flow through a collector into receiving reservoir 10 as they accumulate, they are automatically sent with pumps 11 for averaging and mechanical purification. 

The sediment from the conical bottoms of the settling boxes is continuously withdrawn into reservoir 17. It is partially removed as dirt and partially sent with pumps 18 and 26 to installation 27 to dehydrate. At the stage of biochemical purification the clarified waste waters from settling boxes 16 self-flow into the top channel of the clarified water of aerotank 10. The aerotank is a six-section open concrete precast reservoir with bubble and aeration systems. All sections of the aerotank function parallel to each other. Each consists of two corridors the oxidation corridor, where the process of biochemical purification takes place, and the regeneration corridor, which serves to prepare silt for purification in the oxidation corridor. 

Fig. 21. Diagram of the biochemical purification of waste waters 1 - slushers 2 -slaking apparatuses 3 - heat exchanger 4, 28, 29 - transporters 5 - screw trap 6, 10, 17, 23 - reservoirs 7 - bin 8, 11, 12, 18, 21, 24, 26 - pumps 9 - neutraliser 13, 16, 22, 25 - settling boxes 14 - damping chamber 15 - averager 19 - aero-tank 20 - biogenic tank 27 - pressure filter...

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