EnglischneuMammothRotor04.07.2010

8/11/2019 EnglischneuMammothRotor04.07.2010

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Passavant

MAMMOTH ROTOR

Products& ServicesAeration Systems


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Products & Services

Design and development of the MAMMOTH ROTOR The MAMMOTH ROTORwas introduced to biologicalwastewater treatment in 1963. Its predecessors were

aeration rotors with only a small diameter. The MAM-MOTH ROTOR then having a diameter of 1 m and anoverall length of up to 9 m enabled the applicationrange of such surface aerators to be extended to lar-ger aeration tanks. Over 3500 plants with approx. 52kmof installed rotors are now in operation world-wide.

ProcessThe MAMMOTH ROTORprovides for the oxygen enrich-ment as well as an ideal mixing of the activatedsludge to enable an even distribution inside the acti-vated sludge tank. The oxygen enrichment can becontrolled by various means; by connecting and discon-necting complete assemblies, by adjusting the im-mersion depth or the speed by means of pole changingor frequency conversion. These characteristics enablea flexible application of the MAMMOTH ROTORfor vari-ous operating methods and multiple control strategies.

Nitrification with simultaneous denitrificationIn a tank which is commonly designed as circulatingtank the process steps nitrification and denitrification

run simultaneously. By suitably arranging and con-trolling the aerators, oxygenic areas are created for thenitrification and simultaneously anoxic areas for thedenitrification.The respective ratio of volumes for bothareas which is to be observed in terms of the indus-trial process depends on the ammonium content whichcan be measured at any point of the tank.

Nitrification with upstream denitrificationIn the nitrification tank the MAMMOTH ROTORconti-nuously provides for an aerobic environment. Theprocess step for the denitrification takes place prior tothe nitrification at a separate location.

Intermittent denitrificationBy switching off the MAMMOTH ROTOR the normallycontinuous operation for the simultaneous denitri-fication can be extended to intermittent operation. De-pending on the geometry of the tank it may be rea-

sonable to connect agitators in order to maintain a con-tinuous circulation. In particular the option to switchoff the aeration in periods of light load has proven to beextremely economic for this processing method.

2

1 MAMMOTH ROTOR withdrive unit

2 Fixing of the individual

rotor components.

3 Diagram of surface aerationin deep tank with MAMMOTHROTOR and additional circu-lating propeller.

4 Sound level with and withoutsound emission protection.

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Measuring and control technologyThe application area of the MAMMOTH ROTORrangesfrom simple to extremely complex measuring and

control technologies. For simple controls the controlfactor i.e. the intensity of aeration normally depends onthe most important flow parameter, e.g. on the am-monium content. When exceeding the rated value (notenough oxygen for the nitrification) individual MAM-MOTH ROTORSare switched on and when falling belowthis value they are switched off. In return, dependingon the circulating output achieved by the MAMMOTHROTORS, the agitators are also switched on/off. In thisway, the overall energy expenditure is reduced.

The MAMMOTH ROTORis equally suitable for the appli-cation of complex control strategies. Multiple meas-ured variables such as oxygen content, ammonium andnitrate concentration or redox potential are herebyinvolved in evaluating the system status. In accordancewith the calculation of the required aeration intensity,the individual MAMMOTH ROTORSare systematicallyactivated. In so doing, the discharge values and energy

efficiency is optimized.

Passavant-Geiger not only supplies the technical equip-ment. With the well proven AQUALOGICfrom Passavant-Intech it also provides a powerful tool for the aerationcontrol and advanced process optimization. The comple-mentation of the plant engineering with the respectiveequipment for power, measuring and control technologyoffers a comprehensive solution from one source.

Fields of applicationThe MAMMOTH ROTORhas proven a success for mu-nicipal and industrial wastewater treatment. The variety

of applications ranges from simple oxidation ditchesfor low connection loads up to large-scale wastewatertreatment plants, from wastewaters originating fromfood processing which often have a one-sided content ordemanding wastewaters coming from the pharmaceu-tical and petrochemical industry. For plants with lessloads the circulation process receives priority whilst forhigher loads additional aeration rates are required.These diverse tasks can be optimally handled by suitablecombinations of the MAMMOTH ROTORand agitator.

MAMMOTH ROTORin deep tankThe demand for further nitrogen elimination calls forlarger tank capacities than those needed for carbon de-composition alone.For reasons of space and costs acti-vated sludge tanks are commonly built for water depthsof up to 8 m. So far only pressure aeration has beenused for these tanks, however, they can now also beequipped with the MAMMOTH ROTOR. The circulating

power of the MAMMOTH ROTOR

is sufficient for a sedi-ment-free operation up to approx. 3.6 m. With waterdepths > approx. 3.6 m additional agitators are installedand depths up to 8 m can be accomplished withoutfail. By using these agitators the normally continuousoperation of the MAMMOTH ROTORcan be extendedto an intermittent operation for the simultaneous deni-trification.

MAMMOTH ROTOR

with sound insulation

MAMMOTH ROTORwithout sound insulation

100

10

20

30

40

50

70

80

60

100 1000

Distance [m]

S o u n

d p r e s s u r e

l e v e

l [ d B ( A ) ]

Sound level by comparison

3 4


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MAMMOTH ROTOR ConstructionThe MAMMOTH ROTORconsists of a hollow shaft onwhich an assembly of aeration elements is clamped. The

assembly made of fiber-glass reinforced plastic con-sists of separate sections arranged in a convolute wayeach with twelfe axially parallel aeration blades. Thisprovides for a low-noise and shock-free operation. A fle-xible torsion coupling between hollow shaft and gearis used to transfer the torque onto the aeration rotor.

The rotors are up to 9 m long. On the one side they aresupported by the gear and on the other side they runon a movable bearing. A two-stage straight bevel gearpair with flanged three-phase motor is used to powerthe rotor. The MAMMOTH ROTORis mounted inside thetanks underneath wide concrete bridges and is alsoavailable as ready to be installed unit with steel bridge.

Circulating tank for simultaneous operationThe most commonly used is a longitudinal tank with acenter longitudinal partition for the two flow channels

and baffles at the front end. These fixtures are only forfluidic reasons and therefore have a simple structure.The area of flow is always rectangular and withouthaunches at the level base. With this configuration thetank is thoroughly mixed, where always a multiple of the inflow of wastewater is circulated. This ensuresthat there is a fast buffering of impact loads which inso doing increases the process stability.

Other tank designsAlong with the longitudinal tanks, circular combi-tankshave proven to be economic for smaller connectionloads.

Oxygen enrichment and energy consumptionThe performance data listed in Illustration 6 and 7 origi-nates from measurements made on multiple waste-water treatment plants which are equipped with theMAMMOTH ROTORSand represent average values.

O x y g e n e n r i c h m e n t O C

P o w e r c o n s u m p t i o n P

0,75

1,75

2,75

3,75

4,75

5,75

6,75

7,75

0 5 10 15 20 25

Immersion depth [cm]

700 mm; 5 rev m n

P [ k w ] ; O C [ k g 0 2

/ h ] r e l a t i n g t o 1 m r o t o r l e n g t h

O x y g e n e n r i c h m e n t O C

P o w e r c o n s u m p t i o n P

1

2

3

4

5

6

7

8

9

10 15 20 25 30

Immersion depth [cm]

P [ k w ] ; O C [ k g 0 2

/ h ] r e l a t i n g t o 1 m r o t o r l e n g

t h

MAMMOTH ROTOR 1000 mm; 72 rev/min

76

5

5 Simulation of velocity [m/s]in circulating tank (near base,depth 7.5 m) with all circulatingpropellers and rotors in

operation.

6/7 Oxygen enrichment andpower consumption per mof rotor length (with guidebaffle).

0.00 0.15 0.30 0.45 0.60 0.75

Technical Data

Diameter (mm) 1000 700

Length (m) 3.00 9.00 1.00 6.00

Power (kW) 15 45 2,2 22

Speed (min -1) 72 and 72/48 85 and 85/57


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In MAMMOTH ROTORplants with aerosol and soundprotection less germs are emitted than in pressure

aeration plants. Normally no odor emissions occur inaerated tanks. This implies that the nitrification andthe simultaneous denitrification processes in the circu-lating tank are not a potential odor source.

Economic efficiencyWhen evaluating the overall costs for a wastewatertreatment plant you not only have to consider thecapitalized investments but also the respective opera-ting costs. Taking into consideration the additionalinvestments which are required, in most cases a sur-face aeration system will more likely be realizablewith lower expenses than a pressure aeration system.This is normally due to the tanks which require a lesselaborate design. No air lines and additional structuresare necessary.

As regards to operating costs the pressure aerationsystem in pure water seems to be at an advantage in

terms of energy. However, when applied in practicewith activated sludge the efficiency of these aerationsystems is equivalent. The -factor is 1 unlike approx.0.6 for the pressure aeration.The MAMMOTH ROTORshows great advantages in terms of maintenance andservicing costs. Longtime experience gained by opera-tors has proven that the MAMMOTH ROTORhas an ex-tremely long service life. The assemblies are subject tovirtually no wear and require only minor maintenance.

Functional descriptionWhenusinga MAMMOTHROTORtheoxygen isenrichedby means of a continuous and intensive renewal of the

boundary layer between air and the wastewateractivated sludge mixture in the immediate operatingrange of the aeration rotor. At the same time fluidenergy is yielded.This provides for a circulation whichenables activated sludge, wastewater and oxygen tobe mixed accordingly and in less deep tanks ensures asediment-free operation. In deeper tanks the mixingprocess is boosted by additional agitators which eyondthe continuous operation also enable an intermittentoperating mode. By installing guide baffles across thedownstream flow of the aeration rotors, you increasethe oxygen enrichment output and efficiency.

EmissionsGreat attention is paid to emissions coming fromwastewater treatment plants. All plants are checked fortheir environmental impact with regards to emissionssuch as sound, aerosols, germs and odors. Sound emis-sions caused by the MAMMOTH ROTORcan be reduced

by simple means. Concrete bridges under which therotor is installed are the most effective with their up-stream and downstream sides pulled down just abovethe water level as well as a sound protection hood overthe drive unit.With a rotor fully encapsulated in thisway aerosol emission is also eliminated to a large extent.


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Passavant-Geiger GmbHBusiness Unit PassavantPassavant-Geiger-Strasse 165326 Aarbergen, GermanyPhone: +49 6120 28-0

Telefax: +49 6120 [email protected]

Advantages> The MAMMOTH ROTORis exceptional due to its long

service life and sturdy operation with only minor maintenancerequired. Longtime experience has proven this.

> The MAMMOTH ROTORis simple to maintain as it is mountedabove water level and a tank drainage is therefore not required.

> You have a wide application range in terms of control strategiesas well as cleaning purposes.

> The MAMMOTH ROTORcan be used in combination withagitators for water depths of up to 8 m.

> The MAMMOTH ROTORprovides the possibility of simultaneousaerobe sludge stabilization

> There is only a minor influence of oxygen input by ingredientsin the wastewater so that the -factor is 1.

> Independent tests have shown that the emissions causedby the MAMMOTH ROTORare comparable with those causedby pressure aeration.

> The MAMMOTH ROTORis characterized by a higheconomic efficiency due to its sturdiness, long service life andlow maintenance.

EnglischneuMammothRotor04.07.2010

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