pr wastewater treatment plant bad reichenhall en - ifm · the water cycle again in the direction of...

© ifm electronic gmbh Environmental Technology and Building System Automation KIE - ar as on: 01.06.2004 page 1

Project:Project:Wastewater treatment plantWastewater treatment plant

Bad ReichenhallBad Reichenhall

AS-i and sensorsAS-i and sensorsfromfrom

ifm electronic gmbhifm electronic gmbhin wastewater technologyin wastewater technology


Why wastewater treatmentWhy wastewater treatment??

Tasks of a wastewater treatment plant

In order to keep streams and rivers clean, to create and maintain optimum conditions foranimals and plants in and around the lakes, rivers and canals, the water we pollute hasto be purified. Wastewater treatment plants carry out this purification. Wastewatertreatment plants are environmental protection facilities which ensure economicalpurification of wastewater so that it can be released into rivers and streams, thus closingthe water cycle again in the direction of the sea.

A view which we will hopefully have formany more years.

Water purification is not the only task of amodern wastewater treatment plant.During wastewater treatment sludge isproduced. Sludge consists of substanceswhich people discharge into thewastewater treatment plant via thesewerage. Thus sludge is producedwhich nowadays is very difficult andexpensive to dispose of in anenvironmentally-friendly way.

Sewage and sludge treatment are the tasks of a modern wastewater treatment plant.This can only be managed with a lot of help replacing our senses. The varied processesin such a plant are no longer possible without innovative sensors and control systemsreducing wiring complexity. Here the technology provided by ifm electronic gmbh createsnew standards.

Water evaporates from the oceans toform clouds which bring rain. The rainwater which drains into the ground ispumped into towns as drinking wateras well as process water.People need water, not only fordrinking but also for many otherpurposes. During use in thehousehold, bathroom and toilet, bytrade and industry, the clean drinkingwater is soiled.


Picture 3: AS-i Classic module(2DI/2DO) with standardisedmodule lower part for intelligentwiring technology

AS-interface is a control system which reduceswiring complexity and has been on the market forabout 14 years now. AS-interface was developed bya consortium of companies (Festo, SIEMENS, ifmelectronic, etc.) who founded the AS-interfaceInternational Association. Originally, it was onlydeveloped for the field of industrial automation.Today, AS-i is used in many different areas (processtechnology, conveyor technology, etc.). Mostimportantly, the development of AS-interface isbased on the compatibility of all AS-i componentsregardless of who fabricated them. Moreover, thetransmission of data and supply voltage to thesensors and actuators in the field via an unscreenedtwo-wire cable is another major feature of thesystem.

Description of AS-interface (AS-i)

The two-wire cable can either be a standard roundcable (e.g. NYM 2 x 1.5 mm2 or NYM-J 3 x 1.5 mm2)or a yellow profiled cable. The latter is the AS-i flatcable which is connected to the AS-i slaves viastandardised flat cable lower parts by means of theinsulation displacement technology (similar to thesystem used for chains of lights). The AS-i flat cableensures fast and reverse polarity protected wiring –thus time and money can already be saved during theinstallation of the system. AS-i is controlled via acentral control unit, AS-i ControllerE (with one or twoAS-i masters). The masters in the AS-i ControllerEensure the communication of the controller with theup to 62 A/B AS-i slaves (I/O modules and AS-isystem solutions) per AS-i master, which are installedlocally distributed in the whole system.

Picture 4: AS-i ControllerE withProfibus DP interface

AS-i system solutions can for example be AS-i AirBoxes for the pneumatic control ofvalves and actuators, AS-i valve islands, proximity switches with integrated AS-i slavesetc. Another prerequisite of AS-i is a standardised connection of the system to othersystems (e.g. Profibus DP etc.) via the AS-i controller. This enables the establishmentof consistent systems from the sensor/actuator to the control room.


Pumping station (see diagram, )

Flow monitors, type SI, are used for run-dry protection of circulating pumps. Here, theyprevent expensive repairs due to their very fast switching. The calorimetric measuringprinciple of the SI1000 is perfectly suited for this application. Moreover, the easyhandling of the unit as regards switch point setting is also very convenient. Flow canbe monitored on site by means of the chain of 11 LEDs.

In the pumping station the pumps must be protected. Defective pumps are a majorcost factor which can be minimised at any time by means of inexpensive monitoringsensors.

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Flush-mounted pressure sensors from ifm electronic monitor the suction side of thepumps. This ensures that they are reliably switched-off if no medium is conveyed anymore. Pressure transducer and pressure display are implemented on site using oneprocess connection. The high protection rating of the units provides sufficient safetyeven in wet environments.

Macerators (see diagram, )

Sludge pump system (see diagram, )

The sludge pump system is run at a pressureof 4 to 8 bar. Pressure transducer and pressuredisplay are implemented here using only oneprocess connection. The ifm pressure sensortype PN3024 has a binary output as well as ananalogue output. This facilitates the control ofthe machine. Moreover, no additional flangesfor display units are required and thus excludedas sources of leakage.

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A clearly visible 7-segment display facilitatesthe work of the user. Even if the lightingconditions are bad, the lit displays can beclearly read. Using the two operating buttons allrelevant settings are made on site. Due to themenu guidance, setting of the sensor is carriedout quickly and at a low cost.

The pressure side of thepumps is monitored foroverpressure to protect theplant. The ifm pressuresensors switch the pumps offreliably in case ofoverpressure. The pressuresensors type PN used forseal water monitoring protectthe mechanical seals of thepumps in case of too lowpressure.

Pressure sensors are used to provide run-dry protection for macerators for raw sludgetransport. Here again, the failure of the pumps represents a high cost factor which canbe minimised at any time by means of inexpensive monitoring sensors.

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Slide valve control in pumping station (see diagram, )

All slide valves from thecompany Auma are operatedwith compressed air in thepumping station. Due to theuse of the 4/2-way valves typeAC2055 (AirBox) with AS-icapability only the yellow AS-icable and a central air supplyare required. As aconsequence, the compressedair pipes leading to theactuators are very short. Thelower losses in the pipes resultin important cost savings asregards the generation ofcompressed air.

The AS-i AirBoxes are screwed onto standardised lower parts into which the AS-icable is inserted. They control the slide valves and, moreover, the end positions aretransmitted to the controller via the two binary inputs. A high protection rating (IP67)and stainless-steel screws ensure reliable operation even in wet environments. Withthe jack plug in the standardised AS-i module lower part addressing of the modules ismade easy. Thus, valuable time is saved during commissioning. Power supply and theinput states are indicated by the integrated LEDs.

Inductive sensorsThe inductive sensors type IGT200 from ifmelectronic are used on the slide valves tomonitor the end positions. A high protection ofIP68/IP69K and the robust modular designmake this sensor ideally suited for thisapplication. The M12 connector with gold-plated contacts moreover facilitates handlingwhen exchanging an actuator. Easy setting ofthe units is ensured by the increased sensingrange of 12 mm [nf].

The connection of the sensors to the controllercan be quickly and reliably established bymeans of prewired cables type E11409 with alength of two metres. There are two binaryinputs per AS-i AirBox AC2055. The powersupply for the sensors also comes from the AS-i modules. Signal processing is carried out inthe controller. Here again, IP68 is guaranteed.

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Binary input modulesTo pick up the various binarysignals and to transmit them tothe controller, AS-i input modulestype AC2451 are used. Here, upto four sensors with standardisedM12 connectors are connected.The power supply of theconnected sensors is generatedfrom the AS-i module. Having ahigh protection of IP67 andstainless-steel screws thismodule is very well suited for thisapplication. Power supply andinput states are indicated on siteby means of the integratedLEDs.

ControllerE for process control support

AS-i power supplies:One AS-i power supplyis required per AS-i lineto ensure the powersupply of the modules.In this application thepower supply typeAC1218 from ifmelectronic is used.Robust rail mountingand high quality aretwo features of thisseries.

A freely programmable AS-i ControllerE (type AC1305) to IEC-61131-3 from ifmelectronic can be used for signal preprocessing to relieve the higher-level controller(process control system). Due to the connection as a slave in the Profibus DP networkpreprocessing of binary as well as analogue I/O signals is possible in the AS-iControllerE. Only information which is important for the process control system istransmitted by the ControllerE. All control tasks for AS-interface are assumed by theControllerE. Information relevant for AS-i is displayed on the integrated multifunctionaldisplay. Moreover, the LEDs provide important information for the AS-i network. TheAS-i ControllerE can also be used as a pure Profibus DP gateway to transmit all AS-idata to the process control system. Programming then has to be carried out in theprocess control system.


Companies involved:

gip GmbHGesellschaft für innovative PlanungMr. Lorenz GeckelerUnterer Graben 582362 Weilheim/Obb.Tel.: 0881/9276400Fax: 0881/92764002e-mail: [email protected]

GAT Gesellschaft für Anlagentechnik GmbHMr. Werner KammermeierAlte Nürnberger Str. 1693059 RegensburgTel.: 0941/8103-0Fax: 0941/8103-19e-mail: [email protected]

M.A.R.S. GmbHMr. Roland WernerOttmaring 4392345 DietfurtTel.: 08464/602733Fax: 08464/602732e-mail: [email protected]

Customer:City of Bad ReichenhallMr. Fritz Oberbigler, SG TiefbauRathausplatz 883435 Bad ReichenhallPhone: 08651-775-276Fax: 08671-775-204E-Mail: [email protected]

The following ifm ifm employee was in charge of the project:Mr. Rainer Engelmann, ifm branch bayernPhone: 089/80091-71Fax: 089/80091-12E-mail: [email protected]

We would like to thank all those involved at the Wastewater Treatment Plant Bad Reichenhall

for the good co-operation.

If you have any questions regarding this project report or if you are interested inother reports please contact:

ifm electronic gmbhGlobal Key IndustriesEnvironmental Technology and Building System AutomationTeichstraße 4,45127 Essen, GermanyPhone: +49 201/ 24 22 –186 or –468Fax: +49 201/ 24 22 – 654E-mail: [email protected] www.ifm-electronic.com

Project:

Wastewater treatment plant Bad Reichenhall

Date:

Originator:

Plan nr.:

AS-i and sensors in wastewater technology

Plan: 24.05.2004The diagram is an extract frompublications made by the association.The latter is responsible for thecorrectness.

KIE - ar

SC_ABW_3.ppt

ifm electronic gmbhessen Environmental Technologyand Building System Autom.

Wastewater treatmentWastewater treatment plant, Bad Reichenhall plant, Bad Reichenhall

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13

4

run-dry protection for pumps

macerators

sludge pump system

slide valve control

123

4

pumping station

inlet

screensludge separator sand

hoppergritchamber

primarysedimentationtank

contact tank

secondary clarifier 2secondary clarifier 1

return sludge

raw sludge chute

digester 2digester 1sludge

hopper

pre-thickener

phosphate tank

propane gas

tank

service water

gastank

heating

outlet

centrifuge

block-type thermal power station

ventilators

faecalchute

pr wastewater treatment plant bad reichenhall en - ifm · the water cycle again in the direction of...

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