Rheda-Wiedenbrueck

Efficient air for wastewater treatment plants

If modernisations in wastewater treatment plants are due, as a rule the permanently reducing limit values of ammonium, nitrate and phosphate are pushing the investment decisions. If it concerns the budget, in view of the climate protection and the finances it pays off to include the energy efficiency in the plans. In view of the fact that just the air supply of the aeration often accounts for more than 70 per cent of the operating costs in this field, it soon becomes clear why efficiency improvements pay off especially here - and this with high return on investment periods. This is exactly how wastewater treatment plant Rheda-Wiedenbrück (326,000 population equivalents) planned. They are currently testing a brand-new control concept for the AERZEN blower technology, the AERsmart control combination.

In 2013, the modernisation work of the wastewater plant began. Connected are the citizens of the Rheda-Wiedenbrück region as well as Germany’s largest pig slaughterhouse. A project objective was, to supply the biology more efficiently with air, by not only replacing old ventilation grids by new, but also installing these 30 cm deeper at the ground of the aeration basins. “In view of the surface of the six basins we could increase our processing volume by several hundred cubic metres”, explains wastewater manager Hendrik Wulfhorst. Subsequently, however, 30 cm space gained mean an increase of the system pressure of 30 mbar, which had to be considered accordingly concerning the design of the blower technology.

Before the modernisation of the plant, the biology had been run with a high excess of oxygen in the basins, in particular to cover safely the fluctuations concerning the entry values of the slaughterhouse. Finally, with the order to reduce the operating costs and the associated CO2-emission, a clear objective of the project was, to couple in future the aeration of the basins considerably more closely with the fluctuating wastewater load and the resulting oxygen consumption. This implied in the first step the needs-oriented speed control of the totally four blower units made by AERZEN.

More intelligent air supply

The setpoint values are generated by the PLC (programmable logic controller) from the data measured in the wastewater - mainly in the form of ammonium and nitrate concentrations. In addition, there is an intelligent control system of the diaphragm regulating valves. They close slowly, when the required oxygen saturation in the water of the corresponding basin has been achieved. To avoid that this closing leads to a higher pressure - and consequently resistance - in the pipe, in parallel, the PLC reduces the target pressure. “Otherwise we would destroy energy by means of the diaphragm regulating valves, as within a constant pressure regulation the blowers have to work against the pressure loss caused by the diaphragm regulating valves. With a sliding pressure control, we are now regulating considerably more intelligently and efficiently”, Markus Haverkamp, project engineer from the supporting planning company aquaconsult, makes clear. For the base load supply of the biology, forming alternately a circuit of ventilated and unventilated basins with three purification stages, the engineering office in Hanover instructed with planning and realisation selected among others a turbo blower made by AERZEN. 

Turbo blower for the base load

The type AT 150-0.8S-G5 achieves an intake volume flow of 4,800 cubic metres per hour with a motor nominal power of 143 kW at an intake pressure of 1 bar and a final pressure up to 1.8 bar. For Cord Utermann, sales engineer at AERZEN, turbo blowers are classical representatives of energy-optimised base load machines which should run permanently for 24 hours within the nominal value parameters since then they operate at the highest economic efficiency. “As with almost any turbo technology, the energetic efficiency falls as soon as the machines are driven into the partial-load range”, explains Utermann. As a consequence, concepts are to be developed which care for the energy-efficient cleaning of dirt loads varying during the day from high to low. For an optimum of energy efficiency in a wastewater treatment plant, this approach means that the air requirement, exceeding the base load, has to be covered by displacement machines like positive displacement blowers and rotary lobe compressors. They are strong in high control ranges between 25% and 100% and have good efficiency, also in part-load operation. Therefore, two AERZEN packaged units type Delta Hybrid (D 62 S) and one Delta Blower (GM 80 L) are also part of the compound system in the wastewater treatment plant in Rheda-Wiedenbrück.

AERZEN has developed the AERsmart in order that this quartet does not only cover the necessary oxygen for the aeration tanks by a safe process but also generates the required air volume in the most energy-efficient way in the compound system. According to Cord Utermann, “the high art of the control engineering is to create the transitions between the overlaying operating areas as fluently as possible and as energy-efficient for every load as possible, i.e. to operate the different machines in the combination always at total optimum.” Those are resulting from “every load complying with the real need” according to Markus Haverkamp. This “always includes upward and downward peaks”. Since three different machines with diverging operation ranges and efficiencies are applied in the wastewater treatment plant in Rheda-Wiedenbrück, their operation must be co-ordinated in such a way “that the number of switching operations will be as low as possible. Since the permanent switching-on and switching-off would increase wear”, the project engineer of aquaconsult reveals. “An efficient air distribution among the aeration tanks (sliding pressure control, intrusion of disturbances as for example NH4-N, amount of water etc.) and the efficient machine selection are necessary for an optimal overall efficiency. This is realised by means of the new control system of AERZEN.” 

The oxygen demand in the three clearance stages is the basis for the optimisation of the control system with the AERsmart control. The indices are processed by the central PLC of the plant and the resulting target pressure is transferred by Profibus to the blower control. AERsmart then cares for the optimally combined operation of the four packaged units in relation to energy saving. “The turbo blower used here has, for example, the highest efficiency at a capacity of 83 per cent”, explains Cord Utermann. If the air requirement is beyond this value, it can be more efficient, to switch-off the base load machine completely and to cover the relatively low air requirement by both Delta Hybrid machines. “Our bacteria do not care where the oxygen comes from”, Hendrik Wulfhorst says with a smile. But the manager of the wastewater treatment plant points out that the blower technology was projected in the run-up to the modernisation so that the performance of the turbo blower should be sufficient for the “normal” daily requirement.

As an interim result, the wastewater treatment plant in Rheda-Wiedenbrück could save about 30 per cent energy in the biology with the energy-optimised blowers and a relatively simple process control which is more closely linked to the prevailing actual values. AERsmart provides further five to eight per cent due to the optimisation on blower level. The field test in the wastewater treatment plant will prove how much this will be in a longer operating phase. Rheda-Wiedenbrück is the first wastewater plant in Germany testing the AERsmart under real conditions. “We need the application on site as we can only recognise the complex connections of a wastewater treatment plant in field; this cannot be reproduced on a test bench. This is why the intensive cooperation with our customers is so important, as only this proceeding provides us with a close application reference for future-oriented developments”, summarises Cord Utermann.

Information & documents

You have questions? LET'S TALK

Find your regional contact and get personal advice.

Aerzener Maschinenfabrik GmbH (Headquarter)

Reherweg 28

31855 Aerzen

Phone: +49 5154 81-0

Fax: +49 5154 81-9191

Emmerthaler Apparatebau GmbH

Langes Feld 4

31860 Emmerthal

Phone: +49 5155 622-0

Fax: +49 5155 622-11

Aerzen Turbo Europe GmbH

Freibusch 2-4

31789 Hameln

Phone: +49 5151 92384 0

Aerzen Digital Systems GmbH

Hefehof 8

31785 Hameln

Phone: +49 5151 40302660

AERZEN Deutschland GmbH & Co. KG (Sales)

Reherweg 28

31855 Aerzen

Phone: +49 5154 81 4000

Aerzen do Brasil Ltda

Rua Dionysio Rito, n° 300, Distrito Industrial III, L14 Q D

13213-189 Jundiaí

Phone: +55 11 4612-2021

Fax: +55 11 4612 0232

AERZEN SLOVAKIA, s.r.o.

Pezinská 18

901 01 Malacky

Phone: +421 34772 5531

Fax: +421 34772 5529

- Sales Office South West

Brückenstraße 2a

66740 Saarlouis-Fraulautern

Phone: +49 6831 76828 0

Fax: +49 5154 81 716410

Aerzen Argentina SRL

Domingo de Acassuso 4743

B1605BFO Munro, Buenos Aires

Phone: +54 11 47622351

AERZEN France S.A.S

Zone Industrielle 10, Avenue Léon Harmel

92168 Antony Cedex

Phone: +33 1 46741300

Fax: +33 1 46660061

AERZEN BELGIUM N.V.

A.De. Coninckstraat 11

3070 Kortenberg

Phone: +32 2 757 22 78

Fax: +32 2 7572283

AERZEN SCHWEIZ AG

Gewerbepark Morgenstern Im Alexander 4

8500 Frauenfeld

Phone: +41 52725-0060

Fax: +41 527250066

AERZEN Nederland B.V.

Bedrijventerrein Nieuwgraaf Fotograaf 3

6921 RR Duiven

Phone: +31 26 3197530

AERZEN INTERNATIONAL RENTAL B.V.

Typograaf 5

6921 VB Duiven

Phone: +31 88 9100050

ASP AERZEN Special Products B.V.

Bedrijventerrein Nieuwgraaf Fotograaf 3

6921 RL Duiven

Phone: +31 26 4463432

Fax: +31 26 4463049

AERZEN FINLAND OY AB

Teollisuustie 15

FI-02880 Veikkola

Phone: +358 9 8194720

Aerzen Colombia S.A.S.

Centro Empresarial Metropolitano, Bodega 27, Módulo 2 (Autopista a Medellín, km 3,4) Cota, Cundinamarca,

Código Postal 250017 Código

Phone: +57 601 841 5730

Fax: +57 601 841 5730

Aerzen Austria Handelsges.m.b.H.

Gewerbepark Tresdorf II/1

2111 Tresdorf

Phone: +43 2262 74388

Fax: +43 2262 74399

AERZEN POLSKA Sp. z.o.o.

Al. Niepodleglosci 18

02-653 Warszawa

Phone: +48 22 489 55 22

Fax: +48 22 489 55 27

AERZEN HUNGÁRIA KFT.

Alíz Utca 4

1117 Budapest

Phone: +36 1 4392200

Fax: +36 1 4391922

AERZEN CZ s.r.o.

Hraniční 1356

69141 Břeclav

Phone: +420 519 326 657

Fax: +420 519 326658

AERZEN IBÉRICA S.A.U

Calle Adaptación 15-17

28906 Getafe (Madrid)

Phone: +34 91 642 4450

Fax: +34 91 642 2903

AERZEN IBERICA S.A. SUCURSAL EM PORTUGAL

Rua Alfredo Lopes Vilaverde, 15B Escritório 3

2770-009 Paço de Arcos

Phone: +351 21 468 2466

Fax: +351 21 468 2467

AERZEN MACHINES LTD.

Aerzen House, Langston Road

IG10 3SL Loughton, Essex

Phone: +44 2085028100

Fax: +44 2085028102

AERZEN ASIA PTE LTD

61 Woodlands Industrial Park E9 E9 Premium, #07-01

757047 Singapore

Phone: +65 6254 5080

Fax: +65 6254 6935

asia@aerzen.com

company profile

Aerzen Taiwan Machinery

Branch office of Aerzen Asia No.170, Ln. 879, Guangfu Rd., Bade Dist.,

Taoyuan City 33457

Phone: +886 3 366 6660

Fax: +886 3 366 6536

taiwan@aerzen.com

company profile

AERZEN SCANDINAVIA AB

Östra Bangatan 20

19560 Arlandastad

Phone: +46 8 59441880

Fax: +46 8 59117209

Aerzen Scandinavia Norway

Raveien 320

3184 Borre

Phone: +47 33 29 22 12

Aerzen Scandinavia Denmark

Industrivej 2

5550 Langeskov

Phone: +45 78 72 92 90

AERZEN USA CORPORATION

108 Independence Way

Coatesville, PA 19320

Phone: +1 610 380 0244

Fax: +1 610 380 0278

AERZEN CANADA INC.

980 Rue Valois, Suite 100 Vaudreuil-Dorion

J7V 8P2 Quebec

Phone: +1 450 424 3966

Fax: +1 450 424 3985

Aerzen México S.A. de C.V.

Cerrada Uniroyal # 18-A, Col. La Michoacana

Metepec, 52166

Phone: +52 722 235 9400

Fax: +52 722 235 9401

AERZEN MAKINE San. Ve Tic. Ltd. Sti.

IMES Sanayi Sitesi, C Blok, 308. SK, No:14, Y.Dudullu

34776 Ümraniye Istanbul

Phone: +90 216 420 00 32

Fax: +90 216 420 00 79

turkey@aerzen.com

company profile

AERZEN Machines (India) PVT. LTD.

Plot No. E-115/116, G.I.D.C , Manjusar, Tal. Savli, Dist:

Vadodara-391 775 Gujarat

Phone: +91 2667 264-817

Fax: +91 2667 264-818

india@aerzen.com

company profile

AERZEN ITALIA SRL

Via Raffaello Sanzio, 52

20021 Bollate (MI)

Phone: +39 02 6707 5277

Fax: +39 02 6707 5003

AERZEN MACHINERY (SHANGHAI) CO., LTD

No. 655 Yuan Dian Road, Min Hang District

Shanghai 201108

Phone: +86 21 3323 9000

Fax: +86 21 3323 9199

Aerzen Romania S.R.L.

Sat Tunari Comuna Tunari Sos. De Centura nr. 25A

RO 077180 Judet Ilfov

Phone: +40 21 243 1883

Fax: +40 21 243 1884

Aerzen ME - FZE

DSO-DDP-Office-A1-222 Dubai Silicon Oasis P.O. Box: 341445

 Dubai

Phone: +971 0 432 431 66

Aerzen Adria d.o.o.

Varazdinska ulica, II odvojak 3

42000 Varazdin

Phone: +385 42 370 808

Fax: +385 42 370 018

Aerzen Australia Pty Ltd

57-59 Rodeo Drive

3175 Dandenong

Phone: +61 3 97067702

Fax: +61 3 9706 8584

Aerzen Chile SPA

Limache 3363 – Bodega 13

CP: 2520642 Viña del Mar

Phone: +56 32 235 8900

Aerzen Andina Perú SAC

Carr. Panamericana Sur Km. 29.5 Almacenes F-08 y F-09 ZI Megacentro – Altura Puente Vidu

 Lurin – Lima

Phone: +51 1 434 3831

AERZEN NORTH AFRICA LLC

Sheraton Housing 35 el moltaka el araby, Nozha elgedida. Appt - 7, 8, 9.

 Cairo

Phone: +20 2 22698855

Fax: +20 2 22696611

Aerzen AIRGAS (PTY) Ltd.

175 Domkrag Street, Robertville Ext. 1

Roodepoort, Johannesburg

Phone: +27 0 11 474 2193

Fax: +27 0 11 474 2321

ANIS AHMED & BROTHERS

4-Jinnah Cooperative Housing Society, Block 7/8, Main Sharea Faisal

75350 Karachi

inddiv@aabros.com.pk

company profile

MANGRINOX S.A.

14, Grevenon Str.

11855 Athens

Phone: +30 210-3423201-3

Fax: +30 210-3459967

Aerzen Adria d.o.o.

Varazdinska ulica, II odvojak 3

42000 Varazdin

Phone: +385 42 370 808

Fax: +385 42 370 018

SHIPSHORE (CYPRUS) LTD

Patraikou 21-23, Flat 101, Palouriotisa TK 1048, P.O. Box 25283

1308 Nicosia

Phone: +357 22441222

Fax: +357 22490641

L.A Engineering & Consulting Ltd

PO Box 2907, 25 Ha‘ela Street

40500 Even Yehuda

Phone: +972 9 8996544

Fax: +972 9 8996547

MEAKOMP OOD

Ul. Archaritza 2A

4006 Plovdiv

Phone: +359 32 966 681

Fax: +359 32 966 702

Aerzen Adria d.o.o.

Varazdinska ulica, II odvojak 3

42000 Varazdin

Phone: +385 42 370 808

Fax: +385 42 370 018

Airgas Compressors (PTY) Nigeria Limited

3, Adebukola Omolabake Street, Off Eric Omobude Street, Ifako Bus Stop, Along Oworonsoki - Ogudu Expressway

 Lagos

Phone: 00234 0 1 843 4234

Aerzen Adria Serbia d.o.o.

Representative: Ljubomir Živković Zlatiborska 5/dj

11420 Smederevska Palanka

Phone: +381 26 210-032

Fax: +381 26 210 -037

Aerzen Thailand Co., Ltd

36/60 Village No. 5, Phlu Ta Luang, Subdistrict, Sattahip District

20180 Chonburi

Phone: +66 0 38 020 090

Fax: +66 86 664 1337

AERZEN ASIA PTE. LTD

Representative office of AERZEN ASIA PTE. LTD Floor 8th, Unit 802A, Dai Minh Convention Tower, 77 Hoang Van Thai, Tan Phu Ward, District 7, T + 84 28 3554 2590

 Ho Chi Minh City

Phone: + 84 28 3554 2590

Aerzen Turbo Co, Ltd

800 Jeongjung-ri, Osong-eup, Heungdeok-gu, Cheongju-si,

Chungcheongbuk-28220 Korea

Phone: +82-43-238-6500

Fax: +82 70 4170 4567

local partner: DEWA Projekt OÜ

Väike-Ameerika 15

10129 Tallinn

Phone: +372 50 39239

AERZEN FINLAND OY AB

Teollisuustie 15

FI-02880 Veikkola

Phone: +358 9 8194720

Aerzen Australia - New Zealand Office

Unit 17a Hobill Avenue Wiri

2104 Auckland

Aerzen Australia Pty Ltd

57-59 Rodeo Drive

3175 Dandenong

Phone: +61 3 97067702

Fax: +61 3 9706 8584

AERZEN MACHINES LTD.

Unit 6a, Castlecomer Business Park, Kilkenny Rd, Ballyhimmin

R95 Castlecomer, Co. Kilkenny

Phone: + 353 567807085

Aerzen Korea Ltd

Hyundai Terrace Tower, E-dong #608, 7, Yeonmujang 5ga-gil, Seongdong-gu,

04782 Seoul

Phone: +82 44 277 6500

Fax: +82 2 6463 0064

Aerzen Turbo Co, Ltd

800 Jeongjung-ri, Osong-eup, Heungdeok-gu, Cheongju-si,

Chungcheongbuk-28220 Korea

Phone: +82-43-238-6500

Fax: +82 70 4170 4567

Aerzen Machines Ltd

Aerzen House, Langston Rd IG10 3SL United Kingdom

 Loughton

Phone: 020 8502 8100

Aerzen Arabai Ltd.

Abed Al-Mis’hal Tower 9th Floor, office 907, Building 3958, District 35514 Al Jubail, Kingdom of Saudi Arabia

 

Phone: +966 13 362 8826

Contact us