Cost-effective and greener wastewater treatment

Many waste­water treat­ment plants are active­ly pur­su­ing a cam­paign of improved ener­gy effi­cien­cy. Bauer Gear Motor opti­mised the ener­gy use of a plant in Bayreuth, Ger­many, reduc­ing the envi­ron­men­tal bur­den and the ener­gy costs with an inno­v­a­tive geared motor solu­tion for the plant of the future.
The orig­i­nal sys­tem, built in 1999, was com­posed of mul­ti­ple 1.5 kW Direct On Line (DOL) asyn­chro­nous induc­tion motors run­ning at 50 Hz. The motors were sup­plied by Bauer Gear Motor (Type BF50-35A/D09LA4-TF‑D) and had been run­ning with­out any fail­ures since their instal­la­tion. How­ev­er, as their ener­gy effi­cien­cy could­n’t reach the lev­els of the lat­est tech­nol­o­gy, it was decid­ed to retire the exist­ing sys­tem and spec­i­fy a hi-tech alternative.
As the orig­i­nal equip­ment sup­pli­er was invit­ed to sug­gest a solu­tion that would con­tin­ue to oper­ate with the same lev­el of reli­a­bil­i­ty whilst deliv­er­ing cut­ting-edge ener­gy effi­cien­cy. Bauer’s cre­den­tials as a leader for inno­v­a­tive, ener­gy effi­cient geared motor solu­tions made it an ide­al part­ner for the project.
The ini­tial request from the client was to replace the orig­i­nal motors with IE3 induc­tion motors — this is what is typ­i­cal­ly seen as the stan­dard ‘ener­gy effi­cient solu­tion’ in the water indus­try. How­ev­er, as a result of Bauer’s assess­ment of the facil­i­ties, it became evi­dent that the waste­water treat­ment plant could fur­ther ben­e­fit from the spec­i­fi­ca­tion of PMSMs run­ning at the same fre­quen­cy, 50 Hz.
The ben­e­fit with PMSMs was not only the ener­gy sav­ings; they also have the advan­tage for the cus­tomer to con­trol all  gear­mo­tors direct from the office via “ProfiNet Bus sys­tem”. A fur­ther huge ben­e­fit proved to be, that with the intel­li­gent invert­er duty and bus sys­tem, the ser­vice tech­ni­cians can mon­i­tor the per­for­mance of the motors and imme­di­ate­ly see on the mon­i­tor if any appli­ca­tion isn´t run­ning well.
The EtaK2.0 also pro­vides addi­tion­al com­mu­ni­ca­tion and con­trol capa­bil­i­ties. More pre­cise­ly, the built-on invert­ers send a con­stant flow of data to the pro­gram­ma­ble log­ic con­troller (PLC) via the wide­ly used PROFINET indus­tri­al eth­er­net stan­dard con­nec­tion. This enabled the con­di­tion of each unit to be mon­i­tored remote­ly, with­out the need for phys­i­cal inspection.
In this way, the waste­water treat­ment plant could ben­e­fit from an auto­mat­ed net­work and be ready for Indus­try 4.0 and the Indus­tri­al Inter­net of Things (IIoT). Fur­ther­more, by enabling high­er con­trol capa­bil­i­ties, signs of fail­ure could be detect­ed in an eas­i­er and quick­er way, while min­imis­ing main­te­nance activ­i­ties and costs.
With this project, the com­pa­ny proved that ener­gy effi­cien­cy improve­ments can not only reduce the costs for gen­er­at­ing, trans­mit­ting, and dis­trib­ut­ing ener­gy from pow­er plants to the end facil­i­ty, but can also sub­stan­tial­ly reduce oper­at­ing and main­te­nance costs.