Efficiency gains through modelling Wastewater technology It is the activation process which accounts for the lion‘s share of the electricity used in the treatment of wastewater. In energy studies, it is worth taking a closer look at the processes, especially in this case. Armin Meister, and his engineering office, rely on dynamic modelling methods from system theory for the analysis and optimisation of existing systems in wastewater treatment plants. With this structured approach, the physics engineer at the wastewater treatment plant in Bingen has succeeded in significantly reducing the energy requirement through conceptual changes, and the use of modern hybrid blowers from AERZEN. At the same time, the plant‘s elimination performance has increased dramatically. The biggest leverage is process improvementThe blower technology can be operated on site via a touch panel.Pushing processes and the environment forward through modelling: for the wastewater treatment plant in Bingen, which has been designed to cater for a population equivalent of 80,000, this far-reaching approach has led to a considerable improvement and stabilisation of the cleaning performance. The energy savings in the area of activating sludge are divided between conceptual improvements, and the use of better machine technology. “Besides staff costs and maintenance costs, energy costs and discharge values also determine our operating costs,” says Meister. Lower discharge values mean a reduction in the wastewater levies which have to be paid to the national government. Investments therefore pay off twice. The optimised processes require careful technical design, so that systems can be run as continuously as possible at the optimal load point with the aid of a fast and dense network of sensors. Meister investigated load curves spanning several years, and based on this he designed the modelling. The modelling forms the basis for defining future requirements for the compressor stations. “This made it possible to select the most suitable assembly in terms of energy consumption and overall cost-effectiveness, while ensuring the appropriate technical requirements for wastewater treatment and the necessary redundancy.” This led to the selection of AERZEN rotary lobe compressor, type Delta Hybrid. Here, two air conveying processes are combined in one machine: Root’s principle as full pressure compression for low pressure, and the screw compressor principle with internal compression for higher pressure. Calculations show that the rotary lobe compressor requires up to 15 percent less power than conventional compressors for absolutely oil-free air conveying.Operation at optimal load pointNew meets old: the old-fashioned blowers now serve as redundancy and standby for peak loads.Four Delta Hybrid machines are required, which cover almost 90 percent of all operating cases, so that the older and less energy-efficient assemblies are only used for rare high-load or redundancy events. In view of the optimal load points, the rotary lobe compressors with graduated capacities and correspondingly adapted motor sizes are used for two independent compressed air systems. The largest Delta Hybrid rotary lobe compressor, type D62S, with 110 kW motor rating and 1,000 mbar maximum differential pressure, supplies up to 3,500 cubic metres per hour. The D36S, D24S and D12S models are smaller dimensioned and deliver 2,150, 1,390 and 690 cubic metres per hour with motor ratings of 75, 55 and 30 kW respectively. The two smaller assemblies are installed in the engine house, which also houses the older machinery. The two large Delta Hybrid machines are located outdoors. A simple roof protects them from the weather.Robust design for outdoor useTwo Delta Hybrid machines are placed under a protective roof outside the wastewater treatment plant.The decision to install the two Delta Hybrid, types D62S and D36S, outdoors, was made for two reasons: not enough available space and inadequate ventilation in the engine house. The Joule-Thomson effect, which occurs during air compression, means that the compressed gas mixture heats up, as the molecules move closer together due to the higher pressure. An increase of 100 millibars results in a temperature delta of +10 degrees centigrade. This increases the required compression effort due to reduced air density and lower oxygen content of the intake air. Installed outdoors, the Delta Hybrid machines can dissipate heat losses much more effectively into the environment and in turn suck in air that is not thermally preloaded. This correlation has the same effect on energy efficiency as the use of technology tailored to performance. One aspect to consider at this point: the operation of the rotary lobe compressors with a frequency inverter for demand-oriented and thus economical speed control of the drive motor. The four sizes of the Delta Hybrid with their scaled motor rating also make it possible to operate the load points most frequently occurring with optimal efficiency. In addition, the high adjustment range of the Delta Hybrid machines ensures that there are large areas of overlap between the assemblies. These areas are necessary, in order to ensure optimal adjustment of all operating points and stable compliance with the control specifications, even in case of continuous load changes of the system. This is particularly important as the activator basins of the Bingen wastewater treatment plant are not divided into fixed zones for ammonium degradation and nitrification. Rather, the areas of the different biodegradation processes can be variably adapted to the contamination loads by connecting the basin zones and the precise air control of the surface ventilators mounted on the basin floor. The areas into which air can be brought, and in what quantity, can be adjusted as required by means of control valves. There is a sliding pressure control system, so that valves, that are closed too far, do not cause the back pressure in the supply pipe to rise. This is based on the optimal interaction of volume flow, flap position and pressure. “Throttles, which are closed too far simply waste energy. 100 millibar more pressure means 20 percent more energy consumption,” the planner explains. “When it comes to improving the quality of a plant, precise, stable control methods, which are tuned to the speed of the coupled processes, are indispensable,” he adds. In Bingen, a multi-stage control process operates in the background with pressure control as the leading variable for the compressor adjustment, and with a delay time of about half a minute. The control of the oxygen concentration in activation zones with settling times of about 10 to 15 minutes, which act on the control valves in the compressed air supply, is time decoupled from this. Their position ensures continuous adjustment of the system pressure and thus triggers the above mentioned sliding pressure control.
Securing subsidies for energy efficiency Thanks to public subsidy programmes, energy efficiency now has a double pay off. In order to exploit this potential, AERZEN will offer its customers comprehensive support in the areas of energy efficiency, energy recovery and resource management together with the state-subsidised e.qua network. The climate protection targets adopted by the German government are accompanied by numerous subsidy programmes that can be used by operators of water management facilities. A distinction must be made between concept and investment subsidies for energy in the context of climate protection.Customer-oriented support by AERZEN and e.qua ranges from measuring volume flow requirements, energy analysis and optimisation and the preliminary clarification of suitable funding options for energy concepts to support in applying for funding.One example is sewage treatment: wastewater treatment plants are among the largest energy consumers in municipalities. With the latest technologies, considerable amounts of energy can be saved. In order to meet the increased requirements of the water and wastewater industry, AERZEN has paid special attention to the energy efficiency of its assemblies. In addition, well thought-out solutions for waste heat utilisation can be provided. AERZEN thus also meets the political targets set for energy efficiency and energy generation.
Delta Blower series extended With the Generation 5 positive displacement blowers AERZEN has set new standards. Now, the series is extended by two new blower stages: GM 110 S and GM 130 S types close the gaps in the volume flow range. The figures “110” and “130” stand for intake volume flows of 110 and 130 m³/min respectively (6,660 and 7,800 m³/h). Previously, there had been a jump from 90 m³/min (5,400 m³/h) to up to 150 m³/min (9,000 m³/h) and with it also a jump in the nominal diameter from DN250 to DN300. With the new blower sizes, this volume flow range is now finer graded, which brings decisive advantages for plant manufacturers and operators in terms of investment costs, dimensions and control range.What is also new: the enhanced Delta Blower series G5plus. Energy efficiency is currently the most important focus, particularly in the field of compressor technology where energy costs exceed 90% of the life-cycle-costs. AERZEN has always been a standard setter to develop more efficient and environmentally friendly processes. To expand upon the success of the AERZEN Delta Blower series, an exciting new design sets energy saving records. The new G5plus series distinguishes itself by increased energy efficiency of up to 5% and significantly reduced dimensions.Experience the new blower sizes at the trade fair stand of Aerzener Maschinenfabrik at the IFAT in Munich and the ACHEMA in Frankfurt.
This is AERZEN Performance³ AERZEN defines Performance. as an individual solution for the oxygen supply of biological aeration in waste water technology. Individual assemblies of Delta Blower positive displacement blowers, Delta Hybrid rotary lobe compressors and Aerzen Turbo blowers of the AERZEN range of products or a combination of assemblies of different efficiencies and regulating ranges can be used. What is so special about Performance³ Every technology has its strengths, but is also subject to physical limitations. By means of a possible technology mix and the use of different sizes, the individual strengths of assemblies can be added to a highly efficient combination with the best control range. The AERZEN Performance³ concept takes into account the respective requirements of a plant and offers you a rightsized solution that suits you and your plant perfectly. You will be supported by AERZEN wastewater experts during the entire process until your Performance³ solution is found. How does AERZEN proceed? In a first step, the load profile of a wastewater treatment plant is evaluated and important parameters for the following calculations are determined. If this load profile is not known it makes sense to record the measured value before. For this purpose, AERZEN uses its AERaudit product which is used to measure the volume flow and other important variables during operation of a plant (see page 2).An analysis of the recorded load profile forms the basis for the Performance³ process. At the beginning, the solution space consists of a multitude of variants. Taking your plant requirements into account, AERZEN will develop the Performance³ solution that best suits you and your plant.
New Head of Opportunity Engineering in Supply Process Gas On 1 September 2017, Carsten Holldack assumed responsibility for the group Opportunity Engineering in the Supply Process Gas division. The graduate mechanical engineer, born in 1970, has more than 20 years of professional experience in the field of rotating equipment. His previous roles were in development, product management and salesmanagement. The “Opportunity Engineering” group at the Aerzen site, led by Holldack, consists of six experienced process gas specialists.
Klaus Peter Glöckner new member of the General Management Since 1 December 2017, the General Management of Aerzener Maschinenfabrik consists again of three persons: Graduate engineer Mr. Klaus Peter Glöckner completes the Management team and has got to know the company intensively over the past few months. Klaus Peter Glöckner is responsible for the EMEA region. He was previously employed as Chief Sales Officer and Managing Director at Messrs. Kelvion.
Aerzen Colombia celebrated its 10th anniversary On 27 September 2017, Aerzen Colombia S.A.S., based near the capital, Bogotá, celebrated its tenth anniversary. The subsidiary, which when it opened was called Aerzen Andina, started out as an agency of Aerzen Iberica. This developed into two separate subsidiaries - Aerzen Colombia, which now has 15 employees, and Aerzen Andina Peru, where four colleagues are currently employed. The markets in Bolivia, Ecuador and Venezuela are supervised by commercial agents. Ricardo Castillo, Managing Director of Aerzen Colombia, is pleased about the tenth birthday celebrations: “We hope to be able to celebrate many more anniversaries and to contribute to the growth of the AERZEN group.”
