Today’s wastewater plants are dealing with aging infrastructure, increasingly stringent regulations, escalating operating and energy costs and budgetary constraints. The availability of funding for plant improvements is often hard to come by, forcing plants to do more with less. Siemens has announced solutions to assist these plants in becoming more sustainable through better energy management, including energy analysis modeling and innovative technologies to automation and financing.
“Energy management entails a wide range of solutions, from reducing biosolids to adding the latest biological treatment processes, high efficiency aeration solutions and control systems to project financing,” said Lutz Kranz, head of global municipal business for Siemens Water Technologies. “There is no one solution that fits everyone. So, we look at the total project to determine water quality and treatment needs and then recommend options, which may include multiple technologies and automation. We also look to see if we can offer attractive financing options to help get high-return, energy minimization projects moving.”
Siemens can help engineers and owners determine whether they need to improve one specific area or the whole treatment operation to achieve the lowest lifecycle cost, based on what is best for their plants and budgets. The long-term goal is to help them get as close as possible to net-zero energy.
Understanding power consumption is a key component to determining technology solutions for wastewater treatment. Siemens’ engineers use a proprietary power calculator tool that takes into account regionalized energy cost trends, anticipated start-up volume and diurnal flow patterns. They then run “apples to apples” economic comparisons of the company’s broad range of technologies to determine which ones will save owners the most in energy costs.
Wastewater treatment historically accounts for about 25% of a municipality’s total energy use. Within the wastewater plant, energy costs are the second largest operations and maintenance expense after labor. Biological processes account for 55% to 70% of this energy use, depending on plant design. This excludes energy and other costs for biosolids dewatering and disposal.
Siemens offers a biological process optimization program that evaluates specific cost factors such as energy use, labor and disposal. The program integrates several key wastewater operations, including biological, solids separation, solids treatment and controls, to significantly reduce energy costs. For example, a California wastewater treatment plant was able to reduce biosolids production by 70% and the aeration requirements from their aerobic digester by more than 90% with the Cannibal interchange bioreactor system from Siemens.
Another way plants can save on costs is by adding control and telemetry systems that make the whole process more efficient. Siemens can integrate all processes under a unified, easy to operate control system that maximizes the energy efficiency of the treatment technologies and also gives the engineer and owner a single point of responsibility in coordinating the control strategy and operation. As an example, the Link2Site Flex system is a wireless-to-Web remote monitoring and control solution that can be added to equipment or processes to optimize operation through reduced maintenance and service costs.
When municipalities need an alternative to traditional funding methods, Siemens Financial Services offers tax-exempt financing, which spreads the cost of capital equipment acquisition over the life of the assets being financed; it fits today’s equipment life cycles and helps keep technology up to date. This financing can be used to support traditional project delivery models and also alternative project delivery models including equipment lease-purchase, design-build, design-build-finance and guaranteed savings performance contracts.
“The future of energy management lies in being able to close the gap between what we can help customers achieve today and achieving net-zero energy in the future,” says Marc Roehl, global product manager for biosolids technologies at Siemens Water Technologies. “We know that the energy value of municipal wastewater is 10 times greater than the energy required to treat it. But we only re-use a fraction of that energy. We’re working to change that.”
Mechanically enhanced biodrying (MEB--a new technology that is in the pilot testing stage--is being developed as a result of industry requests for a versatile end product that could be used for fertilizer or fuel and that could be created with less energy than standard thermal drying technologies. It also addresses the challenges of biosolids composting when wood waste and other carbon-rich soil amendments are in short supply.
Research on a “green” solution for wastewater treatment is underway at Siemens Water Technologies’ global R&D center in Singapore. The new process, which extracts energy from municipal wastewater, will result in a 30% lower solids yield. Energy content in wastewater is harvested as biogas and converted to energy to create a plant that approaches energy independence. The lower solids volume produced will mean lower handling costs for owners and reduced transportation and management costs. Pilot testing is slated for October 2010, with commercial introduction scheduled for 2012.
Source: Siemens
