The Philadelphia Water Department

What new technologies have you been evaluating or implementing?

The Philadelphia Water Department has been collaborating with local researchers and other local resources to evaluate resource recovery technologies, including biodiesel production from wastewater scum and carbon and nitrogen recovery from wastewater through indigenous algae processes. To improve nutrient management and advance sludge handling, our staff has been investigating sidestream deammonification technologies, side stream ammonia recovery feasibility, and anaerobic digestion enhancement strategies. These strategies include increasing biodegradable organic carbon availability, and introducing aircraft deicing fluid or food waste as external carbon sources to increase biogas production.

So far, Philadelphia Water has implemented a variety of energy-related projects and technologies which include the following highlights: 

• Biosolids Recycling: The newly constructed thermal drying facility in the Philadelphia Renewable Bio-fuels Facility uses biogas from the adjacent water pollution control plant to off-set natural gas purchases. The facility produces Class A pellets which are either sold as a fertilizer mix or an alternative fuel for a lime kiln. 
   
• Biogas Cogeneration: A new combined heat and power facility has been constructed at our Northeast Water Pollution Control Plant to capture methane generated from the existing sewage treatment process. The captured biogas can provide up to 85% of the annual electrical requirements for plant operations.
   
• Wastewater Geothermal: PWD's sewage geothermal installation at the Southeast Water Pollution Control Plant extracts thermal energy from sewage arriving at the plant and uses it to heat the plant’s compressor building and gallery space. Although the initial, grant funded installation is no longer in operation due to maintenance sustainability issues, proof of concept was achieved and efforts are underway to implement a more robust version of the technology.  
   
• Solar Array: Philadelphia Water’s first large solar panel system consists of 1,014 solar panels located at our Southeast Water Pollution Control Plant. Renewable solar energy generates a small portion of the electricity reducing demand and off-setting electrical power.
   
• Aircraft Deicing Fluid: Philadelphia Water has been accepting aircraft deicer fluid from the Philadelphia International Airport since 2008 and feeds this to the anaerobic digesters at its Southwest Water Pollution Control Plant. This increases the production of energy-rich methane gas that Philadelphia Water can use to power plant operations and reduce our dependence on non-renewable energy sources.

What technologies are you interested in investigating?

Besides supporting the upcoming Arisdyne sludge pre-treatment study, we are also interested in investigating resource recovery technologies for extracting nutrients and other resources, such as metal salts, ammonia, and PHA. As co-digestion efforts increase, digester performance is paramount, with improvements to existing infrastructure becoming more interesting, like digester mixing, pre-digestion hydrolysis, better prediction of organic destruction rates and production of solids. The department routinely researches technologies to advance process instrumentation, sensor-based control and automation, nutrient recovery, greenhouse gas emissions reduction, energy independence, chemical costs optimization, and system resilience. 

What are your facility’s drivers/needs?

As with all regulated utilities, Philadelphia Water’s core driver is to comply with regulations in a cost effective manner. However, our vision goes beyond this immediate goal and into the future. Philadelphia Water is moving towards becoming a utility of the future, and as such we are a strategic partner in the City’s plans for becoming a sustainable, resilient city. We are considering ways to reduce greenhouse gas emissions, to increase alternative energy generation while reducing energy consumption and to manage nutrients. One of our current focus areas is food waste co-digestion for increased biogas recovery.    

How has LIFT helped, or how would you like LIFT to help your facility?

LIFT has effectively provided various platforms for subscribers to network with manufacturers, researchers and peer utilities. For example, the sidestream deammonification workshop organized by LIFT provided a great opportunity for us to exchange not only technical experiences, but also financial procurement challenges and strategies. We were able to use the information and knowledge gained through LIFT while conducting our own feasibility assessment. 

We would like LIFT to help us identify collaborative research opportunities with peer utilities interested in the same technologies as we are. In addition, we are interested in studying scalability to assess potential challenges when adopting a new technology. LIFT’s assistance coordinating among utilities and consolidating funding resources can be a great help in accelerating new technology implementation.

Also, ammonia recovery is an important concept for the development of the utility of the future. Ammonia recovery reduces use of primary fuels, reduces GHG, returns nutrients to the soil, addresses food scarcity, and short circuits the destruction cycle. LIFT is an excellent platform to lead the wastewater sector into truly becoming resource recovery facilities. We would like LIFT to help sponsor an ammonia recovery pilot project.  

If there is one technology you could pilot or collaborate on tomorrow, what would it be?

With the interests in nutrient recovery and energy neutrality, we would pilot a technology that targets renewable resource recovery and produces either energy or a commercialized commodity.