Projects

Phase 1 Plant Improvements Project

In 2010, two Komline Sanderson Gravity Belt Thickeners were installed. The GBT's thicken a blend of primary clarifier sludge and waste activated sludge from 1.1% total solids to a 5% sludge prior to sending it to our anaerobic digesters.

Improvements were also made to our anaerobic digesters. A new sludge mixing system was installed in the secondary digester, making it a third primary digester. All of these units were emptied, cleaned and sealed. Many of the centrifugal pumps were replaced with grinders and lobe pumps.

In addition, several roofs were replaced on the facility's buildings and the Laboratory and Administration Building was refurbished.

Ostara Process

When the digesters were emptied to be cleaned, massive amounts of struvite were discovered. This material is formed when orthophosphate, magnesium, and ammonium compounds react under the right environmental conditions. The struvite also was found in all of the digester piping, prompting the replacement of these pipes with those lined with glass.

In 2008, City staff were made aware of Ostara Nutrient Recovery Technologies. This firm had developed a process that removed the dissolved phosphate from waste streams and formed a phosphorus-rich fertilizer. Not only has this process reduced the orthophosphate loading back on the WWTP eliminating the need for chemical treatment, but it also significantly reduced maintenance costs associated with unwanted struvite formation in pumps and piping.

After an exhaustive cost-benefit analysis, it was determined that the annual plant operating expenses could be reduced by $80,000 if it were to utilize this technology. A pilot study using our centrifuge centrate confirmed the viability of this process. In 2009, agreements were executed between Ostara, the City of York, and the York City Sewer Authority.

In September of 2010, the Ostara process went online. Today it is performing as expected.

For more information go to www.ostara.com
 

Phase 2 Plant Improvements Project

This phase began in early 2010 and is expected to be completed in 2012. The primary focus of the project will be to modify the existing biological processes to comply with our total nitrogen and phosphorus limits.

Other work includes a major upgrade to our power distribution system, modifications to secondary clarifiers, new bar screen installation, and additional building modifications.

Microturbine Installation

In the last 1980s a co-generation system was installed that used methane gas produced in our anaerobic digesters to produce both power and heat. This process could also generate additional power using utility gas. In early 2010 a cost analysis of this system indicated increased operating expenses (primarily due to maintenance).

The plant engineer and management staff reviewed other technologies. A decision was made to replace the existing 1500 Kilowatt system with micro-turbines manufactured by Capstone. One 600kW unit (comprised of three 200kW micro-turbines) will run using the digester methane gas. Another 100kW unit (comprised of five 200kW micro-turbines) will use utility gas.

This system is expected to produce 2.5 million kWh per year while significantly reducing NOx, SOx, and CO2 emissions.

For more information please visit www.capstoneturbine.com.

Computer Upgrade Project

Since 1988 the York Wastewater Treatment Plant has been utilizing a computer system to monitor and control the various plant processes. In 2009 it was decided to upgrade this system using "off the shelf" hardware. In addition, programming logic was written so that the operator interface would be more intuitive. Plant staff worked with the developer in the design of the graphics.

The installation of the new equipment, while still maintaining computer control has been a challenge. During the cut-over of the various plant process controls, both the old and the new systems were online.

When the upgrade completed in 2011 senior members of management will have remote access control via a secure VPN.