IMPLEMENTED STAFF IDEAS
It is the philosophy of the York WWTP to encourage plant staff to come up with ideas that will improve plant efficiency. Several ideas were implemented in order to reduce downtime and lower maintenance costs.
Motorized Gate Operators
During the last plant upgrade (1991) hand-operated gate operators were installed at several different locations. While this improved operation and maintenance on various processes, it became more difficult for an operator to open and close them. After reviewing several options, it was found that the existing gate operators could be retrofitted with motorized units. Now operators can easily open and close the gates in a short period of time. A few of the gates can also be operated from the WWTP computers.
Primary Clarifiers Modifications
When these units were renovated in the 1990s steel chains were replaced by plastic chains. This simple switch has dramatically reduced labor costs to maintain these units. Little, if any, maintenance is needed to maintain their operation. In addition, influent gate operators were installed to replace the slide gates that had been used. The slide gates took two people at least one hour to put into place. This had to be done by using a backhoe.
Bar Screen Operation
When the outside air temperature dropped below freezing the bar screen rake would freeze up on the bar screen. Plant operators corrected this problem by installing a curtain wall that hung down from the upstream and downstream gates. They also placed old belt press media across the grating. This trapped the heat given off by the raw influent water and kept the unit from freezing.
Sand Filter Bridge Operation
During the cooler months of the year condensation would form on the steel above the sand filter bridge tracks. When the track became wet, the bridge drive wheels would spin in place. To remedy this issue, plant staff mounted leaf blowers on the bridge and pointed it ahead of the bridge drive. The track stayed dry and the drive wheels stopped spinning.
Train 2 Central Scum Pump
For years pumping scum from our primary clarifiers using the existing diaphragm pumps was a chore. They routinely clogged up or had debris get caught in their ball check valves. This meant plant personnel had to open them up and clean them out at least one time per week. Installing this centrifugal pump eliminated the headache and saved approximately 50 manhours annually. This system has been in service for several years now with little maintenance needing to be performed.
Grit Pump
Plant maintenance mechanics came up with an improved system of removing grit using a standard centrifugal pump. Maintenance costs were reduced by over 200 manhours per year.
Process Water Pipe
Process return flows used to just dump directly into our primary influent channel with very little mixing. Plant staff came up with the idea of extending the pipe so that this flow would be well mixed prior to entering the primary clarifiers. It also allowed for more accurate flow measurements.
Hot Water System
For years the plant staff struggled to keep grease from building up in the primary sludge line leading to the anaerobic digesters. After experimenting with several different systems (chemical and physical), the plant staff settled on a very simple solution. Heat approximately 600 gallons of water to 180 degrees, pump it into the pipe, and melt the grease from the inside walls. This system has performed beyond our expectations. Pumping rates went from 100 gpm to 200 gpm with just three cleanings and has saved approximately $5,000 in pump maintenance each year.
Digester Scum Mixing Pump
As with our grit system, the same centrifugal pump (only larger) was used to replace an older scum-breaking pump on our anaerobic digesters. This system is less maintenance intensive then the older one.
Update: In 2007 a new mixing system was installed in the two primary digesters (Vaughan). The system mentioned above was then removed.
Utility Water Pump Station 
The plant maintenance staff replaced our existing 60 HP Fairbanks Morse utility water pumps with these 40 HP Carver utility water pumps. These pumps run off of energy efficient motors that use approximately 33% less power to supply the water needs of the facility.
D.A.F.T. Pump 
In August of 2002 the treatment plant personnel tested a new type of pump that entraps tiny air bubbles in the water used to float waste activated sludge. After a 30-day trial run, the staff was impressed enough with its operation that it became a permanent installation. This pump operates on 10 less HP and has allowed two air compressors and two pressure vessels to be taken off line. In addition, total solids in the floated sludge increased by approximately ten percent.
Primary Sludge Pumping
Since 1990 the primary sludge from the York facility was pumped by running pump suction lines in a tunnel over 100 feet to the primary sludge pumps. Then these pumps had to pump the sludge back through the same tunnel in order to get to the anaerobic digesters. In July 2002 the plant maintenance supervisor suggested the installation of a pump in the tunnel to eliminate the long suction and discharge distances. Since the pump was installed the pumping rates have increased from 100-gpm to greater than 250-gpm.
