The Town is going forward with the construction of a new biological filtration treatment plant to treat manganese, along with the continuation of present treatment processes. At this time, we have the project scheduled to be advertised on May 10th with a bid opening of June 8th. We are anticipating an executed contract and notice to proceed by June 30th at this time. Our latest April reading for manganese was 0.24 ppm.
In October 2016, into the first week of November, a process called ice pigging was used to clean from our Treatment Plant out into our major transmission lines in the lower section of West Main St., North Quinsigamond Ave. and Old Mill Rd. The process does a more in depth cleaning of difficult sections of piping than hydrant flushing can accomplish alone, to remove buildup of manganese and sediment.
We are building on the success of this project by completing a comprehensive unidirectional flushing program along the Main St. transmission corridor from Old Mill Rd. through the center of Town to South St., including intersecting streets along the route and southerly in the Grafton St. quadrant this week. This upcoming week, starting on Monday April 24th, we will be continuing this work northerly in the Boylston and Prospect St. areas from the center of Town to Hill St., including all adjacent areas.
All of this work is critical to water quality and the reduction of incidences of water discoloration. Once the transmission lines are cleared, we are preparing to bid out for robotic cleaning of all our water tanks to start early summer. We will be beginning with our lower service tanks and progress to our high service and reduced high tanks. This process should also greatly help lessen occurrences of water discoloration to our customers. A new well source Home Farm 6-5 has been drilled and tested with a bid opening for valving and controls to connect into the system on April 26th. The water yield and quality is excellent. Manganese results are at 0.005 ppm, which is extremely low and the hexavalent chromium level is at 0.14 ppb, again very low. This will allow us to limit pumping at our Home Farm 6-3 well, which shows much higher levels of manganese and hex chrome.
Our latest hexavalent chromium results for our finished water is 5.5 ppb sampled on 4/14/17. This overall number remains low to this point and well within the 100 ppb MassDEP and EPA maximum containment limit. The Town continues to work with MassDEP and the adjacent business, Metso Flow Control, to acquire additional information on the movement of hexavalent chromium toward our property and identify the possible source. The environmental engineering firm working for Metso has installed six new ground water monitoring wells and repaired one existing monitoring well on their property. All of their monitoring wells, along with our monitoring wells installed near our property, were sampled last week and results are expected in another week.
The Town is working with the firm of AdEdge Water Technologies to pilot test a biological treatment process for hexavalent chromium removal. We are working with the state to develop a pilot test proposal and new technology approval. We are anticipating a pilot test startup in early September, 2017.