RJN Group Inc. teamed up with AH Environmental to perform night flow isolations in the city of Newport News, Va. Night flow isolations were utilized in the sewer evaluation to quantify the amount of infiltration entering a sewer system.
Night flow isolations involve isolating sewer line segments and measuring the suspected infiltration. Approximately 1,000 linear ft of sewer lines are isolated for evaluation. The flow isolations are performed during low-flow periods, between the hours of midnight and 6:00 a.m. The isolated lines with significant flows during these hours are most likely to have significant infiltration.
As a sub-consultant to AH Environmental, RJN worked numerous nights and performed approximately 500 flow isolation setups. In addition to working at night flow isolations, RJN and AH Environmental worked together to manage traffic control during nighttime setup. The night flow isolation project began in the summer of 2009 and was completed at the end of 2010.
Source: RJN Group