Commenter:
Marie-Christine Belanger, Premier Tech Aqua
5. Treatment System Sampling Requirements
Field sampling protocols must recognize the inherent variability of wastewater characteristics, both in terms of the household use patterns and with regard to normal peaks and valleys in loading. For this reason, performance sampling conducted only once annually must allow for standard deviation on an individual system basis, though a more strict adherence remains justified for the collective data mean. More specifically, the sampling requirement should be modified to allow for standard deviation as follows:
The owner of each small AOSS is required to submit an initial grab sample of the effluent from the treatment unit and have the sample analyzed in accordance with 40 CFR Part 136 or alternative methods approved by the U.S. Environmental Protection Agency within the first 180 days of operation. Thereafter, if the treatment unit has received general approval, a grab sample is required once every five years. Samples shall be analyzed for BOD5 and, if disinfection is required, fecal coliform. Treatment units utilizing chlorine disinfection may alternatively sample for TRC instead of fecal coliform. Sample results shall be submitted to the local health department by the 15th of the month following the month in which the sample was taken. When samples are taken only once annually, results from each individual system shall be compliant if no more than double the applicable standard, in order to allow for standard deviation. The cumulative mean of all individual annual samples shall not exceed the applicable effluent quality standard.
