Sewage testing and sampling method

Sewage sampling and monitoring points are arranged for the first type of pollutant sampling points: they are all located at the discharge outlets of workshops or workshop treatment facilities or the discharge outlets of facilities that specialize in treating such pollutants. (Category 1 pollutants include: total mercury, alkylmercury, total cadmium, total chromium, hexavalent chromium, total arsenic, total lead, total nickel, benzo(a)pyrene, total beryllium, total silver, total alpha radioactivity , total β radioactivity, active chlorine, asbestos, vinyl chloride) sampling points for the second type of pollutants: all located at the outlets of the pollutant discharge units. Note: When monitoring the efficiency of the overall sewage treatment facilities, set sampling points at the sewage inlets of various sewage treatment facilities and the general outlet of sewage facilities; Sampling frequency of unit’s deduction setting Sampling point Supervisory monitoring: no less than 1 time per year Enterprise self-monitoring: generally at least 3 times per production day In order to confirm the sampling frequency of self-monitoring, the unit of pollutant discharge should carry out the sampling frequency of each production under normal production conditions. Intensive monitoring is carried out within the period (if the period is within 8 hours, sample once per hour; if the period is greater than 8 hours, sample once every 2 hours) Sampling method a. Sampling from pipes, canals, etc. Take samples at the water outlet, use containers or polyethylene barrels directly, and pay attention to the even distribution of suspended substances. b. Sampling from the sewage pipeline: sampling in the sewage pipeline, due to the retention of the pipeline wall, the flow velocity at different parts of the same section is different, the pollutants are not evenly distributed, and the concentration varies greatly. Therefore, when the water depth of the sewage pipeline is greater than 1m, samples can be taken from the surface down to 1/4 of the depth as wastewater samples representing the average concentration. If it is less than or equal to 1m, only 1/2 depth of wastewater samples can be taken. c. Sampling from containers, storage tanks, waste water pools, etc.: For small containers containing waste liquid, stir well before sampling, and then take samples. For large storage tanks or waste water pools with uneven pollutant distribution, multi-point layered sampling can be performed according to specific conditions. A self-made load frame can be used, and a polyethylene plastic sample container is fixed in the frame, which is submerged in the waste water for sampling.