What is the minimum ambient flow for using no purge sampling
What is the minimum ambient flow for using no purge sampling methods?
There is really no minimum flow in a low yield setting through the well screen zone. Just like a diffusion sampling device or a passive sampler is anticipating that it can get a representative sample based on exchange of water from the formation in the well screen zone, the contaminants themselves can diffuse through the sand pack and through the slots in the screen just as they can diffuse through the pores in a membrane.
In a high yield setting, I would do some kind of study based ITRC guidance documents concerning low purge and passive devices.
There is really no minimum flow in a low yield setting through the well screen zone. Just like a diffusion sampling device or a passive sampler is anticipating that it can get a representative sample based on exchange of water from the formation in the well screen zone, the contaminants themselves can diffuse through the sand pack and through the slots in the screen just as they can diffuse through the pores in a membrane.
In a high yield setting, I would do some kind of study based ITRC guidance documents concerning low purge and passive devices.