– Pre-sampling well washing
The monitoring wells should be washed before groundwater sampling. This
requires pumping the standing water out of the well, so that the fresh water in the
aquifer can flush into the well. The wells are washed using Bailer one day before
sampling. For areas with low background value of sand content, washing comes to
an end when the groundwater effluent is visually clear and transparent. For areas
with high background value of sand content, washing is completed until the error is
less than 10% among three consecutive observed values of such water parameters
as pH, temperature and conductivity.
– On-site measurement
Items are measured on site if possible, including water table, water temperature, pH,
conductivity, turbidity, chromaticity, flavor level, macroscopic objects, and ORP.
– Sample collection
Groundwater samples are taken after on-site measurement. A total of 80 samples
categorized into 10 groups are collected from the landfill. Preservatives are added as
needed for different tests. Immediately after the sampling is completed, the containers should be tightly sealed and labeled (to indicate monitoring well number,
sampling date and time, monitoring items, samplers, and etc.).
– Sample storage
Water samples of heavy metals are stored in 125 mL plastic bottles with nitric acid
added as preservatives. Water samples of VOCs are stored in glass bottles that have
contained the concentrated hydrochloric acid solvent and polytetrafluoroethylene
(PEFE) gasket. For the analysis of SVOCs, ammonia nitrogen and nitrate nitrogen,
1 L brown glass bottles with the PEFE gasket are used to collect water samples. For
the analysis of other indicators, water samples are stored in 40 mL purge and trap
bottles with the upper space left. In addition, 250 mL plastic bottles are used to
collect water samples of permanganate index; 500 mL sterile ground
glass-stoppered bottles are used to collect water samples of total coliforms and total
bacteria, and they should be wrapped with tin foil. All samples should be tightly
sealed with PEFE films and kept in the low temperature incubators.
• Detection and analysis
A total of 75 indicators are included for groundwater monitoring. For 8 natural
background ions (mandatory) and 31 conventional indicators (mandatory), all
samples taken at the monitoring wells should be analyzed. For 36 characteristic
indicators, analysis should be conducted to all background monitoring wells and the
pollution diffusion monitoring well nearest to the landfill. Based on test reports, the
172
5 Application Cases
The monitoring wells should be washed before groundwater sampling. This
requires pumping the standing water out of the well, so that the fresh water in the
aquifer can flush into the well. The wells are washed using Bailer one day before
sampling. For areas with low background value of sand content, washing comes to
an end when the groundwater effluent is visually clear and transparent. For areas
with high background value of sand content, washing is completed until the error is
less than 10% among three consecutive observed values of such water parameters
as pH, temperature and conductivity.
– On-site measurement
Items are measured on site if possible, including water table, water temperature, pH,
conductivity, turbidity, chromaticity, flavor level, macroscopic objects, and ORP.
– Sample collection
Groundwater samples are taken after on-site measurement. A total of 80 samples
categorized into 10 groups are collected from the landfill. Preservatives are added as
needed for different tests. Immediately after the sampling is completed, the containers should be tightly sealed and labeled (to indicate monitoring well number,
sampling date and time, monitoring items, samplers, and etc.).
– Sample storage
Water samples of heavy metals are stored in 125 mL plastic bottles with nitric acid
added as preservatives. Water samples of VOCs are stored in glass bottles that have
contained the concentrated hydrochloric acid solvent and polytetrafluoroethylene
(PEFE) gasket. For the analysis of SVOCs, ammonia nitrogen and nitrate nitrogen,
1 L brown glass bottles with the PEFE gasket are used to collect water samples. For
the analysis of other indicators, water samples are stored in 40 mL purge and trap
bottles with the upper space left. In addition, 250 mL plastic bottles are used to
collect water samples of permanganate index; 500 mL sterile ground
glass-stoppered bottles are used to collect water samples of total coliforms and total
bacteria, and they should be wrapped with tin foil. All samples should be tightly
sealed with PEFE films and kept in the low temperature incubators.
• Detection and analysis
A total of 75 indicators are included for groundwater monitoring. For 8 natural
background ions (mandatory) and 31 conventional indicators (mandatory), all
samples taken at the monitoring wells should be analyzed. For 36 characteristic
indicators, analysis should be conducted to all background monitoring wells and the
pollution diffusion monitoring well nearest to the landfill. Based on test reports, the
172
5 Application Cases