3. Assessment of groundwater environmental conditions of the hazardous
wastes landfill
(1) Assessment of groundwater quality
① Assessment method
The groundwater quality is assessed according to the Class III standard of Quality
Standard for Groundwater, by the “standard index method” for individual factors.
If the standard index is greater than 1, it indicates that the groundwater quality
factor has exceeded the prescribed quality standard. The larger the index value, the
more serious the exceedance.
② Assessment results
I. Assessment results of high flow period
According to the sampling results, the sensory indexes (chroma, visible particulate
matter, smell, taste, and water temperature) of the five samples are normal. Among
the 49 indexes, 33 indexes with standard values provided in the Quality Standard
for Groundwater were selected for the assessment of groundwater quality, including
17 indexes, i.e. volatile phenol, cyanide, cadmium, cobalt, lead, hexavalent chromium, HCH, DDT, barium, iron, nickel, manganese, copper, beryllium, mercury,
selenium and sulphide, which are below the limit of detection and hence negligible
in their impact on water quality, and 16 indexes which are assessed, with the results
as shown in Table 5.125.
As can be inferred from Table 5.125, #4 well of the five groundwater monitoring
wells has all the indexes in compliance with the Class III standard in the Quality
Standard for Groundwater except for the total number of bacteria, and the other 4
wells have various monitored indexes exceeding the Class III standard, of which the
total number of bacteria is found to have too great excess multiple, possibly caused
by misoperation in sampling or testing, and is required to be retested next time by
stricter procedure, to avoid too big error in the results. Excluding the total count of
bacterial, among the five monitoring wells, the three indexes of #1 monitoring well
including the ammonia-nitrogen, total soluble solids and total coliforms, the
ammonia-nitrogen and total hardness of #2 monitoring well, the four indexes of #6
monitoring well including ammonia-nitrogen, total soluble solids, permanganate
index and total hardness, and the ammonia-nitrogen, permanganate index and total
coliforms of 7# monitoring well exceeded the Class III standard, with the
ammonia-nitrogen of #1, #2, and the total soluble solids of #6, #7 having the largest
excess multiple of 1.130, 0.330, 0.129 and 15.7 respectively.
II. Assessment results of level period
The sampling in level period was conducted on November 2, 2015. From the
sampling results, it is known that the sensory indexes (chroma, visible particulate
matter, smell, taste, and water temperature) of the five samples are normal. 28 indexes were selected for testing in the level period, by eliminating the indexes
372
5 Application Cases
wastes landfill
(1) Assessment of groundwater quality
① Assessment method
The groundwater quality is assessed according to the Class III standard of Quality
Standard for Groundwater, by the “standard index method” for individual factors.
If the standard index is greater than 1, it indicates that the groundwater quality
factor has exceeded the prescribed quality standard. The larger the index value, the
more serious the exceedance.
② Assessment results
I. Assessment results of high flow period
According to the sampling results, the sensory indexes (chroma, visible particulate
matter, smell, taste, and water temperature) of the five samples are normal. Among
the 49 indexes, 33 indexes with standard values provided in the Quality Standard
for Groundwater were selected for the assessment of groundwater quality, including
17 indexes, i.e. volatile phenol, cyanide, cadmium, cobalt, lead, hexavalent chromium, HCH, DDT, barium, iron, nickel, manganese, copper, beryllium, mercury,
selenium and sulphide, which are below the limit of detection and hence negligible
in their impact on water quality, and 16 indexes which are assessed, with the results
as shown in Table 5.125.
As can be inferred from Table 5.125, #4 well of the five groundwater monitoring
wells has all the indexes in compliance with the Class III standard in the Quality
Standard for Groundwater except for the total number of bacteria, and the other 4
wells have various monitored indexes exceeding the Class III standard, of which the
total number of bacteria is found to have too great excess multiple, possibly caused
by misoperation in sampling or testing, and is required to be retested next time by
stricter procedure, to avoid too big error in the results. Excluding the total count of
bacterial, among the five monitoring wells, the three indexes of #1 monitoring well
including the ammonia-nitrogen, total soluble solids and total coliforms, the
ammonia-nitrogen and total hardness of #2 monitoring well, the four indexes of #6
monitoring well including ammonia-nitrogen, total soluble solids, permanganate
index and total hardness, and the ammonia-nitrogen, permanganate index and total
coliforms of 7# monitoring well exceeded the Class III standard, with the
ammonia-nitrogen of #1, #2, and the total soluble solids of #6, #7 having the largest
excess multiple of 1.130, 0.330, 0.129 and 15.7 respectively.
II. Assessment results of level period
The sampling in level period was conducted on November 2, 2015. From the
sampling results, it is known that the sensory indexes (chroma, visible particulate
matter, smell, taste, and water temperature) of the five samples are normal. 28 indexes were selected for testing in the level period, by eliminating the indexes
372
5 Application Cases