(d) Hydrogeological conditions
• Groundwater type and endowment conditions
According to the endowment conditions, groundwater in the landfill site can be
divided into the pore water of Quaternary loose rocks and the fissure water of
shallow weathered magmatic rocks. More specifically, the fissure water mainly
exists in the fissures of shallow weathered diorite (d) and the pore water in the
Middle and Lower Pleistocene ice-borne layer (Q
1−2 fg
l ). According to the local
hydrogeological data, the aquifer of the Middle and Lower Pleistocene ice-borne
layer is rich in water with hydraulic conductivity up to 7.56 m/d, and the depth to
water table ranges from 2.5 to 3.3 m.
• Groundwater runoff, recharge and discharge conditions
The landfill is located in Shenxian Ditch, a primary tributary of the Anning River.
As groundwater in the site is dominated by Quaternary loose rock pore water and
magmatic rock fissure water, the two types of aquifers are recharged by precipitation and replenish each other. After recharged by precipitation, the pore water
infiltrates into the magmatic rock aquifer or flows into the Shenxian Ditch through
short-range runoff. The fissure aquifer receives replenishment from precipitation
and overburden Quaternary aquifer. Controlled by factors such as topography,
geology and surface water flow, the fissure water is discharged along the direction
of fissures to springs in front of mountains or transported to the bottom of the ditch
before it reaches the Anning River (Figs. 5.26 and 5.27).
(2) Landfill overview and status quo
Put into use in 2013, the landfill occupies an area of about 46,400 m
2 and has a
storage capacity of 599,000 m
3 and a service life of about 17 years. Currently,
103,200 m
3 of solid waste has been stockpiled with dump height reaching 14 m.
According to the field investigation and related landfill design data, the main
functional areas related to the groundwater environment include the refuse dam,
reservoir seepage control system, leachate treatment station, leachate collection
system, and interceptor ditch. Though the landfill is in condition, the structural
facilities and functional areas are prone to pollution. Due to the small cross-section
of interceptor ditch, rainwater likely overflows into the landfill site in the rainy
season, which leads to an increase in leachate production and groundwater pollution
risk. The current landfill operation is as shown in Fig. 5.28.
(3) Background investigation of groundwater environment
(a) Groundwater exploitation and utilization
According to the field investigation, there are totally 107 households from
Fengshou Village within 403–1083 m from the landfill. Among them, eight
households have drilled wells for water use, of which the depth to water table
ranges from 2.5 to 3.3 m, and the rest 99 households resorts to surface water.
212
5 Application Cases
• Groundwater type and endowment conditions
According to the endowment conditions, groundwater in the landfill site can be
divided into the pore water of Quaternary loose rocks and the fissure water of
shallow weathered magmatic rocks. More specifically, the fissure water mainly
exists in the fissures of shallow weathered diorite (d) and the pore water in the
Middle and Lower Pleistocene ice-borne layer (Q
1−2 fg
l ). According to the local
hydrogeological data, the aquifer of the Middle and Lower Pleistocene ice-borne
layer is rich in water with hydraulic conductivity up to 7.56 m/d, and the depth to
water table ranges from 2.5 to 3.3 m.
• Groundwater runoff, recharge and discharge conditions
The landfill is located in Shenxian Ditch, a primary tributary of the Anning River.
As groundwater in the site is dominated by Quaternary loose rock pore water and
magmatic rock fissure water, the two types of aquifers are recharged by precipitation and replenish each other. After recharged by precipitation, the pore water
infiltrates into the magmatic rock aquifer or flows into the Shenxian Ditch through
short-range runoff. The fissure aquifer receives replenishment from precipitation
and overburden Quaternary aquifer. Controlled by factors such as topography,
geology and surface water flow, the fissure water is discharged along the direction
of fissures to springs in front of mountains or transported to the bottom of the ditch
before it reaches the Anning River (Figs. 5.26 and 5.27).
(2) Landfill overview and status quo
Put into use in 2013, the landfill occupies an area of about 46,400 m
2 and has a
storage capacity of 599,000 m
3 and a service life of about 17 years. Currently,
103,200 m
3 of solid waste has been stockpiled with dump height reaching 14 m.
According to the field investigation and related landfill design data, the main
functional areas related to the groundwater environment include the refuse dam,
reservoir seepage control system, leachate treatment station, leachate collection
system, and interceptor ditch. Though the landfill is in condition, the structural
facilities and functional areas are prone to pollution. Due to the small cross-section
of interceptor ditch, rainwater likely overflows into the landfill site in the rainy
season, which leads to an increase in leachate production and groundwater pollution
risk. The current landfill operation is as shown in Fig. 5.28.
(3) Background investigation of groundwater environment
(a) Groundwater exploitation and utilization
According to the field investigation, there are totally 107 households from
Fengshou Village within 403–1083 m from the landfill. Among them, eight
households have drilled wells for water use, of which the depth to water table
ranges from 2.5 to 3.3 m, and the rest 99 households resorts to surface water.
212
5 Application Cases