(3) Secondary drainage layer. In order to monitor and detect the leakage of the
primary impermeable layer, a secondary drainage layer is arranged between the
primary impermeable layer and the secondary impermeable layer for collecting
and draining the leachate. The side wall of the secondary drainage layer adopts
composite HDPE mesh (non-woven fabric + HDPE mesh + non-woven fabric)
as the water discharge layer, the bottom layer uses 300 mm graded pebbles as
the collection and drainage layer, and the drainage pipes gathered at the bottom
HDPE to drain the leachate to the leachate monitoring well.
(4) Secondary impermeable layer. The secondary impermeable layer adopts the
rigid reinforced concrete sump. In order to improve the impermeability performance, impermeable concrete is added with waterproof agent and waterproof coating is applied to the inner wall.
(5) Base layer. The base layer is made of the modified bentonite.
(4) Production and disposal of wastewater, effluent and waste residue
① Wastewater and effluent
During hazardous waste disposal, there are acid and alkaline wastewater,
wastewater of waste oil distillation, wastewater of cyanide-containing effluent
treatment, initial rainwater of the plant area, equipment and ground washing water
and domestic sewage of workers in the plant area. All wastewater and effluent are
collected, subject to biochemical treatment in the sewage treatment station and
reused as reclaimed water in the disposal center.
I. Production wastewater
The received acid and alkaline wastewater, heavy metal-containing wastewater,
effluent, equipment and ground washing water and other production wastewater and
effluent are sent to a physico-chemical treatment workshop for reduction or oxidation and precipitation, and the treated clear liquid and pretreated oily wastewater
are sent to a sewage treatment station for biochemical treatment.
II. Treatment of landfill leachate
The landfill site is a 138 m  60 m  12.5 m reinforced concrete sump designed
with a rigid structure. A steel structure sliding awning is provided above the sump
for rain-proof. The moisture content of all incoming landfill waste is less than 80%,
so there is no leachate discharged from the landfill.
III. Treatment of wastewater from lead-acid battery recovery
The wastewater mainly comes from the separation unit of the lead-acid battery
recovery device, and the water is acidic and lead-bearing. The device is provided
with an independent sewage treatment system, the water is in closed circulation
5.5 North China
291
primary impermeable layer, a secondary drainage layer is arranged between the
primary impermeable layer and the secondary impermeable layer for collecting
and draining the leachate. The side wall of the secondary drainage layer adopts
composite HDPE mesh (non-woven fabric + HDPE mesh + non-woven fabric)
as the water discharge layer, the bottom layer uses 300 mm graded pebbles as
the collection and drainage layer, and the drainage pipes gathered at the bottom
HDPE to drain the leachate to the leachate monitoring well.
(4) Secondary impermeable layer. The secondary impermeable layer adopts the
rigid reinforced concrete sump. In order to improve the impermeability performance, impermeable concrete is added with waterproof agent and waterproof coating is applied to the inner wall.
(5) Base layer. The base layer is made of the modified bentonite.
(4) Production and disposal of wastewater, effluent and waste residue
① Wastewater and effluent
During hazardous waste disposal, there are acid and alkaline wastewater,
wastewater of waste oil distillation, wastewater of cyanide-containing effluent
treatment, initial rainwater of the plant area, equipment and ground washing water
and domestic sewage of workers in the plant area. All wastewater and effluent are
collected, subject to biochemical treatment in the sewage treatment station and
reused as reclaimed water in the disposal center.
I. Production wastewater
The received acid and alkaline wastewater, heavy metal-containing wastewater,
effluent, equipment and ground washing water and other production wastewater and
effluent are sent to a physico-chemical treatment workshop for reduction or oxidation and precipitation, and the treated clear liquid and pretreated oily wastewater
are sent to a sewage treatment station for biochemical treatment.
II. Treatment of landfill leachate
The landfill site is a 138 m  60 m  12.5 m reinforced concrete sump designed
with a rigid structure. A steel structure sliding awning is provided above the sump
for rain-proof. The moisture content of all incoming landfill waste is less than 80%,
so there is no leachate discharged from the landfill.
III. Treatment of wastewater from lead-acid battery recovery
The wastewater mainly comes from the separation unit of the lead-acid battery
recovery device, and the water is acidic and lead-bearing. The device is provided
with an independent sewage treatment system, the water is in closed circulation
5.5 North China
291