Outline of Japan-Korea Tunnel Plan-Environmental Assessment (Environmental Impact Assessment)-

Tunnel standard specification / shield method (water pollution prevention)

Water pollution prevention

When polluted water is generated due to construction work, in order to prevent water pollution in public water areas, etc., relevant laws and regulations must be observed and appropriate measures must be taken.



As a factor of water pollution due to shield construction,

① Underground spring
② Drainage by the groundwater level lowering method
③ Generation of polluted water due to cleaning of various machines and vehicles

and so on.Contaminated water mainly needs to remove suspended solids (SS).In addition, when cement or chemicals are mixed, it is necessary to adjust the hydrogen ion concentration (pH) and pay attention to the oil content.

Regulations on water pollution

(12) Water Pollution Control Law (see Articles XNUMX and XNUMX)
It establishes emission standards for water discharged from factories and business establishments with specific facilities into public water bodies.

(12) Sewerage Law (see Article XNUMX, Articles XNUMX-XNUMX of the Enforcement Ordinance)
It regulates the discharge of polluted water into the sewer.

③ River Act (see Article 16 of the Enforcement Ordinance)
Procedures for discharging polluted water (50 m3 / day or more) into rivers are stipulated.

④ Fisheries Resources Protection Law (see Article 18)
For the purpose of protecting marine resources, construction work in areas stipulated by law is regulated.

⑤ Natural Parks Act and Natural Environment Conservation Act (see Articles 13 and 25 of the same)
It regulates drainage in areas such as national parks and quasi-national parks.

⑥ Ordinance
Many prefectures or ordinance-designated cities have enacted pollution control ordinances, sewerage ordinances, waste treatment ordinances, fishery rights ordinances, etc., and construction wastewater may be regulated.

⑦ Provisional guidelines for construction work by the chemical injection method
It stipulates the selection, design, construction and water quality monitoring of construction methods necessary to prevent the occurrence of human health damage and pollution of groundwater, etc. by the chemical injection method.

Preventive measures

Before the start of construction, the source of polluted water and its influence, the degree, related laws and regulations, regulation values, etc. must be investigated, and appropriate purification treatment must be carried out to drain the water.In addition, it is necessary to measure and report the amount of discharged water, water quality, etc. in accordance with the regulations.

Survey item

(XNUMX) The system of the river to be released, the amount of water, the quality of water, the status of water use, etc.
(XNUMX) Regulations based on laws and ordinances such as drainage standards, necessary procedures and notifications, etc.
③ Water quality, amount, etc. of polluted water or waste water generated by construction
④ Sludge (sludge) treatment method
⑤ Site for installation of purification treatment facility, etc.

Processing method

① Suspended solids
Settle using a coagulant in a sand basin, settling basin or coagulation settling basin.

② Sludge
Solidified by sun drying or mechanical dehydration.

③ Flowing water
Discharge the supernatant water of the sedimentation basin or sedimentation layer.

④ pH
Alkaline or acidic water is discharged after adjusting the pH.

⑤ Oil content
Oil in the discharged water is removed by floating or adsorbing and separating.
(Reference: "Tunnel Standard Specification-Shield Construction Method Established in 2006", Japan Society of Civil Engineers)

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