1.0.1 This code is formulated with a view to making the design of water supply & drainage engineering of iron and steel enterprises conform to the national guidelines, policies and regulations, unifying the engineering construction standards, improving the engineering design quality, and achieving advanced technology, safety and reliability, economy and rationality, energy conservation and emission reduction, and convenient management.
1.0.2 This code is applicable to the design of water supply & drainage engineering for construction, renovation and extension projects of iron and steel enterprises (including special steel mills).
1.0.3 The design of water supply & drainage engineering of iron and steel enterprises shall be based on the overall planning of iron and steel enterprises approved by the relevant government departments. The selection of water sources, locations of water treatment plants, water transmission and distribution pipelines, plant outlets, recycled & reused water utilizing rate, quantity of water intake per ton of steel, etc. shall meet the requirements of the overall planning.
1.0.4 When the industrial wastewater and domestic sewage drainage pipelines of iron and steel enterprises are connected to the water drainage system or water body with public sewage treatment system, the drainage water quality must meet the requirements of the relevant national and local discharge standards.
1.0.5 In addition to this code, the design of water supply & drainage engineering of iron and steel enterprises shall also comply with those stipulated in the current relevant standards of the nation.
2 Terms
2.0.1 quantity of water intake
quantity of water taken from the self-built or jointly-built water intake facilities of the iron and steel enterprises, regional or urban water supply projects, and tail water of power plants, as well as water purchased by iron and steel enterprises, but excluding the quantity of seawater, brackish water, rainwater, and reuse water from the wastewater of enterprises
2.0.2 quantity of water intake per ton of steel
ratio of annual quantity of water intake to annual steel output in iron and steel enterprises, expressed in m3/t
2.0.3 fresh water consumption per ton of steel
ratio of annual industrial fresh water consumption to annual steel output in iron and steel enterprises, expressed in m3/t
2.0.4 raw water
untreated water obtained from water sources
2.0.5 industrial fresh water
general term for finished water made from raw water, including process fresh water, soft water, demineralized water, pure water and so on
2.0.6 process fresh water
one kind of industrial fresh water, which is used as the makeup water of water recirculation system or as the raw water for producing soft water and demineralized water
2.0.7 soft water
water in which the hard components (mainly calcium ions and magnesium ions in water) are removed or reduced to a certain extent
2.0.8 demineralized water
water in which the salts (mainly strong electrolytes dissolved in water) are removed or reduced to a certain extent
2.0.9 pure water
water in which both the strong and weak electrolytes are removed or reduced to a certain extent
2.0.10 water for serial reuse
water that is used by a user and then made available for reuse by a sub-user without water treatment
2.0.11 reuse water
wastewater that is recycled either directly or after treatment
2.0.12 meteorological data
specific meteorological parameters such as wet bulb temperature, dry bulb temperature, atmospheric pressure and relative humidity used in the design and calculation of cooling towers
2.0.13 non-contact cooling water recirculation system
cooling water recirculation system that transfers heat indirectly between the recirculating cooling water and the cooled medium
2.0.14 system capacity
sum of all effective water storage volumes in the cooling water recirculation system
2.0.15 acid regeneration
process of regenerating and recycling waste acid
2.0.16 reclaimed water
undrinkable water derived from domestic sewage and wastewater, which, after being treated, reaches the prescribed water quality standards and is made available for miscellaneous purposes in domestic, municipal and environmental areas
2.0.17 unit project
project responsible for a single production process in an iron and steel complex
2.0.18 plant-wide wastewater
blowdown water, process wastewater and domestic sewage collected from various production workshops through combined system or separate system
2.0.19 sewage depth processing
further water treatment process of domestic sewage or industrial wastewater after primary and secondary treatments, so that the water meets certain reuse water standards and then can be used as a water resource for production or life
3 Quantity of water intake and water quality index
3.1 Quantity index of water intake
3.1.1 The quantity index of water intake per ton of steel for newly-built iron and steel complexes shall not be greater than 6m3/t.
3.1.2 The quantity index of water intake per ton of steel for renovated or extended iron and steel complexes shall not be greater than 7m3/t.
3.1.3 The quantity index of water intake per ton of steel for newly-built special steel mills shall not be greater than 8m3/t, and that for renovated or extended special steel mills shall not be greater than 10m3/t.
3.2 Water quality index
3.2.1 When raw water needs to be treated, it shall be treated in a centralized manner. For the unit projects with special requirements for water quality, the raw water may also be treated separately after technical and economic comparison.
3.2.2 The water quality indexes for industrial fresh water and reuse water shall be determined according to local water source conditions, water quality requirements of each water recirculation system and cycle of concentration of circulating water, etc., and should meet the requirements of Table 3.2.2.
Table 3.2.2 Water quality indexes for industrial fresh water and reuse water
Index Unit Process fresh water Soft water Demineralized water Reuse water
pH value - 7~9 7~9 6.5~9 6~9
Suspended solids mg/L ≤10 ≤5 ≤1 ≤20
Full hardness mg/L (in CaCO3) ≤150 ≤10 ≤2 ≤450
Ca hardness mg/L (in CaCO3) ≤100 ≤2 ≤1 ≤300
M-alkalinity mg/L (in CaCO3) ≤110 ≤110 ≤1 ≤330
Chloride ion mg/L (in CL) ≤220 ≤200 ≤1 ≤660
Sulfate ion mg/L (in SO42-) ≤80 ≤80 Not detected ≤240
Total iron mg/L (in Fe) ≤1 ≤1 ≤0.1 ≤3
Soluble SiO2 mg/L (in SiO2) ≤6 ≤6 ≤0.1 ≤18
Oil content mg/L ≤2 ≤1 Not detected ≤5
Conductivity μs/cm ≤500 ≤500 ≤10 ≤3,000
Residue after evaporation (dissolved) mg/L ≤300 ≤300 ≤5 ≤1,000
Ammonia-nitrogen mg/L ≤10 ≤10 ≤1 ≤10
CODcr mg/L - - - ≤100
Notes:
1 The probability of each water supply index shall be above 90%.
2 When groundwater is the main water source, its full hardness shall not exceed 200mg/L.
3 The demineralized water produced by the central water plant should be determined according to the quality of Grade 1 demineralized water. For single users with higher water quality requirements and adopting centralized treatment, an external pipeline shall be added, and Grade 1 demineralized water may be provided by the central water plant and then processed in depth by the user itself.
1 General provisions 2 Terms 3 Quantity of water intake and water quality index 3.1 Quantity index of water intake 3.2 Water quality index 4 Water supply & drainage system 4.1 General requirements 4.2 Water supply system 4.3 Water drainage system 4.4 Water recirculation system 4.5 Water reuse system 4.6 Rainwater utilization system 5 Pump station 5.1 General requirements 5.2 Pump station arrangement 5.3 Water pump selection and configuration 5.4 Auxiliary facilities 6 Non-contact cooling water recirculation system 6.1 General requirements 6.2 Cooling 6.3 Water stabilizing facilities 6.4 Water makeup facilities 7 Contact cooling water recirculation system 7.1 General requirements 7.2 Equipment and slab spray cooling water recirculation 7.3 BFG cleaning water and used water from converter fume cleaning 7.4 BF slag granulation water recirculation 7.5 Laminar cooling water recirculation 8 Wastewater treatment 8.1 General requirements 8.2 Treatment of wastewater containing oil and emulsion 8.3 Treatment of wastewater from cold rolled strip temper mill 8.4 Cr-containing wastewater treatment 8.5 Acid-containing wastewater treatment 8.6 Alkali-containing wastewater treatment 8.7 Plant-wide wastewater treatment 8.8 Coking wastewater treatment 9 Emergency water supply system 9.1 General requirements 9.2 Emergency water users, emergency water supply output and duration 9.3 Emergency water supply facilities 10 Sludge thickening and dewatering 10.1 General requirements 10.2 Sludge thickening 10.3 Sludge dewatering 10.4 Coking sludge treatment and disposal 11 Testing and control 11.1 General requirements 11.2 Online testing 11.3 Control 12 Water supply & drainage pipelines 12.1 General requirements 12.2 Pipeline arrangement 12.3 Pipe gallery and pipe bridge arrangement 12.4 Pipe materials and fittings 12.5 Pipeline insulation 12.6 Pipeline corrosion prevention 12.7 Pipeline foundation Explanation of wording in this code List of quoted standards
1 General provisions
1.0.1 This code is formulated with a view to making the design of water supply & drainage engineering of iron and steel enterprises conform to the national guidelines, policies and regulations, unifying the engineering construction standards, improving the engineering design quality, and achieving advanced technology, safety and reliability, economy and rationality, energy conservation and emission reduction, and convenient management.
1.0.2 This code is applicable to the design of water supply & drainage engineering for construction, renovation and extension projects of iron and steel enterprises (including special steel mills).
1.0.3 The design of water supply & drainage engineering of iron and steel enterprises shall be based on the overall planning of iron and steel enterprises approved by the relevant government departments. The selection of water sources, locations of water treatment plants, water transmission and distribution pipelines, plant outlets, recycled & reused water utilizing rate, quantity of water intake per ton of steel, etc. shall meet the requirements of the overall planning.
1.0.4 When the industrial wastewater and domestic sewage drainage pipelines of iron and steel enterprises are connected to the water drainage system or water body with public sewage treatment system, the drainage water quality must meet the requirements of the relevant national and local discharge standards.
1.0.5 In addition to this code, the design of water supply & drainage engineering of iron and steel enterprises shall also comply with those stipulated in the current relevant standards of the nation.
2 Terms
2.0.1 quantity of water intake
quantity of water taken from the self-built or jointly-built water intake facilities of the iron and steel enterprises, regional or urban water supply projects, and tail water of power plants, as well as water purchased by iron and steel enterprises, but excluding the quantity of seawater, brackish water, rainwater, and reuse water from the wastewater of enterprises
2.0.2 quantity of water intake per ton of steel
ratio of annual quantity of water intake to annual steel output in iron and steel enterprises, expressed in m3/t
2.0.3 fresh water consumption per ton of steel
ratio of annual industrial fresh water consumption to annual steel output in iron and steel enterprises, expressed in m3/t
2.0.4 raw water
untreated water obtained from water sources
2.0.5 industrial fresh water
general term for finished water made from raw water, including process fresh water, soft water, demineralized water, pure water and so on
2.0.6 process fresh water
one kind of industrial fresh water, which is used as the makeup water of water recirculation system or as the raw water for producing soft water and demineralized water
2.0.7 soft water
water in which the hard components (mainly calcium ions and magnesium ions in water) are removed or reduced to a certain extent
2.0.8 demineralized water
water in which the salts (mainly strong electrolytes dissolved in water) are removed or reduced to a certain extent
2.0.9 pure water
water in which both the strong and weak electrolytes are removed or reduced to a certain extent
2.0.10 water for serial reuse
water that is used by a user and then made available for reuse by a sub-user without water treatment
2.0.11 reuse water
wastewater that is recycled either directly or after treatment
2.0.12 meteorological data
specific meteorological parameters such as wet bulb temperature, dry bulb temperature, atmospheric pressure and relative humidity used in the design and calculation of cooling towers
2.0.13 non-contact cooling water recirculation system
cooling water recirculation system that transfers heat indirectly between the recirculating cooling water and the cooled medium
2.0.14 system capacity
sum of all effective water storage volumes in the cooling water recirculation system
2.0.15 acid regeneration
process of regenerating and recycling waste acid
2.0.16 reclaimed water
undrinkable water derived from domestic sewage and wastewater, which, after being treated, reaches the prescribed water quality standards and is made available for miscellaneous purposes in domestic, municipal and environmental areas
2.0.17 unit project
project responsible for a single production process in an iron and steel complex
2.0.18 plant-wide wastewater
blowdown water, process wastewater and domestic sewage collected from various production workshops through combined system or separate system
2.0.19 sewage depth processing
further water treatment process of domestic sewage or industrial wastewater after primary and secondary treatments, so that the water meets certain reuse water standards and then can be used as a water resource for production or life
3 Quantity of water intake and water quality index
3.1 Quantity index of water intake
3.1.1 The quantity index of water intake per ton of steel for newly-built iron and steel complexes shall not be greater than 6m3/t.
3.1.2 The quantity index of water intake per ton of steel for renovated or extended iron and steel complexes shall not be greater than 7m3/t.
3.1.3 The quantity index of water intake per ton of steel for newly-built special steel mills shall not be greater than 8m3/t, and that for renovated or extended special steel mills shall not be greater than 10m3/t.
3.2 Water quality index
3.2.1 When raw water needs to be treated, it shall be treated in a centralized manner. For the unit projects with special requirements for water quality, the raw water may also be treated separately after technical and economic comparison.
3.2.2 The water quality indexes for industrial fresh water and reuse water shall be determined according to local water source conditions, water quality requirements of each water recirculation system and cycle of concentration of circulating water, etc., and should meet the requirements of Table 3.2.2.
Table 3.2.2 Water quality indexes for industrial fresh water and reuse water
Index Unit Process fresh water Soft water Demineralized water Reuse water
pH value - 7~9 7~9 6.5~9 6~9
Suspended solids mg/L ≤10 ≤5 ≤1 ≤20
Full hardness mg/L (in CaCO3) ≤150 ≤10 ≤2 ≤450
Ca hardness mg/L (in CaCO3) ≤100 ≤2 ≤1 ≤300
M-alkalinity mg/L (in CaCO3) ≤110 ≤110 ≤1 ≤330
Chloride ion mg/L (in CL) ≤220 ≤200 ≤1 ≤660
Sulfate ion mg/L (in SO42-) ≤80 ≤80 Not detected ≤240
Total iron mg/L (in Fe) ≤1 ≤1 ≤0.1 ≤3
Soluble SiO2 mg/L (in SiO2) ≤6 ≤6 ≤0.1 ≤18
Oil content mg/L ≤2 ≤1 Not detected ≤5
Conductivity μs/cm ≤500 ≤500 ≤10 ≤3,000
Residue after evaporation (dissolved) mg/L ≤300 ≤300 ≤5 ≤1,000
Ammonia-nitrogen mg/L ≤10 ≤10 ≤1 ≤10
CODcr mg/L - - - ≤100
Notes:
1 The probability of each water supply index shall be above 90%.
2 When groundwater is the main water source, its full hardness shall not exceed 200mg/L.
3 The demineralized water produced by the central water plant should be determined according to the quality of Grade 1 demineralized water. For single users with higher water quality requirements and adopting centralized treatment, an external pipeline shall be added, and Grade 1 demineralized water may be provided by the central water plant and then processed in depth by the user itself.
Contents of GB 50721-2011
1 General provisions
2 Terms
3 Quantity of water intake and water quality index
3.1 Quantity index of water intake
3.2 Water quality index
4 Water supply & drainage system
4.1 General requirements
4.2 Water supply system
4.3 Water drainage system
4.4 Water recirculation system
4.5 Water reuse system
4.6 Rainwater utilization system
5 Pump station
5.1 General requirements
5.2 Pump station arrangement
5.3 Water pump selection and configuration
5.4 Auxiliary facilities
6 Non-contact cooling water recirculation system
6.1 General requirements
6.2 Cooling
6.3 Water stabilizing facilities
6.4 Water makeup facilities
7 Contact cooling water recirculation system
7.1 General requirements
7.2 Equipment and slab spray cooling water recirculation
7.3 BFG cleaning water and used water from converter fume cleaning
7.4 BF slag granulation water recirculation
7.5 Laminar cooling water recirculation
8 Wastewater treatment
8.1 General requirements
8.2 Treatment of wastewater containing oil and emulsion
8.3 Treatment of wastewater from cold rolled strip temper mill
8.4 Cr-containing wastewater treatment
8.5 Acid-containing wastewater treatment
8.6 Alkali-containing wastewater treatment
8.7 Plant-wide wastewater treatment
8.8 Coking wastewater treatment
9 Emergency water supply system
9.1 General requirements
9.2 Emergency water users, emergency water supply output and duration
9.3 Emergency water supply facilities
10 Sludge thickening and dewatering
10.1 General requirements
10.2 Sludge thickening
10.3 Sludge dewatering
10.4 Coking sludge treatment and disposal
11 Testing and control
11.1 General requirements
11.2 Online testing
11.3 Control
12 Water supply & drainage pipelines
12.1 General requirements
12.2 Pipeline arrangement
12.3 Pipe gallery and pipe bridge arrangement
12.4 Pipe materials and fittings
12.5 Pipeline insulation
12.6 Pipeline corrosion prevention
12.7 Pipeline foundation
Explanation of wording in this code
List of quoted standards
