Title: 国家分别在2002年和2005年制定和颁布了有关《城市污水再生利用》的五项标准：
Author: Liu Xujun
Last saved by: Sasha Rodrigues
Company: International Water Association

Water quality standard for reclaimed wastewater in China

The complete standard series for the reclaimed wastewater consist of the following six national standards, which were issued by the central government in the period from 2002 to 2005：

－The reuse of urban recycling water- Classification Standard（GB/T 18919-2002）
－The reuse of urban recycling water-Water quality standard for urban miscellaneous water consumption（GB/T 18920-2002）
－The reuse of urban recycling water-Water quality standard for scenic environment use (GB/T 18921-2002)
－The reuse of urban recycling water-Water quality standard for industrial water consumption(GB/T 19923-2005)
－The reuse of urban recycling water-Water quality standard for groundwater recharge(GB/T 19772-2005)
－The reuse of urban recycling water-Water quality standard for  farm irrigation (GB 20922-2007)

During the practice of the usage of the reclaimed wastewater, the above national standard should be taken into account based on the actual usage of the reclaimed wastewater. The five water quality standards cover the most possible cases of the reuse of the reclaimed wastewater. 

1.	The reuse of urban recycling water- Classification Standard（GB/T 18919-2002）
The standard has divided the usage of reclaimed wastewater into five different categories as shown in table 3-1. 
table 3-1 The category of urban recycling water　　　　　　　　　　　　
Serial number | category | scope | example
1 | Agriculture, forestry, animal husbandry and fishery water | farm irrigation | Seeds, food and feed crops, cash crop
| | afforestation and seedling | Seeds, nursery stock, nursery garden, ornamental plants
| | livestock and breeding | Livestock, farm animal, poultry
| | aquaculture | freshwater aquaculture
2 | Urban miscellaneous water | urban landscaping | public lawn, residential district greening
| | flush the toilet | flush the toilet
| | Road cleaning | Urban roads washing and spraying
| | Car wash | Car wash
| | building operations | Cleaning, irrigating and dust suppression of construction plant, the concrete preparation and maintenance、the irrigating of concrete member and buildings
| | fire control | Hydrant, water cannon
3 | Industrial water | cooling water | straight-flow, recirculate-flow
| | Washing water | Cinder and ash flushing, washing
| | boiler water | Medium and low pressure boiler
| | process water | Dissolving, water bath, stewing, rinsing, hydraulic mining, hydraulic handling, humidifying, diluting, beneficiation, Oilfield reinjection
| | Water for Production | Slurry, the chemical formulation products, coating
4 | Environmental water | recreational water environment | Riverway, lakes and waterscape
| | Ornamental water environment | Riverway, lakes and ornamental waterscape
| | Wetland water environment | natural wetlands restoration, constructed wetland
5 | Source of supply water | Supplement of surface water | rivers、lakes
| | Supplement of groundwater | Recharging water source, fresh water supply to prevent the seawater invasion, backfilling the groundwater

2.	The reuse of urban recycling water -Water quality standard for industrial water consumption(GB/T 19923-2005)
The industrial use of reclaimed wastewater is classified as following five categories: 
- Cooling water: including straight-flow and recirculate-flow supply water; 
- Washing water: including the water used to flush cinder and ash, remove smoke and dust and wash etc.; 
- Boiler water: including the supply water for medium and low voltage boiler etc;
- Process water: including the water used in dissolving, water bath, stewing, rinse, hydraulic mining, hydraulic handling, humidifying, attenuation, stir, beneficiation and Oilfield reinjection etc.; 
- Water for Production: including Slurry、the chemical preparation、coating etc. 

When urban recycling water was used for industries, all criterion included in the table 3-2 should be met. In the case of using urban recycling water produced from municipal wastewater, except full filling the criterion in table 3-2, the Chemical toxicology character of reclaimed water should also comply with the upper limit value of each index of “the first class of pollutants” and “Selective control items” listed in the Discharge standard of pollutants for municipal wastewater  treatment plant（GB18918）. In the case of using recycling water as cooling water (including straight-flow and recirculate-flow supply water) and washing water, the criteria listed in table 3-2 should be met and the recycling water can also be mixed with fresh water for cooling. 

Table 3-2 reclaimed water used as industrial water - water quality standard
Serial number | Control items | Cooling water | The washing water | Boiler feed water | Process and product water
| | DC cooling water | Open cycle cooling water system to add water | | |
1 | pH | 6.5－9.0 | 6.5－8.5 | 6.5－9.0 | 6.5－8.5 | 6.5－8.5
2 | SS（mg/L）≤ | 30 | － | 30 | － | －
3 | NTU≤ | － | 5 | － | 5 | 5
4 | chroma≤ | 30 | 30 | 30 | 30 | 30
5 | BOD5mg/L）≤ | 30 | 10 | 30 | 10 | 10
6 | COD Cr（mg/L）≤ | － | 60 | － | 60 | 60
7 | Fe（mg/L）≤ | － | 0.3 | 0.3 | 0.3 | 0.3
8 | Mn（mg/L）≤ | － | 0.1 | 0.1 | 0.1 | 0.1
9 | Cl-（mg/L）≤ | 250 | 250 | 250 | 250 | 250
10 | SiO2≤ | 50 | 50 | － | 30 | 30
11 | Total hardness（CaCO3/mg/L）≤ | 450 | 450 | 450 | 450 | 450
12 | TN（CaCO3 mg/L）≤ | 350 | 350 | 350 | 350 | 350
13 | Sulfate（mg/L）≤ | 600 | 250 | 250 | 250 | 250
14 | Ammonia nitrogen（mg/L）≤ | － | 10① | － | 10 | 10
15 | TP（以P计 mg/L）≤ | － | 1 | － | 1 | 1
16 | TDS（mg/L）≤ | 1000 | 1000 | 1000 | 1000 | 1000
17 | oil（mg/L）≤ | － | 1 | － | 1 | 1
18 | LAS（mg/L）≤ | － | 0.5 | － | 0.5 | 0.5
19 | Residual chlorine②（mg/L）≥ | 0.05 | 0.05 | 0.05 | 0.05 | 0.05
20 | Fecal coliform≤ | 2000 | 2000 | 2000 | 2000 | 2000
Note: ① In the case that the heat exchanger is made of copper, ammonia nitrogen of circulating cooling water system should be less than 1 mg/L. ② the residual chlorine at the endpoint of networks.

3.	The reuse of urban recycling water-Water quality standard for urban miscellaneous water consumption（GB/T 18920-2002）

This standard applies to the toilet flushing, road cleaning, fire control, urban landscaping, vehicle washing and construction. The water quality for the above usage should meet the criteria listed in the Table 3-3. When the recycling water was used to produce the concrete, its quality should also meet the relevant provisions included in JGJ 63. 

Table 3-3 urban miscellaneous use - water quality standards
Serial number | Items | Toilets Flushing | Road sweeping / fire control | Urban landscaping | Vehicle washing | construction
1 | PH | 6.0～9.0
2 | chroma≦ | 30
3 | Olfactory | No odor
4 | NTU   ≦ | 5 | 10 | 10 | 5 | 20
5 | TDS（mg/L）≦ | 1500 | 1500 | 1000 | 1000 | —
6 | BOD5 （mg/L）≦ | 10 | 15 | 20 | 10 | 15
7 | Ammonia nitrogen (mg/L) ≦ | 10 | 10 | 20 | 10 | 20
8 | LAS (mg/L) ≦ | 1.0 | 1.0 | 1.0 | 0.5 | 1.0
9 | Fe (mg/L) ≦ | 0.3 | — | — | 0.3 | —
10 | Mn (mg/L)≦ | 0.1 | — | — | 0.3 | —
11 | DO(mg/L)≦ | 1.0
12 | Total residual chlorine (mg/L) | contact 30min later≥1.0, The endpoint of pipe network≥0.2
13 | Total coliform  ≦ | 3

4.	The reuse of urban recycling water-Water quality standard for scenic environment use (GB/T 18921-2002)

The scenic water refers to water used to create urban landscape or waterscape, such as river, lakes, waterfalls, fountains, and entertainment etc. 
The water quality for the above usage should meet the criteria listed in the table 3-4. 

In such case, it is better to use the municipal sewerage as source and to avoid using the industrial wastewater. When the water body of landscape or waterscape is supplied fully with the reclaimed wastewater, the hydraulic retention of water should be less than 5 days. In the case that the water temperature is more than 25 ℃, the retention time should not exceed 3 days; in the case that the water temperature is less than  25 ℃, the retention time could be extended, especially in water, it could be extended to a month. 
Table 3-4 landscape water standard of reclaimed water(unit: mg/L)
Serial number | item | Ornamental landscape water | Entertainment landscape water
| | river | Lake | Waterscape | river | lake | waterscape
1 | Basic requirements | No debris, no odor
2 | pH   ≤ | 6~9
3 | BOD5     ≤ | 10 | 6 | 6
4 | SS      ≤ | 20 | 10 | ——
5 | NTU   ≤ | —— | 5
6 | DO  ≥ | 1.5 | 2.0
7 | TP    ≤ | 1.0 | 0.5 | 1.0 | 0.5
8 | TN    ≤ | 15.0
9 | Ammonia nitrogen    ≤ | 5
10 | Fecal coliform≤ | 10000 | 2000 | 500 | Not detected
11 | Residual chlorine    ≥ | 0.05
12 | Chroma    ≤ | 30
13 | oil  ≤ | 1
14 | LAS    ≤ | 0.5

Note 1: in the case that recycling water transported by pipeline, the chlorine disinfection should be applied; in other cases, the disinfection method is not addressed. 
Note 2: When the wastewater treatment is not equipped with nitrogen and phosphorus removal, it is highly recommended to cultivate the water plants, with which the nitrogen and phosphorus could be controlled within the limit listed in the table 3-4, meanwhile the above water plants has the economic advantages.

5.	The reuse of urban recycling water-Water quality standard for farm irrigation (GB 20922-2007)

Reclaimed wastewater for irrigation use should meet the criteria listed in the table 3-5-1 and 3-5-2. For fiber crops (cotton, sisal hemp) and dry field corn, the reclaimed water can be treated only by primary treatment (physical treatment); for paddy field grain or vegetable, the reclaimed water should be treated by secondary treatment (physical plus biological treatment). 

Table 3-5-1 Maximum limited index of basic control item and water quality (unit: mg/L)
Number | Basic control item | Irrigated crop’s type
| | Fiber crops | dry field corn Oil crops | paddy field grain | vegetable
1 | BOD _5 | 100 | 80 | 60 | 40
2 | COD _Cr | 200 | 180 | 150 | 100
3 | SS | 100 | 90 | 80 | 60
4 | DO ≥ | | 0.5
5 | pH | 5.5~8.5
6 | TDS | None saline-alkali land 1000, saline-alkali land area 2000 | 1000
7 | Chloride | 350
8 | Sulfide | 1.0
9 | Residual chlorine | 1.5 | 1.0
10 | Petroleum | 10 | 5 | 1
11 | Volatile Phenol | 1.0
12 | LAS | 8.0 | 5.0
13 | Mercury | 0.001
14 | Cadmium | 0.01
15 | Arsenic | 0.1 | 0.05
16 | Chrome (Ⅵ) | 0.1
17 | Lead | 0.2
18 | Number of fecal coliforms(a/L) | 40000 | 20000
19 | Number of ova of roundworm (a/L) | 2

Table 3-5-2 Maximum limited index of selective control item and water quality (unit: mg/L)
Number | Basic control item | limiting value | Number | Basic control item | limiting value
1 | Be | 0.002 | 10 | Zn | 2.0
2 | Co | 1.0 | 11 | Boron | 1.0
3 | Cu | 1.0 | 12 | Vanadium | 0.1
4 | fluoride | 2.0 | 13 | Cyanide | 0.5
5 | Fe | 1.5 | 14 | Trichloracetic aldehyde | 0.5
6 | Mn | 0.3 | 15 | Acrolein | 0.5
7 | Mo | 0.5 | 16 | Methanal | 1.0
8 | Ni | 0.1 | 17 | Benzene | 2.5
9 | Se | 0.02 | | |