GB 28936-2012Discharge standards of water pollutants for reeling industry (English PDF)

1 Scope of application

1 The document fixes the water pollutant discharge limits for reeling industry enterprises and production facilities, the monitoring and supervisory monitoring requirements that go with them, and the provisions on implementation and supervision of the standard itself.

It applies to the management of water pollutant discharge from existing reeling industry enterprises or production facilities.

It applies to the environmental impact assessment of construction projects of reeling industry enterprises, to the design of their environmental protection facilities, to the environmental protection acceptance on completion, and to the management of water pollutant discharge after the projects have gone into production.

It applies to discharge behaviour permitted by law. The siting of newly established pollution sources, and the management of existing pollution sources inside specially protected areas, are dealt with under the relevant provisions of the Water Pollution Prevention and Control Law of the People's Republic of China, the Marine Environment Protection Law of the People's Republic of China and the Environmental Impact Assessment Law of the People's Republic of China, and under the related regulations and rules.

The water pollutant discharge control requirements laid down here apply to the act of an enterprise discharging water pollutants, directly or indirectly, beyond its legal boundary.

2 Normative references

The document states that it cites the following documents or clauses of them.

GB/T 6920-86 Water quality - Determination of pH value - Glass electrode method; GB/T 11893-89 Water quality - Determination of total phosphorus - Ammonium molybdate spectrophotometric method; GB/T 11901-89 Water quality - Determination of suspended substance - Gravimetric method; GB/T 11914-89 Water quality - Determination of the chemical oxygen demand - Dichromate method.

HJ/T 195-2005 Water quality - Determination of ammonia nitrogen - Gas-phase molecular absorption spectrometry; HJ/T 199-2005 Water quality - Determination of total nitrogen - Gas-phase molecular absorption spectrometry; HJ 505-2009 Water quality - Determination of five-day biochemical oxygen demand (BOD5) - Dilution and seeding method; HJ 535-2009 Water quality - Determination of ammonia nitrogen - Nessler's reagent spectrophotometry; HJ 536-2009 Water quality - Determination of ammonia nitrogen - Salicylic acid spectrophotometry; HJ 537-2009 Water quality - Determination of ammonia nitrogen - Distillation-neutralisation titration; HJ 636-2012 Water quality - Determination of total nitrogen - Alkaline potassium persulfate digestion ultraviolet spectrophotometry; HJ 637-2012 Water quality - Determination of petroleum oils and animal and vegetable oils - Infrared spectrophotometry.

Two administrative texts are cited as well: the Measures for the Administration of Automatic Monitoring of Pollution Sources (Order No. 28 of the former State Environmental Protection Administration) and the Measures for the Administration of Environmental Monitoring (Order No. 39 of the same body).

3 Terms and definitions

3.1 reeling facility - an enterprise that takes silkworm cocoons as its main raw material and, through the operations of selecting, cocoon cooking, reeling, re-reeling and finishing, produces raw silk, dupion silk and doupion silk together with by-products such as waste silk, silk waste ends and pupae; both mulberry silkworm reeling enterprises and tussah silkworm reeling enterprises are included.

3.2 existing facility - a reeling production enterprise or production facility that, before the date this standard takes effect, has been built and put into production or whose environmental impact assessment document has been approved.

3.3 new facility - a construction project for a reeling production facility, new, rebuilt or extended, whose environmental impact assessment document is approved on or after the date this standard takes effect.

3.4 effluent volume - the quantity of wastewater discharged by a production facility or enterprise that has no further function, including every kind of externally discharged wastewater directly or indirectly related to production (domestic sewage of the plant area, and drainage from plant boilers and power stations, are counted in).

3.5 benchmark effluent volume per unit product - the upper limit set on the wastewater discharged per unit of raw silk product, used to check discharge concentrations.

3.6 direct discharge - the act of a discharging unit releasing water pollutants directly into the environment.

3.7 indirect discharge - the act of a discharging unit releasing water pollutants into a public wastewater treatment system.

3.8 public wastewater treatment system - an enterprise or body that collects wastewater through sewer pipes or similar means, provides wastewater treatment for two or more discharging units, and whose own discharge can meet the relevant discharge standard; municipal wastewater treatment plants of every scale and type and area treatment plants (industrial parks, development zones, industrial clusters and the like) are included, and the degree of treatment is to reach secondary treatment or better.

4 Pollutant discharge control requirements

4.1 From 1 January 2013 to 31 December 2014 existing mulberry silkworm reeling enterprises apply the water pollutant discharge limits of Table 1; from 1 January 2015 existing tussah silkworm reeling enterprises apply the same limits.

Table 1 is headed "discharge concentration limits and benchmark effluent volume per unit product for existing facilities" and is given in mg/L, the pH value excepted. For each pollutant it carries one limit for direct discharge and one for indirect discharge: pH value 6~9 and 6~9; chemical oxygen demand (CODCr) 100 and 200; five-day biochemical oxygen demand 40 and 80; suspended substance 70 and 140; ammonia nitrogen 25 and 40; total nitrogen 30 and 50; total phosphorus 1.0 and 1.5; animal and vegetable oils 15 and 15.

The benchmark effluent volume per unit product in the same table is 1 200 m3/t. The monitoring position for all the pollutants listed is the total wastewater outfall of the enterprise, and the effluent volume is metered at the same position as the discharge monitoring point.