Environmental Code of Practice for Non-Integrated Steel Mills: appendix A

Appendix A: Methodologies for the Calculation of Environmental Performance Indicators

• A.1 Methodology for Calculation of Particulate Emissions from Electric Arc Furnaces (Recommendation RN102)
• A.2 Methodology for Calculation of Total Suspended Solids Discharges for non-integrated Steel Mills (Recommendation RN108)
• A.3 Methodology for Calculation of Water Use/Recycle for non-integrated Steel Mills (Recommendation RN110)

A.1 Methodology for Calculation of Particulate Emissions from Electric Arc Furnaces (Recommendation RN102)

• The Indicator should be based on liquid steel produced (steel tapped into ladle, not including liquid heel).
  
• The following particulate sources should be included in the Indicator:
  • primary particulate emissions from the electric arc furnace operations including charging, melting, and refining;
  • fugitive particulate emissions from the above electric arc furnace operations that are collected by the secondary emission control system;
  • fugitive particulate emissions that are not collected by the secondary emission control system, including tapping and slagging;
  • particulate emissions from ladle metallurgy, vacuum degassing, and continuous casting; and
  • particulate emissions from the flux handling and injection systems.
    
• All emission testing should be carried out downstream of the emission control devices.
  
• Measurement of the particulate emissions from the electric arc furnace emission control device(s) should be carried out in a manner that is consistent with the emission testing methodology referred to in Recommendation RN101.
  
• Testing should be carried out during normal operations, i.e., upset or malfunction conditions should be excluded.
  
• The particulate emission discharge from the emission control device(s) for the primary and secondary systems for one production cycle (one heat of steel) should be calculated in accordance with the formula:
  (P × Fp + S × Fs) × Δt) = Ed
  where:
  • P is the primary emission control system particulate emission concentrations;
  • Fp is the primary emission control system gas flow at standard conditions;
  • S is the secondary emission control system particulate emission concentrations where applicable;
  • Fs is the secondary emission control system gas flow at standard conditions;
  • Δt is the duration of the production heat cycle; and
  • Ed is the total particulate emissions discharged from the control devices for the production heat cycle.
    
• The calculation of fugitive particulate emissions from the electric arc furnace operations should be based on a fugitive emission factor that is widely used in the industry (e.g., EPA AP 42) for each phase of the operations and the estimated capture efficiency of the secondary emission collection system. Fugitive particulate emissions should be calculated in accordance with the formula:
  [Ef × (1 - Sc)] × Δt = Fe
  where:
  • Ef is the fugitive particulate emission factor for the electric arc furnace operation;
  • Sc is the secondary emission collection system estimated capture efficiency;
  • Δt is the duration of the production heat cycle; and
  • Fe is the fugitive particulate emission discharge to the atmosphere.
    
• The calculation of particulate emissions from the particulate emission control devices for other operations should be based on testing of the emission control devices. The formula that should be used is:
  ∑[Flp × Ff1 × Δt = Fle
  where:
  • Flp is the control device particulate concentration;
  • Ff1 is the control device gas flow at standard conditions;
  • Δt is the duration of the production cycle;
  • ∑[Flp × Ff1 × Δt is the sum of the particulate discharges from the emission control devices; and
  • Fle is the total particulate emissions discharged from the flux emission control devices for the duration of the production heat cycle.
    
• The mass emission factor for a heat of steel should be calculated for a complete production cycle of a heat of steel in accordance with the formula:
  (Ed + Fe + Fle) / Sp = MEF
  where:
  • Sp is the liquid steel production; and
  • MEF is the mass emission factor for the production of one heat of steal.
    
• The Environmental Performance Indicator is the average of the mass emission factors for three production cycles.

A.2 Methodology for Calculation of Total Suspended Solids Discharges for non-integrated Steel Mills (Recommendation RN108)

a) For facilities without cold forming and finishing operations:

• The Indicator should be based on liquid steel produced (steel tapped into ladle, not including liquid heel).
  
• Wastewater from the following discharge sources should be included in the Indicator:
  • steelmaking operations including ladle metallurgy, vacuum degassing, and continuous casting;
  • hot forming operations;
  • cold forming and finishing operations where applicable;
  • direct cooling;
  • environmental control operations; and
  • service activities (e.g.: maintenance and steam generation);

All wastewater discharges to receiving water bodies should be included (non-contact cooling water not included). Wastewater discharges to municipal treatment facilities that meet the municipal wastewater quality requirements should not be included.

• Wastewater sampling and analyses should be carried out in a manner that is consistent with the methodology referred to in Recommendation RI107 and is downstream of the wastewater treatment facilities where applicable.
  
• Wastewater flow measurement should be carried out in a manner that is consistent with the methodology referred to in Recommendation RI110 and is downstream of the wastewater treatment facilities where applicable.
  
• The total suspended solids measurement for the Indicator should be based on a 30-day average.
  
• The total suspended solids discharge should be calculated in accordance with the formula:
  ∑(TSS × Fw × Δt) / Sp = Ti
  where:
  • TSS is the total suspended solids concentration;
  • Fw is the flow of each wastewater discharge;
  • Δt is the elapsed time of the measurement period (e.g., 30 days);
  • ∑(TSS × Fw × Δt) is the sum of the discharges;
  • Sp is the liquit steel production for the measurement period; and
  • Ti is the total suspended solids Environmental Performance Indicator.

b) For facilities with cold forming and/or finishing operations:

The only change from (a) is that the wastewater discharges from the cold forming and finishing operations should be included.

A.3 Methodology for Calculation of Water Use/Recycle for non-integrated Steel Mills (Recommendation RN110)

Sources of wastewater discharges should include those resulting from direct-contact cooling, environmental control operations, production operations including direct iron reduction, steel making, cold forming, finishing, and service activities (e.g., maintenance and steam generation).

• Wastewater discharges should include discharges to receiving water bodies and to municipal treatment facilities.
  
• Water use on the basis of a once-through system, should be calculated based on flow measurements or engineering calculations for all uses.

Wastewater discharge on the basis of actual cascading and re-circulation, should be calculated based on discharge flow measurements, engineering calculations or engineering estimates.

• Flow measurements should be carried out in a manner that is consistent with the methodology referred to in Recommendation RI110 for operating units and downstream of the wastewater treatment facilities where applicable.
  
• The recycle rate should be calculated in accordance with the following principles and formula:
  • Once-through flow is measured, calculated, or estimated for the following activities:
    • Direct-contact cooling flow + process water flow + potable water flow = total once-through water flow or TWF)
  • Actual water discharge flow is measured, calculated, or estimated for the following activities:
    • Direct-contact cooling discharge flow + process water discharge flow + potable water discharge flow = Total wastewater discharge flow or TWD)
  • The recycle rate is then:
    (TWF -TWD) / TWF = Wr
    where:
    • Wr is the water recycle rate.