СНиП на английском языке SNiP 2.04.03-85
6.328. The design calculation of the exhaust ventilation system shall proceed from the amount of released
hydrogen; in this, the required capacity of a fan qfan, m3/hr, shall be determined from an expression:
qfan = (40 — 50) Wek qH , (103)
where qH is the specific volume of released hydrogen, l/m3, which can be taken from Table 57.
ELECTROCOAGULATORSWITH STEEL ELECTRODES
6.329. Electrocoagulators with steel electrodes shall be employed for treatment of waste water (effluents)
of enterprises in various industries with the purpose of its purification from hexavalent chromium and other
metals, with the waste water inflow not in excess of 50 m3/hr, the hexavalent chromium content within 100
mg/L, the initial total content of ions of nonferrous metals (zinc, copper, nickel, cadmium, trivalent
chromium) within 100 mg/L with concentration of ions of each metal to 30 mg/L, the minimum total salt
content of waste water of 300 mg/L, and concentration of suspended matter up to 50 mg/L.
6.330. The pH value of the waste water shall be, with simultaneous presence in it of:
hexavalent chromium, and ions of copper and zinc,
4 — 6, with the concentration of chromium of 50 — 100 mg/L;
5 — 6 with chromium concentration of 20 -50 mg/L;
6 — 7 with chromium concentration under 20 mg/L;
hexavalent chromium, nickel and cadmium,
5 — 6 with chromium concentration over 50 mg/L;
6 — 7 with chromium concentration under 50 mg/L;
ions of copper, zinc and cadmium (in the absence of hexavalent chromium), above 4.5;
ions of nickel (in the absence of hexavalent chromium), above 7.
6.331. The body of an electrocoagulator shall be protected from the inside with acid-proof insulation, and
equipped with a ventilation arrangement.
6.332. In design calculations of electrocoagulators, there shall be taken:
the anode current density, 150 — 250 A/m2;
the time of stay of waste water in an electrocoagulator, up to 3 minutes;
the spacing of adjacent electrodes, 5 — 10 mm;
the velocity of flow of waste water in the inter-electrode space, not lower than 0.03 m/sec;
the specific input of electric power for removal from waste water of 1 gram of Cr6+, Zn2+, Ni2+, Cd2+
or Cu2+ with the presence of only one of these components in the waste water, respectively, 3.1; 2 — 2.5; 4.5
- 5; 6 — 6.5; and 3 — 3.5 A-hr;
the specific input of metallic iron for removal from waste water of 1 gram of hexavalent chromium,
2 — 2.5 g; and the specific input of metallic iron for removal of 1 gram of nickel, zinc, copper and cadmium,
respectively, 5.5 — 6; 2.5 — 3; 3 — 3.5; and 4 — 4.5 grams.
6.333. With the presence in waste water of only one of the above components, the required current value,
Icur, A, shall be determined from an expression:
Icur = qw Cen qcur, (104)
where qw is the throughput of the unit, m3/hr;
Cen is the initial concentration of the component to be removed, g/m3;