| 摘要 |
Quantity of dissolved organic material is reduced by addition of nitrate prior to pptn. or biological treatment, partic. where the nitrate is added at an early stage and its quantity is regulated in accordance with oxygen demand prior to final treatment. The use of nitrate in combination with other oxidants e.g. oxygen or trivalent iron is also claimed. The sewage is also recirculated to provided sufficient time for the nitrate to function, and to prevent nitrogen content of the outgoing water from rising. - The method reduced formation of hydrogen sulphide in the sewer system. Nitrate can be added to the sewer pipe system or at all sizes of sewage works. The nitrate is added as Calcium nitrate or Saltpetre, pref. as soln. (Provisional Basic previously advised in week 8940) (5pp Dwg.No.0/0) |
