Dosing Free Nitrous Acid as an Alternative Sulphide Control Technology for Pressure Sewers in Germany

Sulphide build-up in pressure sewers has been identified as the main cause for occurrence of odour and corrosion sewer systems. Despite efforts to optimize commonly used control technologies such nitrate iron salts reduce sulphide emission, continuous addition these chemicals is still required. A biocidal agent free nitrous acid can be added intermittently, less frequently, smaller quantities whilst achieving total control. So far, laboratory field studies Australia USA have successfully proven applied use this technology, exhibiting its strong effects during intermittent addition. In study, nine trials were made assess application (FNA) an alternative technology Germany. The pilot plant Berlin Water Utility Company was perform at a technical scale using supply raw sewage. FNA exposure times ranging from 5 24 h varying concentrations investigated. effectiveness treatment monitored online hydrogen (H2S) gas dissolved-sulphide sensors installed plant. Effective only possible dosing periods, with rapid resumption production <12 0.08 0.56 mg HNO2-N L−1 suggesting slight inhibitory effect. more pronounced effect observed exposed >0.29 L−1. Overall, study demonstrated that biofilms resistant inadequate develop effective strategy.