The present application relates to abatement processes and systems of nitrogen oxide (NO.sub.x) contained in exhaust gases, more in particular produced by stationary burner and combustion systems. The NO.sub.x are removed by reduction using a catalyst and a reducing agent that is introduced into the exhaust gases and being mixed therewith. The mixture is then conducted over the catalyst resulting in conversion of the NO.sub.x in environmentally neutral N.sub.2 and H.sub.2O. The present application more in particular relates to a mixing system for such a NO.sub.x abatement system to mix the exhaust gases with the reducing agent.

Methods for making and installing inversion filling systems for reservoirs, including but not limited to providing a first transition conduit assembly and a second transition conduit assembly; where the first transition conduit assembly includes a first inversion chamber housing connected to a first transition conduit, and the first inversion chamber housing includes a frustoconical portion; where the second transition conduit assembly includes a second inversion chamber housing comprising a frustoconical portion connected to a second transition conduit; positioning the first transition conduit assembly above an inlet of the reservoir, creating a first inversion gap; positioning the second transition conduit assembly above the first transition conduit assembly, creating a second inversion gap; and extending the first transition conduit into the frustoconical portion of the second inversion chamber housing.

A hydrodynamic cavitation generating device and a method, including: a wheel disc, being provided with a plurality of flow passages, an orifice plate is provided inside the flow passages, and a throat orifice is provided on the orifice plate; a driving mechanism, being connected to the wheel disc, and configured to drive a rotation of the wheel disc; and a water-inlet pipe, being arranged fixedly, fitting with a first side end face of the wheel disc, and may inject water into the flow passage when being aligned with the flow passage; the cavitation effect obtained by using the hydraulic cavitation generating device is better.