Abstract: A water treatment plant with two-stage filtration for purification of surface water sources with low turbidity and low temperature. The flow rate of this integrated water treatment should be less than 2 m3/sec (≈46 mgd). The integrated two-stage filtration plant with one flash mixer, six roughing filters, with upward flow, six high rate dual media filters, with downwards flow, and a clearwell is recommended for surface water sources with turbidity less than 100 NTU, color less than 75 UC, coliform less than 20,000/100 mL, algae less than 2,000 ASU/mL, TOC less than 4 mg/L, iron less than 1.5 mg/L, taste and odor less than 5 TON, alkalinity less than 200 mg/L, hardness less than 150 mg/L. For maximum values of alkalinity and hardness given above, and for optimal value of pH, the color has to be less than 40 UC, when alum is to be used. Filter effluent turbidities are foreseen to be 0.1 NTU or less.

Abstract: Disclosed herein is a filter surface washer with 8 nozzles and 4 orifices for non-air-scouring of filter medium. The filter surface washer is conceptually original device for sand and dual media rapid filters by gravity. With this type of device, the surface of the filter bed should be washed effectively for a very short period of time. The filter surface washer is very effective for 1 m2 (˜11.0 ft2) of filter area. For each surface washer are required 2.5-3 l/sec/m2 (3.5-4.3 gpm/ft2). The velocity of water jet in nozzle orifice should be 12-14 m/sec (39-46 ft/sec). The height of orifice of the nozzle (H0) from top of the filter surface should be 0.1-0.142 m. The values of velocity gradient will be 1000-1500 1/sec for diameter of nozzle's orifice d0=6 mm (¼″), and for diameter of 4 orifices d0=0.003 m (⅛″), in lower part of the device. These values of velocity gradients should be realized when water level above the filter will be H=0.1-0.

Abstract: A hydrodynamical dispersive flash mixing system with six pressured water jets and one nozzle for the injection of aluminum sulfate solution. The flash mixer, conceptually original, is highly recommended for medium, large, and extra large diameters of influent pipeline. The flash mixer introduced is very effective, flexible, reliable and cost savings. The flash mixer obtains an optimal coagulation, avoids clogging of pipes and nozzles with aluminum hydroxide scale, avoids the effects of water temperature, and controls the changes of flow capacity and coagulant dose. The hydrodynamical dispersive flash mixer with pressured water jets can be installed inside or outside the influent pipeline. One option is described for the installation of flash mixer inside the pipeline and three options for installing it outside the influent pipeline. Also, four alternatives are presented for the connection of the flash mixing system with the liquid chemical feed system.