Abstract: A high rate, upflow filtration system is described in which a compressible, fibrous lump filtration media is compressed to adjust the porosity and collector size of the media in the bed and to provide a porosity gradient within the bed proceeding from more porous to less porous in a direction opposite to the flow of fluid so that filtration proceeds in a direction from a more porous to a less porous filter bed. Larger particles are removed by the more porous media and successively smaller particles are removed as the filter bed becomes less porous. The system is capable of reducing the turbidity of influent municipal wastewater from about 8 NTU to about 2 NTU at a wastewater flow rate of from about 820 to 1230 L/m2·min (20 to 30 gal/ft2·min), at a bed compression ration of from about 15 to 40 percent, and at a backwash rate of from about 1 to 6 percent based on the total wastewater passing through the filter.

Abstract: A grit-and-grease removal system includes a grit channel for degritting water by promoting settling of grit to the bottom of the channel, the grit being removed from the bottom of the channel by a traveling bridge-type grit removal device supporting a submerged grit pump. The system further includes an elongate grease channel arranged to receive degritted water from the grit channel, and having a plurality of grease skimmer pipes extending across the channel above the water level. The grease skimmer pipes are spaced apart along the length of the grease channel, and each grease skimmer pipe includes a plurality of fluid discharge orifices or nozzles spaced along the length of the pipe and oriented to blow fluid obliquely onto the water surface in the direction of a discharge end of the grease channel so as to move grease floating on the surface to the discharge end.

Abstract: A grit-and-grease removal system includes a grit channel for degritting water by promoting settling of grit to the bottom of the channel, the grit being removed from the bottom of the channel by a traveling bridge-type grit removal device supporting a submerged grit pump. The system further includes an elongate grease channel arranged to receive degritted water from the grit channel, and having a plurality of grease skimmer pipes extending across the channel above the water level. The grease skimmer pipes are spaced apart along the length of the grease channel, and each grease skimmer pipe includes a plurality of fluid discharge orifices or nozzles spaced along the length of the pipe and oriented to blow fluid obliquely onto the water surface in the direction of a discharge end of the grease channel so as to move grease floating on the surface to the discharge end.

Abstract: A high rate, upflow filtration system is described in which a compressible, fibrous lump filtration media is compressed to adjust the porosity and collector size of the media in the bed and to provide a porosity gradient within the bed proceeding from more porous to less porous in a direction opposite to the flow of fluid so that filtration proceeds in a direction from a more porous to a less porous filter bed. Larger particles are removed by the more porous media and successively smaller particles are removed as the filter bed becomes less porous. The system is capable of reducing the turbidity of influent municipal wastewater from about 8 NTU to about 2 NTU at a wastewater flow rate of from about 820 to 1230 L/m2·min (20 to 30 gal/ft2·min), at a bed compression ratio of from about 15 to 40 percent, and at a backwash rate of from about 1 to 6 percent based on the total wastewater passing through the filter.

Abstract: A grit-and-grease removal system includes a grit channel for degritting water by promoting settling of grit to the bottom of the channel, the grit being removed from the bottom of the channel by a traveling bridge-type grit removal device supporting a submerged grit pump. The system further includes an elongate grease channel arranged to receive degritted water from the grit channel, and having a plurality of grease skimmer pipes extending across the channel above the water level. The grease skimmer pipes are spaced apart along the length of the grease channel, and each grease skimmer pipe includes a plurality of fluid discharge orifices or nozzles spaced along the length of the pipe and oriented to blow fluid obliquely onto the water surface in the direction of a discharge end of the grease channel so as to move grease floating on the surface to the discharge end.

Abstract: An activated sludge treatment process and apparatus are provided for denitrification of a trickling filter plant effluent in which the nitrate nitrogen to BOD5 ratio can be maintained at less than or equal to 0.18 without the use of a nitrate monitor to control supplemental dosing with carbonaceous organic compounds or their salts. The apparatus is equipped with a turbidity meter, a phosphate monitor, and with a substrate storage tank for the addition of carbonaceous organic substrate. The substrate is added immediately at the end of the oxic phase and is continued until phosphate release is detected. Accordingly, the phosphate monitor functions as an indicator of nitrate respiration in the anoxic phase.

Abstract: Activated sludge process for biological waste water treatment comprises controlling the supply of oxygen to a single tank reactor in response to the phosphate concentration in the anaerobic phase independent of turbidity. The oxic phase is initiated if the maximum turbidity set point is exceeded in the usual manner. However, if the phosphate concentration exceeds its maximum set point before the turbidity reaches a maximum, then the oxic phase is initiated to end phosphate release. Acetic acid can be added to increase phosphate elimination at the end of the anaerobic phase, prior to switching on the supply of oxygen.

Abstract: A method for biologically removing approximately seventy-five percent of the phosphate contaminants from wastewater comprises controlling the aerator to a single activated sludge tank according to the turbidity of the water and the effluent requirements. Oxic, anoxic, and anaerobic reactions occur sequentially over the entire volume of the single reactor. Greater phosphate removal requires a simultaneous chemical precipitation.

Abstract: A method for the treatment of wastewater wherein the turbidity level of the wastewater is monitored to control the operation of the aerating units, while simultaneously, the oxygen concentration in the aerating tank is monitored to control the staging of the aaerating units between the maximum and minimum turbidity levels.

Abstract: An apparatus for introducing gases in the form of fine bubbles into a fluid is described, in which a diffuser pipe for a perforated distributor hose is mounted on a gas supply pipe. The diffuser pipe is constructed in one piece, extends transversely across the gas supply pipe, and is attached to the same by means of clamping elements. An opening for the passage of the gas is provided between the diffuser pipe and gas supply pipe. A pair of plugs positioned in the diffuser pipe define a flooding chamber at each end of the pipe and a gas-carrying chamber positioned medially therebetween. The apparatus is particularly suitable for the aeration of activation tanks for waste water.