Abstract: A wastewater treatment method and apparatus including a denitrification (anoxic) chamber for denitrifying wastewater, an aeration basin with Bio-Wheel for aerating the wastewater, and a membrane device in which sludge particles are separated out of the wastewater, leaving clean discharge water and reusable sludge. Sludge from the membrane chamber floor is sent back to the aeration basin or denitrification chamber or both. Excess sludge is wasted or held for further processing. Preferably, the method and apparatus facilitate both activated sludge and fixed film processes.

Abstract: A filter cloth of long pile fiber bundles is used as a tertiary filter in a wastewater processing method. The filter may be backwashed by a rotating suction head which does not touch the filter cloth. A combination of countercurrent and horizontal flow dislodges entrained solids from the filter cloth. Mounting of the filter media as modular components permits increased capacity within a single tank while avoiding down time in changeover of filter media.

Abstract: An apparatus for filtering suspended solids from a liquid having a group of filters mounted inside a filter chamber. The filters divide the chamber into dirty liquid chambers and clean liquid chambers. A wash assembly is disposed within the chamber having vacuum/pump heads in contact with the filters rotates within the chamber. The vacuum/pump heads are connected to a pump and vacuum source located either within or without the apparatus. The vacuum/pump heads either vacuum material up or spray material therefrom in order to clean the filters. As the wash assembly rotates, the vacuum heads are able to contact and clean the entire surface of the filters. The filters are reasonably mounted in the chamber such that they may be removed from the chamber for servicing/replacement without the need to drain the chamber or enter the chamber.

Abstract: A piezoelectric polymer (PVDF) hydrophone array consists of multiple layers disposed symmetrically about a stiffener layer. The stiffener layer prevents flexural modes in the operating frequency band and provides a mounting structure for acceleration noise cancellation. The piezoelectric polymer layers are attached to the stiffener layer either directly or through intervening layers which provide mechanical vibration isolation of the polymer and stiffener layers.

Abstract: The composite transducer of this invention comprises a prior art longitudinal vibrator-type transducer for transmission of energy and a piezoelectric polymer hydrophone attached to the radiating face of the transducer for the receiving function. During transmission the receiver transducer is short-circuited, and during reception the transmitter transducer is terminated in an electrical impedance that optimizes receiver response and minimizes transducer self-noise. The frequency response of the polymer hydrophone is relatively flat and extends over a much greater frequency range than the transducer.