Abstract: A water supply pipe has a tubular liner of a polyolefin elastomer/plastomer installed therein. The polyolefin elastomer/plastomer includes a substantially linear ethylene inter-polymer with a narrow molecular weight distribution from 1.8 to 2.2.

Abstract: A water supply pipe has a tubular liner of a polyolefin elastomer/plastomer installed therein. To install it, a messenger pig is attached to a line that pulls the liner through the pipe. The liner is produced by extrusion and die drawing during extrusion.

Abstract: This invention relates to means of qualitative and quantitative analysis of microbial populations potentially present in a sample. These means notably comprise the use of at least one RNA-targeted oligonucleotide probe for in situ hybridization in whole cells; followed by the extraction of those probes which have become hybridized by separation from their target and elution from the microbial cells; as well as the detection and measurement of said extracted probes.

Abstract: A water supply pipe has a tubular liner of a polyolefin elastomer/Plastomer installed therein. The polyolefin elastomer/plastomer includes a substantially linear ethylene inter-polymer with a narrow molecular weight distribution from 1.8 to 2.2.

Abstract: Device for use in rehabilitation of water supply pipes includes a tubular liner (10) which is deployed through a pipe (11) for example by a line attached to a messenger pig which is propelled through the pipe. The liner (10) has a multi-lobed pleated cross-section, and is of a polyolefin elastomer material, e,g, a substantially linear ethylene inter-polymer. The liner is extruded and die drawn during extrusion to produce a reduced diameter highly oriented structure.

Abstract: Process for controlling the retention time of the sludge undergoing clarification in a process for treating wastewater by activated sludge comprising a recirculation of the activated sludge from the clarification stage into the biological basins, characterized in that the rate of sludge recirculation (Qr) is varied so as to maintain a constant recirculated sludge concentration (Cr) while at the same time guaranteeing a retention time (RT) of the sludge undergoing clarification of less than a critical value (RTmax).

Abstract: A process is disclosed for regulating the aeration in a biological wastewater treatment plant using a carbon removal stage, a nitrification stage and a denitrification stage. The process includes the step of continuously measuring the value of oxidation-reduction potential of the treated medium as well as measuring oxygen concentration of the treated medium during aeration phases. This permits maintaining aeration if the oxygen concentration falls within a preselected reference range. Alternately there is reduction of the aeration if the oxygen concentration is above the preselected reference range, or increasing the aeration if the oxygen concentration falls below the preselected reference range.

Abstract: An apparatus for the separation of a solid/liquid suspension by filtration includes a tank filled with a suspension to be treated. At least one cavitied plate is located in the tank and has at least one internal cavity. The plate is immersed in the suspension to be treated. The plate is inclined with respect to the vertical and only a lower inclined face of the plate is covered with a filter medium, the upper face being solid. The compartment of the cavitied plate communicates with a conduit which collects filtered suspension. Gas flushing pipes are positioned below the plate for emitting gas bubbles that pass across the filter medium and remove material clinging thereto.

Abstract: A Method for regulating the disinfection of a liquid includes a number of stages. At one stage of the said disinfection (stage 2), the activity of at least one enzyme is measured by bringing the microorganisms which may be present in the liquid into contact with a substrate capable of revealing the activity of the enzyme, this enzymatic activity being referred to as specific activity. At another stage (stage 1), prior to stage 2, there occurs measuring the activity of the same enzymes. This activity being referred to as initial activity. The next stage involves translating, for each enzyme, the specific activity and initial activity, into levels of microorganisms surviving in the liquid at stage 2 of the disinfection by means of a reference system pre-established with the aid of a sample of the liquid collected at stage 1 and then exposed to increasing doses of disinfectant.

Abstract: This method uses the on/off sequences of an aeration system of treatment basins. The sequences are imposed by the running of a treatment process, to estimate the respiration of biomass, the latter being measured during non-aeration phases. There is an initial determination, from the concentration of dissolved oxygen, of the change in the amount of oxygen contained in the aeration basin. There is a subsequent determination of the amount of oxygen leaving the aeration basin, the amount of oxygen entering the basin during the non-aeration phase being regarding as zero. Next is a determination, on the basis of the information collected in the above steps, of the respiratory capacity of the purifying biomass. There is then a determination of the mass of suspended matter in the purifying biomass and calculation, from the respiratory capacity of the biomass and from the sludge concentration, of the amount of oxygen consumed per unit mass of biological sludge and per unit time.

Abstract: A process is disclosed for monitoring the integrity of hollow fiber filtration modules and for detecting leaks of treated liquid through a fiber completely or partially broken. It operates continuously and in filtration mode, without production shutdown. The process includes detecting the noise caused by the passage of the liquid through a ruptured fiber. The noise signal thus obtained is amplified. The amplified signal thus obtained is compared with a threshold noise level, within the same range of frequencies, which is characteristic of intact modules, this comparison making it possible to detect whether or not the module is intact.

Abstract: A method of monitoring and managing biomass stock of treatment plants employs activated sludge. An aeration basin receives an effluent and a concentration of suspended matter in the basin is measured. A change in concentration is then analyzed and a maxima of this concentration is determined which corresponds to periods of hydraulic underperformance. A total biomass mass is estimated, and the rate of extraction of biomass is adjusted.

Abstract: Method of monitoring the efficiency of the aeration systems of biological basins of a wastewater treatment plant, characterized in that it consists in: i) measuring the throughput (Qt) of the plant and the rate (Qr) of recirculation of the mixed liquor from the clarifier to the aeration basin; and ii) measuring the concentration of dissolved oxygen in the aeration basin so as: a) to establish, during an aeration period, the material balance between oxygen supplied, oxygen consumed and oxygen discharged with the effluent; b) to establish, during a non-aeration period, the material balance between oxygen consumed and oxygen discharged with the effluent; c) to determine the amount of oxygen consumed by the biomass based on the two material balances established above; and d) to determine, from the data obtained at a), b) and c) , the value of the transfer coefficient &agr;kLa under the conditions of the measurement.