摘要:
A process for decontaminating a solid material contaminated with an organic pollutant wherein the solid material contains grains with a particle size of up to 60 microns, which includes the steps of: (a) extracting the organic pollutant from the solid material containing grains with the particle size up to 60 microns by using a microemulsion which includes a thermodynamically stable, macroscopically homogeneous and optically transparent mixture of water, an apolar hydrophobic solvent, and a surfactant to form a cleaned solid material and a pollutant-containing microemulsion; (b) separating the cleaned solid material from the pollutant-containing microemulsion; and (c) splitting the pollutant-containing microemulsion into a surfactant-rich phase and a pollutant-containing phase.
摘要:
The coalescence and release of bubbles from packing that supports the growth of microorganisms is promoted by mechanical action on the packed bed arrangement, in particular by continuous or intermittent vibrations, rotations, or by rocking motions. With particular advantage, a reactor vessel which is typically tubular is filled with packing upon which microbial growth is sustained, preferably leaving a free space of 10% to 35%, in particular 15% to 20%. The reactor vessel has an axis that is substantially horizontal but preferably inclined by at least about 3.degree., and is set continuously or intermittently, for example, by an axle drive or by means of friction wheel drive, into rotational or rocking motions about that axis. The gas can be discharged, for example, via valves and a cam mechanism. Alternatively, a vent pipe, taken through the hollow shaft on the discharge side and upwards, can be provided behind a screen plate. Pipes that are parallel to the axis and that have openings, which are protected by finlike rims with slots, feed liquid or gas to the biomass-containing system in the reaction vessel. In another embodiment, a vertical reactor is equipped with packing provided on vibrating plates which are set into vibration, preferably intermittently. For denitrification, a nitrate-nitrite degradation stage can be provided upstream of the reactor vessel.
摘要:
Aerobic purification of waste water with intermittent batchwise supply of waste water to the activated sludge tank from which the treated waste water drains continuously is disclosed, in which the nitrate content in the waste water is simultaneously reduced by throttling the aeration of the activated sludge tank, starting with the admission of the waste water to the tank, to values equivalent to less than or equal to 0.5 mg/l dissolved oxygen. In particular, aeration may be off until such time as the nitrate content in the tank has dropped below 5 mg/l, in particular below 1 mg/l. In the case of urban waste waters a cycle time of about 1 hour is expediently employed under these circumstances and the aeration is shut off for about 5 minutes, starting from the rapid admission of the waste water charge. Preferably, inlet charges are less than or equal to 30%, in particular between about 5% and 20%, of the tank capacity. In this procedure, nitrate present is degraded in the phase involving oxygen throttling, while in the subsequent phase (over longer times) ammonium fed in with the waste water supplied is converted into nitrate, provision being made for a sufficient population of nitrifying bacteria in the tank.
摘要:
A method is provided for optimally supplying autotrophic organisms with CO.sub.2 nutrient, the requirement for the nutrient fluctuating in dependence on growth and thus on the incident light, temperature and the density of the organisms. The pH in a culture channel containing the organisms is continuously measured and the introduction of CO.sub.2 into the culture channel is regulated in response to the measured pH. An arrangement is provided for practicing the method and comprises a channel in which a suspension of the organisms can be moved in one direction, at least one discharge means in the channel for introducing the CO.sub.2 gas into suspension, at least one control member connected to the discharge means for controlling the operation of the discharge means, at least one pH measuring means in the channel for immersion into the suspension, and a circuit connecting the pH measuring means and the control member to actuate the control member for introducing the CO.sub.2 in response to the pH measured by the pH measuring means.