WASTEWATER TREATMENT PLANT FOR OLIVE OIL PROCESSING EFFLUENTS COMPRISING A ROTATING BIOLOGICAL CONTACTOR WITH THE ADDITION OF LINEAR OR CIRCULAR MOTION

Abstract: The invention refers to the capacity of an aerobic bioconversion system for the wastewater treatment of an olive oil processing plant, concerning the phytotoxicity reduction by means of a biocontactor having various shapes, which is either rotating and in line or in circle moving, while the treated wastewater is stationary or only statistically rotating, while the treated wastewater is moving. The invention refers to an additional transport motion either of the biocontactor, implemented by placing the biocontactor on a trolley-frame, or of the treated wastewater with the rotating biocontactor remaining fixed, implemented by kinetic energy addition to the liquid (in all its treatment phases, especially while the gel phase) by means of mixers etc. The additional transport motion of the biocontactor allows treatment of a multiple wastewater volume. The suggested capacity increase allows for multiple greater efficiency of the whole plant in constructional and operating point of view, comparing with the biocontactor of the former technique. The invention is applicable for bioreactors with aerobic microorganisms, whose breathing time can be practically utilized for the additional suggested motion (linear or circular) of either the biocontactor or the treaded wastewater, as is the case in olive oil processing plants.

Description: DESCRIPTION WASTEWATER TREATMENT PLANT FOR OLIVE OIL PROCESSING EFFLUENTS COMPRISING A ROTATING BIOLOGICAL CONTACTOR WITH THE ADDITION OF LINEAR OR CIRCULAR MOTION The invention refers to the capacity increase of an aerobic bioconversion system for the wastewater treatment of an olive oil processing plant consisting of a biocontactor having various shapes which is either rotating and simultaneously moving in line or in circle, while the treated wastewater is stationary or only rotating statically, while the treated wastewater is moving. It is applicable for bioreactors with aerobic microorganisms, whose breathing time can be practically utilized for the motion (linear or circular) of the biocontactor or the treated wastewater, as is the case in olive oil processing plants, aiming at the reduction of the wastewater phytotoxicity. In particular, it is an improvement of the aerobic bioconversion technique for wastewater of olive oil processing plants using a rotating biocontactor. The biocontactor is half submerged inside a tank with olive wastewater having a neutral pH. The biocontactor is seated on fixed points, rotates on a horizontal shaft and performs no other motion. The biomass that grows in the tank of the contactor is of dual form : suspended and superjacent on the filling material. The superjacent biomass grows on the particles of the filling material. The suspended biomass grows inside the wastewater volume of the bioreactor. The wastewater volume in the bioreactor is low and almost equal to the half volume of the statically rotating biocontactor. As a result, the volume remaining for the growth of the suspended biomass is also low, as is the volume of the wastewater to be treated. The method with such a layout for the contactor results in huge capital and operating cost, since the process requires a multiple contactor system for the bioconversion of large wastewater volumes. The present invention features an additional motion of the rotating biocontactor, of various shapes, in an olive wastewater aerobic bioconversion process using microbial colonies with breathing time step practically usable for this motion. The addition of another motion except for the rotation results in multiple increase of the wastewater volume to be treated by the same biocontactor. The additional motion is implemented by the movement of either the rotating biocontactor or the wastewater. When the motion is applied to the rotating contactor, this is carried out by placing the contactor on a moving transport trolley. The latter moves either in line to-and-fro or in circle depending on the shape of the tank (rectangular or circular). When the motion is applied to the wastewater, which fills an oval-shaped tank (Carousell type), this is carried out by placing various types of mixers (propellers, pumps or Mammut-rotors) at a fixed point in the tank. The biocontactor is also at a fixed place and rotates around its horizontal shaft, thus letting the wastewater flow through it. The breathing time of the microorganisms must be practically usable. The time required for a full lap of the trolley or the wastewater must be less or equal to the time needed by the microorganisms for their next inhalation. Adjustment of the movement velocity or detainment time is possible. The tank dimensions, the movement velocity and the detainment time at each processing plant are adjusted depending on the volume of the wastewater in combination with the breathing time of the aerobic microorganisms for the specific wastewater. The direction of rotation is always the same with the motion of the trolley or the wastewater, in order for this motion to be supported. With the former technique the biocontactor inoculates microorganisms, mixes and oxygenates. With the additional motion the same biocontactor inoculates, mixes and oxygenates a multiple tank volume and thus a greater wastewater volume. This occurs because during the transport motion the contactor continuously inoculates the whole active tank volume with microorganisms, thus increasing the population density of the suspended biomass, continuously mixes the whole active tank volume (suspended biomass) bringing the lower microorganisms to the upper - rich in oxygen - layer of the tank and oxygenates the whole active tank volume (suspended biomass), since the lap time step is less than the breathing time step of the microorganisms. Practically, as many times the biocontactor volume fits the volume of the reduced tank length for a full lap, the capacity of the system is multiplied by as many times in regard to the former technique. Respectively, in the case of the moving wastewater with stationary, rotating biocontactor the same mechanisms of capacity increase are actuated. This increase makes the system more efficient and inexpensive in regard with the former technique. A way of applying the invention on olive oil processing plant wastewater in rectangular tanks, is described below, with reference to drawings explaining the specific implementation, where : Drawing No 1 features the plan view of the bioreactor, which, according to the invention, includes the transport motion of the biocontactor using a swing- moving trolley-bridge. Drawing No 2 is the A-A view of the tank - bioreactor, where the front view of the biocontactor and the swinging trolley system are shown. Drawing No 3 is the B-B view of the tank - bioreactor, where the side view of the biocontactor and the two different transmission systems are shown. According to the drawings the wastewater bioconversion system is placed in a rectangular tank (20) of suitable dimensions with the incoming olive oil wastewater. This system consists of the rotating biocontactor and the trolley- bridge which ensures the support of the whole biocontactor system plus its horizontal - swinging movement across the tank. The trolley-bridge consists of a rectangular support frame (21) whose motion is achieved via a four-wheel rolling system (25). The shafts (23) of the wheels are fixed to the underpart of the frame with roller bearings (26), which cling to it with bolts. One of these shafts is the driving one. The wheels roll on two rails (24) of upside-down T-cross section, which lie fixed horizontally along and on top of the tank side walls. The transmission system for the driving trolley shaft consists of a protected against the weather electrodrive (27), with rpm fluctuation possibility, which is placed firmly on a metal mount welded to the frame, a system of two gears (28,29) and a heavy duty chain. The gear of the electrodrive (28) moves via the chain the driving gear which is firmly welded on the shaft of the driving wheel pair. The turn direction of the electrodrive shaft, and thus the movement direction of the frame changes each time the trolley reaches the end of the tank, with the help of a terminal switch (there is also an auxiliary) which is actuated by touch on the side wall at the end of the railway. The biocontactor (22) rotation shaft (30) support on the frame (21) is achieved with two straps (31) and two roller bearings (32). The straps of V-shape are made of stainless steel reinforced plate of rectangular cross-section and actually hang onto the frame fixed with bolts. The roller bearing (32) of the biocontactor rotation shaft (30) is fixed with bolts in the underpart of each strap and on top of it. The bearings are waterproof, self-lubricating and easy to dismantle, since they are suitably placed in a removable rectangular shell. This ensures easy assembly and disassembly of the biocontactor. The biocontactor transmission system consists of an electrodrive (33) protected from weather and firmly placed on a metal mount welded onto the frame and a system of cog wheel (34), cog rim (35) and a heavy duty chain (36). The driving gear (34) is set on the shaft of the electrodrive, while the moving rim (35) lies on the biocontactor shaft welded to its one end. The turn direction of the electrodrive shaft, and thus the rotation direction of the biocontactor changes each time the trolley reaches the end of the tank, with the help of the same terminal switch. The direction of rotation is always the same with the linear motion of the trolley, in order for this motion to be supported. The system embodies an electrical switchboard - cabinet of thin metal plate which includes a main switch, an automatic star-triangle switch for the biocontactor rotation, an automatic switch for the trolley to-an-fro motion, a current phase supervisor switch with terminal switches, a cable suspension system and telecontrol switches. It also includes a soft starter to avoid any vibration problems at the rotation set-off. The start of the biocontactor and frame electrodrives proceed with a time lag, the contactor starting first in order to avoid overloading of the system and at the same time help the movement of the trolley. Another way of applying the invention for olive oil processing plant wastewater in a Carousell-type tank is described below, with reference to drawings explaining the specific implementation, where : Drawing No 4 is the plan view of the bioreactor, featuring, according to the invention, the transport motion of the liquid wastewater with mixing devices (propellers) in the tank. Drawing No 5 is the plan view of the bioreactor, featuring, according to the invention, the transport motion of the liquid wastewater with mixing devices (propellers and Mammut rotors) in the tank. It is the same biocontactor (22) described in the earlier example, except that its rectangular support frame (21) is firmly placed on the tank side walls and performs no other movement. There are two mixers (37) submerged inside the Carousell-type tank (38), placed firmly on a mount (39), which supply the wastewater with the necessary kinetic energy to perform full laps flowing each time through the rotating biocontactor. In Drawing No 5 one of the mixers (37) is alternatively replaced with a rotating Mammut rotor (40), firmly placed on the tank side walls. The Mammut rotors not only supply the wastewater with the kinetic energy, but also support its oxygenation.

Claims: CLAIMS 1. Olive oil wastewater aerobic bioconversion plant, that reduces phytotoxicity and converts wastewater into an ecological biofertilizer and that consists of : - Equalization tank for the olive oil wastewater reception, aiming at the pH reduction, e.g. with the addition and stirring of Ca(OH) 2 - A tank, inside which the bioreactor is placed, having the shape of a rotating biocontactor. - A rotating biocontactor of cylindrical shape, with filling material for the fixed- bed microorganism growth and rotation mechanism in low rpm. The biocontactor shaft is horizontally placed at a fixed point and the contactor half submerged in the wastewater turns around its shaft with the help of the rotation mechanism. - The biocontactor surface is perforated letting the liquid to flow through easily. The contactor consists of two, three or more compartments full with the fixed-bed filling material and are accesible through manholes. Some compartments, between full ones, remain void of filling material and serve as expansion zones of the liquid during the rotation. The compartments are vertically fixed on the horizontal rotation shaft by means of transverse beams. The horizontal rotation shaft is fixed on two self-lubricating pillow-shaped blocks. - Treated wastewater exit unit with a pumping device suitable for thick liquids, since the specific way of treating the wastewater raises its viscosity. The olive oil wastewater aerobic bioconversion plant for biofertilizer production with reduced phytotoxicity is characterized by an additional transport motion (linear or circular) of the rotating biocontactor. The biocontactor lies on a trolley-frame, carrying it along the tank, inside which the biocontactor is submerged. The biocontactor never ceases to turn around its shaft while moving along the tank. On the biocontactor seating frame there is a transmission mechanism with speed regulator and moves on rails (cogged or not), which are based on the edge of the tank side walls and follow the shape of the tank. The biocontactor turn direction is the same as the trolley movement direction, so that both motions are acting synergistically and not the one against the other. In this way energy is saved. The dimensions of tank, biocontactor and trolley-frame, as well as the biocontactor rotation and transport velocity adjust according to local conditions. The size of the installed power is such, that in all treatment phases, specially at the final phase when the liquid starts to jell, covers the unhindered movement of the trolley and the rotation of the biocontactor. 2. The olive oil wastewater aerobic bioconversion plant, which reduces phytotoxicity and converts wastewater into an ecological biofertilizer, as described in claim No 1, is characterized by a rotating biocontactor on a fixed position of the tank with the liquid (in all its treatment phases, especially while the gel phase) carried towards the rotating biocontactor. The tank is Carousell-type or circular, and the liquid motion is initiated by means of mixers, pumps or Mammut-rotors etc. The amount of kinetic energy is such, that the moving liquid, in all its treatment phases, especially while its final gel phase, can complete a full lap before the next breath of the microorganisms.

Inventors: SISKOS DIMITRIOS, SISKOS, DIMITRIOS
Applicants: SISKOS DIMITRIOS, SISKOS, DIMITRIOS
Application year: 1999
Main classification: C02F3
IPC codes: C02F3