Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/04—Aerobic processes using trickle filters
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/12—Activated sludge processes
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/12—Activated sludge processes
  • C02F3/1236—Particular type of activated sludge installations
  • C02F3/1268—Membrane bioreactor systems
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/28—Treatment of water, waste water, or sewage by sorption
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

• the present invention basically relates to the sector of treatment for depuration of waste waters. More specifically, it regards a modular biological system, which in what follows will be also called "Bi oscavenger” , with combined hybrid aerobic microbiological process, of the total -oxi dati on suspended-bi omass and adherent-bi omass type.
• the water to be treated is introduced into the system through the percolator, where it undergoes a first biological treatment by the adherent biomass.
• an aerated tank Present underneath the percolator is an aerated tank, which functions both as vessel for collection and recycling in the percolator and as vessel for activated-sludge biological treatment.
• the air necessary for the oxidation process is forcedly blown into the tank, whereas in the percolator natural aeration is added to the one coming from the oxidation tank.
• the Bi oscavenger that is described is a transportable and modular system having various accessories already pre-arranged and installed on skids so as to guarantee easy installation and adaptability to any situation.
• biofilters present serious drawbacks that are limiting use thereof: • poor physical character st cs of the bi omass, with possible uncontrolled detachment thereof and consequent problems of functionality and continuity of performance ;
• adherent-bi omass systems regards the possibility of rendering the time of cellular permanence independent of the time of hydraulic retention without carrying out any recycling. This entails also the possibility of increasing the concentration of biomass with reduction of the volumes of the reactors and/or of the production of sludge. In addition, it is to be noted that the problems linked to sedimentability of the sludge, which are typical of suspended-bi omass systems, are not present.
• the biological towers are activated more slowly than the activated-sludge treatment processes, precisely because it is necessary to wait the time necessary for formation of the biological film on the inert substrate.
• all the treatment systems with adherent cultures require a transient starting step, that is more or less long, but that generally is in any case longer than that of an activated-sludge system.
• the biological tower is moreover affected by temperature oscillations, above all in winter periods.
• TF/AS Trickling Filter / Activated Sludge
• TF/SC Trickling Filter / Solids Contact
• Both of the processes use the trickling filter, an activated-sludge aeration tank, and a secondary settler.
• the effluent from the trickling filter is directly supplied to the activated-sludge process without passage through an intermediate clarifier, whereas the recycle from the secondary settler is introduced into the activated- sludge tank.
• a possible mod f cat on proposed for just the TF/SC process consists in inserting a supply sump in a central position in the secondary settler for flocculation and of a recreation tank for the recycle sludge.
• the TF/AS process is commonly used where there is carried out a coarse biological treatment with trickling filter, which is able to remove only 40-70% of the BOD at input.
• the organic load applied to the trickling filter is relatively modest, and the purpose of the aeration vessel is to carry out removal of the residual soluble BOD and develop a mass of activated sludge with flocculation properties, which incorporates inside it the dispersed solids produced following upon the phenomenon of stripping of the biofilm of the trickling filter.
• the process is able to produce a high-quality effluent, with reduced content of SS (Suspended Solids) and BOD.
• the time of hydraulic permanence and the time of cellular permanence of the aeration vessel of the TF/SC process are rather short. This process can be used for nitrification since, if the organic load is kept sufficiently low, the nitrification process may be set up in the trickling filter.
• Another set of combined processes envisages that the stream of recycle sludge will be introduced directly into the trickling filters and that the aeration vessel may not even be present.
• These filters are designated by the terms ABF (Activated Biofilter) and BF/AS (Biofilter / Activated Sludges), according to whether the activated-sludge tank is present or not .
• the ABF process ( Figure 3) is able to produce a final high-quality effluent provided that only modest loads are applied in the trickling filter.
• the BF/AS process is used ( Figure 4), which envisages integrating the ABF process with an aeration vessel.
• the BF/AS process is very similar to the TF/AS process, differing therefrom only in that the recycle stream is introduced into the trickling filter rather than into the activated-sludge vessel .
• a further set of combined systems is the one formed by a trickling filter and an activated-sludge process functioning in series, with an intermediate settler between the two previous units. This protects the activated-sludge treatment from toxic or inhibiting substances and from an excess load of solids in the case of treatment of waste waters with very high loads.
• a second line for recycling to an MBR reactor is present downstream of the oxidation tank.
• EP 0004528 A2 Also known from EP 0004528 A2 is a technical solution in which a floatation vessel is used instead of the mechanical separator.
• the vessel described in the document EP 0004528 A2 is in fact a floatation vessel designed to separate the aqueous sludge from the purified water. Moreover, this aerated vessel is not set immediately underneath the trickling filter. Even though there is suggested the combined use of the trickling filter and the activated-sludge vessel, the flows are managed in parallel and not in series as in the present invention. It is hence a treatment system based on altogether different principles.
• DE 20 2006 014291 Ul basically regards upgrading of old trickling filters produced by Schreiber, which envisage positioning of the tank of the secondary clarifier underneath the percolator.
• the tank of the secondary clarifier is converted into the one that is defined "aeration vessel". Mention is made of the fact that the aeration vessel envisages a ventilation system and that within said vessel a pump is inserted for lifting the waters from the aerated vessel to the top of the percolator.
• the solution presented in the document DE 20 2006 014291 Ul differs from the solution according to the present invention in so far as in the German document the influent is introduced first into the activated-sludge tank, whereas in the case of the present invention the influent is introduced into the percolator together with the recycle amount coming from the activated-sludge tank.
• the solution proposed by DE 20 2006 014291 envisages building a new secondary clarifier with recycle flows both from the bottom and from the top of the clarifier.
• an MBR reactor is present that envisages recycling with the activated-sludge tank and discharge of the surplus sludge from the bottom thereof.
• W0 2013/136939 Al describes a system that envisages a pre-treatment by means of an anaerobic reactor and a distributor that clearly divides two flows: a first one passes through the trickling filter and a second one goes directly to an MBR system. No kind of interaction is envisaged between the two flows, nor any recycling in so far as two distinct treatments are carried out in parallel.
• WO 2013/136939 Al regards a technical solution that is altogether different from the present invention.
• FIGS 1 to 4 show known treatment systems
• Figures 5 and 5bis show schematically the basic elements of a preferred embodiment of the invention, also called “Bi oscavenger” ;
• FIGS. 6 and 6bis regard a variant of the invention, referred to as “WRT” (Water Recovery Technologies), where other treatments are added to the combined biological treatment;
• WRT Water Recovery Technologies
• Figure 7 is a scheme of a continuous-backwash ascending-flow deep filter.
• Figures 8 and 8bis show a further variant of the invention, which envisages a plurality of additional treatments upstream and downstream of the combined biological treatment of Figures 6-6bis.
• the Bioscavenger system implements a combined treatment process with the peculiarity of combining the two technologies - trickling filter and activated sludge - in a single very compact treatment module.
• the waste water to be treated is introduced upstream of the trickling filter 1 together with a recycle stream 7 coming directly from the activated- sludge tank 2.
• the flow that has traversed the filter 1 from top downwards is directly collected by the activated-sludge tank 2, precisely thanks to the fact that, according to a peculiar characteristic of the invention, the trickling filter 1 rests directly on aforesaid tank 2.
• This configuration in addition to ensuring small overall dimensions, provides benefits since it enables increase of the efficiency of the percolator and more stable treatment results, notwithstanding the daily or seasonal variations of atmospheric temperature and humidity.
• a reactor 3 where the liquid mixture present in the oxidation tank 2 is recycled 8.
• MLR membrane separation
• the subject of the present invention is the Bioscavenger system ( Figure 5), which constitutes the biological section that constitutes the main part of the water-treatment system referred to as WRT (Water Recovery Technologies) formed by the combination of other technologies.
• the Bioscavenger system generates a process of combined, adherent-bi omass and suspended- biomass, biological treatment by means of a trickling filter or percolator 1 with structured filling made of self-supporting plastic material 5 set above an activated-sludge tank 2.
• a trickling filter or percolator 1 with structured filling made of self-supporting plastic material 5 set above an activated-sludge tank 2.
• it is a honeycomb structure designed to create criss-cross channels: this system enables the biological treatment process to be carried out in little space and with maximum efficiency.
• the treatment process that is obtained by the Bioscavenger system according to the present invention envisages that the influent to be treated will be sent on to the percolator 1 together with an amount of recycle coming directly from the activated-sludge tank 2, and in this differs substantially from the TF/AS, TF/SC, ABF or BF/AS processes.
• the influent is subjected to the adherent-bi omass treatment process.
• the trickling filter 1 rests directly on the activated-sludge tank 2 by means of perimetral infill walls 6 that are equipped with purposely provided slits that can be adjusted to facilitate natural aeration.
• the water that trickles from the base of the percolator 1 drops by gravity directly into the aerated activated-sludge tank 2, where it is subjected to the suspended-bi omass treatment process.
• the water that permeates through the membranes constitutes the purified effluent 9, whereas the solids are withheld within the reactor.
• the recycle that goes to the activated-sludge tank 2 is adjusted for controlling the concentration of the sludge within the biological reactor 3. This concentration is moreover controlled by means of drainage of the concentrated sludge 10 present on the bottom of the biological reactor 3.
• the biological reactor 3, in which the membrane separation unit is immersed is constituted by a tank with conical bottom (or with a bottom shaped like a pyramid turned upside down) 11 ( Figure 5).
• the membranes 4 are kept under stirring, in the filtration step, by means of a coarse-bubble aeration system 12 installed underneath the membrane unit 4.
• said aeration system 12 moreover enables an acceptable concentration of dissolved oxygen to be maintained in the biological reactor 3.
• the major part of the surface of the activated-sludge tank 2 is covered by the percolator 1 itself. Consequently, to the aeration that would naturally be obtained in the latter, there is advantageously added an amount of forced air that is blown 17 into the activated sludge 2, and that rises up the percolator 1.
• the air that comes from the activated-sludge tank 2 presents good characteristics for the biological activity in the percolator 1, it still presenting a fair amount of oxygen and an optimal temperature and humidity.
• the activity of the percolator 1 is affected to a much lesser extent by the oscillations of ambient temperature, above all in the winter period, since the air coming from the activated-sludge tank 2 has a temperature and a humidity that are much more constant than atmospheric temperature and humidity.
• another advantage of the present invention is represented by the fact that, in the case where shallow activated-sludge tanks are used - where the poor transfer of oxygen notoriously represents a significant problem -, this low efficiency of aeration of the sludge is compensated by a higher efficiency in the percolator.
• the process implemented by the Bioscavenger system moreover envisages direct recycling between the percolator 1 and the activated-sludge tank 2, unlike what occurs in the TF/AS, TF/SC, ABF or BF/AS processes.
• an influent with a very high load sent directly to the percolator 1 could give rise to phenomena of toxicity on the adherent bacterial population, not enabling an adequate development thereof or, in the worst case, causing elimination thereof.
• the sludge collected in the settler which in itself is a fluid the characteristics of which could aggravate the phenomena of toxicity on the adherent biomass, is recycled.
• chemi co-physi cal pretreatment by addition of specific substances, either in liquid form or in solid form (e.g., zeolites, activated carbons, lime, etc.).
• specific substances either in liquid form or in solid form (e.g., zeolites, activated carbons, lime, etc.).
• This pretreatment is of fundamental importance in the case where the industrial waste water were to have a heavy content of organic and inorganic substances that might inhibit the growth of the biomass.
• adsorbent materials e.g., activated carbons
• exchanger materials e.g., zeolites, resins
• chemi cal - neutralization reagents and/or chemical precipitation reagents This vessel may be aerated in order to raise the concentration of dissolved oxygen in the effluent and to desorb the dissolved VOCs.
• the mixture can be sent on to a specific sand filter 14 in order to separate the saturated materials and the suspended solids (see Fi gure 6) .
• the effluent thus filtered will be suitable for undergoing the biological treatment.
• Filtration with a granular filtering means can be carried out, in a preferential embodiment, with a specifically designed continuous-backwash ascending- flow deep filter (Figure 7).
• This filter concentrates the suspended solids in an effluent, which, in a preferential embodiment, can be sent on to a rotary vacuum filter 15.
• This filter carries out mi crof i 1 trati on of the incoming flow and dehydration of the suspended solids removed from the flow.
• the mi crof i 1 tered water can thus be sent on to the percolator 1.
• the surplus sludge of the biological process could be sent on to the rotary vacuum filter 15. In this way, a single dry residue would be obtained from the entire treatment.
• the rotary vacuum filter 15 there may be used a precoat filtration system in which a porous filtering cushion is provided, which includes materials activated by adsorption or by ion-exchange. In this way, there would be re-introduced in the percolator 1 a mi crof i 1 tered flow with a lighter content of dissolved substances that could be noxious for the biological process .
• Said filter 16 could, among other things, guarantee the quality of the effluent treated also in case of faulty operation of the biological compartment .
• the system thus configured ( Figure 8) not only guarantees an excellent quality of the effluent, but is able to treat even very complex industrial effluents, both as regards variety of suspended and/or dissolved substances and as regards the concentrations of the latter.
• WRT Water Recovery Technologies
• the system according to the invention affords high levels of efficiency with minimum overall dimensions, a small number of mechanical apparatuses, and low consumption levels.
• the Bioscavenger system presents as strong points: minimum overall dimensions, modules that can be pre-fabri cated and already fitted out, in the factory, with all the necessary accessories, the fact of not producing sludge to be disposed of, the fact of enabling recovery of water in little space, control of emission of bad odours in the atmosphere, and excellent adaptability of the system to very variable seasonal flows.
• the main advantage of the Bioscavenger system is that it enables all the benefits of a biological depuration to be achieved in places where so far this was not possible for reasons of system encumbrance. Thanks to its high efficiency and to the minimum encumbrance, it is possible not only to discharge the water in compliance with the law, but also to bring the quality of the water to a level such that it can be reused.

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• Life Sciences & Earth Sciences (AREA)
• Biodiversity & Conservation Biology (AREA)
• Microbiology (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Activated Sludge Processes (AREA)

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Citations (5)

• 2015
  • 2015-08-06 IT ITUB2015A002938A patent/ITUB20152938A1/it unknown
• 2016
  • 2016-08-01 WO PCT/IB2016/054621 patent/WO2017021869A1/en active Application Filing

Patent Citations (5)

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