SMBR Process with Peenox Floating Media

Transcription

1 SMBR Process with Peenox Floating Media Fixed-film fluidized media reactor Media added to the bioreactor Retaining screen A simple screen retains the media in the bioreactor The media is fluidized by air Clarifier Influent Effluent Sludge Extraction Traitement des eaux et des boues SMBRMD / Média PeenoxMD Tratamiento deprocédé aguas y lodos Page 1 Tél.: y Fax :

2 Technology Mabarex Inc. has developed in Quebec, a fixed film biological treatment process commercialized under the brand name SMBR (Suspended Media Bio-Rector). The media s brand name is Peenox. This technology is particularly well adapted to high loads or variable loads, such in industrial effluents food plants, leachate landfill sites and petro-chemical waste water treatment plants. It also allows increasing the capacity of existing plants in order to meet more stringent BOD 5 and ammonia nitrogen regulations. This technology is characterized by the following elements: The Peenox media, made of plastic HDPE (high density polyethylene), used as a support for the growth of large biomass concentrations. A coarse bubble aeration system, according to every specific application. Carrier retaining screens, to keep the media inside basin (reactor). The Peenox media offers a large surface available for the fixed biomass to grow. The presence of this fixed biomass increases the loading rate, which allows the treatment of more soluble pollution per cubic meter of tankage volume than conventional technologies. The SMBR technology is suitable for the construction of new installations and the upgrade of existing biological wastewater plants. In this case, Peenox media is directly added inside of the existing basins, and the aeration system is adapted with the new design. The SMBR technology can be used for BOD and nitrogen removal applications. Multi-stage treatment can be design according to effluent requirements. In summary, the key elements of the process are: Fluidized Bio-Reactor with floating media is used for reduction of BOD/COD and nitrogen Complete nitrification and denitrification Low influent concentrations (i.e. 200 mg/l BOD or less) High influent concentrations (i.e. : mg/l BOD or more) Tratamiento de Procédé aguas y lodos SMBR MD / Média Peenox MD Page 2

3 Description Peenox The Peenox media consists of a small cylinder and the internal shape looks somewhat like a honeycomb. It is divided into multiple chambers that offer a large contact surface for the bacteria to grow on. Only internal surfaces are used for process design. The plastic material used is chemically inert and protected against UV radiations. Its relative density is approximately 0.95, which enables the media to float. The geometry used offers an excellent ratio between specific surface and total surface. Therefore, the shape provides a strong structural strength. Peenox MD Media R&D showed that it is not enough to offer a large protected surface for to attach and develop biomass on media, but protected surfaces have been maximized in order to avoid risks of media clogging. An optimum compromise had been reached to allow an efficient circulation of water although the chambers. 18 days 50 days 65 days Typical Biomass Only biomass growth on protected surfaces, i.e. into chambers, is considered to define the available specific area. The biomass is continuously released from the media to the liquid phase by shocks with others media. The average thickness of the biomass is less than 1 mm, which allows water for freely circulation through media chambers. Physical media properties let to very important fixed biomass concentrations within a relatively small volume of treatment. Tratamiento de Procédé aguas y lodos SMBR MD / Média Peenox MD Page 3

4 The protected areas inside the chamber authorized the installation of slow-growth biomass species, which represents an important advantage when nitrification of the waste water is required. The volume fraction taken the media in the reactor is selected to provide a completely mixing effect of the media by the air system injection. In a standard project, the volume of filled fraction of media lies between 25 and 70% of the useful volume of the basin. This technology offers many advantages: This technology offers the possibility to increase the treatment capacity of a wastewater plant simply by adding media in the bioreactor. The SMBR technology makes it possible to double (and more) the treatment capacity compared to conventional treatment having a similar volume tankage. The internal media surfaces protect the biomass from abrasion, a phenomena that happens on external surfaces. In the event of a toxic shock, the restarting of the process is very fast. In general, when a toxic shock occurs, the micro-organisms fixed on the inferior layers of the media are protected by the first layers. We also have to consider the specialization capacity of the biomass in contact with liquid. The biomass can be easily adapted to the presence of substances which are normally no biodegradable with conventional biological treatments. This adaptive capacity is particularly an advantage with variable industrial effluents. The SMBR technology might consist of several stages of treatment. Those configurations offer the opportunity of the development of specific biomasses in each stage, which allows superior purification efficiency. The more stages there are, the better the results. Compared to other biological treatment technologies, the SMBR technology is particularly well adapted to cold water. Tratamiento de Procédé aguas y lodos SMBR MD / Média Peenox MD Page 4

5 Screen Screens have to be installed at the basin inlet and outlet in order to retain the Peenox media inside of the bioreactor. Due of the media size, screen openings are relatively large, 10 mm. Screen surfaces are tolerate to velocity ranging between 150 and 300 m/h (50 to 100 gpm/pi ²) with low head losses. Accumulation of debris on the screen is usually very limited; the permanent media collision on screens under water level ensures a constant clean operation. Aeration System The aeration system has three (3) main following functions: Provide oxygen to the micro-organisms for organic pollution oxidation. Provide sufficient energy to mix the media in order to fluidize the bioreactor. Quickly mix the incoming wastewater in the bioreactor to homogenize the bioreactor volume. According to the specific application or to the presence of existing equipments, the air distribution system will be designed with coarse bubbles or medium bubbles. In the case of coarse bubbles, they are sheared in smaller bubbles in the media fluidized bed. Media slow down raising velocity by factoring the air bubbles, and increase the rate of oxygen transfer. Air is usually used as the source of oxygen. Sizing of air blowers are carried out using the following elements: Organic load to be treated (BOD 5, nitrogen, suspended solids). Air flow required to assure mixing of the media. Basin volume and geometry. Filled fraction of media in the basin. Tratamiento de Procédé aguas y lodos SMBR MD / Média Peenox MD Page 5

6 Typical operation of a standard installation The SMBR combines the advantages of an activated sludge with the advantages of fixed film biomass systems. The main advantages compared to conventional activated sludge are: Biomass concentration is less important. A larger variety of micro-organisms species are present. Simple and easy to operate. More sludge is digested within the bioreactor. High biomass concentrations offer excellent treatment capacities with smaller bioreactor footprints. In the situation of an existing activated sludge system, it is possible to increase treatment capacity by 50 to 100% and providing a better effluent as well. The aeration system installed on the bottom of the bioreactor assures a constant mixing of the media. The specific density guaranties a uniform distribution of the media within the bioreactor. During the start-up of SMBR TM installations, micro-organisms present in raw wastewater are quickly fixed on the media. Biomass development is fast and all specific surfaces will be usually colonized in a few days. Organic pollution is essentially degraded by the biomass fixed on the media (biofilm). A part of the organic matter is partially degraded by the free faction of biomass (TSS) in suspension in the liquid phase. The top layer of the biofilm is continuously released by the normal attrition processes and by the growth of sub-layers. The free biomass going out of the bioreactor with the water flow is intercepted by solid separation equipments before the discharge to the environment. The solid separation can be carried by using conventional mechanical clarifier, dissolved air flotation unit or sedimentation systems. SMBR sludge production (release of biomass at the water outlet) represents a fraction of the total biomass present in the bioreactor that reducing the mass load applied on clarifiers. Tratamiento de Procédé aguas y lodos SMBR MD / Média Peenox MD Page 6

7 SMBR Technology advantages: No need to control sludge age No need to control F/M Ratio No need to control a sludge blanket Retrofitting an activated sludge system by increasing biomass concentration in the bioreactor won t increase the concentration of suspended solids and won t overload the existing clarifier. The concentration of suspended solids will decrease significantly. (i.e.: from 3000 mg/l with activated sludge to 300 mg/l or less with an SMBR ). Also, the operation of SMBR TM systems is much easier to handle with very low level solids concentration in effluents. Pilot units are available for evaluation of the application SMBR TM biological treatment, when necessary, special industrial effluents. Layout Tratamiento de Procédé aguas y lodos SMBR MD / Média Peenox MD Page 7

8 The SMBR TM bioreactors can be arranged in several configurations, depending on the raw water and the effluent requirements: SMBR bioreactor with or without sludge return. Installation of the media in an existing activated sludge (IFAS). SMBR bioreactors installed in series. Bioreactors installed ahead of aerated lagoons. Mabarex SMBR uses our own proprietary Peenox media. You certainly can rely on the Mabarex team. We are proud to have delivered at least 50% of BOD 5 removal capacity installed in Quebec, industries and municipalities combined. Tratamiento de Procédé aguas y lodos SMBR MD / Média Peenox MD Page 8