JPS6366516B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to converting carbon, phosphorus and nitrogen values in BOD-containing liquids into high energy biomass that can be usefully used as plant or animal nutrition or in the fermentation industry. More specifically, the products of the invention contain N,
The present invention relates to highly nutritious laboratory animal feeds prepared from P and BOD containing mixtures, such as suspensions or solutions of carbohydrates. The present invention also relates to the production of high efficacy fertilizers by treatment of BOD-containing wastewater. The present invention also relates to active and dense biomass that can be used effectively during fermentation processes. Techniques for using biological sludge (sludge that contains living organisms and is called sludge) to improve the effectiveness of fertilizers are known, and some of them have been successfully put into practical use. [An example is milorganite fertilizer manufactured in Milwaukee, USA]. In addition, local governments and wastewater treatment companies have attempted to treat and use sludge in wastewater to produce compost or high-efficiency fertilizers. Unfortunately, the fact that the untreated sludge used in the past is actually used is extremely rare due to the fact that the content of elemental phosphorus varies from about 1 to 2% by weight. Ind. & Eng. Chem. (Anal. Ed.) Volume 11 No. 5
(See pages 281-238). According to the invention, animal nutrition (e.g. poultry,
The product, which can be used as fish or crustacean food) or as plant nutrition (fertilizer) or applied to fermentation processes, is kept under anaerobic conditions, i.e. virtually NOx _- free at 0.7 ppm. It is produced by first forming a mixture by mixing a food source and activated biomass in the form of a BOD-containing liquid under conditions that have a lower dissolved oxygen (DO) concentration. It is further desirable that the amount of DO be less than 0.5 ppm, and usually less than 0.4 ppm. throughout the entire zone and within the anaerobic zone during the total treatment period.
It is important to maintain the amount of DO below certain limits. Sequestrations in the anaerobic zone at times of above-critical DO levels should be avoided, as should intermittent periods of high DO levels. It is during this initial operational step of the anaerobic process that the formation of non-fibrous biomass takes place. In fact, non-fibrous biomass is formed under anaerobic conditions, i.e. low DO
This is proof that the condition is maintained. vice versa,
The formation of fibrous biomass indicates failure to maintain anaerobic conditions. This appears especially in the earlier parts of anaerobic operation. Note that fibrous or non-fibrous herein refers to the state after microorganisms have propagated. When operated in a continuous flow regime, the production of certain microorganisms capable of sorption of BOD in anaerobic conditions requires an anaerobic initial zone for their growth, unlike for other types of microorganisms. Maintaining a sexual state is required. High DO beyond the limit
The appearance of isolated zones of high DO levels, or intermittent periods of high DO within these zones, is counterproductive to the growth of this type of microorganism.
Slightly higher DO levels can be tolerated for short periods of time once the desired microorganisms have been obtained by maintaining anaerobic conditions. However, if the high DO levels persist for a significant period of time, they can become harmful, resulting in the desired microorganisms being lost and replaced by normal biomass. The food source also needs to contain appropriate amounts of nitrogen, phosphorus and potassium in relation to the BOD concentration, so that the desired stoichiometry of these elements in the product is maintained. Concentration can be imparted. It is estimated that approximately 30-100% of the removed BOD is converted to products for this purpose. Typically, the amount of phosphorus (as elemental phosphorus) is at least about 2% by weight of the dry product, the amount of potassium (as elemental potassium) is also at least about 1%, and the amount of nitrogen is (as elemental nitrogen). It is also at least about 5% by weight. Food sources, of course, also contain (although sometimes only in trace amounts) other elements normally required to sustain life, such as sulfur, magnesium, zinc, calcium, manganese, copper, and others. These elements are considered known in the art and include, in addition to those specifically mentioned above, carbon,
Contains hydrogen, iron and sodium (WH
“Botany-A Functional” by Mr. Muller
3rd edition). These elements are normally contained in adequate amounts in groundwater. The active biomass used in this step is the same biomass produced later in the process of the invention, which is effectively selective for non-fibrous microorganisms that can sorb significant amounts of BOD under anaerobic conditions. This refers to the use of biomass to produce biomass. The force for active transfer of BOD-containing substances from the aqueous solution into the cell wall is provided by the hydrolysis of polyphosphates stored inside the cell or in the cell wall, and inorganic phosphates are transferred from the biomass to the aqueous phase. It is theoretically clarified that it is forced. It is believed that the initial contact of this particular biomass with a BOD-containing solution under anaerobic conditions will be extremely favorable to the growth of the type of biomass that has the best ability to store polyphosphate. This is because this type of biomass has a much stronger ability to sorb the food present therein under anaerobic conditions. The mixture from the anaerobic treatment is then contacted with an oxygen-containing gas under conditions selected to maintain a dissolved oxygen level of at least about 1 ppm.
This contact is effective in oxidizing the BOD previously sorbed by the biomass in the mixture, thereby substantially lowering the internal BOD content;
And generates energy. During this oxic or aerobic treatment, the energy consumed by hydrolysis of polyphosphate under anaerobic treatment is compensated and the polyphosphate is regenerated and accumulated within the biomass. is removed, thereby removing phosphate values from the aqueous portion of the mixture. This oxidized mixture is separated into an upper liquid and a more concentrated biomass. At least a portion of this separated biomass is used as the activated biomass in the initial stage of anaerobic mixing with the BOD-containing liquid. A remaining portion (usually all of the residue) of the separated biomass is recovered as a product. In cases where animal or plant nutrition is to be produced, the concentrated biomass may also be subjected to drying and/or pasteurization procedures to convert it into a form that is more convenient to handle and safer for use. . However, in some cases it may be advantageous to add live biomass to the soil while it is still moist, thereby reducing the cost of drying. Another approach is to mix seeds and live biomass at the time of planting. The living biomass produced by this process has the characteristic of having a higher concentration than normal because it contains a large amount of polyphosphate, and has the ability to survive for a long time due to the energy contained in the polyphosphate. ing. These properties clearly make the product according to the invention sufficiently useful for application in fermentation industry. In another embodiment, particularly suitable for the treatment of wastewater where denitrification is required, a portion of the mixture may be subjected to anaerobic treatment followed by oxic or aerobic treatment. It can be recirculated under anoxic conditions into an anoxic zone intervening between the treatment and the oxygen treatment. The purpose is to denitrify the nitrite and/or nitrate radicals produced by the oxidation of ammonia during oxygen treatment. The term "anoxic" as used here refers to the amount of dissolved oxygen in the mixture.
conditions where the nitrates and/or nitrites are maintained at a level not exceeding 0.7ppm (preferably below 0.5ppm, more preferably below 0.4ppm), and where nitrates and/or nitrites are added in the initial stages of anoxic treatment. It shows. Similar to anaerobic treatment, and in anoxic treatment,
It is also important that the DO amount is maintained below a particular limit throughout the entire band and during the entire treatment period. The creation of isolated areas with high DO levels or the intermittent occurrence of areas with high DO levels should also be avoided, but the biggest problem in this case is that the denitrification effect is lost. This is clearly manifested in the loss of good sludge properties if excessive DO exists in the anaerobic zone. In fact, oxygen-containing gases are generally not intentionally introduced into anaerobic or anoxic processes. In contrast, in oxygen or aerobic treatments, oxygen-containing gases are intentionally introduced. The concentration of total nitrates and/or nitrites in the mixture recycled to the anoxic process is usually greater than 2 ppm expressed as elemental nitrogen. Nitrate and/or nitrite radicals are reduced to elemental nitrogen gas in anoxic treatment. The nitrate and/or nitrite added to the anoxic zone is obtained by recycling to the anoxic treatment, and the oxygenated mixture is obtained from the oxygen or aerobic treatment. This mode of operation provides a means to reduce the nitrogen content of the effluent when the product is derived from the treatment of BOD-containing wastewater. It will be appreciated that the products of the present invention may be made by either a batch process or a continuous flow process. Therefore, when operated as a continuous flow process, the following is included within the scope of the invention. This means placing an anaerobic contacting zone in the early stages of the operation where the BOD-containing influent is mixed with the recirculated biomass under anaerobic conditions to form a mixed liquor and also to sorb BOD from its aqueous phase. It is to make it happen. The mixture from the first anaerobic zone then passes through a subsequent oxygen or aerobic zone where it is treated under oxygen conditions. The material from the oxygen zone then passes through a settling zone (or clarifier) in which the richer biomass is precipitated from the upper liquid.
A portion of the biomass is removed from the settling zone and recovered as product, while another portion of the settled biomass is recycled to the initial anaerobic zone. If intermediate anoxic treatment is used, the anoxic zone is located midway between the anaerobic zone and the oxic zone, and the effluent mixture from the anaerobic zone passes through the anoxic zone and The process mixture is passed through an oxygen zone and a portion of the oxygenated mixture from the oxygen zone is recycled back to the anoxic zone. When operating as a batch process, the BOD
The containing aqueous solution is mixed with the activated biomass obtained from the previous cycle to produce a mixture that is then initially treated under anaerobic conditions. After anaerobic treatment, the mixed liquor is then treated in the same container under oxygen conditions. After oxygenation, the materials are separated into a surface cleaning liquid, a more concentrated biomass layer, and at least a portion of the biomass layer recovered as product. The particular products produced by the process steps described above have relatively high phosphorus contents. This means that, for example, a comparison can be made between the typical phosphorus content obtained in wastewater sludge and the product according to the invention.
This is especially true when compared to the elemental phosphorus content typically obtained when wastewater is used as the BOD-containing influent. That is, as previously mentioned, typical analyzes of more conventional wastewater sludges have phosphorus contents (expressed as phosphorus) in the range of about 1 to about 2% by weight, but according to the present invention, the same standard An analysis of approximately 5-10% by weight of phosphorus (in the dry state) is obtained. This high analytical value is due to the fact that the process used for the product produced here removes all soluble as well as hydrolyzable phosphorus in the influent, which is then used as biomass. This can be attributed to its ability to incorporate biologically active species into biomass. In particular, it is important to emphasize that these high phosphorous contents result from the incorporation of soluble and hydrolyzable phosphorus from the BOD influent into the biomass, and that (biota) cell wall and/or its interior as a large content of polyphosphate. Although the existence of inorganic polyphosphates in biology is widely known, their phenomena are poorly understood [“Bacteriological
30, pp. 772-794 (1966)].
However, no technique has hitherto been used to intentionally introduce high concentrations of polyphosphate into the biomass used for the treatment of BOD-containing solutions. In addition, the products of the present invention are generally compared to significantly higher nitrogen assays, i.e., nitrogen assays that are less than about 5% and amount to about 3% commonly reported for prior art wastewater sludges. 6 expressed as elemental nitrogen on a dry basis.
~8% by weight. Similarly, the potassium assay values of the products of the present invention are relatively high compared to values of about 1% or less reported for fertilizers made from wastewater treatment plants such as milorganite. That is, it can range higher than about 1% expressed as K ₂ O. The particularly high phosphorus content of the product produced according to the invention is due to the virtually complete transfer of phosphorus from the BOD-containing influent into the biomass. In this connection, it is noted that the phosphorus content in the biomass is a function of the amount of phosphorus available to the system and the amount of biomass produced.
As seen in later examples, the phosphorus expressed as P wt% ranges from about 5 wt% or more, and is contemplated, e.g., when the phosphate to BOD ratio is high in the influent food source. It can be increased to about 20% by weight or more. The wet biomass products of the present invention are believed to be unique. This is particularly the case when producing fertilizers from wastewater, where the biomass or sludge of the present invention has little or no tendency to acquire unpleasant odors during the drying process. Without being bound to this, it is believed that the energy released from the high polyphosphate content of the biomass is responsible for sustaining life within the biomass until the final act of pasteurization.
Decay or decay of dead biomass is therefore largely avoided. This theory is supported by microscopic examination of biomass showing that phosphorus is stored as large inclusions within the cell walls. When the biomass products of the present invention are used as fertilizers, the phosphorus in the biomass is available to plant life in the same way as fixed nitrogen. The fact that the nitrogen is mostly bound as proteins and the phosphorus is mostly bound as polyphosphatides makes the fertilizer products of the invention of particular value since their components are expected to have delayed release properties. It will be understood that having. When used in animal or fish feed, the BOD content of the influent is carbohydrates such as glucose, sucrose, starch or effluents from the pulp and paper industry. The BOD-containing food, of course, also contains the inorganic substances mentioned above. Additionally, the living biomass products of the present invention have utility in the fermentation industry due to their high density (for ease of separation) and energy content. The present invention will be explained in more detail below based on the drawings. FIG. 1 shows an activated sludge wastewater treatment facility. The incoming wastewater for treatment, either settled sewage from the first settling tank or otherwise, is introduced via an inlet line 10 into a tank 12 defined in the anaerobic zone. As shown in FIG. 1, a partition 14 located within the tank 12 is provided with a reciprocal structure designed to provide staged flow through the zone bounded by the tank 12. The zone is divided into series hydraulic stages 16, 18 and 20 that communicate with each other. Each hydraulic stage is provided with stirring means 22. Although FIG. 1 shows a division of the tank 12 into three stages, each with an agitation means, it will be appreciated that more or fewer stages may be used. Various techniques can be used to maintain the zone regulated by tank 12 under anaerobic conditions, such as covering the tank and/or providing a blanket of carbon dioxide, nitrogen or other inert gas. techniques may be used, but the particular technique shown in FIG. 1 uses a nitrogen purge gas that is passed into and bubbled into the mixture. As characteristically shown, a line 24 passes through the bottom of tank 12 to each stage 16, 18 and 2.
Nitrogen is introduced at 0. Through this technology,
Anaerobic conditions are maintained with DO levels below 0.7 ppm. NO _x amount is 0.3ppm or less by other means,
Preferably it is maintained at 0.2 ppm or less. The anaerobic treatment mixture is introduced through line 26 into tank 28 where the mixture is treated under oxygen conditions. As shown in this figure, three partitions 30 form four interconnected series hydraulic stages 3 with zones regulated by tanks 28.
2, 34, 36 and 38. Liquid aeration within tank 28 is accomplished by squirting air into the bottom of each hydraulic stage of tank 28 by means of a sparger 40. In operation in this zone, the amount of dissolved oxygen is approximately
Maintained above 1ppm. Alternatively, oxygen or oxygen-enriched air is introduced via spargeer 40. When using oxygen, oxygen-enriched air or oxygen-containing gases of the desired purity, suitable means of covering all or part of the aerobic or oxygen zone can be envisaged. If desired, instead of or in addition to the sparger, the oxygenation zone can be provided with a mechanical aerator. As shown in FIG. 1, tank 28 is partitioned into four hydraulic stages, although more or fewer stages may be used if desired. However, since the uptake of phosphate by the biomass is recognized to be a first-order reaction with respect to the soluble phosphate concentration, it is preferred that several stages are used. Therefore, low phosphate contents in the liquid effluent and high phosphate contents in the biomass are most economically obtained by economically staged flow regimes. Following oxygen treatment in tank 28, the treated mixture enters clarifier 42 through line 41;
There, it is separated into an upper layer of clear liquid 44 and a more concentrated biomass 46. The upper liquid 44 is withdrawn from the clarifier 42 by line 48 and removed from the system. The richer biomass 46 is removed from the bottom of the clarifier 42 by line 50 and the flow in line 50 is split into flows in line 52 and line 54. As shown in FIG. 1, the flow in line 52 is recycled by pump 56 and line 58 and to the first stage 16 of tank 12 for treating the BOD-containing influent under anaerobic conditions. be returned. Now, if you refer to Figure 2, there is line 54.
Further processing of the biomass contained in the stream is indicated. This portion of the biomass from the clarifier 42 of FIG. 1 is directed to a thickener 60 which provides further separation into a second upper liquid phase 62 and a second, more concentrated biomass phase 64. A second upper liquid phase 62 is removed from the thickener 60 by line 66 and recycled into tank 12 of FIG. 1 via pump 68, line 70 and line 72. A second, more concentrated biomass phase 64 is removed from the thickener 60 by line 74 and directed into a filter 76 for further separation between liquids and solids. A centrifuge, filter press or other known device for separating liquids and solids may be used in place of filter 76. Superaid can also be added to filter 76 via line 78 if desired.
The liquid separated by the filter 76 is transferred to a line 80,
It is removed via pump 82 and passed by line 84 into line 72 where it is returned to the anaerobic tank 12 shown in FIG. 1 along with the second upper liquid in line 70. The solids separated at filter 76 are passed to a drying system 88 as shown by line 90. As shown in FIG. 2, air and fuel are introduced into furnace 92 by lines 94 and 96, respectively. Hot gas from furnace 92 is passed by line 98 into drying system 88 where it is used to provide final drying and sterilization of the solid biomass product. Gas from drying system 88 is removed therefrom by line 100 and passed through heat exchanger 102 to recover heat therefrom. The cooled gaseous stream is then transferred by line 104 from heat exchanger 102 to cyclone separator 106
, where any solid fines are recovered from the gaseous stream and removed from cyclone 106 by line 108 . The substantially solids-free gas is transferred to cyclone separator 106 and line 11.
is ejected from the system by 0. The separated solid biomass product is transferred to line 1
12 from the drying system 88;
Passed to product storage facility 114. As shown in FIG. 2, solid fines removed from the gaseous stream in separator 106 are directed by line 108 into line 112. Figure 3 shows that the anoxic zone is the anaerobic zone (tank 12) and oxygen zone (tank 2) of the diagram shown in Figure 1.
8) shows a schematic diagram of a continuous flow process between Therefore, the same parts in both FIG. 1 and FIG. 3 will be given the same number. Therefore, in FIG. 3, the inflow of wastewater is shown to be conducted via an inlet line 10 to a tank 12 which regulates the anaerobic zone. Similarly, the treated wastewater is separated in the clarifier 42 into a first upper liquid phase 44 and a more concentrated biomass phase 46 . The biomass phase 46 is removed from the clarifier 42 by line 50 and split into streams 52 and 54. As shown in FIG. 2, the flow in line 54 is directed to a thickener 60 and the liquid separated by the thickener 60 and filter 76 is transferred to
(see Figures 1 and 3).
(see figure). In the flow diagram shown in FIG. 3, the anaerobically treated wastewater is removed from tank 12 by line 26 and directed to tank 120 which regulates the anaerobic treatment zone. As illustrated in FIG. 3, the tank 120 includes three successive interconnected hydraulic stages 122,
It is divided into 124 and 126. Various techniques can be used to maintain the zone regulated by tank 120 under anoxic conditions, such as covering the tank and providing a blanket of carbon dioxide, nitrogen or other inert gas. The particular technique shown in Figure 3, which can be employed, is the use of nitrogen gas that is passed through and bubbled through the mixture.
Specifically, each stage 1 through the bottom of the tank 120
Line 25 (an extension of line 24) is shown leading nitrogen into 22, 124 and 126. By this technique, the DO amount of the mixed liquid in tank 120 is
Maintained below 0.7ppm. Each stage 12
2, 124 and 126 also have a tank 120
A stirring handle 130 is provided to ensure sufficient mixing of the materials within. Also shown in FIG. 3, the internal recirculation circuit includes lines 132, pump 134 and lines 136.
Contains. As shown in this figure, the oxygenated mixture is transferred to the last hydraulic stage 3 of tank 28.
8 by line 132 and through pump 134 and line 136 to the first hydraulic stage 122 of the anoxic zone of tank 120.
recycled to It is by this very means that NO _x -containing substances in the form of nitrite and/or nitrate radicals are introduced into the anoxic zone. In all other respects, the wastewater treatment system of FIG. 3 corresponds to the wastewater treatment system shown in FIG. However, there will be an upper liquid 44 removed from the clarifier 42 by line 48 with a reduced amount of nitrogen. FIG. 4 illustrates a batch process operation for the production of biomass products according to the present invention. In this figure, inlet hopper 210 is provided with a valve 212 that allows a metered amount of BOD-containing food source to enter reaction tank 214. A stirring means 2 is provided in the tank 214 to ensure sufficient mixing of the contents within the tank 214.
16 are provided. A gas sparger 218 is located near the bottom of tank 214 and is in turn connected to an external inlet gas manifold 220 . Also shown in this figure are a valved nitrogen inlet line 222 and a valved oxygen inlet line 224 connected to the gas manifold 220. A valve-operated biomass extraction line 226 is provided at the bottom of the tank 214. In addition, a stored oxygen probe 228 that can detect and display the amount of dissolved oxygen in the substance in the tank 214 is connected to the tank 214.
4. Finally, the tank 214 includes a tube 230 having an inlet end located a predetermined distance above the bottom of the tank 214 and an opposite end to which a pump 232 is connected.
A liquid extraction or outlet system is provided consisting of: During operation, a predetermined amount of
BOD-containing food source is introduced from hopper 210 into tank 214 through operation of valve 212 . Stirring means 216, in order to prepare a mixed liquid,
It is activated to provide thorough mixing of the BOD-containing influent and the previously conditioned activated biomass in tank 214. Dissolved oxygen probe 2
28 senses the DO level in the mixture so that proper control thereof can be maintained. Therefore, during the initial anaerobic treatment stage, a valve-operated nitrogen inlet line 222 introduces nitrogen into a gas manifold 220 which is in turn connected to a gas sparger 218 so that the nitrogen gas is mixed in the tank 214. Bubbles upward through the liquid. This is effective in maintaining dissolved oxygen levels below the desired level. If the DO level is too high, it will be detected by the DO probe 228 and the nitrogen introduction rate may be increased. When the anaerobic treatment phase is completed, the introduction of nitrogen through the nitrogen inlet line 222 is stopped and oxygen (either in the form of pure oxygen, air or oxygen-enriched air) is introduced into the valve-operated oxygen inlet line 224.
through gas manifold 220 to sparger 218 where oxygen is introduced into tank 2
The mixture is bubbled upward through the mixture in 14. Once the oxygen or aerobic treatment phase is complete, the introduction of oxygen-containing gas through inlet line 224 is stopped. After the introduction of oxygen is stopped, the mixture in tank 214 is allowed to stand still to facilitate separation of the upper liquid phase from the more concentrated biomass phase. After such precipitation has occurred, pump 232 is activated to remove the upper liquid from tank 214 via outlet tube 230. A valve operated biomass outlet line 226 is then opened to remove a portion of the richer biomass phase from the bottom of tank 214. The remainder of the biomass phase flows into the inflow
It is retained in tank 214 for mixing in the next batch of BOD-containing food source. A portion of the biomass phase withdrawn via the valve-operated outlet line 226 is transferred to a second upper liquid phase 236.
and a thickener 234 for a more complete second separation into a more concentrated biomass phase 238.
be introduced within. The biomass phase is passed by tube 242 to a drying zone 244 where substantially all water is removed, while the upper liquid phase is removed from the system by tube 240. The final dried biomass product is conveyed from zone 244 by line 246 to product storage 248. Examples are given below to explain the present invention in more detail. Example 1 In this example, the procedure used to produce a nutritional material according to the invention suitable for use as a fertilizer includes an initial anaerobic treatment followed by an oxygen or aerobic treatment. The device used was the first
It is similar to the type shown in the figure and contains an anaerobic zone partitioned into five hydraulic stages, each with a capacity of 1.2, each having stirring means. The first zone was maintained under anaerobic conditions by nitrogen flushing, which kept the measured DO levels below 0.15 ppm throughout the operation. The oxygen or aerobic zone is also
It was partitioned into five equal hydraulic stages with a capacity of three each. Each of these oxygen stages was maintained under oxygen conditions by a jet of air, and the DO levels in all stages remained above 1.8 ppm throughout the operation. A clarifier or settling tank was provided to receive the effluent from the oxygen zone. In the clarifier, a separation takes place between the upper clear liquid and the more concentrated activated biomass (sludge).
The biomass was removed from the bottom of the clarifier and separated into two parts, while the upper liquid was decanted and removed from the system. One of the separated sludges was pumped back to the first stage of the anaerobic zone, while the other was removed from the system and recovered as product. The BOD-containing food sources used in this example were:
It was urban wastewater with high phosphorus content. Test data for the influent is shown in Table 1 below. Influent was fed into the system at a rate such that the influent residence time (IDT) was 3.66 hours. A portion of the separated sludge returned to the initial anaerobic zone was then recycled at a rate of approximately 18% by volume based on the influent flow rate. This was effective in obtaining a nominal residence time (NRT) of 0.176 hours for each stage in the anaerobic zone and 0.442 hours for each stage in the oxic zone. The portion of the sludge or activated biomass that was not recycled to the first anaerobic zone was separated from the supernatant, filtered, and dried at 105° C. for 24 hours.
The test data for this dry product of the invention are also shown in Table 1 along with the test data for the separated supernatant liquid.

Table 1 The data presented in Table 1 indicate that the particular process used to produce the products of the present invention is effective in providing a nutrient source with relatively high nitrogen and phosphorus content. I understand that. that such products are produced during the conversion of a substantial amount of the ammonia content of the influent to the more acceptable nitrite and/or nitrate radical forms, and that the process substantially converts the ammonia content of the influent into It will also be appreciated that total removal of phosphate takes place. The phosphate portion is recovered in the form of a dry solid product. Example 2 In this example, the product produced was a nutrient source suitable for use as animal feed. The procedure used to obtain such products first involves anaerobic treatment, followed by anoxic treatment, and finally oxygen or aerobic treatment. The particular apparatus used, as shown in Figure 3, contained an anaerobic zone divided into three hydraulic stages, each stage having a capacity of 1.2, each equipped with stirring means. It is being This initial anaerobic zone was maintained in an anaerobic state by a nitrogen flush, which maintained the measured DO levels below 0.1 ppm throughout the operation. The anoxic zone was also partitioned into three equal hydraulic stages, each with a capacity of 1.2. Each of these stages was maintained under anoxic conditions with a nitrogen purge, and the DO content in all anoxic stages remained below 0.1 ppm throughout the operation. The oxygen or aerobic zone was partitioned into four equal hydraulic stages with a capacity of two each. Each of the oxygen stages was maintained under oxygen conditions by injecting a mixture of nitrogen and air such that the amount of oxygen in the outflow gas was approximately 18%. The DO levels in all these stages are kept above 1.75 ppm throughout the operation. As in the apparatus of Example 1, a clarifier or settling tank was provided to receive the effluent from the oxygen zone. Once again, the upper layer of purified liquid and the more concentrated activated biomass were separated in the clarifier. Means were provided for decanting the upper liquid and removing it from the system, while other means were provided for removing the biomass from the bottom of the clarifier. This biomass was separated into two parts.
One portion of the biomass was recovered as product removed from the system while the other portion was pumped back to the first stage of the anaerobic zone. The equipment used in this example also includes an internal recirculation circuit consisting of tubing and pumps, so that the mixed liquid is removed from the last stage of the oxygen zone and recirculated to the first stage of the anoxic zone. be operated on. The BOD-containing food source used in this example was a glucose solution. Influent testing data is shown in Table 2 below. Influent was introduced into the anaerobic zone at such a rate that the influent residence time (IDT) for the entire three-zone system was 3.16 hours. A portion of the separated sludge returned to the first anaerobic zone was then recycled at a rate of 30% by volume based on the rate of influent flow. A portion of the mixture formed in the last stage of the oxygen zone was returned to the first stage of the anoxic zone at a recirculation rate of 239% by volume based on the influent flow rate. This was effective in obtaining a nominal residence time (NRT) of 0.192 hours per stage in the anaerobic zone, 0.074 hours per stage in the anoxic zone, and 0.123 hours per stage in the oxic zone. The part of the activated biomass not recycled to the first anaerobic zone was separated from the supernatant, filtered and dried at 105°C for 24 hours. Test data for the dry product of this invention are also shown in Table 2 along with other test data for the separated surface liquid.

TABLE The data presented in Table 2 above demonstrate the production of food suitable for use as animal feed produced from pure carbohydrate feedstock. The product has high nitrogen, phosphorus and potassium assays, and in addition contains significant amounts of magnesium (another element essential for life).
Moreover, these essential values are present in accordance with their high carbon and hydrogen contents and are therefore usually in a form suitable as nourishment for animal life. Example 3 The product produced in this example is useful as activated biomass in fermentation operations. The specific procedure used was a batch process separate from the continuous flow operation shown in Examples 1 and 2. The specific equipment used was similar to that described in FIG. In this example, N-, P-, and BOD
A measured amount of the included food source was introduced into the reaction tank. During the first treatment stage, anaerobic conditions were maintained in the tank by introducing nitrogen through a sparger placed at the bottom of the tank. Throughout this anaerobic phase, the amount of DO measured is essentially 0.
was maintained. Nitrogen release was then stopped and treatment continued in a second aerobic or oxygen treatment stage. Oxygen conditions were maintained by oxygen release. The amount of DO maintained during the oxygen phase is
It was 5.0. The BOD-containing food source used in this example was municipal wastewater. The test data for the inflow is in the third section below.
shown in the table. The influent is 0.5 during the anaerobic phase.
The oxygen phase was maintained in the system to give a total influent residence time (IDT) of 1.5 hours, with a nominal residence time (NRT) of 1.0 hours.
A portion of the separated sludge retained from this example for use during the first anaerobic stage of the next batch and retained from the previous batch for use in the first anaerobic stage of this batch is supplied. 50% by volume based on the total influent. The sludge or activated biomass portion not retained for later use in the first anaerobic stage of the batch operation was removed from the tank, filtered, and dried at 105° C. for 24 hours. The test data for this dried product is shown in Table 3 along with the test data for the separated upper liquid.

TABLE The above data represent high nitrogen and phosphorus containing products employing a batch operation process. It is also noteworthy that the product has relatively high N and P assay values, although the associated nitrogen and phosphorus content in the influent is relatively low.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a continuous flow process according to the present invention using anaerobic and oxygen zones. FIG. 2 is a schematic diagram illustrating the processing of biomass obtained from a continuous flow process. FIG. 3 is a schematic diagram showing a continuous flow process using anaerobic, anoxic and oxygen zones. FIG. 4 is a schematic diagram illustrating the batch process operation of the present invention. 10... Inlet line, 12, 28... Tank, 1
4,30...Partition, 22...Stirring means, 16,1
8, 20, 32, 34, 36, 38...Hydraulic stage, 24, 26, 41, 48, 50, 52, 5
4,58...line, 40...spargeer, 56,
68... Pump, 42... Purifier, 44... Upper layer liquid, 4
6...Dense biomass, 60...Shickner, 76
... Filter, 88 ... Dry operation system, 102 ... Heat exchanger, 106 ... Separator, 210 ... Inlet hopper,
228...DO probe.

Claims (1)

[Scope of Claims] 1 (a) Under anaerobic conditions substantially free of NO ^- _x and having a dissolved oxygen content of less than 0.7 ppm,
The mixing of the nitrogen-, phosphorus- and BOD-containing influent with the activated biomass to form a mixture, which results in the selective production of non-fibrous microorganisms capable of sorbing BOD under anaerobic conditions; b) oxidizing the BOD in the mixture such that its removal is induced by contact with an oxygen-containing gas under conditions selected to maintain a dissolved oxygen content of at least 1 ppm; ) settling the oxidized mixture to separate the upper liquid from the more concentrated biomass; (d) using a portion of the separated biomass as activated biomass in an initial mix with a BOD-containing influent; and (e) recovering the other portion of the precipitated and separated biomass as a product; an improved high nitrogen and phosphorus content biomass produced by; 2. The biomass product of claim 1, wherein said anaerobic conditions are selected to result in a dissolved oxygen concentration of less than about 0.5 ppm. 3. The biomass product according to claim 1, wherein the anaerobic state is maintained by contacting the mixed liquid with nitrogen gas. 4. The biomass product of claim 1, wherein the product is used as plant or animal nutrition and the BOD-containing influent is wastewater. 5 said influent also contains an ammonia-containing material;
The mixture is treated under anoxic conditions after the anaerobic treatment and before the oxidation treatment with an amount of dissolved oxygen not exceeding 0.7 ppm and containing about
5. A biomass product according to claim 4, wherein the oxidizing mixture having a concentration of more than 2 ppm of nitrate and/or nitrite radicals is mixed during anoxic treatment. 6. The biomass production of claim 5, wherein the oxidizing mixture added to the anoxic treatment is added in an amount corresponding to from 100 to about 400% by volume of the fresh influent used in the initial anoxic treatment. thing. 7. The biomass product of claim 5, wherein the activated biomass fed to the anaerobic process is mixed with the influent in an amount corresponding to about 10 to about 50% by volume of the influent. 8. The total treatment time under anaerobic and oxidizing conditions does not exceed about 3 hours.
Section biomass products. 9. The biomass product of claim 5, wherein the total processing time under anaerobic, anoxic and oxidizing conditions does not exceed about 3 hours. 10. A biomass product according to claim 1, wherein said product is used as a living microorganism in the fermentation and said steps (a) to (e) are carried out by a batch type process. 11 The process steps described above are carried out in a continuous flow process in a separated zone, and a portion of the separated biomass used as activated biomass is recycled to the initial anaerobic zone. The biomass product according to item 1. 12 The process steps are carried out in a continuous flow process in a separated zone, and a portion of the separated biomass used as activated biomass is recycled to the first anaerobic zone and the oxidation from the oxygen zone is 6. A biomass product according to claim 5, wherein the mixed liquor is recycled to the anoxic zone. 13. Claims 11 or 12, wherein the oxygen zone comprises a series of at least two hydraulically different compartments in continuous liquid flow communication.
Biomass products as described in Section. 14. The biomass product of claim 1, wherein the BOD-containing influent is a carbohydrate solution or suspension. 15. Claim 11 or 12, wherein the anaerobic zone comprises a series of at least two hydraulically different compartments in continuous flow connection.
Biomass products as described in Section.