JP2017077511A - Water treatment system and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase in size and maintenance cost of circulatory system of water applied for fish cultivation water tank or the like.SOLUTION: A treatment water tank (3) is arranged in a circulatory system of water (CM) to a water tank (1) and a concentration part for concentration by absorbing ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in introduced water is arranged in the treatment tank. Thereby suppression of increase in size and maintenance cost of the circulatory system can be achieved because ammonia nitrogen, nitrite nitrogen and nitrate nitrogen are incorporated by microorganisms including aerobic bacterium and anaerobic bacterium propagating in the concentration part and can effectively be separated at a state with concentrating them.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water treatment system and method, and more particularly to a technology for purifying while circulating water stored in a water storage unit used for breeding organisms, for example, an aquarium for cultivating seafood on land. It is.

  In general, when aquaculture and the like are cultivated on land, in a closed environment such as an aquaculture tank, there is a problem of residual or increased concentration of ammonia nitrogen contained in excreta. Therefore, Patent Document 1 discloses a technology for removing ammonia nitrogen by constituting a water circulation system for the aquaculture tank and performing biological treatment (aerobic treatment) using nitrifying bacteria in the circulation process. Is disclosed. On the other hand, Patent Document 2 discloses that nitrate nitrogen is further denitrified after aerobic treatment. Although nitrate nitrogen is low in toxicity, the technology disclosed in Patent Document 2 is useful because it causes adverse effects on fish and shellfish reared when the concentration is high.

JP 2005-295939 A Japanese Patent Laying-Open No. 2015-61513

  However, as disclosed in Patent Document 2, since two steps of aerobic treatment and denitrification treatment are required, the circulation system including a water storage section such as a water tank is increased in size and maintenance costs are increased. It was to bring.

  Therefore, an object of this invention is to provide the water treatment system and method which can suppress the enlargement of the circulation system containing water storage parts, such as a water tank, and the increase in maintenance cost.

  For this purpose, the water treatment system of the present invention is arranged in a water circulation path with respect to the water storage part, and the microorganisms absorb and concentrate the ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the introduced water. And a separation unit that separates the concentrate from water.

  Further, the water treatment method of the present invention includes a concentration step that is disposed in a water circulation path with respect to the water reservoir and absorbs and concentrates ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the introduced water. And a separation step of separating the concentrate from water.

  According to the present invention, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen are incorporated into microorganisms containing aerobic bacteria and anaerobic bacteria that are proliferating in the concentration section, and these are efficiently separated in a concentrated state. Therefore, it is possible to suppress an increase in the size of the circulation system and an increase in maintenance costs.

It is a block diagram showing typically one embodiment of a water treatment system to which the present invention is applied. It is a block diagram which shows typically other embodiment of the water treatment system to which this invention is applied. It is a block diagram showing typically another embodiment of a water treatment system to which the present invention is applied.

  Hereinafter, the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments described below.

  In addition to the aquaculture tank (culture tank) and ginger, the aquarium / zoo display tank, artificial pond, or goldfish and tropical fish at home, etc. Includes small aquarium used. In addition, not only marine organisms that normally stay in the sea, such as fish, shellfish, crustaceans, and whales, but also marine organisms that normally live in the sea, That is, sea animals such as sea lions, fur seals, sea otters, polar bears, penguins, turtles and the like can also be included.

(Outline of water treatment system)
One embodiment of the water treatment system shown in FIG. 1 is applied to, for example, a fish tank for fish culture, and from a water reservoir, that is, a water tank 1, through a treated water tank 3 that performs immersion membrane treatment and foam separation. , A circulation path CM returning to the water tank 1 is included.

  The treated water tank 3 is provided with an immersion membrane 5 as a concentrating part and a foam separating part 7 as a separating part. For the filter medium of the immersion membrane 5, an MF (microfiltration) membrane or a UF (ultrafiltration) membrane can be used, and an NF (nanofilter) membrane can also be used. May be. The immersion film 5 is always washed with bubbles generated with the introduction of air from a blower 9 described later. The foam separation unit 7 floats the substance (including microorganisms) adsorbed and concentrated on the gas-liquid interface of the fine bubbles while guiding the substance to the preferred portion of the upper part of the treatment water tank 3 together with the bubbles.

  The bottom of the treatment water tank 3 and the foam separation part 7 are connected to the membrane treatment part 11 and are formed on the top of the sludge-like pollutant and foam separation part 7 that has settled at the bottom of the treatment water tank 3 as the pump P2 is driven. The stable foam is introduced into the film processing unit 11. The membrane treatment unit 11 separates the sludge from the sewage, and the resulting treated water returns to the water tank 1 via the reflux path CR, as indicated by the dashed arrows. As the filter medium used in the membrane treatment unit 11, an appropriate one can be used, and a film having a small pore diameter and a filter medium having a large porosity may be used in combination.

  In the present embodiment, the blower 9 is connected to the water tank 1 in addition to the treated water tank 3. Thereby, aeration of the water tank 1 is performed with the blower 9, and the amount of dissolved oxygen can be adjusted. If necessary, a plurality of blowers 9 may be installed instead of one. Further, in the present embodiment, the blower 9 is also connected to the foam separation unit 7 via the ozone generator 13. Although this configuration is not essential, it is easy to form stable foam by introducing ozone into the foam separator 7, and it is possible to efficiently remove and sterilize scale, scum, and slime in the foam separator 7. It becomes.

  The water introduced from the water tank 1 to the treated water tank 3 as the pump P1 is driven is biologically treated by microorganisms that are propagated in the circulation system. More specifically, the immersion membrane 5 concentrates aerobic fungi including ammonia oxidizing bacteria and nitrite oxidizing bacteria, and anaerobic fungi that denitrify nitrate nitrogen, and is contained in the introduced water. Ammonia nitrogen is captured by ammonia oxidizing bacteria, nitrite nitrogen is captured by nitrite oxidizing bacteria, and nitrate nitrogen is captured by anaerobic fungi. Therefore, microorganisms that have taken in ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen are concentrated in the portion of the immersion membrane 5, while the permeated water from the immersion membrane 5 returns to the water tank 1.

  In order to maintain the performance, the immersion film 5 is always washed with bubbles generated with the introduction of air from the blower 9. Along with the cleaning, the biofilm formed on the membrane surface is peeled off, adsorbed to the gas-liquid interface of the fine bubbles by the foam separation unit 7, and is induced as a stable foam to a preferred portion above the treatment water tank 3.

  As described above, in this embodiment, instead of adopting a two-step sequential process of an aerobic (nitrification) process and an anaerobic (denitrification) process, nitrogen propagated by the immersion film 5 disposed in the treated water tank 3. The fungi that have taken in the compounds can be concentrated and efficiently discharged from the system by the foam separation unit 7.

  Cleaning of the immersion film 5 is performed by constantly bubbling with the blower 9, but chemical cleaning performed by appropriately adding chemicals into the treated water tank 3 can also be combined. The timing of chemical cleaning can be determined based on the performance degradation / recovery of the immersion film 5, and for this purpose, for example, a sensor that detects a transmembrane pressure difference of the immersion film 5 can be included. In addition, if the tendency of performance degradation of the immersion film 5 and the tendency of performance recovery by chemical cleaning can be predicted statistically or experimentally, the start / end time of chemical cleaning is instructed based on time management. It may be a thing.

(Other)
The present invention is not limited to the embodiment described above and the modifications described in various places, and various changes, replacements, deletion of components, addition of other components, and the like are possible.

  FIG. 2 is an embodiment according to a modification of the water treatment system shown in FIG. 1, in which a circulation path including a denitrification tank 15 is added to the water tank 1. As described above, nitrate nitrogen is also denitrified in the treatment water tank 3 by anaerobic fungi, but the embodiment of FIG. 2 is effective when the denitrification treatment is insufficient by itself. In addition, you may provide the denitrification tank 15 in the return path of the treated water from the treated water tank 3 to the water tank 1. FIG. In any case, since the removal of the nitrogen compound is also performed in the treated water tank 3, the denitrification tank 15 may be smaller than that provided alone.

  In addition, as shown in FIG. 3, the treatment water tank 23 is connected to the bottom of the water tank 1 to form a circulation path, while the foam separation part 27 can be directly arranged in the water tank 1. In this embodiment, the sewage flowing out from the bottom of the water tank 1 is purified by circulating to be returned to the water tank 1 through the treated water tank 23 and returned to the treated water tank 23 again by the foam separation unit 7. The treated water tank 23 may be configured so that aerobic fungi and anaerobic fungi are mixed in the same manner as the treated water tank 3 of the embodiment of FIG. 1, and is divided into sections so that they exist separately. It may be.

  Moreover, the pump should just be arrange | positioned in the appropriate position which needs the smooth transfer of water. Further, if it is necessary to block the flow path, a valve may be arranged at an appropriate position. In addition, in the water treatment method, each part is automatically turned on / off using a control system and a control procedure as shown in FIGS. 2 and 3, and at least a part is manually turned on / off. You may do.

DESCRIPTION OF SYMBOLS 1 Water tank 3, 23 Treated water tank 5 Immersion membrane 7, 27 Foam separation part 9 Blower 11 Membrane treatment part 13 Ozone generator P1, P2 Pump CM Circulation route CR Reflux route

Claims (4)

A concentration unit that is arranged in a water circulation path to the water storage unit and absorbs and concentrates ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the introduced water;
A separation unit for separating the microorganism and water;
A water treatment system comprising:   The water treatment system according to claim 1, wherein the concentration unit further includes an immersion membrane. The water treatment system according to claim 1, wherein the separation is foam separation. A concentration step that is arranged in the water circulation path to the water reservoir and absorbs and concentrates ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the introduced water;
A separation step of separating the microorganism and water;
A water treatment method comprising: