JPS6012119B2 - Wastewater purification method using vascular plants - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of treating sewage and its secondary treated water, or desorbed liquid from human waste treatment and its activated sludge treated water, as well as polluted and eutrophic lake water, river water, groundwater, etc. Excessive dissolved or suspended nitrogen compounds and other substances that cause abnormal proliferation of photosynthetic organisms, such as those of herbs and tall trees, are removed to the extent that they promote the abnormal proliferation of phytoplankton, zooplankton, and wetland plants in environmental waters. The present invention relates to a method for purifying wastewater by growing vascular plants on shelves placed horizontally in water.

In general, methods for purifying wastewater such as sewage and wastewater and contaminated natural water using photosynthetic organisms include the oxidation pond method and photosynthetic bacteria culture method using lower photosynthetic microorganisms, The rice field method, the floating tray method, the floating chestnut plant method, the tatami right method, the mountain stream method, the nursery method, etc. have been implemented or proposed in the past for those using plants (including tube bundle plants).

Among these methods, the photosynthetic bacteria culture method requires that the culture solution (waste water or polluted water) be highly concentrated. However, such wastewater and polluted water generally have low concentrations of nutrients, making it difficult to apply them. The disadvantage of the oxidation pond method is that it is difficult to separate the grown algae from the water, and the treatment cost is high. In addition, algae that have formed and substances suspended in the water to be treated settle in the oxidation pond, accumulate on the bottom, and are temporarily separated from the treated water, but the accumulated organic matter decomposes and becomes part of the oxidation pond. Some or most of it is leached back into the water, becoming a secondary source of pollution. Therefore, the main function of the oxidation pond is only to change the chemical form of pollutants, but not to remove impurities from wastewater, which is the basis of water purification. Compared to the method using photosynthetic microorganisms as described above, the method using higher vascular plants has the advantage that the plants generated as a product of water treatment are large and easy to remove, and it is similar to the oxidation pond method. ``Development of this implementation layer has been desired because it has advantages such as being able to selectively use plant types that are effective for specific water purification, and therefore easier to manage.''

However, in the paddy field method, the roots penetrate deep into the rice bran at the bottom of the water, so it takes a lot of effort to remove the plants.
Furthermore, the organic matter flowing in with the water to be treated accumulates in the soil and rots, making the rhizosphere of plants anaerobic and inhibiting plant growth, making it inefficient. Another drawback of this paddy field system is that the passage of the water to be treated becomes uneven due to the overgrowth of plants, and the treated water does not flow uniformly, reducing the effective area of the treatment pond. The floating dish method loses stability as plants grow and increase in weight, and the suspended matter in the wastewater that is trapped during the stabilization is released by wind and waves and flows out together with the treated water. Another drawback is that it is very difficult to maintain because it can topple over or be submerged in water during strong winds. For the floating-leaved plant method, Eicholniacras
lpes Solms〉Pond and duckweed (Philippines Solms)
nor) using a pond. However, water hyacinth and duckweed will wither even within the frost cover in winter. For this reason, it is inappropriate as a method for purifying wastewater or raw water for irrigation, which must be constantly treated throughout the year. The nursery method is a method in which plants are planted on a sand layer formed in water, and is the same as the tatami stone method and mountain stream method used for the cultivation of wasabi and parsley. Like the paddy field method, this method has the disadvantages that it is not easy to remove plants and that the water to be treated is unevenly distributed. Its use in water treatment makes it very difficult to operate. By the way, the physiological activity of living things is generally utilized.

Temperature is an important environmental condition for the treatment of wastewater and polluted water. Water treatment methods that use heterotrophic microorganisms, such as bacteria, filamentous fungi, or photosynthetic bacteria, rapidly become less effective when the water temperature drops below 10 to 15 qo, and especially in winter, they require low loads or flooding. necessary, and the cost will be high. However, there are many autotrophic photosynthetic plants whose physiological activity rapidly declines if the water temperature exceeds 2 to 5°C. Therefore, methods for purifying wastewater and polluted water using these have the advantage of significantly reducing treatment costs for winter protection. Perennial herbs and trees that grow in the boreal and temperate regions as well as in the loin zone have a production rate (Product rate).
There are many species whose annual growth potential (Mty) is comparable to that of photosynthetic plankton (algae). Therefore, by utilizing the ecological, physiological, and chemical compositional characteristics of these plants, we can purify wastewater and polluted water that have negative economic benefits, and at the same time, we can use the plants generated as by-products of water treatment to become effective. It has become desirable to develop advanced biological treatment techniques that can be used. Vascular plants are said to be higher plants, and their tissues consist of roots (absorption of water and nutrients), stems (transport of substances between roots and leaves), leaves (carbon assimilation), and flowers (reproduction). action).

Roots are generally found in the soil and are responsible for the absorption of water and nutrients, while also providing an ecological niche for soil microorganisms and other animals.
So-called soil and rhizosphere (Rhizospher)
form e). These ensure the survival of the plant itself. That is, ecologically and soil microbiologically, plant roots and soil (composed of inorganic matter, organic matter, microorganisms and animals) constitute the transport of water and nutrient substances and other physical conditions necessary for growth. It is already a known fact that this is a requirement. This fact means that symbiosis with soil, that is, with soil microorganisms, is a necessary condition for the proper growth of general vascular plants (hereinafter referred to as plants). However, it is also well known that plants can grow without such trenches, ie, the intervention of microorganisms. Hydroponics, a solution cultivation method also known as pebble cultivation or hydroponics, is a cultivation method based on the fact that plants can grow normally even without symbiosis with microorganisms and other soil organisms. However, the nutrient concentration of general wastewater and polluted water is lower than that of the cultivation solution used for solution cultivation, fluctuates dramatically, and sometimes lacks several essential nutrients. Furthermore, the water to be treated has a large biochemical oxygen demand (hereinafter referred to as 80D) and suspended matter, which are disadvantageous for solution cultivation. For these reasons, it is completely difficult to apply the solution cultivation method as it is as a method for purifying wastewater or polluted water. Another reason why it is difficult to apply the solution cultivation method to the treatment of sewage is that the generation of bacteria, molds and fungi is inevitable in sewage treatment, This is because the proliferation of these microorganisms creates unfavorable conditions for solution cultivation. To summarize the above, in order to technically realize a method for purifying wastewater or polluted water using plants, the device must satisfy the following conditions.

(i) Low and variable nutritional conditions and high BO
Plants should grow vigorously even when in contact with wastewater or polluted water characterized by D.

(ii) Scales that are easy to harvest and that can be economically removed and separated from water by absorbing and synthesizing substances that cause pollution and eutrophication of environmental waters.

Side Dissolved oxygen and hydrogen ions (pH) must be at a sufficient concentration to maintain the physiological activity of roots and prevent water from rotting.

G macronutrients (N, P, K,
The abundance ratio of S, Ca, Mg) is within the appropriate range, and the micronutrients (Fe, Cu, Zn, 1, Mn, Co, Mo
, Se, Sn) should continue to exist sufficiently around the roots.

M In the first place, wastewater and polluted water are not sterile or inanimate water, so rather than trying to remove microorganisms that occur around the roots or in the treated water through sterilization, it is necessary to actively make them effective. To find the evidence and develop effective application technology.

The purpose of the present invention is to satisfy the above-mentioned conditions, and the underwater roots of plants planted on a shelf installed horizontally in water or at a slight angle with the horizontal are placed in the surrounding area. The agglomerated aggregates, which are composed of inorganic and organic fine solids and aquatic microorganisms and are concentrated in micronutrients, effectively form an underwater soil over the entire water ditch pond, and eliminate the clinging underwater pseudo-soil. In order to impart an appropriate amount of kinetic energy to the water being processed as it passes through the rhizosphere in order to make it mechanically strong against destruction, an appropriate flow velocity is applied to the water passing through the ditch pond, and some turbulence is added to the flow. Purification of wastewater using vascular plants, which is characterized by generating water flow and raising the water level to gradually expand the rhizosphere area in response to increased water and nutrient requirements accompanying plant growth. The purpose is to provide a method.

The principle of the present invention is that the mechanism of purification of wastewater and polluted water by plants is strengthened by the increased demand for water and nutrients during plant growth through photosynthesis, and by the corresponding underwater roots and slow movement of water. This is based on the inventor's research results that the increase in activity between roots, microorganisms, and other animals occurs in the rhizosphere, which is composed of an underwater pseudo-soil formed in . As is clear from the above description, the underwater pseudo-soil is composed of inorganic and organic solids, which are the constituent elements of the soil base material, and soil organisms.

In order to make the water purification function described above even more effective, the following conditions are necessary.

{a' To quickly mix the water to be treated in the rhizosphere so as not to cause even a partial shortage of dissolved oxygen. {b-The aggregates of inorganic and organic fine solids and microorganisms that make up the aquatic loam do not separate from the rhizosphere and reduce the biological activity of the rhizosphere, thereby reducing the supply of nutrients to plants. thing. To prevent a decline in aerobic activity due to a decrease in dissolved oxygen, which often occurs in the summer, by depositing W-separated aggregates at the bottom of a water ditch pond and decomposing them anoxically. 'd} Effectively remove suspended matter in the inflowing water to be treated and fragments of underwater artificial shelters that may have broken away, into a solid plate that has been well adapted to the flowing water environment with moderate turbulence. To make it adhere. For this purpose, it is necessary to increase the flow velocity and water level of the water channel, and to create an appropriate amount of turbulence by making the bottom of the channel uneven, and to spread the water sufficiently over a wide daughter area. However, if the flow velocity of the water to be treated passing through the plate sphere and the energy of the turbulence are higher than necessary, the underwater pseudo-soil will mechanically collapse and flow out together with the treated water. For this purpose, it is necessary to devise a method for passing water through the water ditch pond. This can be countered by installing a channel with a high flow velocity in the ditch pond with an uneven bottom (for example, paved with gravel or pebbles) and a device to raise the water level (for example, a movable weir). I can do it.

In other words, a channel with a high flow velocity is provided below the daughter area. Water flows quickly through this channel, and part of its kinetic energy is imparted to the water in the rhizosphere as turbulent flow due to the uneven structure at the bottom. For this reason, water flows slowly through the rhizosphere while mixing. At the same time, the water to be treated is quickly distributed throughout the pond through channels with a high flow rate, and dissolved and suspended substances, that is, nutrients, are uniformly captured by each underwater simulator at the same time. Growth and microbial activity in the rhizosphere can be maximized. In addition, in order to cope with the increase in water and nutrient requirements associated with plant growth, the water level is raised to expand the rhizosphere to the upper layer, increasing both the amount of roots and the amount of submerged soil. and increases the amount of nutrients captured by the underwater pseudo-soil. In order to embody the above principle, the types of plants to be planted in water ditch ponds should be those that have a strong propagation power through hydroponic cultivation and have an average production volume of 1 in fixed carbon equivalent.
It is desirable that the amount is 0 evening/pillow/other y or more.

Below is Nastunium, a member of the oil family.
oHicinaleR. An example using Br) will be described. Embodiment 1 FIG. 1 is a plan view of a case where industrial wastewater containing mainly ammonia is combined with domestic wastewater, and the wastewater treated in an oxidation pond is purified in a ditch pond.

The water ditch pond 1 is surrounded by a surrounding outer wall 2, and has a water conduit 5 inside.
is formed.

The water channels 5 are partitioned by partition walls 3, and adjacent ones have a lotus passage at one end, and gravel 4 is spread at the bottom. In the water near the water surface of this water channel 5,
As shown in FIG. 2, a shelf 6 having a gap through which drainage water passes is provided horizontally, and a watercress 7 is grown on the upper part of the shelf 6. Then, the underwater simulator 8 is formed by the growth of this rhizosphere. Also, in one corner of Mizoike Pond 1,
A water-receiving bit 10 is provided in the first-stage water conduit 5 to allow drainage from a well-known oxidation pond 9 to flow therein.
In addition, a treated water bit 12 equipped with a movable weir 11 is provided at the other corner, which is suitable for the final stage of the water channel 5.Furthermore, an anti-frost cover 13 and an illuminator 14 are provided at the top. The aeration pond 15 transfers the treated water from the ditch pond 1 to the movable weir 11,
The treated water is introduced via the water channel 13 and atomized by the aerator 16, and the dissolved oxygen, pH,
A well-known measuring device 17 for monitoring turbidity, oxidation-reduction potential, conductivity, water temperature, etc., and outside temperature is attached.

The Qinzhuang machines 18 and 19 are for supplying nutrients.

That is, although the nutrient balance of the drainage water in the ditch pond 1 is measured by a regulating device, the growth of the watercress 7 may still be restricted due to a lack of one or more nutrients.
In this case, it is provided for replenishment, and is configured to inject the required amount of nutrients into the water receiving bit 10 and the intermediate water conduit 5. The treated water from the aeration pond 15 is discharged into the river or reused, but some of it flows into the water receiving bit or the intermediate water conduit 5 by the pump 20', and is discharged into the water ditch pond 1. Nutrient balance, dissolved oxygen and pH of wastewater
Make adjustments.

The underwater submersible channel 5 is provided with water surface water 7, submerged pseudo-soil 8 made of its rhizosphere, gravel 4 spread on the bottom, etc., so that as shown in Fig. 2, there is a connection between the bottom and the daughter zone. A distant current zone A with a high flow rate is formed between the two.

In addition, a grain velocity zone B where the flow velocity is slow is formed in the rhizosphere above the shelf 6. Furthermore, a photosynthetic zone C is formed by the leaves and stems of the watercress 11. Furthermore, since the water ditch pond 11 is provided with a frost-proof cover 13 and an illuminator 14 on the upper part, a heat retention/light irradiation zone ○ is formed by these.

The Dutch oak 7 planted in the water ditch 5 first entered the planar expansion phase, covering the entire surface of the water, and at the same time, roots developed into a mat in the area separated by the shelf 6 and the water surface, and were carried by the oxidation pond runoff. Suspended matter is captured to form underwater pseudo-soil 8.

After passing through the planar expansion phase and entering the vertical expansion phase, the growth decreases as it progresses further and reaches the peak phase, so in order to increase the growth again, the movable weir 11 installed in the water extraction facility is operated to raise the water level. When the BOD of the inflow water to the water ditch pond 1 increases or the water temperature suddenly rises, the dissolved oxygen in the treated water decreases, the underwater pseudo-soil 8 collapses, the turbidity increases, and in severe cases, the treated water becomes It smells like hay and reduces the effectiveness of the treatment. In such a case, the aerator 16 of the explosion pond 15 is used to increase the dissolved oxygen content of the treated water to 60% or more. As a result, the turbidity was always below 3, and the transparency was also above 2. The BOD and turbidity of the inflow water to the water ditch pond 1 were high and fluctuated, but the BOD and turbidity of the treated water were extremely low and stable. The parameters for obtaining good treated water in this case are the flow velocity in the final flow zone A, the water circulation ratio, the water level of the water conduit 5 (the distance between the shelf 6 and the water surface), and the water depth (the distance between the shelf and the bottom). ), respectively, the flow rate in fast flow zone A is 30 to 20 shipboard/sec, the water circulation ratio is 1 to 5, and
Set the water level in the range of 50 to 50W sail and the water depth in the range of 200 to 100 meters. The growth rate of Dutch cucumber is 1-2 throughout the year.
It is within the range of 5 evenings (carbon amount equivalent)/ship/ship y, and in winter, if kept warm with frost protection etc., it is possible to make it more than about 5 evenings-C/day. The removal rate of ammonia and nitrogen by this apparatus was approximately 95-100%, and the removal rate of total nitrogen was 20-95% throughout the year. Example 2
Figure 4 shows a flow diaphragm suitable for purifying polluted and blackened small rivers in large cities.

Sewage and secondary treated water from sewage treatment plants are discharged and become anaerobic and rotten, with no remaining oxygen and no fish to live in. The treated water is pumped up from the river 21 with a pump 22, and first sent to a settling pond. 23, and the light water is purified in the first water ditch pond 24. Next, the water is aerated in the first aeration pond 25 and further purified again in the second water ditch pond 26, and the treated water is re-aerated in the second aeration pond 27, and a portion is discharged through the fish monitoring pond 28. Aerators 29, 30 are installed in the first aeration pond 25 and the second aeration pond 27.
and pumps 31 and 32 are installed respectively, and a portion of the treated water is returned to the first ditch pond 24 and the second ditch pond 26, respectively. Furthermore, the first aeration pond 25 and the second aeration pond 27
The treated water bits 33 and 34 at the outlet of the
A measurement system 35 is installed to monitor pH, turbidity, etc. In this embodiment, the cross section of the water groove is shown in FIG. The weight-shaped portion 36 in FIG. 5 is the rhizosphere zone B, and the lower basin-shaped portion 37 is the flow velocity zone A, and these are separated by a shelf 38. 39 is the water surface of the ditch, and above it is the photosynthetic zone C consisting of medicinal stems of watercress.

The treated water entering the first ditch pond 24 from the sand settling basin 23 is BOD
is always more than 50 feet, and in order to maintain aerobic conditions in the water ditch pond, the flow velocity in flow velocity zone A is set at 100 to 100 m/sec.
In order to raise the circulation ratio to 5, the ratio of the cross-sectional area of the flow velocity zone A to the cross-sectional area of the rhizosphere zone B is reduced. With the equipment shown in this flow diagram, the BOD and turbidity of the treated water are extremely low, less than 30 cm, and no plexus was detected. We were able to obtain water in which animals such as fish, goldfish, and killifish can normally live.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of an embodiment of the present invention, FIG. 2 is a sectional view taken along the low D line in FIG. 1 in the direction of the arrow, and FIG. A cross-sectional view taken along the arrow EO direction,
FIG. 4 is a flow diagram showing another embodiment of the present invention, and FIG. 5 is a sectional view of a main part applied to another embodiment of the present invention. 1... Water ditch pond, 5... Hydroponic waterway, 6.
...Fence, 7...Dutch cucumber, 8...
...Underwater pseudo-soil. Figure 2 Figure 3 Figure 1 Figure 4 Figure 5

Claims (1)

[Claims] 1. A shelf with voids through which the water to be treated passes is installed below the water surface and above the bottom in a waterway through which the water to be treated flows, and most of the leaves and stems are exposed to the atmosphere at the top. The roots of the vascular plant are planted, and a slow zone of the water to be treated is formed above the shelf by the flow velocity below the shelf, and in this slow zone, the underwater roots of the vascular plant and the water to be treated are Form an underwater pseudo-soil with the substances to be removed captured from the water, thereby growing the vascular plants, and raise the water level of the waterway as the vascular plants grow, making the underwater pseudo-soil effective. A method for purifying wastewater using vascular plants characterized by retaining the wastewater.