JPH0346200B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Field of Application> This invention removes nutrients from water by using river, lake, and marsh water and drainage water rich in nutrients (hereinafter collectively referred to as eutrophic water) for cultivating valuable plants. It relates to a water purification method for removing. <Conventional technology> Traditionally, the main method of water purification has been to oxidize and decompose organic matter in water, but since nitrogen and phosphorus, which are decomposition products, cause large numbers of plankton, It has become clear that this method cannot be used as a method for purifying nutrient-rich water, which is currently a problem. Additionally, methods have been considered in which nutrient salts such as nitrogen and phosphorus in water are removed by adsorption or precipitation, but these methods are generally not practical due to their high cost. On the other hand, attempts have been made to purify the nutrient salts in nutrient-rich water by having them absorbed by plants. Plants such as water hyacinth have a particularly high ability to concentrate nutrient salts in water and are easy to manage because they float on the water surface. Research is focused on floating plants. However, since there are few ways to use the grown water hyacinth, a purification method by cultivating valuable plants is desired. Hydroponic cultivation, on the other hand, is widely used as a method of cultivating valuable plants, and generally supports and fixes the plants on a gravel bed or float bed, and uses much higher concentrations of nitrogen and water than eutrophic water. This is done by feeding liquid fertilizer containing nutrients such as phosphorus. When hydroponic cultivation is performed using nutrient-rich water instead of liquid fertilizer, plants grow poorly due to lack of nutrients, which is impractical from both the viewpoints of cultivating valuable plants and water purification. <Problems to be solved by the invention> Even when hydroponic cultivation is carried out using the above-mentioned nutrient-rich water, particles such as plankton in the nutrient-rich water will adhere to the roots of plants if cultivation continues for a while. At the same time, small animals that eat these plankton begin to live around the roots. As a result, decomposed products of plankton and small animal feces are supplied to plants as nutrients. However, in the case of hydroponic cultivation using a gravel bed, particles such as plankton and feces clog the gravel bed, resulting in poor oxygen supply. It becomes oxygen deficient. On the other hand, in the case of hydroponic cultivation using a floating bed,
As shown in Figure 2, the plant roots 1 hang down into the water below the float bed 2, so it is difficult for underwater particles such as plankton to attach to the roots and for small animals that eat plankton to grow around the roots. However, the small animal feces 3 do not accumulate around the roots but fall below the roots and are washed away. As a result, it becomes difficult for the decomposed products of the feces 3 to be effectively supplied to the plants as nutrients, and the plants suffer from poor growth due to lack of nutrients. Therefore, this invention solves the above-mentioned problems when performing hydroponic cultivation using eutrophic river, lake, and marsh water, and effectively uses decomposed products of plankton and small animal feces as nutrients for plants. The purpose of this work is to provide a method that can compensate for the lack of plant nutrients in nutrient-rich water, thereby cultivating valuable plants and purifying nutrient-rich water. . <Means and effects for solving the problem> That is, the present invention places a stock of a valuable plant without supporting or fixing it in a waterway having width, depth, and a gentle slope, and places a stock of a valuable plant within a substantial part of the roots of the plant. The water depth is such that the water is below the water surface and completely reaches the bottom of the waterway, and river/lake water or nutrient-rich wastewater is flowed into the waterway at a flow rate that does not wash away the plant stocks.
This is a water purification method by cultivating valuable plants, which is characterized by cultivating the valuable plants and purifying the river, lake, marsh water and wastewater at the same time. According to the method of the present invention, the nutrient salts in nutrient-rich water such as river/lake water or nutrient-rich wastewater are absorbed by valuable plants, so that the nutrient-rich water is purified. On the other hand, particles such as plankton in the water and decomposition products such as small animal feces compensate for the nutritional deficiencies of nutrient-rich water and maintain good plant growth. That is, particles such as plankton in rich nutrient water adhere to the roots of plants, and small animals that eat these plankton gather around the roots, and decomposed products of plankton and small animal feces are supplied to the plants as nutrients.
In this invention, as shown in FIG.
By setting the water flow 12 to such a level that the plant 10 does not float or be washed away and at a water depth within a predetermined range, water is constantly flowing to the roots 13 of the plant, and plankton and other The decomposed product 14 of feces can be effectively absorbed by the roots 13. As a result, it is possible to eliminate the oxygen deficiency around the roots caused by clogging of the gravel bed, as seen in hydroponic cultivation using a gravel bed, and furthermore, it is possible to eliminate the lack of oxygen around the roots caused by clogging of the gravel bed. It is possible to solve the problem of not being able to use decomposed products of plankton and feces as nutrients as in cultivation. In this invention, the water depth is generally reduced to 2 to ensure that a substantial portion of the plant's roots are below the water surface 15 and completely reach the channel bottom 16.
It should be within the range of ~20cm. In other words, when the water depth is less than 2 cm, most of the roots of most plants protrude above the water surface, resulting in poor supply of nutrients and poor growth. On the other hand, when the water depth exceeds 20 cm, most plants float to the surface without their roots reaching the bottom of the channel, as shown in Figure 2.
Roots may no longer be able to effectively absorb decomposed matter from plankton and feces, or in some plants even the stems and leaves may become submerged, resulting in poor growth. Of course, such water depth varies depending on the type of plant being cultivated, but in the present invention, regardless of the type of plant being cultivated, it is possible to ensure that a substantial portion of the roots 13 are below the water surface 15 and that the water channel is It is necessary to adjust the water depth to an optimum level within the above range so as to completely reach the bottom 16. Additionally, the flow rate of water flowing into a waterway varies depending on the depth of the water, the slope of the waterway, and the size of plant stocks, but it is possible that plant stocks placed in a waterway without support or fixation may be washed away. The flow velocity should be such that there is no Generally, the speed may be adjusted appropriately within the range of 6 to 60 m/hour. Although the width and slope of the waterway are not particularly limited, the width is approximately 1 m or less, and the slope is generally approximately 1/100 to 4/100. In particular, the width of the waterway is preferably approximately 30 to 60 cm, as it is preferable for plant stocks to grow across the entire width in order to distribute water evenly between the roots.
It is preferable to set the waterway width to approximately Valuable plants that can be cultivated by the method of this invention include vegetables, raw vegetables, spicy vegetables, soft vegetables, green onions, tuberous roots,
A wide range of vegetables such as eggplants, cucumbers, and beans, as well as rice, have been confirmed to be cultivable through experimental cultivation, including rice, taro, yachigashira, mulberry mulberry, black mulberry mulberry, black mullet, japonica, spearmint, Examples include lemon balm, tomatoes, cucumbers, eggplants, green onions, celery, Japanese apricots, Japanese chrysanthemums, lettuce, Japanese cucumbers, watercress, Japanese soybeans, soybeans, pakuchiyoi, Japanese soybeans, and soybeans. <Example> The present invention will be further explained by giving examples below. Example 1 A vinyl chloride sheet (0.2 mm thick) was laid on the inner surface of the board to create a waterway with a width of 40 cm, a length of 15 m, and an inclination of 1/100, and water from a moat in Tsuchiura City was collected at 15 tons/day. Watercress was cultivated from April to August by flowing water into this waterway at a flow rate of 20 m/hour and an average depth of about 7 cm. v Watercress germinated and took root one after another from the stems, spread out, and grew into a pine-like shape. I harvested the well-elongated stems twice a week, but each plant doubled in size in an average of one month, so I separated and divided the plants. The water purification effect and watercress yield are shown in the table below.

【table】

[Table] Note: *Suspended solids

[Table] For comparison, watercress was cultivated by pouring the same water as used in this example into a waterway of the same size, placing a perforated float on the water surface, and setting the water depth to 20 to 30 cm. As a result, the roots of the watercress were just floating in the water without reaching the bottom of the waterway, and they began to wither around the 10th day of cultivation, and by around the 30th day, most of the plants had died. Example 2 A channel with a width of 40 cm, a length of 8 m, and an inclination of 2/100 was created with the same structure as in Example 1, and lake water from Lake Kasumigaura was pumped at 8 tons/day.
The water was flowed into this waterway at a flow rate of 12 m/hour and at an average depth of about 7 cm, and was cultivated from August to October. Similar to watercress, Japanese rhinoceros sprouted one after another from its stems, took root, spread out, and grew into a pine-like shape. I harvested the branches twice after they had grown well, but the branches grew quickly and the branches became crowded, and the size of each branch doubled in an average of one month, so I separated them and divided them. The water purification effect and the yield of kushinsai were as shown in the table below.

【table】

[Table] <Effects of the Invention> According to the method of the present invention as described above, water can be reduced by utilizing nutrients in rich nutrient water such as river lake water and nutrient-rich wastewater for the growth of valuable plants. In addition, the lack of nutrients can be compensated for by making the decomposition products of plankton and small animal feces in the water effectively available to plant roots. As a result, it is possible to kill two birds with one stone by purifying water and harvesting valuable plants. In addition, when carrying out this invention, it is sufficient to simply push the stocks of valuable plants into the waterway without using a gravel bed or a float bed, so not only can costs be reduced in terms of equipment, but also This method also has the advantage of being extremely easy to divide stocks. Additionally, according to the present invention, the following secondary effects can also be obtained. Weed seeds do not germinate because they are submerged or washed away, so weeds do not grow. Larvae of aquatic insects that feed on plankton in the water grow around the roots, and many spiders that target the adults attach themselves to the plants being cultivated, so pests do not become a problem and insecticides are not used. There will be no need. Because nutrient-rich water contains a wide variety of microorganisms, pathogenic bacteria do not grow in waterways to the extent that they become a problem.
There is no need to use disinfectants etc. When loaches are placed in waterways where plants are cultivated, they can efficiently grow and multiply by feeding on the organisms that live on the roots of the plants.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the principle of the method of the present invention, and FIG. 2 is an explanatory diagram of hydroponic cultivation using a conventional floating bed. 10... Plant stock, 11... Waterway, 13...
Roots, 14...Decomposition products of plankton and feces, 15...
...Water surface, 16... Channel bottom.

Claims (1)

[Claims] 1. Placing stocks of valuable plants without supporting or fixing them in a waterway that has width, depth, and gentle slope, and the water depth is such that a substantial part of the roots of the plants are below the water surface and completely reaches the bottom of the waterway; Moreover, the feature is that river/lake water or nutrient-rich wastewater is allowed to flow through the waterway at a flow rate that does not wash away the plants, thereby cultivating the valuable plants and purifying the river/lake/marsh water and wastewater at the same time. Water purification method by cultivating valuable plants.