JPS58180283A - Method for decreasing concentration of nitrous acid in fishpond - Google Patents

Abstract

PURPOSE:To decrease the feed rate of active carbon in fishpond, by spraying active carbon in the pond according to the volume of water in the pond and the amt. of the feces released by fishes and adsorbing the nitrous acid in the water of the pond on the active carbon. CONSTITUTION:Preferably powdery active carbon is sprayed uniformly in a fish raising pond in accordance with the volume of water in the pond and the amt. of the feces released by fishes so that the nitrous acid in the pond is adsorbed on the active carbon. The active carbon adsorbing the nitrous acid and foreign matters are discharged from the pond and at least water is required to be supplied to the pond at about 10day/cycle rate in order to maintain the freshness of the water. The active carbon to be sprayed in a day is preferably 720-1,350g if the volume of the water in the pond is 50t and the amt. of the released feces is 3.6kg per ton in order to maintain the concn. of the nitrous acid in the pond at <=0.5-0.6ppm at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reducing nitrite concentration in a fish pond for eel, rainbow trout, yellowtail, etc.・In fish ponds, if the concentration of nitrous acid caused by the excreta of farmed fish exceeds a certain level, the concentration of nitrite in the fish ponds will be removed. ◇ For example, if the nitrite concentration in the fish pond exceeds aS) pm for adult fish, the concentration of nitrite for young fish exceeds 8 to 7 ppm, and the concentration of nitrite in the pond exceeds 8 to 7 ppm. There is a risk that farmed fish may suffer from nitrous acid poisoning, leading to mass mortality. In order to prevent such ridges, conventionally, a large amount of water is constantly poured into the fish pond, and the stocking amount in a short cycle (for example, 1 ton of water) is reduced to 8.
In the case of 6 kg, the method used was to replace it every 3 days/night). However, in this case, not only does a large amount of water be used, but the water used must be heated to a predetermined temperature depending on the type of fish being farmed, the season, etc., which increases fuel costs. I had a bout of nausea.

In order to solve the above-mentioned problems, the present invention spreads activated carbon to the fish pond according to the water volume and stocking amount of the fish pond, and adsorbs the nitrous acid in the fish pond with the activated carbon. A method for reducing nitric acid concentration is provided.

That is, by using activated carbon to reduce the nitrite concentration in fish ponds, it is possible to reduce the amount of water injected into fish ponds, thereby saving water and fuel required for fish farming. This is what I did.

In the present invention, powdered activated carbon is preferably evenly spread over the fish pond depending on the water volume and stocking amount of the fish pond, and the activated carbon adsorbs nitrous acid in the fish pond. Therefore, the lower the nitrite concentration in the fish pond, the better, and it is most preferable to keep it at 0.6 to 0.67 ppk or less at all times. on the other hand,
I have already applied 1 coat of nitrous acid, removed activated carbon and foreign matter from the fish pond, and kept it for at least 10 days to maintain the freshness of the water.
It is required that water be passed to the fish pond at a rate similar to the cycle. In order to keep the nitrite concentration in the fish pond below 00 fathom to 0 O-pp at all times while keeping the amount of water injected to the required minimum limit, the following amount of activated carbon should be added to the fish pond regularly, preferably every day. Needs to be sprayed.

Amount of spraying for 1 molar p (@) = (4~?, 5) x Amount of water in fish pond (t) x Amount of water 1 tml

For example, if the water volume of the fish pond is Sot and the amount of stocking for 1 is 5.11 kg, the amount of xamD sprayed is (
4~), 5) xsoxs, 5=vz.

In this case, even if the amount of sprayed per day is less than 11001, it is possible to reduce the nitrite concentration to a certain extent, but the bad nitrate a** degree can be reduced by 0.6p.
It is impossible to keep it below Shiho. On the other hand, Todoroya 0Ik on the 1st
When the amount of IIJ is l, s sc g O, the saponity of nitrite is about O10 PPMlK, but the daily rate) N e 35
This value UFt hardly changes even if it is spread over 0 HjbL. It seems that Mori and the old fish are constantly discharging their excrement. In addition, the amount of water injected into the fish pond every 10 days? If the amount of activated carbon applied per day is less than the above lower limit, the nitrite concentration can be reduced to 0. ! Although it is possible to maintain the amount of water at 0.6 ppm or less, increasing the amount of water injection in this manner impairs the purpose and effect of the present invention, which is to save water and fuel required for fish farming.

On the other hand, in the case of fish ponds with extremely high nitrite concentrations, spraying several times to several times the amount of charcoal into the fish ponds will reduce the nitrite concentrations all at once, and the next day's production will begin. Activated carbon of the above-mentioned amount is to be sprayed regularly, preferably every day. Examples are given below to demonstrate the present invention. The present invention is not limited to these Examples.

<Example 1. The following concrete fishpond yc1. ooog 65 powdered activated carbon per day
Water was sprayed every 9 o'clock for a day, and the nitrite concentration was measured every time. Water volume of 90 fish ponds: 60 Average weight: 12.5 g) Water amount 1: Feeding amount of Todoroki: 3.6 kg Water injection amount = 6 t/day (10 days/cycle) The above scooping results are shown in Figure 1. x, the concentration of nitrite was 8 ppm, but after spraying activated carbon, it rapidly decreased to about 0.6 ppm on the 6th day.
m), and after 1st on the 15th, it was maintained at about 0.3spp.

Example at the beginning! A concrete fish pond that showed an extremely high nitrite concentration of S4ppm (excluding nitrite concentration)
The conditions were the same as those in the fish pond in Example 1. 18 kg of powdered activated carbon was sprinkled at once on the fish pond, and the nitrite degree was measured every hour for 24 hours after the spraying. The measurement results are shown in Figure 2. Shown below. As shown in the figure, the nitrite concentration, which was initially 34 ppm, rapidly decreased after the activated carbon was sprayed, and reached about 0.8 ppm after 24 hours.

As explained above, in the present invention, activated carbon is scattered in the fish pond according to the water volume and stocking amount of the fish pond, and nitrous acid in the fish pond is adsorbed by the activated carbon. Since the nitric acid concentration can be reliably lowered, it is possible to keep the fish pond in an environment suitable for fish cultivation even if the amount of water injected into the fish pond is kept to the minimum necessary limit. Therefore, water and fuel required for fish farming are significantly saved.

[Brief explanation of drawings]

Figures 1 and 3 are graphs showing changes over time in nitrite concentration in fish ponds sprinkled with activated carbon.

Claims (1)

[Claims] 1. Decreasing the concentration of nitrous acid in a fish pond characterized by scattering activated carbon in the fish pond according to the water volume and stocking amount of the fish pond, so that the activated carbon adsorbs nitrous acid in the fish pond. Method.