JPS5932199B2 - Treatment method for wastewater containing sodium alginate resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating wastewater containing a sodium alginate resin.

Recently, sodium alginate has been used in a wide range of applications as a water-soluble synthetic polymer, for example, as a sizing agent, food processing, and paints, and its usage is gradually increasing. Ru.

However, most of it is water-soluble polymer and has C/C properties and is dissolved in water for use, so it is discharged as an aqueous solution. A considerable amount of sodium alginate is contained in the desizing waste liquid.

Sodium alginate itself is usually harmless, but if a large amount of sodium alginate is disposed of as it is, it is not desirable in terms of environmental pollution, and it is desirable to develop an appropriate treatment method.

To date, there have been no reports of biodegradation of sodium alginate; however, microbial decomposition and assimilation of polyvinyl alcohol, a water-soluble synthetic polymer, is known. Under these circumstances, the present inventors searched widely in nature for excellent bacteria capable of assimilating sodium alginate, and as a result, Pseudomonas
It was discovered that sodium alginate can be assimilated and decomposed by culturing bacteria of the genus Sodium alginate in a medium containing sodium alginate as a carbon source, and using this bacterium, it is possible to decompose and remove the resin from wastewater containing sodium alginate resin. However, using this bacterium alone would require a considerable amount of time to reduce the TO value of pollutants other than sodium alginate resin in wastewater, and the scale of the wastewater treatment facility would also need to be expanded. We also identified the problem at the same time, and as a result of further investigation, we found that by treating wastewater containing sodium alginate resin with at least one species of bacteria belonging to the genus 7 Eudomonas added to aerobically biologically treated sludge. He discovered the effect of lowering the TOD inside to near zero and completed the invention.

Bacteria of the genus Pseudomonas used as new effective bacteria in the method of the present invention can be collected from a wide range of natural sources such as the sea, swamps, and industrial wastewater. Specifically, for example, pseudomonas
as ) KP-15 (Feikoken Deposit No. 3742
) can be mentioned.

The mycological properties of this strain are as shown in Table 1 below.

The sodium alginate resin-containing wastewater to be used in the method of the present invention means any wastewater containing sodium alginate having a structure represented by the following formula.

Sodium alginate assimilation as used in the present invention refers to a phenomenon in which bacterial cells ingest and consume sodium alginate as a carbon source, and the extent to which the polymer chains of sodium alginate are simply cleaved to form a low polymer. It doesn't mean anything.

Therefore, in the present invention, the degree of assimilation is clearly expressed by the degree of decrease in TOD (total oxygen demand) of the culture solution.

The general activated sludge referred to in the present invention refers to sludge obtained by treating municipal sewage and general industrial wastewater at a temperature of Refers to treatment methods using aerobic microorganisms such as the Mizusawa bed method, rotating disk aeration method, contact method, and oxidation pond method.

In order to treat wastewater containing sodium alginate resin by the method of the present invention, if the degree of contamination is high, the wastewater must be diluted with water as appropriate, and then used in advance in a suitable breeding apparatus at °C. Bacteria of the genus Pseudomonas obtained by aerobic growth at ℃ are grown using aerobic methods such as activated sludge method, submerged fixed bed method, sprinkling bed method, rotating disk aeration method, contact method, and oxidation pond method. When the wastewater containing sodium alginate resin is poured into a chemical treatment device and treated through the device, the sodium alginate resin is quickly decomposed and the TOD value decreases, and the treated water is directly discharged into rivers. There is no problem with releasing water into the water.
It can be water quality.

Bacteria of the genus Pseudomonas that assimilate and decompose sodium alginate-based resins are fixed together with other microorganisms on wood, branches, etc.
Some ℃・ flows through wastewater together with activated sludge and comes into contact with the wastewater to purify it, but these organisms breed well when mixed together, and if the two are mixed together and the moon-viewing method is used, wastewater treatment can be improved. It is convenient for industrial implementation because the equipment conventionally used for temperature control can be used as is.

The operating conditions such as temperature and pH when carrying out the method of the present invention should be similar to the operating conditions for the aerobic biological treatment method used for general wastewater purification treatment. However, it is desirable that the nitrogen and phosphorus content added before treatment be slightly higher than in the case of general wastewater.

That is, ammonium sulfate, urea, etc. are used as nitrogen sources using TODIO (
Nitrogen content is 1 to 5 grams per liter, and monopotassium phosphate, dipotassium phosphate, phosphoric acid, etc. are added as a phosphorus source so that the phosphorus content is 0.25 to 2.5 grams per TODlooP. It's okay if you do.

No other special conditions are required; however, the processing capacity is greatest at a temperature of about 20 to 37°C, and the processing speed will be faster if the agitation and air intake are sufficiently large.

The residence time of wastewater in the aeration tank is usually several hours to 24 hours, and the residence time can be shortened by increasing the amount of bacteria in the tank.

Regarding the amount of bacteria in the tank, the concentration of bacteria in the wastewater is 100 to 800 °C for sodium alginate resin assimilating and degrading bacteria.
For example, activated sludge suspended solids (ML) in activated sludge method
SS) concentration is suitably 200 to 15,000 ppm.

However, these numerical ranges are not limited.

Further, the pH of the wastewater needs to be adjusted to 6 to 8, preferably around 7, during treatment.

Further, according to the method of the present invention, there is no particular problem even when wastewater containing sodium alginate resin, sediment, and polyvinyl alcohol resin is treated at the same time.

The bacteria that assimilate or decompose the sodium alginate resin mentioned above are all floc-forming bacteria, so they can be easily separated from treated wastewater, and have been used in the past, for example.
It can be easily separated in the settling tank of activated sludge treatment equipment.

As described above, according to the method of the present invention, it has become possible to treat real wastewater containing sodium alginate resin at a temperature of .degree. C., which has been considered difficult until now.

The present invention will be specifically explained below with reference to Examples.

Example 1 Sodium alginate (reagent grade) was dissolved in water 11 and TO
D is measured and diluted with water to obtain TODlooOppm,
To this, urea and phosphoric acid are added as nutrients to TOD:N:P
= 100:5:2.5 ratio and used as waste water.

Pseudomonas -KP- which was acclimatized and multiplied in this wastewater for one month
15 (Feikoken Bacteria deposit number, No. 3742), industrial wastewater treatment activated sludge, and both at a ratio of 1:1.
Using three types of sludge mixed in the proportions of 1 to 100 ml, the activated sludge method was used to create an aeration tank with a capacity of 51. MLSSlooo.

ppm, aeration tank PH7-8, aeration tank temperature 30℃Aeration: tank D05ppm, sludge return rate 100%, aeration time 4.7 hours, changing the TOD of the wastewater mentioned above and gradually increasing the load continuously, approximately 2 After several months, the results shown in Table 2 were obtained.

Claims (1)

[Claims] 1 When treating wastewater containing sodium alginate resin using an aerobic biological treatment method, Pseudomonas (pseudomonas
A method for treating wastewater containing a sodium alginate resin, the method comprising using general activated sludge to which bacteria of the genus Eudomonas) have been added.