JPH0428401B2 - - Google Patents

Description

[Detailed description of the invention]

Background of the Invention Sludge is generated in wastewater treatment facilities such as sewage and human waste treatment plants, food processing, slaughterhouses, manufacturing industries, etc., and polymer flocculants are often used to dewater such sludge. It's summery. The sludge cake produced by dewatering is either disposed of (for example, incinerated) immediately after the dewatering process, or stored in a dewatered cake hopper and then disposed of.
The latter is usually the case, and the current situation is that the dehydrated cake is stored in the hopper for a certain period of time and then disposed of. Among the sludge cakes treated in this manner, those containing a large amount of organic matter are susceptible to decomposition, and as the sludge cake is stored in the hopper, decomposition progresses and a foul odor is generated, which poses a major problem in terms of environmental hygiene. In order to solve this problem, methods have been proposed in which a deodorizing agent is mixed with the sludge before dewatering, or a method of spraying the deodorant on the cake after dewatering. However, these methods are not necessarily satisfactory. For example, when spraying a deodorizer onto a dehydrated cake, it is difficult to uniformly spray the minimum amount, whereas when mixing a deodorant into sludge before dewatering, it is relatively easy to achieve uniform dispersion. Many of the commonly used deodorants are liquids that are poorly soluble in water, so they have to be added in the form of an emulsion, but the surfactant used for this purpose causes the liquid to foam, causing problems in the dehydration process and This is because it causes difficulties when processing the liquid (for example, by activated sludge method).Also, from the point of view of polymer flocculant users, dehydration work is difficult because it requires the extra work of adding deodorizing agent. SUMMARY OF THE INVENTION The present invention aims to provide a solution to the above-mentioned problems, and aims to provide a solution to the above-mentioned problems. This objective is achieved by incorporating it into a flocculant. Therefore, the flocculant composition according to the present invention consists of a polymeric flocculant and an auxiliary agent adsorbed on humus solids. Effect: By blending auxiliary agents such as deodorants with adsorption to a specific adsorbent solid, that is, humus, it is possible to reduce the effects seen when using deodorants. All of the above problems have been solved. That is, the flocculant composition according to the present invention is a so-called one-package type that has deodorizing and other functions, and the user does not have to add a deodorant separately. Not only is it hassle-free, but surfactants are not used unless specifically desired, so there is no problem with bubbles in the liquid after dehydration.Also, since humus is water-insoluble, in that case, The deodorizing agent adsorbed there is also transferred to the sludge cake as a water-insoluble substance during the dehydration process and is present in the cake at a high concentration, so this combined with the fact that there is little escaping into the liquid makes deodorization more efficient. This is often done. The auxiliary agents that should be added are not limited to deodorants, but may also be preservatives, so if an appropriate preservative is used, the problem of spoilage can be fundamentally solved.Detailed Description of the Invention Polymer flocculant A variety of flocculants made of water-soluble polymer substances, that is, polymer flocculants, are publicly known and in use, and any one can be used in the present invention.Used for dewatering sludge Specific examples of polymer flocculants include cationic polymers such as N-dialkylamino methacrylate alone or copolymers, acid adducts thereof or quaternized products thereof, and acrylamide alone or copolymers. In addition, mono- or copolymers of nonionic polymers such as acrylamide, and mono- or copolymers of anionic polymers such as acrylic or methacrylic acid or salts thereof (specifically, polyacrylamide, etc.) (partial hydrolyzate), and others. In order to better enjoy the effects of the present invention, the polymer flocculant is preferably in the form of powder or granules. This is because when adding auxiliary agents, which are often poorly water-soluble liquids, if the polymer flocculant is powder or powder, uniform dispersion is impossible and the polymer flocculant This is because powders or particles tend to stick to each other. However, it goes without saying that the effects of the present invention can also be obtained when the polymer flocculant is in liquid form. Adsorbent Solid The adsorbent solid used in the present invention is humus. It is desirable that the humus is at least as fine as the powder or granule particles of the polymer flocculant to which it is added. It can be said that it is preferable that the humus soil be as fine as possible in order to avoid giving the impression of a foreign body. In some cases, the humus may be colored to make it more visible. A preferred adsorbent for use in the present invention is humus, as described above. Preferred adsorbents for use in the present invention are humic soil or humic soil treated by oxidation, etc., and humic soil oxidized, particularly oxidized with heated air, is particularly preferred. Humic soil is soil that usually contains 20% or more of humus, which is obtained by dividing the remains of plants and animals through the action of microorganisms. In the present invention, the term "humus" includes soil that has been treated with heated air, other oxidizing gases, and other oxidizing agents as described above. Auxiliary Agents There are various types of auxiliary agents that should be adsorbed onto the above adsorbent and incorporated into the polymer flocculant. Specific examples include deodorants and fragrances such as acetone phenone, benzyl acetate, p-
Dichlorobenzene, cinnamic acid caldehyde, anethole, diphenyl ether, vanillin, methyl salicylate, β-phenylethyl alcohol, oxycitronellal, phenyl acetaldehyde,
Examples include piperonal, vegetable essential oils, disinfectants such as benzalkonium chloride, benzethonium chloride, etc., antifoaming agents such as silicone oil, higher alcohols, and the like. These auxiliary agents can be used as they are or diluted with a solvent, and solid ones can be dissolved in a solvent or emulsified, and one or more of them can be mixed with humus and adsorbed. . Production of Composition The composition of the present invention, which contains a polymer flocculant and an auxiliary agent adsorbed on humic soil as essential components, can be produced by any means that can uniformly mix the two. The two may be mixed all at once in a final predetermined ratio, but since the amount of adsorbed auxiliary agent in the humus soil is smaller than that of the polymer flocculant, it is best to mix the humus according to the method commonly used for blending small amounts of ingredients. It is also possible to prepare a composition containing a final predetermined amount or more of the auxiliary agent adsorbed on the soil, and then mix it with the polymer flocculant. The ratio of the amount of the polymer flocculant to the auxiliary agent adsorbed on the humus soil may be appropriately determined depending on the purpose or type of the auxiliary agent, the type of sludge cake, storage conditions (climate and period), and other factors. To give a specific example, for every 100 parts by weight of polymer flocculant, about 1 to 20 parts by weight of auxiliary agent, about 5 to 100 parts by weight of humus,
It is. Note that the ratio of the amount of humus soil to the auxiliary agent is usually about 100 parts by weight of the former to about 100 parts by weight of the latter. The flocculant composition of the present invention consists of the above-mentioned essential components, but may contain auxiliary components, such as an inorganic powder as a liquid aid for sludge cake, if necessary. Example 1 Acrylamide, a cationic flocculant, and N,N-dimethylaminoethyl = polymer flocculant
A copolymer with a quaternized methacrylate (A) and a partially hydrolyzed polyacrylamide (B), which is an anionic flocculant, were used. A masterbatch having the following composition was used and mixed at a polymer flocculant:masterbatch ratio of 10:1 to produce a polymer flocculant having a deodorizing function.

[Table] Rumi〓
The following sludge was used.

[Table] A polymer flocculant containing each masterbatch is added to each sludge, and the sludge is coagulated and dehydrated to obtain a dehydrated sludge cake. This was placed in a sealed container, and after 1 hour, the odor concentration in the container was determined by a three-point comparative odor bag method.

[Table] From the above results, it was confirmed that the mixture of deodorant-adsorbing humus soil has a deodorizing effect on various types of sludge dewatering cakes. It was also found that even more deodorizing effects can be obtained by combining and absorbing several types of aromatic components. The dehydrated sludge cake obtained in this test was placed in a sealed plastic container, and the concentrations of hydrogen sulfide gas and methylamine, which are usually particularly abundant among the malodorous gas components generated, in the gas phase of the container were measured and compared over time. The results are shown in Tables 4 and 5.

【table】

[Table] Based on the above results, dehydration of sludge using a polymer flocculant, such as the masterbatch formulation, has a sustained effect on odor generation not only during sludge dewatering but also during subsequent storage of dehydrated cake. This was recognized. Example 2 At a sewage treatment plant, a diluted flocculant composition was added to sludge and dewatered using a decanter-type dehydrator, and the odor at the outlet of the dehydrated cake was measured. (1) Properties of target sewage sludge TS 2.47% SS 2.30% PH 6.1 Organic content 55.6% (2) Flocculant composition (a) Example composition (wt%) Polymer flocculant (above A) 90 Humus soil (above) 7.5 Deodorant (p-diclobenzene + pine oil (1:2)
Weight ratio)) 2.5 (b) Comparative example composition (wt%) Molecular flocculant (same as above) 90 Diatomaceous earth 7.5 Deodorant (same as above) 2.5 (3) Operating conditions (a) Flocculant: concentration of 0.2% by weight Dilute with tap water and use with flocculant addition rate of 1.0%. (B) Sludge treatment amount: 20m ³ /H Cake moisture content: 76.1% (Example) 76.3% (Comparative example) (4) Odor measurement (A) Odor concentration: Three-point comparative odor bag method (B) Odor components : By Gastec gas detection tube (Hydrogen sulfide: #4LL, Methyl mercaptan: #71, Ammonia: #3L, Amines:
#180). (5) Results The results obtained were as shown in Table 6.

【table】

Claims (1)

[Scope of Claims] 1. A flocculant composition comprising a polymer flocculant and an auxiliary agent adsorbed on humic soil. 2 in the form of free-flowing powder or granules;
A flocculant composition according to claim 1. 3. The flocculant composition according to claim 1, wherein the polymer flocculant is in the form of a solution. 4. The flocculant composition according to any one of claims 1 to 3, wherein the auxiliary agent is a deodorant or a perfume.