JPS5929099A - Assistant for dehydrating sludge - Google Patents

Abstract

PURPOSE:To provide an assistant for dehydration which can improve the dehydratability of org. sludge by using N-(3-alkoxy-2-hydroxy propyl) trialkyl ammonium salt having a specific structure. CONSTITUTION:An assistant for dehydrating sludge is incorporated therein with >=1 kinds N-(3-alkoxy-2-hydroxy propyl) trialkyl ammonium salts expressed by the general formula (R1 is an alkyl group of 6-18C atom, R2 is an alkyl group of 1-18C atom and X is a halogen atom). This assistant for dehydration is added in the form of an aq. soln. to concd. sludge, and the sludge is caused to react for about 1-60min whereby the sludge is treated. The high dehydration efficiency is obtd. if such assistant for dehydration is used, and the dehydrated cake of decreased moisture content is obtd.

Description

[Detailed description of the invention] This invention relates to a dewatering aid for organic sludge generated from industrial processes.

In general, organic sludge generated through biological wastewater treatment contains gelatin-like viscous substances with high water retention secreted by bacteria, fungi, and protozoa living there, or hydrophilic colloids made from gelatin-like viscous substances. Therefore, even if dehydration is performed in that state, filtration resistance is high and dehydration is difficult. Conventionally, diatomaceous earth has been used to improve the dewatering properties of such sludge.

Dehydration aids such as sawdust, fibers, and fly-a-sonyu.

Alternatively, methods have been used to reduce the sludge resistance by adding inorganic flocculants such as slaked lime and ferric chloride to the sludge to adsorb or enlarge the hydrophilic colloids contained therein. . but.

In these methods, since a large amount of dehydration aid is generally used, the dehydration effect cannot be achieved unless a coagulant is added, and furthermore, the use of such a coagulant can cause corrosion of the equipment.

A large amount of ash is generated when the resulting dehydrated cake is burned.

f) Severe negative effects occur.

On the other hand, a method of treating sludge with a polymer flocculant is also known, and in this method, a slightly wrinkled polymer flocculant produces flocs with larger particle sizes, thereby reducing filtration resistance. Therefore, cationic polymer flocculants are now widely used as dehydration aids. However, the main effect of the polymer 1 flocculating agent is cross-linking adsorption. Although this flocculant enlarges flocs and is convenient for reducing filtration resistance, it binds to gelatin-like viscous substances. The drawback is that its ability to remove the water molecules present is relatively small. Therefore, even if a cationic polymer flocculant is added to surplus sludge or mixed sludge in an amount of 0.3 to 0.6% per SS weight and centrifuged or compressed, the water content of the dehydrated cake remains as high as 80 to 90%. The actual situation shows that.

An object of the present invention is to provide a dewatering aid that can eliminate the above-mentioned drawbacks of the prior art and significantly improve the dewatering properties of organic sludge generated from various wastewater treatment plants.
-alkoxy-2-hydroquinopropyl) trialkylammonium salt type sludge dewatering aid.

The dehydration aid according to the present invention has the general formula (■); [wherein R1 represents an alkyl group having 6 to 18 carbon atoms, R2 each represents an argyl group having 1 to 18 carbon atoms, and X is a halogen It is characterized by containing one or more types of N-(3-alcoquine-2-hydroquinopropyl)trialkylammonium salts represented by the following formula:

In the general formula (■), the alkyl group may be a straight chain or a branched chain, and examples of the alkyl group having 1 to 18 carbon atoms include a methyl group, an ethyl group, a propyl group, a hexyl group, an octyl group, These include a denyl group, a dobnol group, a tetrazofur group, a hexade/l group, an octadel/l group, and the like. X represents a halogen atom such as fluorine, chlorine, bromine or iodine.

The dehydration aid of the present invention may be present in the form of a powder, an aqueous solution or a powder, and may contain ammonium of the general formula (I) alone, as a mixture of two or more of them, or as a mixture of two or more of the It may also be included as a mixture with a dehydration aid.

The compound of general formula (D) is currently used as an antistatic agent in the textile industry, resin industry, etc.
It was not previously known that it was effective as a sludge dewatering aid.

The N-(3-alkoky/-2-hydroquinopropyl)trialkylammonium salt used in the present invention has '3-alkokyne-2-
Due to the presence of hydroxy/propyl groups, it has an affinity for water and dissolves in solid-liquid two-phase systems, generally directing its hydrophilic groups toward the liquid phase and its hydrophobic groups repelling and expelling water to the solid phase. It has the property of oriented adsorption. Due to this property, the compound of general formula (I) exhibits a remarkable dewatering effect on sludge.

In fact, it shows a significantly higher dehydration effect compared to the effect of conventional polymer flocculants. However, when R2 is a long-chain alkyl group, the affinity with water decreases. shows a tendency to Therefore, when adding the ammonium salt of general formula (1) and using it as a dehydration aid, it is necessary to take into consideration the number of carbon atoms in the alkyl group of i'j and L12. For example, R2 is an alkyl group having 6 or more carbon atoms.

For example, a methyl group, an ethyl group, or a proton group.
In some cases, it may be added directly at the water temperature.

d On the other hand, when one of R2 is an alkyl group having 10 to 18 carbon atoms and the other R2 is an alkyl group having 6 or less carbon atoms, the solubility is increased and the sludge surface is In order to promote oriented adsorption, it is advantageous to heat the sludge to its Kraft point (a temperature at which solubility rapidly increases) or higher.

The temperature of the sludge is usually 30 to 60°C, preferably 30 to 50°C.
Advantageously, the treatment is carried out for 1 to 60 minutes after reaching the Kraft point.

9 The dehydration effect of the ammonium salt used in the present invention is
It depends on the properties of the sludge being treated. Even if the dehydration aid of the present invention is directly added to sludge with a VSS/SS value of 70% or less, a dehydrated cake with a nearly constant moisture content of 65 to 70% can be obtained. SS value is 70%
For higher quality sludge, it is important to pre-treat it before adding it. Preferable pretreatment is a method in which the sludge is washed with water or an acid (pH: 0 to 30), and gelatin-like viscous substances that form the slime layer are removed from the system.

In this way, by using the dehydration aid of the present invention, a high dehydration effect can be achieved and a dehydrated cake with a significantly reduced moisture content can be obtained.

Next, the present invention will be described in detail based on Examples, but the present invention is not limited thereto.

Example: Excess sludge generated at the IU city sewage treatment plant was collected using the natural sedimentation method.
The VSS/SS thus obtained was concentrated to 0200~/l.
N-(3-Fdecylalkoxy-
2-hydrogy/globil) triethylammonium chloride [Cl2H250CI(2CH(OH)CH2N
(C2H5)3ct) was made into an aqueous solution, 2,500 mg of it was added, and the mixture was reacted for 60 minutes at room temperature. After the reaction is complete.

Part 1 per time. OOml through a Nutsche filter (P cloth: Naio: y501B, suction pressure: -400renHY,
? Filtration area: 100tm2. (Appropriate time: 5 minutes) Dehydrated cake O, F4 was obtained.

When the moisture content was measured according to the sewage test method, it was 712%.

As a control, the zero moisture content of a sample with no additives and a sample with a polymer flocculant [Brestol 444, 0.3% (W/W)] added was 986%.

It was 853%.

Example 2 Excess sludge generated at the Y city sewage treatment plant was treated using the natural sedimentation method.
The VSS/SS thus obtained was concentrated at 300 mg/lt.
SS/S zero value sludge xzKN, -(dodenoralcoki/-
2-Hydroquinepropyl) triethylammonium chloride was directly added at the same a degree as in Example 1 and a dehydration test was conducted, but no dehydration effect was observed (water content =
96%).

Previous f = e, <7) Concentrated dirt iM (S s = = 1330
After adding 4 t of water to 1 t of 0 mg/l, Vssn 5S = 83% and washing once with water, 3325 mf of N-(dodenyl alkoxy 7-2-hydroquinepropyl) triethylammonium chloride was added as an aqueous solution. .

I got it.

As a control, the moisture content of a sample without additives and a sample with polymer flocculant [Brestol 444, 0.3% (W/W) added] was 97.3%.

It was 866%.

Example 3 Surplus sludge generated at the U City sewage treatment plant was processed using the sedimentation concentration method.
This concentrated sludge (VSS/S
S value 68%) 11KN - (F tesilflucoquine -
2-hydroxypropyl)-)methyl-hexadecyl ammonium chloride CCl2H250CH2CH(O
H) CH2N(CH3) 2C16H33] was added to the mixture and reacted for 10 minutes at 35-36°C.

Thereafter, the operation was performed in the same manner as in Example 1, and the water content was 70.8%.
A dehydrated cake was obtained.

As a control, the content of a sample without additives and a sample with polymer flocculant (Brestol 444, 0.5% (''/W) added) was measured and found to be 986%, respectively.

It was 853%.

Example 4 Excess sludge generated at the Y city sewage treatment plant was treated using natural sedimentation method.
This concentrated sludge (VS
S/SS value 83%) 1t was reacted with N-(door'zylalkoxy 2-hydroxyglobyl)-dimethyl-hegisadecylammonium chloride according to Example 3, but no dehydration effect was observed. (moisture content 957%)
.

Each time, 1 ton of thickened sludge from me was soaked in N/100 hydrochloric acid (PH2,
0)1. After washing in a centrifuge three times with tZ2.

N-(dodecylalkoxy/-2-hydroxypropyl)
-dimethyl-hexadenolammonium chloride 3
Add 0% suspension/1 me of Shu liquid and incubate at 35-36℃ for 10 minutes.
Allowed to react for minutes. Thereafter, operations were performed according to Example 1 to obtain a dehydrated cake with a water content of 703%.

As a reference, the moisture content of a sample without additives and a sample with polymer flocculant [Presto-A'444K, 0.5% (=/W) added] was measured and found to be 97.3%, respectively.

It was 86.6%.

Procedure supplement IF document (method) % formula % l Indication of the case Patent Application No. 1988], 3727.5 No. 2, Name of the invention Sludge dewatering aid 3 Relationship with the person making the amendment Patent applicant address 〒 101 Chiyo, Tokyo] 1-1-14, Kanda, 1-ku, 4 Uramasa Order date: November 12, 1980 (Shipping date: November 30, 1980) MP# Ri-Aimei no Kei, -11 The content of the 6th supplementary explanation (the scope of the 11th patent claim is amended as shown in the attached sheet).

(2) Page 4, line 9 of the specification] The second line is amended as follows.

Claims (1) General formula (I): [wherein R1 represents an alkyl group having 6 to 18 carbon atoms, R2- each represents an alkyl group having 1 to 18 carbon atoms, and X is a halogen atom] ]
- A sludge dewatering aid characterized by containing one or more types of (3-alkoxy/-2-hydroquinopropyl) trialkylammonium salts.

The sludge dewatering aid according to claim 1, comprising +21N-(3-dodecylalkoxy-2-hydroxypropyl)triethylammonium chloride.

The sludge dewatering aid according to claim 1, which contains (3) N-(dode/lualcoquino-2-hydroquinepropyl)-dimethyl-hexadecyl ammonium chloride.

that's all 505-

Claims (1)

[Claims] (1) General formula (■): [In the formula, R1 represents an alkyl group having 6 to 18 carbon atoms, R2 each represents an alkyl group having 1 to 18 carbon atoms, and X represents a halogen represents an atom]
A sludge dewatering aid characterized by containing one or more types of (3-alkoxy/-2-hydroxypropyl) trialkylammonium salts. +2) The sludge dewatering aid according to claim 1, which contains N-(3-dodecyl alkoxy/-2-hydroxypropyl) triethylammonium chloride. (3) The sludge dewatering aid according to claim 1, which contains N-(totinoalkoxy-2-hydroxy/propyl)-cymedylhexadecyl ammonium chloride.