JPS62125893A - Flocculating method for suspended matter in waste water - Google Patents

Abstract

PURPOSE:To form flocs having high strength by preparing an aq. soln. in which an anionic high-polymer electrolyte and cationic high-polymer electrolyte are dissolved in proximity, adding a large amt. of water thereto to precipitate part of both high-polymer electrolytes, then adding the soln. to waste water. CONSTITUTION:A mixed flocculating agent formed by mixing the anionic high- polymer electrolyte (e.g., Na salt of methacryliamide/metacrylic acid copolymer) and the cationic high-polymer electrolyte (e.g., methacrylic trialkyl ammonoalkyl/ acrylamide copolymer) as well as bivalent metallic salt (e.g., Ca chloride) and/or ammonium salt (e.g., ammonium chloride) is prepd. into the aq. soln. as a preliminary operation and thereafter a large amt. of water is added to bring part of both high-polymer electrolytes into reaction thereby producing the precipitate. Such aq. soln. is added to the waste water and the large flocs having high strength are formed while the flocs generated by the reaction of the unreacted two high-polymer electrolytes and suspended matter are successively taken into the above-mentioned precipitate.

Description

[Detailed description of the invention] "Industrial application field" The present invention treats industrial wastewater, domestic wastewater, etc. with a collector,
A in wastewater! ! This invention relates to nine improved flocculation methods for effectively flocculating all candle materials.

``Prior art'' Conventionally, in order to treat wastewater as described above, an anionic polymer flocculant or a cationic polymer flocculant is added to the wastewater alone and reacted with the turbid substances, or both are added. The method of successive addition and reaction is currently being used.

``Problems to be Solved by the Invention'' In the above-mentioned conventional technology, in the method of adding an anionic polymer flocculant alone, suspended solids are aggregated by cross-linking adsorption, and the resulting flocs are small and have a low strength Iy. When sedimentation or filtration is performed in the bottom diameter process, the speed is slow and dehydration is often poor, and the method of adding a cationic polymer flocculant alone also produces Although there is a slight difference in properties, they are almost the same, and the method of sequentially adding an anionic polymer flocculant and a cationic polymer flocculant has an excellent flocculating effect, and although the result is a large 70 kg, it is a crosslinking adsorption. Therefore, the bonding force is weak, the strength is low, and it is easy to crush. Furthermore, it has poor dehydration properties due to its hydrophilic properties, especially when performing dehydration treatment using furnace cloth such as pressure filtration and belt brestle filtration. Sludge has poor peelability from P cloth,
Dehydration efficiency is also not good. In other words, when the above 70 pieces are dehydrated under pressure, the flocs are crushed and the dewatering channels between the flocs are closed, and the water inside remains without being removed. There are problems such as increasing the dehydration cost of the dehydration vehicle.

The purpose of the present invention is to provide a ninth overall method for flocculating suspended solids in wastewater that solves these problems.

``Means for Solving Problems'' When treating wastewater, the present invention first prepares a co-FJ solution in which an anionic polymer electrolyte and a cationic polymer electrolyte are dissolved in close proximity as a preliminary work. This is a method in which a large amount of water is added to this to precipitate a part of the ampholytic molecules 'α solute, and then waste water (added) is produced. A mixed coagulant consisting of a mixture of a molecular electrolyte, a cationic polymer electrolyte, and a divalent metal salt and/or ammonium salt. After making into an aqueous solution as a Kaneko preparation process, a large amount of water is added to form a part of the polymer electrolyte. The entire reaction is carried out to form a precipitate, and then this aqueous solution is added to the wastewater, and the 70 pieces generated by the reaction between the unreacted polymer electrolyte and the suspended matter are incorporated one after another into the precipitate, and the resulting aqueous solution is then added to the wastewater. This is a method for treating suspended solids in wastewater that cause the formation of flocs with high concentration.

The anionic polymer electrolyte and cationic polymer electrolyte used in the above-mentioned mixed coagulant may be in the form of liquid, paste, or powder. The mixing ratio of both in the mixed flocculant is 10
:1 to 1:10, and outside this range, the aggregation effect decreases. The mixing ratio of the divalent metal salt and/or ammonium salt is such that the weight of the divalent metal salt and/or ammonium salt is 50 to
1000 N, preferably #'1100 to 500X, and these are placed in the same container and mixed to obtain a mixed flocculant.

Types of anionic polymer electrolytes include sodium salt of a copolymer of acrylamide or methacrylamide and acrylic acid or methacrylic acid, sodium acrylamide-2-methylpropanesulfonate copolymer, etc.
As the cationic polymer electrolyte, cationic modifications of methacrylic acid ester polymers and copolymers [e.g., poly(trialkyl methacrylate) (or dialkyl monobenzyl)]
Ammonioethyl base, ethylaminoethyl methacrylate, triethylaminoethyl methacrylate/acrylamide copolymer, N-N-dialkylaminoalkyl methacrylate/acrylamide copolymer, trialkylammonoalkyl methacrylate/acrylamide copolymer These include chloride copolyalkylene polyamines and their rust conductors (for example, polyethyleneimine, alkylated polyalkylene polyamines), and divalent metal salts such as calcium chloride, nitrate, magnesium chloride, and ammonium chloride. As a salt, ammonium chloride,
These include ammonium sulfate, ammonium oxalate, ammonium carbonate, and ammonium nitrate.

Before treating wastewater, the properties of the wastewater, i.e., the type, concentration, and pH of suspended solids, are measured in advance, and the mixed flocculant is prepared by measuring the types of anionic polymer electrolyte and cationic polymer electrolyte and the mixture described above. It is preferred to choose from those with a ratio of 1:10 to 10:1. As a preliminary step before adding to wastewater, it is preferable to first adjust the polymer electrolyte so that it is dissolved in water so that the total amount is about 0.2 to 5.0%, and divalent metal salts and/or The total amount of ammonium salts is adjusted to 0.5 to 20.0%, preferably 1.0 to 10.0%, and the anionic polymer electrolyte is nonionized and the cationic polymer electrolyte is masked. Polyelectrolytes are brought into close proximity to create a co-solution of the following state. By adding and diluting this co-solution with a large amount of water (3 to 10 times 8 degrees), some of the macromolecular coagulants are returned to their original ionicity and reacted with each other to form a precipitate. An aqueous solution of a mixed flocculant is added to the wastewater to cause the unreacted portion of the above-mentioned mountain polymer electrolyte to react with the suspended solids to form flocs, which are then mixed with the above-mentioned precipitates (
It generates extremely large and strong flocs while being taken in one after another. At this time, the amount added is preferably adjusted so that the total amount of the anionic polymer electrolyte and the cationic polymer electrolyte is 0.05 to 5.00 weight X based on the suspended solids.

"Function" When the above-mentioned mixed flocculant is first dissolved in water to create an aqueous solution, it reacts with the anionic polymer electrolytic gtVi divalent metal salt or ammonium salt, or both, to nonionize and maintain hydrophilicity. The cation groups of the cationic polymer electrolytes are masked by the ammonium ions of the ammonium salt, and the polymer electrolytes do not react with each other, but come very close to each other and form a mutually soluble state. When this is diluted by adding 3 to 10 times as much water, a portion of the anionic polymer electrolyte that had been nonionized returns to anionic, and a portion of the acutely cationic polymer electrolyte that was previously masked becomes unmasked. After restoring this ionicity, some of the polymer electrolytes react with each other to form precipitates. Next, when this aqueous solution is added to wastewater, the divalent metal salt and/or ammonium salt reacts with the suspended matter or is diluted, so that the bond with the unreacted 7-ionized anionic polymer electrolyte is weakened. Finally, as the VCFi is cut off, this polymer electrolyte returns to an anionic state, and the unreacted cationic polymer electrolyte co-dissolved is also masked because the ammonium ions that were masking it react with the suspended matter or are diluted. is released and acts as a cationic polymer electrolyte, so the unreacted ionic polymer electrolyte that has recovered reacts with the suspended matter to produce flocs, and the precipitates take in these flocs one after another. However, it grows like a snowball, producing extremely large and strong flocs.

“Example” (1) TPI! , &li company wastewater (suspended solids a K
qonyyi7t, PH/1.7), sodium salt of methacrylamide/methacrylic acid copolymer as an anionic polymer electrolyte, trialkylammonoalkyl methacrylate/acrylamide copolymer as cationic polymer electrolyte, and ammonium sulfate as ammonium salt. were mixed at a ratio of 2:G5, and a mixed flocculant (indicated by M in Table 1) was dissolved in water to give each of Q, 4%, 0.2% and 1. Make an OX co-solution, then add three times the amount of water to this to precipitate a portion of the polymer electrolyte. The anionic polymer electrolyte is 0.4 x 788 times the thionic polymer electrolyte is n,
The mixture was added at a concentration of 2X/ss, processed to yield 70 pieces, which were filtered through a screen to obtain the results shown in Table 1. For comparison, the sodium salt of methacrylamide/methacrylic acid copolymer alone (indicated by c+-1 in Table 1) (treated at an addition rate of 0.6/8S) and the case of methacrylamide/methacrylic acid copolymer Natori'7 M4
n, 4'X/ SS and trialkyl methacrylate monoalkyl acrylamide copolymer 0.2X/s
The case where s was sequentially added (indicated by C4-2 in Table 1) is shown.

Table 1 The flocculation method of this example has better filtration ability than the conventional flocculation method.
The SS removal rate was good, and the moisture content of the cake after filtration was low. In addition, the cake was easily peeled from the cloth F, and the furnace cloth was not clogged.

2) Surplus sludge from activated sludge treatment of wastewater from the J Urinary Treatment Plant (9n00"l'/7, pH 6,7)
The sodium salt of the acrylamide/acrylic acid copolymer of the heptalytic polymer electrolyte, the trialkylammonioethyl methacrylate salt of the cationic molecular electrolyte, and the chloride of the divalent metal salt in a ratio of 1:3:6. A mixed flocculant (indicated by M2 in Table 2) was mixed with water (dissolved in the following method to form a co-solution of 0.2N, 0.6X and 1.2X, and 4 parts of Add water to make sure that some of the polymer electrolyte is precipitated.Next, add this aqueous solution to waste water so that the anionic polymer electrolyte is 0.3%/SS and the cationic polymer electrolyte is (1,9X/88). The flocs produced were dehydrated using a furnace cloth belt press, and the results shown in Table 2 were obtained.For comparison, as a conventional method, a cationic polymer flocculant trialkylar/monoalkyl methacrylate was used.・Acrylamide copolymer chloride alone (second
In the case of treatment with addition rate 1.2%/SS (indicated by C2-7 in the table) and chloride of trialkylammonoalkyl methacrylate/acrylamide copolymer 0.9%/S
S, 0.39g/SET of sodium salt of acrylamide/acrylic acid co-heavy metal product was sequentially added (02-2 in Table 2).
) and the following cases are shown.

Table 2 Compared to conventional methods, the flocculation method of this example has significantly superior filtration ability, good SS removal rate, and very little cake after dehydration. In addition, there was little dirt on the cloth belt 7.

"Effects of the Invention" As described above, the method of flocculating suspended solids in wastewater of the present invention uses an anionic polymer electrolyte and a cationic polymer electrolyte, two
A mixed flocculant made by mixing a valent metal salt and/or an ammonium salt is first dissolved in water to form a co-solution, and a large amount of water is added to this to precipitate a part of the polymer electrolyte.The aqueous solution is poured into waste water. Added and unreacted polymer electrolytic polymer reacts with the turbid substances to form flocs, which are then incorporated into the aforementioned precipitates (which grow like a snowball, making them extremely large, strong, and low in viscosity. As a result, the subsequent solid-liquid separation treatment such as FA% water extraction and dewatering can be effectively performed.Therefore, the wastewater treatment capacity is extremely excellent, and the recovery rate of suspended solids is high. It has many advantages, such as the fact that the cake after filtration and dehydration has a low moisture content, and subsequent processing such as incineration, transportation, disposal, and reuse is easy.

Claims (1)

[Claims] After making a mixed coagulant consisting of an anionic polymer electrolyte, a cationic polymer electrolyte, and a divalent metal salt and/or ammonium salt into an aqueous solution as a preliminary work, a large amount of water is added to dissolve both polymer electrolytes. This aqueous solution is then added to the wastewater, and the flocs produced by the reaction between the unreacted polyelectrolytes and the suspended solids are successively incorporated into the precipitate. A method for treating suspended solids in wastewater, which is characterized by generating large and strong flocs.