KR100955842B1 - Method for Preparing Carbon Source Composition for Denitrification Using a Waste Obtained From a Production Process of 1,4-butanediol, Carbon Source Composition Obtained Thereby and a Denitrification Method Using the Same - Google Patents

Abstract

The present invention discloses a method for producing a composition for denitrification carbon source using 1,4-butanediol producing waste, a composition for denitrification carbon source obtained by the method and a method for denitrifying waste water using the same. Specifically, the present invention provides a method for preparing a composition for denitrification carbon source comprising applying Cannizzaro Reaction to 1,4-butanediol-producing waste and converting formaldehyde present in the waste into formic acid and methanol and denitrification obtained by the method. Disclosed are a composition for carbon sources and a method for denitrifying wastewater using the composition.

1,4-butanediol, waste, denitrification, carbon source

Description

Method for preparing a composition for denitrification carbon source using 1,4-butanediol waste, the composition for denitrification carbon source obtained by the method and the method for denitrification of waste water using the same of 1,4-butanediol, Carbon Source Composition Obtained Thereby and a Denitrification Method Using the Same}

The present invention relates to a method for producing a composition for denitrification carbon source using 1,4-butanediol-producing waste, a composition for denitrification carbon source obtained by the method, and a method for denitrification of waste water using the same.

Generally, wastewater flowing into rivers or coastal waters contains significant amounts of nutrients such as nitrogen and phosphorus in addition to organic matter. These nutrients cause red tide phenomena of eutrophication and phytoplankton reproduction, and fish and shellfish killing due to oxygen deficiency by consuming oxygen in the water.

Nitrogen removal of waste water can be divided into physicochemical methods such as ammonia stripping and ion exchanger and biological methods using microorganisms involved in denitrification. In general, biological methods are used to remove nitrogen from wastewater, in view of lower than expected.

Denitrification by biological methods is shown in <Reaction Scheme 1> and <Reaction Scheme 2>, the nitrification step in which ammonia nitrogen is converted to nitrate by nitrifying microorganisms (Nitrosomonas, Nitrobactor) under aerobic conditions, and nitrate In this anoxic condition, denitrification microorganisms (Pseudomonas, Micrococcus, Bacillus, etc.) are converted into nitrogen gas through a denitrification step.

<Scheme 1>

^{_{NH 4 + + O 2 → NO}} 2 - + O 2 → NO 3 -

<Scheme 2>

NO ₃ ^- + carbon ^{_{(H 2) → NO 2 -}} + carbon _{(H 2) → N 2 +} CO 2 + H 2 O

However, as shown in the reaction scheme, the denitrification step requires a carbon source necessary for the growth of denitrification microorganisms.

In general, organic matter present in wastewater is primarily used as such a carbon source, but wastewater flowing into the sewage treatment plant in Korea is deficient in organic matter with a BOD / TN average of 2-3 (in the modified biological advanced treatment process such as physics). Sensitivity analysis using ASM2d and evaluation of temperature / SRT impact ", 2004, 26 (1), pp 83 ~ 88) As a carbon source for denitrification, it is necessary to supply a carbon source (hereinafter referred to as" external carbon source ") from the outside.

Methanol, ethanol, acetate and the like are currently used as external carbon sources, but these external carbon sources are very expensive.

In view of solving this problem, the present invention discloses a technique in which 1,4-butanediol generating waste can be used as an alternative external carbon source (alternative external substrate) for denitrification of waste water.

The technical problem to be solved by the present invention is to provide a method for producing a composition for denitrification carbon source using 1,4-butanediol production waste.

Other technical problems, specific embodiments, and the like of the present invention will be presented below.

In general, the use of a particular waste or by-product as an external carbon source should be accompanied by an assessment of its denitrification performance as well as a safety assessment of the presence or absence of a toxic component of that waste or by-product (Jung, Eun et al., Feasibility Evaluation of Wastewater as Alternative Carbon Source "Journal of Korean Society of Environmental Engineers 2004 Fall Conference, Chonbuk National University, 2005.11.4 ~ 11.6 pp307-312; Jeong, In-Cheol et al.," Cases of Development and Commercialization of Alternative Carbon Sources based on Microbial Compatibility, " , 2005, 27 (5), pp 491-498).

Therefore, in order to confirm the applicability of the 1,4-butanediol-producing waste used as an alternative carbon source in the present invention as an external carbon source, it is necessary to first examine the presence or absence of toxic substances in the 1,4-butanediol-producing waste through component analysis. If there is a substance, it needs to be removed, and finally it is necessary to assess the denitrification capacity of the non-toxic waste from which the toxic substance has been removed. This process should be considered to be difficult to use as an alternative carbon source if toxic substances are not removed or if the denitrification capacity is assessed to be low.

In general, the process for producing 1,4-butanediol, which is a raw material of synthetic leather adhesive and alkyd resin, is performed by reacting 1,4-butynediol with formaldehyde and acetylene, as shown in <Scheme 3> and <Scheme 4>. 1,4-butynediol) and a step of producing 1,4-butanediol as a target by reacting hydrogen to 1,4-butynediol.

<Scheme 3>

2CH ₂ O (formaldehyde) + C ₂ H ₂ (acetylene) → HOCH ₂ CCCH ₂ OH (1,4-butyndiol)

<Scheme 4>

HOCH ₂ CCCH ₂ OH (1,4-butynediol) + 2H ₂ → HOCH ₂ CH ₂ CH ₂ CH ₂ OH (1,4-butanediol)

In <Scheme 3> of the above-mentioned 1,4-butanediol production process, wastes mainly containing unreacted formaldehyde, methanol, methylal, or the like, as shown in Table 1, that is, 1,4-butyne as a target substance Reaction byproducts are generated except for diols (ie after separation of 1,4-butynediol).

TABLE 1

ingredient Content (% by weight) Formaldehyde 5-30 Methanol 40-90 Methylal 1-20 Other ingredients (moisture, 1,4-butynediol, etc.) Remaining amount

The 1,4-butanediol-producing waste used in the present invention is a waste product produced in <Scheme 3> of the above-mentioned 1,4-butanediol-forming process, that is, a reaction by-product after separating 1,4-butyndiol from the total product after the reaction. to be.

By the way, the waste, although high in methanol content, contains a large amount of formaldehyde, a toxic component. For this reason, the waste is forced to be incinerated by high temperature pyrolysis, and in order to use the waste as an external carbon source, removal of formaldehyde from the waste must be preceded.

In the present invention, Cannizzaro Reaction (Cannizzaro, S. (1853). "Ueber den der Benzoёsaure entsprechenden Alkohol". Liebigs Annalen 88: 129-130) for the removal of formaldehyde from the waste as shown in the following examples; This document forms part of this specification), where the reason for using the Cannizzaro Reaction is that the reaction products are methanol and formic acid, both of which are available as carbon sources, as shown in Scheme 5 below. This is because the removal rate of 100% is shown after 24 hours of reaction as shown in FIG. 1.

Scheme 5

2CH ₂ O + base → HCOOH + CH ₃ OH <using base (NaOH etc.) as reactant>

As such, the present inventors have detoxified 1,4-butanediol-producing waste, and then denitrification ability of the non-toxic waste (hereinafter referred to as "RCS _HP " (high-purity recovered carbon source)) as confirmed in the following experiment. The compliance experiments, OUR TEST and NUR TEST, were compared to methanol, the most commonly used external carbon source.

As a result, as shown in the following Examples and Experimental Examples, it was confirmed that the RCS _HP has high compliance almost similar to methanol, and RBDCOD / COD, which is an index of biodegradability of RCS _HP measured through OUR TEST, is also about The biodegradation rate of 100% was found to be equivalent to that of methanol. The sum OUR, which is closely related to the energy use of the substrate, shows that the amount of sludge generated is low due to the high rate of RCS _HP used as an energy source.

In addition, as confirmed in the following Examples and Experimental Examples, the rate of NOx-N concentration decrease was observed as the acclimation period elapsed through the NUR test, it was confirmed that the NOx-N removal rate is also higher than methanol. Furthermore was the carbon amount required for denitration the C / N non RCS _HP determined that less than methanol, a non-denitration rate is equal to the methanol in terms of NOx removal rate by more than 101.5% when the RCS _HP use the same amount of methanol to or It was confirmed that the above performance. In particular, it was confirmed that RCS _HP shows no toxicity to microorganisms because formaldehyde, which is a toxic substance, was removed.

The present invention is provided on the basis of these experimental results, and in one aspect can be understood as a method for producing a composition for denitrification carbon source.

Method for producing a composition for denitrification carbon of the present invention is to convert the formaldehyde present in the waste to formic acid and methanol by applying Cannizzaro Reaction to 1,4-butanediol generated waste It is characterized by including.

In the present specification, the "1,4-butanediol waste generated" refers to the <Scheme 3> to generate 1,4-butynediol in the 1,4-butanediol production process consisting of the <Reaction Scheme 3> and <Reaction Scheme 4> It is defined as the reaction byproduct after separating 1,4-butynediol from the total product.

The degree of separation of 1,4-butynediol in the above means preferably when more than 98% separated, and more preferably means when fully separated, that is, 100% separated.

The "1,4-butanediol generating waste" can also be defined in terms of constituents, if defined in terms of constituents 5-30% by weight of formaldehyde, 40-90% by weight methanol, 1-20% by weight of methylal and Remaining amount of other components (moisture, 1,4-butynediol, etc.) (in this specification, the residual amount means 100% by weight in combination with the remaining components such as formaldehyde, methanol, and methylal even if present or not present). You can define it.

The resulting denitrified carbon source composition obtained by the method for preparing the denitrified carbon source composition of the present invention has the same meaning as the RCS _HP as described above, that is, formaldehyde is removed to produce nontoxic 1,4-butanediol waste. Means.

Cannizzaro Reaction, on the other hand, is a reaction to generate an alcohol and carboxylic acid by reacting an aldehyde with a base, as described above.

Here, the base is to be understood as a commonly accepted meaning in the art, that is, the base broadly means a substance which gives out a non-covalent electron pair, and narrowly means a substance that can accept a proton (H ⁺ ) and most narrowly an aqueous solution. It means a substance that dissociates in a state to give hydroxide ions. Since Cannizzaro Reaction is made in an aqueous base solution (ie, an alkaline aqueous solution), the meaning of the base may be taken in the narrowest sense herein.

In accordance with the experience of the inventors of many trials and errors, the Cannizzaro Reaction, which converts formaldehyde into methanol and formic acid, can be used in strong base conditions, at atmospheric pressure, in the temperature range of 30 to 100 ° C. and in [OH ⁻ ] / [CH ₂ O] is preferably carried out in the range of 0.5 to 8, more preferably in strong base conditions, at atmospheric pressure, in the temperature range of 40 to 80 ° C. and [OH ⁻ ] / [CH ₂ O] of 0.5 to 4 It is preferably carried out within the range of. Especially found in the following Examples Just as the 60 ℃ temperature, atmospheric pressure, and _{^{[OH -] / [CH 2}} O] = 4 After the reaction was 6 hours when in the condition was used for NaOH showed the removal rate of 98.4% formaldehyde, 9 It is most preferable that the Cannizzaro Reaction is performed under each of the above specific conditions in that the removal rate is 99.9% after the passage of time.

Strong bases can generally be understood as bases whose degree of electrolytic dissociation is close to 1 in conditions such as room temperature, but in the present specification limited to LiOH, NaOH, KOH, Ca (OH) ₂ , or Ba (OH) ₂ . You may understand. Most preferably, the strong base herein means NaOH or KOH.

In another aspect, the present invention provides a composition for denitrification carbon source obtained through the above method.

The composition for the denitrification carbon source of the present invention can be understood as a composition in which at least 95% of formaldehyde is removed from 1,4-butanediol-producing waste from the viewpoint of the removal rate of formaldehyde of 1,4-butanediol-producing waste, more preferably 99% It can be understood as a composition removed above, and most preferably, a composition removed at 100%.

The composition for the denitrification carbon source of the present invention is 83% to 93% by weight of methanol, 3% to 10% by weight of methylal, in terms of the component content ratio after formaldehyde is removed from 1,4-butanediol-producing waste, It can be understood as a composition in which formaldehyde is absent or even present, up to 1% by weight, formic acid is from 2% to 10% by weight, and other substances (moisture, 1,4-butynediol, etc.) remain.

The composition for the denitrification carbon source of the present invention is expected to be able to be used without changing the injection facility in the case of using the existing methanol because the COD concentration is not significantly different from methanol and the denitrification performance is excellent.

In another aspect, the present invention relates to a method for denitrification of waste water comprising the step of contacting the composition for denitrification carbon source with waste water.

Here, the wastewater means all types of domestic sewage and all types of industrial wastewater which require denitrification.

The composition for the denitrification carbon source used in the denitrification method of waste water of the present invention serves as a carbon source of the denitrification step in the denitrification reaction consisting of the nitrification step and the denitrification step as described above.

As described above, according to the present invention, it is possible to provide a method capable of using 1,4-butanediol generated waste as an alternative carbon source and an alternative carbon source obtained by the method.

 The alternative carbon source of the present invention is expected to be able to replace expensive methanol because it has similar denitrification performance to methanol.

Hereinafter, the present invention will be described with reference to Examples and Experimental Examples. However, the scope of the present invention is not limited to these examples and experimental examples.

EXAMPLES Preparation of Denitrification Carbon Source Using 1,4-Butanediol Production Process Waste

Waste generated in <Scheme 3> of wastewater / waste generated in 1,4-butanediol production plant was used. This waste is the waste after 1,4-butynediol is separated from the reaction product of <Scheme 3>, and its properties are shown in Table 2 below.

This waste contains a lot of formaldehyde and is a waste that is forced to be incinerated by high temperature pyrolysis.

Cannizzaro Reaction, represented by Scheme 5, was used to remove formaldehyde from the waste.

Above the reaction temperature is 60 ℃, at normal pressure [OH ^-] and in / [HCHO] = 4 conditions using NaOH to the reaction product while performing 24 hours to determine the removal rate of formaldehyde.

The degree of formaldehyde removal according to the reaction time in the reaction conditions is shown in <Figure 1>, and the formaldehyde-free waste ("RCS _HP ") to be used in this experiment was reacted for 9 hours (< As can be seen from Figure 1> formaldehyde was removed 99.0%) was used and its component content ratio is shown in Table 2 below compared with the waste before the reaction.

TABLE 2

ingredient 1,4-butanediol-producing waste (% by weight) RCS _HP (% by weight) Methanol 83.4 88.7 Methylal 6.0 5.0 Formaldehyde 10.0 0.1 Formic acid - 5.0 Others (moisture, 1,4-butynediol) 0.6 1.2

It can be seen from Table 2 that 99.0% of formaldehyde was removed through the Cannizzaro Reaction.

Experimental Example Experiment for Denitrification Performance of RCS _HP

In order to evaluate the denitrification performance of the RCS _HP having the properties shown in Table 2, a microbial compliance test, an oxygen uptake rate (OUR) test, and a nitrogen uptake rate (NUR) test were performed.

Methanol was used as a control.

In a previous study (Akunna, J. C et al., (1993) "Nitrate and nitrite reductions with anaerobic sludge using various carbon sources: glucose, glycerol, acetic acid, lactic acid and methanol.", Wat.Res. 27 (8 (1303-1312), it has been reported that the time and denitrification capacity required for the substrate varies depending on the type of carbon source, and that the substrate removal and denitrification capacity changes depending on the degree of compliance.

Therefore, in this experiment, a batch test was conducted to accurately evaluate the period, maximum biodegradability and denitrification capacity required for acclimatization required for microorganisms in the sewage treatment process of RCS _HP . Batch experiments were carried out in four identical reactors with an effective volume of 5L and substrate compliance was assessed by evaluating substrate removal capacity with varying operating days. When the operating condition is B were injected with methanol and RCS _HP in each of the two reactors so that the N secondary sewage treatment plant clarifier organic concentration 500 mg / L in the sludge 5L to a constant dilution rate in the batch reactor, NO ₃ -N concentration The KNO ₃ was injected into an initial concentration of 50 mg / L, and the batch reactor C / N ratio was 10 to be performed for 23 days. The experimental procedure was performed by injecting an external carbon source (methanol and RCS _HP ) and nitrate into the anoxic section for denitrification (10 hr) and then removing residual COD that could not be removed in the aerobic section (6 hr). In order to minimize the effect of the hardly decomposable substances remaining in the next cycle, sludge and supernatant were separated by settling section (6 hr) and operated in a total 24hr cycle of supernatant discharge and fresh water supply section (2 hr) for the next experiment. Figure 2 illustrates a batch reactor operation for compliance, and Table 3 summarizes the initial concentration and operating conditions of the compliance experiment.

[Table 3]

       Initial Concentration and Operating Conditions for Acclimation Experiments

The OUR experiment for evaluating the biodegradability of external carbon sources (methanol and RCS _HP ) used a respiratory rate analyzer (Autoload & Biotox) developed by EnvironSoft of <Figure 3>. It consists of a meter. The respiratory rate meter is a device that can continuously measure respiratory rate and consists of a closed and fully mixed respiratory chamber with a respiratory chamber flow rate of 0.75 L / min and a respiratory chamber volume of 0.75 L. When the sludge aerated in the preliminary aeration tank is continuously introduced into the respiratory chamber, the DO of the inlet sludge is measured for 1 minute, and after 1 minute, the flow of the solenoid valve is changed and the DO of the respiratory outlet sludge is measured again for 1 minute. The measured DO value is stored on an attached computer for automatic respiratory rate calculation and used for respiratory rate calculation. At this time, in order to exclude oxygen consumption due to particulate matter and nitrogen in the target material, ATU (Allylthio urea), a nitrification inhibitor, was added to the target material filtered with a GFC-40 filter. OUR measurement was performed by taking 2L of sludge at 4 days intervals while performing continuous batch operation for microbial acclimation experiment in 5L reactor with an effective volume of 5L, and the denitrification ability of the by-products was evaluated with the remaining 3L of sludge. S _O / X _O ratio, the most sensitive factor for respiratory rate measurement, was adjusted from 0.07 to 0.15 through literature and preliminary experiments. The initial COD and microorganism (MLVSS) concentrations of the OUR experiment are summarized in <Table 4>.

TABLE 4

 Initial COD and Microbial (MLVSS) Concentration in the OUR Experiment

The denitrification capacity according to the acclimation period was used to determine the denitrification rate of the external carbon sources (methanol and RCS _HP ) and the COD requirement used to remove 1g nitrate. Batch experiments for the NUR evaluation of external carbon sources (methanol and RCS _HP ) were carried out with the microorganisms used in the acclimation experiments using methanol and RCS _HP as substrates. In the NUR evaluation performed with the remaining 3L sludge except for 2L sludge collected for OUR measurement, organic matter was injected by injecting methanol and RCS _HP so that the initial C / N ratio was 10 in the batch reactor so that organic matter was not a limiting factor during denitrification. Using a concentration of 500 mg / L, KNO ₃ was injected so that the initial concentration of NO ₃ -N 50 mg / L. At this time, the MLVSS concentration in the reactor was maintained at 1.5-3.5g / L, the temperature was maintained in the range of 25 ㅁ 2 ℃ and stirring was carried out for mixing in the reactor throughout the reaction time. 0 ', 10', 20 ', 40', 60 ', 90', 120 ', 180', 270 ', 360' (10 times) minutes to measure the denitrification rate and carbon source removal rate during the denitrification test. Sampling was performed to determine the COD and NO ₃ -N concentrations. Table 5 shows the initial concentration and operating conditions of the NUR experiment.

TABLE 5

Initial concentration and operating conditions of the NUR experiment

The concentrations of NOx-N, SCOD _Cr and NOx-N and SCOD _Cr removed for 6 hours after the initial and 6 hours of injection of nitrate and carbon source for the evaluation of compliance for 23 days are shown in <Figure 4> and <Figure 5>. Respectively. Under all experimental conditions, the C / N ratio, which is the ratio of nitrate nitrogen to carbon source, was maintained at about 9 ~ 10 so that there was no shortage of carbon source necessary for denitrification. As can be seen in FIG. 4, the NOx-N concentration after 6 hours after 10 days of operation was nearly 0 mg / L in both the RCSHP series and the methanol series, indicating that the acclimatization of the denitrifying bacteria to the carbon source proceeded smoothly. In order to assess NOx-N removal ability, SET2 and SET3 increased NOx-N initial concentration to 100 mg / L and 200 mg / L, but after 5 days, almost 0 mg in both RCS _HP and methanol series after 6 hours. It could be confirmed that / L is removed. These results demonstrate that RCS _HP shows nearly comparable compliance with methanol.

The specific respiratory rate (OUR) of the OUR test performed every 7 days using the sludge performing the acclimation experiment using RCS _HP and methanol as a substrate is shown in FIG. 6. The left and right graphs of FIG. 6 summarize the results of four respiratory rate experiments when RCS _HP and methanol were used as substrates, respectively. In the initial acclimatization state, the experiment (RUN1) could not confirm the reaction end point of both the RCS _HP series and the methanol series, but it was confirmed that the end point was apparent in the experiments after the RUN2 in which the acclimation experiment was performed. In addition, the longer the acclimation period, the higher the maximum respiration rate and the shorter the period of oxygen intake. This proves that the acclimation used the carbon source injected into the substrate faster and more actively.

Table 6 summarizes the maximum respiration rate, the sum of respiration rates, and the biodegradable carbon ratio of the OUR experiments. Except for RUN1, where the end point could not be determined, the biodegradable carbon source ratio was 100% for both RCSHP and methanol, indicating that there was no effect of COD increase on external carbon source injection. Indicating the amount of a substrate that is used for energy in the removed substrate sum respiratory rate (Sum OUR) is was shown much higher in the RCS _HP compared to methanol, and the RCS _HP is determined that use high energy source than the biomass growth of microorganisms as compared to methanol . This can be confirmed that the denitrification reaction, which is a reaction for obtaining energy while generating less sludge than methanol when using RCS _HP in the same amount as methanol, is an effective carbon source for denitrification that is predominantly generated.

TABLE 6

Maximum respiratory rate and respiratory rate of OUR experiment, biodegradable carbon ratio

Figure 7 shows the experimental results of the NUR test carried out four times. (A) and (b) showed NOx-N concentrations during 6 hours of NUR test, and (c) and (d) showed SCODCr concentrations. In the case of <7> As you can see in the case of not the conformity of the carbon RUN1 NOx-N and although SCOD _Cr concentration is very slowly decreased over the compliance period, the concentration rate of decline is very ppalrajyeoseo RUN3 there as a substrate for RCS _HP In the case of use, NOx-N was removed after 2 hours after the denitrification experiment and in the case of methanol, after 3 hours. In all experiments, the concentration of carbon source was sufficient, so no inhibition by substrate deficiency occurred. In RUN4 experiments where the initial NOx-N concentration was increased to 200 mg / L, all NOx-Ns were removed after 270 minutes with RCS _HP as substrate and after 360 minutes with methanol.

In order to compare the denitrification rate and the carbon source ratio required for denitrification, the C / N ratio and the denitrification rate after 2 hours after the denitrification experiment are shown in <Figure 8> and summarized in <Table 7>. <Figure 8> (a) As can be seen in a commercial external carbon source is a carbon source necessary for methanol than the RCS _HP for denitrification of nitrate in the C / N ratio of the concentration of low were fewer when using the RCS _HP compared to methanol average about About 90% was required (Table 7).

After 2 hours of denitrification, the denitrification rate increased with longer acclimation period, and the final denitrification rates measured at 23 days of acclimatization were 17.1 and 16.8 mgN / gVSS / hr for RCS _HP and methanol, respectively. As can be seen in (b), the denitrification rate was higher than that of methanol when RCS _HP was used as the substrate, and RUN4 was 1.5% higher than methanol when using RCS _HP , which was superior to methanol when using RCS _HP as the substrate. It is thought to be able to exhibit denitrification.

TABLE 7

C / N ratio and specific denitrification rate after 2 hours after denitrification test

Through the above experimental results, the following conclusion can be drawn.

1) During the acclimation period, NOx-N was increased from the initial 50 to 200, but showed rapid compliance and after 6 hours all concentrations were almost eliminated to 0 mg / L. At this time, the removed carbon source concentrations were 180.5, 324.0 and 584.0 mg COD / L for RCS _HP and 198.3, 324.9 and 643 mgN / L for methanol, respectively. According to the compliance assessment, RCS _HP was found to have high compliance with methanol, which is a commercial external carbon source.

2) RBDCOD / COD, the biodegradability index of RCS _HP measured by OUR test, was about 100%, showing biodegradability equivalent to methanol. Sum OUR, which is related to energy use during substrate use, was 101.7, 122.3, 140.1 mgO ₂ / L for the RCS _HP as the substrate for RUN2, 3, 4, and 127.1, 101.4, 97.6 mgO ₂ / L for the methanol, respectively. This demonstrates that the sum OUR has a relatively high rate of RCS _HP being used as an energy source among the substrates consumed, which is higher than that of methanol, which reduces sludge generation.

3) NUR test showed that the rate of NOx-N concentration decreases as the acclimation period elapses. After 2 hours after denitrification, the NOx-N removal rate was RUN2, 3, 4 when RCS _HP was used as a substrate. respectively, 5.2, 12.5, 17.1 for the mgN / gVSS / hr, was methanol is 4.7, 11.6, 16.8 mgN / a gVSS / hr as with the NOx-N removal efficiency superior denitration performance higher than that of methanol when used for RCS _HP as substrate Judging. In addition, the C / N ratio, the carbon source required for denitrification, was 4.6, 4.7, and 3.2 gCOD / gNOx-N, respectively, in the case of using RCS _HP as the substrate in RUN2, 3, and 4, and 4.8, 5.1, and 3.7 gCOD / for methanol. It was confirmed that less carbon source was required when using RCSHP to denitrate the same concentration of nitrate with gNOx-N.

4) RCS _HP shows the same or better performance than methanol in terms of denitrification rate with a specific denitrification rate of 101.5% or more when used in the same amount as methanol, thereby reducing the reaction time.

5) The carbon source requirement for unit nitrogen removal is 87.2% compared to methanol, which can save about 13% of the carbon source injection.

6) In the case of RCS _HP , a formaldehyde non-toxic product, no microbial toxicity effect was caused by formaldehyde, and the COD concentration was not significantly different from methanol and the denitrification performance was excellent. It can be used without and has the advantage of reducing the amount of carbon used in the same amount of denitrification.

1 is a graph showing the degree to which formaldehyde is removed according to reaction time by applying Cannizzaro Reaction to 1,4-butanediol-producing waste.

2 is a schematic diagram of a batch reactor operation for microbial compliance experiments.

Figure 3 is a photograph of the respiratory rate meter used in the OUR experiment.

Figure 4 is a graph showing the concentration of NOx-N and the removal of NOx-N for 6 hours after the initial injection and 6 hours after the injection of Nitrate and carbon source for 23 days compliance evaluation.

FIG. 5 is a graph showing SCOD _Cr concentrations after initial injection and 6 hours of injection of Nitrate and a carbon source for 23 days of compliance evaluation and SCOD _Cr concentrations removed for 6 hours.

Figure 6 is a graph showing the specific breath of the OUR test carried out every 7 days using the sludge to perform the compliance experiment using the RCS _HP and methanol as a substrate.

7 is a graph showing the experimental results of the NUR test conducted four times.

8 is a graph showing the C / N ratio and the denitrification rate after 2 hours after the denitrification experiment in order to compare the denitrification rate and the carbon source ratio required for denitrification.

Claims (11)

In the 1,4-butanediol production process consisting of <Scheme 3> and <Scheme 4>, the reaction by-product of <Scheme 3> after separating 1,4-butynediol as a target product from the total product of <Scheme 3> And converting formaldehyde into formic acid and methanol by adding a base to a 1,4-butanediol producing waste containing formaldehyde and reacting the formaldehyde with a base. <Scheme 3> 2CH ₂ O + C ₂ H ₂ → HOCH ₂ CCCH ₂ OH <Scheme 4> HOCH ₂ CCCH ₂ OH + 2H ₂ → HOCH ₂ CH ₂ CH ₂ CH ₂ OH The method of claim 1, Wherein the 1,4-butanediol production waste is 5 to 30% by weight of formaldehyde, 40 to 90% by weight of methanol and 1 to 20% by weight of methylal, the method for producing a composition for the denitrification carbon source. The method of claim 1, The base is LiOH, NaOH, KOH, Ca (OH) ₂ , Ba (OH) _{2 The} method for producing a composition for denitrification carbon source, characterized in that selected from the group consisting of. The method of claim 1, The conversion step is in a temperature range of from a normal pressure, 30 to 100 ℃ and _{^{[OH -] / [CH 2}} O] a method for producing a carbon source for denitrification composition, characterized in that is carried out in the range of 0.5 to 8. The method of claim 1, The conversion step is in a temperature range of from a normal pressure, 40 to 80 ℃ and _{^{[OH -] / [CH 2}} O] a method for producing a carbon source for denitrification composition, characterized in that is carried out in the range of 0.5 to 4. The method of claim 1, The conversion step is at ambient pressure, 60 ℃ temperature and _{^{[OH -] / [CH 2}} O] = 4 The method of producing a carbon source for denitrification composition, characterized in that is carried out under the conditions. The method of claim 1, The conversion step is a method for producing a composition for the denitrification carbon source, characterized in that the formaldehyde of 1,4-butanediol generated waste is removed to 95% or more. The method of claim 1, The conversion step is a method for producing a composition for the denitrification carbon source, characterized in that the formaldehyde of 1,4-butanediol generated waste is removed to 99% or more. The method of claim 1, The conversion step is a method for producing a composition for the denitrification carbon source, characterized in that the formaldehyde of 1,4-butanediol production waste is carried out 100%. The composition for denitrification carbon sources obtained by the manufacturing method of the composition for denitrification carbon sources in any one of Claims 1-9. A method for denitrifying wastewater, comprising contacting the composition for denitrification carbon source according to claim 10 with wastewater.

Images