Method for treatment and resource utilization of acidic organic wastewater

Patent metadata

Field	Value
Publication number	US-2021380452-A1
Application number	US-201917285969-A
Country	US
Kind code	A1
Filing date	Oct 17, 2019
Priority date	Oct 18, 2018
Publication date	Dec 9, 2021
Grant date	—

Abstract

Disclosed is a method for the treatment and resource utilization of acidic organic wastewater, comprising: (1) performing activated sludge treatment on acidic organic wastewater; and (2) performing microalgae treatment on the acidic organic wastewater treated in step (1). By means of the combination of activated sludge treatment and microalgae treatment, the present invention can significantly reduce the COD of the acidic organic wastewater. In some embodiments, the use of acclimated activated sludge or activated sludge having a specific microbial flora structure can not only improve the treatment efficiency while shortening the treatment time, but also omit a pH value adjustment step without causing sludge accumulation.

First claim

1 . A method for treatment and resource utilization of acidic organic wastewater, comprising the following steps of:
(1) performing activated sludge treatment on acidic organic wastewater; and (2) performing microalgae treatment on the acidic organic wastewater treated in step (1).

2 . The method according to claim 1 , wherein the acidic organic wastewater is terephthalic acid wastewater; and/or the acidic organic wastewater before the treatment in step (1) has a CODcr content of 3000-30000 mg/L; and/or the acidic organic wastewater has a pH value of 1-5.

3 . The method according to claim 1 , wherein the activated sludge used in step (1) is acclimated activated sludge, and preferably, that is acclimated by a method, comprising:
a first acclimating stage, in which activated sludge used for treatment of municipal sewage is cultivated for 8 to 10 days with acidic wastewater having a CODcr content of 3000-5000 mg/L and a pH value of 1-5; and preferably, at the first acclimating stage, a cultivating temperature ranges from 20 to 28° C., and a dissolved oxygen content is controlled ranging from 2 to 4 mg/L.

4 . The method according to claim 1 , wherein the method of acclimating the activated sludge further comprises a second acclimating stage after the first acclimating stage, wherein, at the second acclimating stage, acidic organic wastewater having a CODcr content of 6000-8000 mg/L, acidic organic wastewater having a CODcr content of 9000-15000 mg/L, and acidic organic wastewater having a CODcr content of 16000-30000 mg/L are used sequentially to cultivate the activated sludge after the first acclimating stage, and the cultivating time all ranges from 1 to 3 days;
preferably, during the second acclimating stage, N and P nutrient substances are added, wherein the source of N nutrient substances is provided by carbamide; the source of P nutrient substances is provided by dipotassium phosphate; and a ratio of COD to N to P is (95-102):(0.8-1.3):(0.7-1.2); and preferably, at the second acclimating stage, cultivating temperatures all range from 20 to 28° C., and a dissolved oxygen content is controlled from 2 to 4 mg/L.

5 . The method according to claim 1 , wherein microbes in the activated sludge comprise Chlorobia, a content of which accounts for more than 10%, preferably more than 15%, and more preferably more than 20%-25% of the total amount of the microbes.

6 . The method according to claim 1 , wherein microbes in the activated sludge comprise Alphaproteobacteria, Sphingobacteriia, Betaproteobacteria, and Chlorobia, a total content of which accounts for more than 50%, preferably more than 60%, and more preferably more than 70% of the total amount of the microbes.

7 . The method according to claim 1 , wherein microbes in the activated sludge comprise Alphaproteobacteria in an amount ranging from 15% to 25%, Sphingobacteriia in an amount ranging from 10% to 15%, Betaproteobacteria in an amount ranging from 15% to 25%, and Chlorobia in an amount ranging from 20% to 25%, relative to the total amount of the microbes and preferably comprise Alphaproteobacteria from 20% to 22%, Sphingobacteriia from 11% to 13%, Betaproteobacteria from 18% to 21%, and Chlorobia from 21% to 25%.

8 . The method according to claim 1 , wherein microbes in the activated sludge comprise Alphaproteobacteria, Sphingobacteriia, and Deinococci;
preferably, a total content of Alphaproteobacteria, Sphingobacteriia, and Deinococci accounts for more than 50%, preferably more than 60%, and more preferably more than 70% of the total microbes; preferably, microbes in the activated sludge comprise Alphaproteobacteria from 30% to 40%, Sphingobacteriia from 20% to 25%, and Deinococci from 8% to 12% and more preferably, microbes in the activated sludge comprise Alphaproteobacteria from 33% to 36%, Sphingobacteriia from 22% to 24%, and Deinococci from 9% to 10%.

9 . The method according to claim 1 , wherein the time period of the activated sludge treatment ranges from 5 to 96 h, preferably from 5 to 48 h; and/or the time of the microalgae treatment ranges from 5 to 240 h, preferably from 12 to 36 h.

10 . The method according to claim 1 , wherein the microalgae used in the microalgae treatment are Chlorella; and, before use, the acclimating treatment is performed on the microalgae in a photobiological device, wherein conditions of the acclimating treatment are cultivating for 10 to 16 days with acidic organic wastewater to be treated and meanwhile providing illumination with an illumination intensity ranging from 3000 to 4100 lux.

11 . The method according to claim 1 , further comprising performing ultraviolet irradiation treatment on the acidic organic wastewater before the activated sludge treatment, and preferably, the time period of the ultraviolet irradiation treatment ranges from 4 to 500 min, more preferably from 5 to 60 min.

12 . The method according to claim 1 , further comprising using carbon dioxide in an industrial purge gas and/or in a biomass gas source as a carbon source for growth of the microalgae, and preferably, the industrial purge gas is a flue gas, in which a content of carbon dioxide may range from 8 to 15 v %, preferably 10 to 12.5 v %, relative to the total volume of the industrial purge gas.

13 . The method according to claim 1 , further comprising recycling microalgae used in the microalgae treatment as a biomass energy material for producing a biomass fuel gas by pyrolysis.

14 . A method of acclimating activated sludge, comprising:
a first acclimating stage, in which activated sludge used for treatment of municipal sewage is cultivated for 8 to 10 days with acidic organic wastewater having a COD value of 3000-5000 mg/L and a pH value of 1-5; and preferably, at the first acclimating stage, the cultivating temperature ranges from 20 to 28° C., and a dissolved oxygen content is controlled from 1 to 5 mg/L, preferably from 2 to 4 mg/L.

15 . The method according to claim 14 , further comprising a second acclimating stage after the first acclimating stage, wherein at the second acclimating stage, acidic organic wastewater having a COD value of 6000-8000 mg/L, acidic organic wastewater having a COD value of 9000-15000 mg/L, and acidic organic wastewater having a COD value of 16000-30000 mg/L are used sequentially to cultivate the activated sludge after the first acclimating stage, and the cultivating time all ranges from 1 to 3 days; and
preferably, at the second acclimating stage, cultivating temperatures all range from 20 to 28° C., and a dissolved oxygen content is controlled to range from 2 to 4 mg/L and from 1 to 5 mg/L, preferably from 2 to 4 mg/L.

16 . The method according to claim 15 , wherein, during the second acclimating stage, N and P nutrient substances are added, wherein the source of N nutrient substances is provided by carbamide; the source of P nutrient substances is provided by dipotassium phosphate; and a ratio of COD to N to P is (95-102):(0.8-1.3):(0.7-1.2).

17 . An activated sludge suitable for treatment of acidic organic wastewater, wherein microbes in the activated sludge comprise Chlorobia, a content of which accounts for more than 10%, preferably more than 15%, and more preferably more than 20%-25% of the total amount of the microbes.

18 . The activated sludge according to claim 17 , wherein the microbes in the activated sludge comprise Alphaproteobacteria, Sphingobacteriia, Betaproteobacteria, and Chlorobia, a total content of which accounts for more than 50%, preferably more than 60%, and more preferably more than 70% of the total amount of

Assignees

• China Petroleum & Chem Corp
• Sinopec Nanjing Res Institute Of Chemical Industry Co Ltd

Inventors

• Li Haitao
• Mao Songbai
• Wang Dong
• Chen Xi

Classifications

• Y02W10/30

  Wastewater or sewage treatment systems using renewable energies · CPC title

• C10B53/02

  of cellulose-containing material (production of pyroligneous acid C10C5/00) · CPC title

• C02F3/322

  use of algae · CPC title

• C02F2101/34

  containing oxygen · CPC title

• C02F11/10

  by pyrolysis · CPC title