Technical assistance: What are the process methods for treating wastewater containing methamine and DMF?

What are the concentrations of methamine and DMF in the wastewater you are dealing with, and what is its pH value?

I’m currently working on similar research as well; if you’re interested, you can message me via the platform

This post was last edited by hesonchang214 on 2010-11-30 21:46. It’s best to recycle it; dealing with it otherwise is very troublesome!

This post was last edited by hesonchang214 on 2010-11-30 21:49. Reply to 4# Sanshengshi Kong: Brother, is your DMF content high? I know some companies that recycle waste liquids; let me introduce them to you!

By recycling the *key, first turning waste into valuable resources and then dealing with the remaining waste, it is possible to generate economic benefits while also reducing the difficulties associated with wastewater treatment.

Could the poster explain the manufacturing process for this project? I have also taken on a project like this at the moment. The water quality provided by Party A contains 280 mg/l of methanol and 10 mg/l of methylamine; therefore, this water quality seems to present no particular challenges. My question is whether the ammonia nitrogen level in this water is very high, as liquid ammonia is used in the production process.

Could the poster introduce some manufacturers that offer processes for treating methamine and DMF wastewater, as well as discuss the effectiveness of these processes? At present, the levels of ammonia nitrogen and COD are too high. Our plant designed to use membrane treatment, but within less than a week of operation the membranes became completely clogged, and the quality of the treated water did not meet the required standards. As a result, the treatment system has been shut down, and the wastewater is forced into the circulating water system, which causes severe corrosion of the heat exchangers in that system as well as serious cavitation problems in the impellers of the circulation pumps.

High-concentration wastewater containing dimethylformamide in chemical plants can be treated using biochemical methods, reducing its concentration in the effluent to below 10 mg/L. When treating acrylic fiber wastewater using the SBR process, when the influent concentration is 3000–4000 mg/L, the effluent concentration can be reduced to 400–600 mg/L, resulting in a removal rate of 75%. The treatment yields good results, with ammonia nitrogen levels in the effluent being less than 10 mg/L. However, dimethylformamide, the main pollutant present, generates nitrogen oxides that are difficult to biodegrade as a result of this treatment, requiring further processing. Therefore, the SBR process is currently suitable only as a pretreatment method. The N,N-dimethylformamide hydrolase (DMFase) produced by Pseudomonas DMF 3/3 plays a very important role in the treatment of dimethylformamide. The isoelectric point of this enzyme is 7.7, and its activity is highest at pH 5–6 at 40°C; it can also degrade N-ethylformamide and N-methylformamide. However, the degradation rates of N,N-diethylformamide, N,N-dimethylethylamide, and unsubstituted amides such as formamide, prolinamide, acetamide, acrylamide, and butyramide are significantly lower. Leather wastewater in the Czech Republic contains dimethylformamide and dimethylamine; it can be treated using the algae species Scenedesmus quadricauda after it has been adapted for this purpose, as it can use these substances as a nitrogen source for growth. Since ammonia is produced during this process, it is very important to control the pH level, and this issue can be resolved by introducing air containing 3% carbon dioxide. A lack of phosphorus is very detrimental to the growth of algae, so it can be treated together with municipal domestic wastewater. When using the aerobic biological method to degrade DMF-containing wastewater, the removal rate of DMF can reach 95.1%. During the cultivation of its activated sludge, diammonium hydrogen phosphate and urea need to be added. When the TOC value of the wastewater treatment load is greater than 0.4 kg/(m3·day), biochemical degradation becomes unstable. During the biochemical treatment process, almost no new sludge is generated, so it can be assumed that DMF is completely oxidized into carbon dioxide and water. In long-term domesticated strains, DMF can serve as the sole carbon source. Nitrogen-containing industrial wastewater, such as that containing formamide, dialkylformamides, monalkylformamides, primary amines, secondary amines, tertiary amines, and quaternary ammonium salts, can be biologically treated using Arthrobacter sp. immobilized on activated carbon. In the activated sludge process, when the volume load is 0.64 kilograms of DMF per (meter3·day), the DMF content in the effluent can be kept below 10 milligrams per liter. With careful operation, the volume load can be increased to 1.44 kilograms per (meter3·day) without the effluent level exceeding 10 milligrams per liter; therefore, biological treatment is effective for dealing with high-concentration DMF-containing wastewater. If wastewater contains formic acid and DMF (1000–3000 mg/L), its treatment efficiency using trickling filters at 25–8°C may be reduced due to the shock load from DMF; however, its degradation capacity is restored after 2–3 days. The maximum capacity for decomposing DMF is 0.37 kilograms per (m3 of filter media volume·day), while the oxidation of nitrogen is 0.06–0.08 kilograms per (m3·day). The TOD and BOD values decrease from 950 milligrams/liter and 755 milligrams/liter respectively to 85 milligrams/liter, with an 88% removal rate for TOD. Simulated wastewater containing methamine, dimethamine, trimethamine, and DMF can be treated using the biological rotating disk method; studies have shown that the addition of phosphorus is unnecessary, nor is a long retention time required. DMF wastewater can be treated using Pseudomonas aminovorans DM-81; the DMF concentration that can be treated reaches 3%, with the fastest decomposition rate occurring at a concentration of 2%. DMF can be degraded by Mycobacterium methanolica TH-35 when treated at 30°C for seven days; the DMF concentration can reach up to 3%, with the fastest degradation rate occurring at a concentration of 2%. Industrial DMF wastewater can be treated using photosynthetic bacteria such as Rhodospilacea, Ectothiorhosporaceae, or Chloroflexaceae sp. Under aerobic conditions, at a pH of 7.5–9.0 and a temperature of 30–35°C, DMF can be removed by up to 95% after a treatment period of about 5 days. DMF can be treated using DMF-acclimated bacteria immobilized in PVA gels, achieving a high removal rate under aerobic conditions. Wastewater containing DMF can be treated by adding sodium hydroxide, which facilitates hydrolysis to produce dimethylamine and formate; dimethylamine is then removed using air, and the resulting mixture is burned with oxygen-enriched air to convert it into nitrogen and carbon dioxide, while the liquid phase can be treated through biochemical methods. In urban wastewater treatment, when the wastewater contains 100–1000 milligrams per liter of dimethylamine and 100–2000 milligrams per liter of DMF, activated sludge can easily adapt to the degradation of these compounds; even a DMF concentration of 2000 milligrams per liter has no significant inhibitory effect on activated sludge. However, when the DMF concentration exceeds 1200 milligrams per liter along with 1200 milligrams per liter of dimethylamine, it does have an inhibitory effect on activated sludge. When DMF is used together with dimethylacetamide, it does not affect the oxygen consumption rate of activated sludge; however, when the concentration of dimethylacetamide is between 0.5 and 5 grams per liter, it has an adverse effect on the degradation capacity of activated sludge. When the concentration of DMF in wastewater reaches 16,000 mg/L, it exhibits a half-maximal tolerance limit for microorganisms within 24 hours; hence its toxicity is low. At a concentration of 8,000 mg/L, it has no significant effect on common bacteria within 10 hours, and it is non-toxic to algae and amoebas. When treated using the secondary activated sludge process, the removal rates of DMF were 72% and 96% within 24 hours, and 85% and 98% within 48 hours. In the activated sludge process, microorganisms use DMF as a source of phosphorus and nitrogen; during metabolism, the intermediate product is dimethylamine, while nitrogen is ultimately released in the form of nitrate. When N-methyl-2-pyrrolidine is treated using the semi-continuous activated sludge process, its metabolites can be analyzed by infrared spectroscopy, and a carbonyl-containing metabolite is detected.