Treatment of hazardous refractory wastewater from natural gas and carpet industries
Abdelrhman Magdy Abdelaziz Shana;
Abstract
4. Summary and Conclusion
Industrial growth trends in Egypt are generally associated with increase in wastewater discharge loaded with inorganic and organic pollutants. Toxic and refractory compounds usually exist in industrial wastewater.
These wastewaters are classified by high loads of hazardous chemicals, thus particularly objectionable if sent out into surface water without treatment. Its negative impact in biomass activity requires a specific treatment cycle that is quite often a combination of (AOP) and biological treatment. In this study, the effectiveness of the treatment processes for removal of hazardous refractory wastewater from natural gas and carpet industries wastewater was investigated. The wastewater generated from subject industries is classified by high level of COD and low BOD values .The BOD/COD is below 0.3 which indicates that this wastewater inhibits the metabolic activity of bacterial seed because of their refractory properties causing biodegradability to be difficult. Therefore, either an effective wastewater pretreatment to increase the BOD/COD ratio followed by biological treatment, or coagulation-flocculation has to be carried out.
4.1. Case study (1)-Natural gas industry
In current research, treatment of gas-associated wastewater from a gas production company located at Alexandria was carried out. Natural gas processing is a sophisticated industrial process developed to purify raw natural gas by removing impurities and many non-methane hydrocarbons and fluids to produce the so called pipeline quality dry natural gas. Typical contents are water vapor, liquid water, acids and dissolved salts.
Natural gas should be sufficiently dehydrated of water vapor to inhibit the formation of methane hydrates within the gas process plant or within the sales gas transmission pipeline. A typical absorption dehydration is called Glycol Dehydration. The wastewater generated from glycol dehydration process is usually contaminated with high organic and inorganic pollutants, classified by high (COD).
Characteristics of this wastewater regarding COD, BOD, TSS and total phenols were 55143, 9562, 385 and 0.8 mg/l, respectively .The wastewater was nearly acidic in nature, the pH ranged between 4.5 and 4.9. As observed, the COD, BOD and TSS exceed the limits of discharging wastewater either to the sea or to the sewerage system.
Thus, a treatment is required for decreasing the organic load. The BOD/COD ratio of 0.17 implies that wastewater has hazardous organics that are hardly biodegradable. Because of the reduced TSS concentration, conventional coagulation precipitation method is not considered adequate. A Fenton reagent [Fe2+/ H2O2] is suggested for degradation of existing soluble organics in the wastewater.
Optimum operating conditions were: H2O2 in concentration of 1.6 M/L (one Stoichiometry with COD), 60 mM/L of Fe2+ ions, at pH around 3 and optimal time of 30 minutes. A corresponding residual COD and BOD were 11365 and 4146 mg/l while phenols were completely removed. Results concluded that,
Industrial growth trends in Egypt are generally associated with increase in wastewater discharge loaded with inorganic and organic pollutants. Toxic and refractory compounds usually exist in industrial wastewater.
These wastewaters are classified by high loads of hazardous chemicals, thus particularly objectionable if sent out into surface water without treatment. Its negative impact in biomass activity requires a specific treatment cycle that is quite often a combination of (AOP) and biological treatment. In this study, the effectiveness of the treatment processes for removal of hazardous refractory wastewater from natural gas and carpet industries wastewater was investigated. The wastewater generated from subject industries is classified by high level of COD and low BOD values .The BOD/COD is below 0.3 which indicates that this wastewater inhibits the metabolic activity of bacterial seed because of their refractory properties causing biodegradability to be difficult. Therefore, either an effective wastewater pretreatment to increase the BOD/COD ratio followed by biological treatment, or coagulation-flocculation has to be carried out.
4.1. Case study (1)-Natural gas industry
In current research, treatment of gas-associated wastewater from a gas production company located at Alexandria was carried out. Natural gas processing is a sophisticated industrial process developed to purify raw natural gas by removing impurities and many non-methane hydrocarbons and fluids to produce the so called pipeline quality dry natural gas. Typical contents are water vapor, liquid water, acids and dissolved salts.
Natural gas should be sufficiently dehydrated of water vapor to inhibit the formation of methane hydrates within the gas process plant or within the sales gas transmission pipeline. A typical absorption dehydration is called Glycol Dehydration. The wastewater generated from glycol dehydration process is usually contaminated with high organic and inorganic pollutants, classified by high (COD).
Characteristics of this wastewater regarding COD, BOD, TSS and total phenols were 55143, 9562, 385 and 0.8 mg/l, respectively .The wastewater was nearly acidic in nature, the pH ranged between 4.5 and 4.9. As observed, the COD, BOD and TSS exceed the limits of discharging wastewater either to the sea or to the sewerage system.
Thus, a treatment is required for decreasing the organic load. The BOD/COD ratio of 0.17 implies that wastewater has hazardous organics that are hardly biodegradable. Because of the reduced TSS concentration, conventional coagulation precipitation method is not considered adequate. A Fenton reagent [Fe2+/ H2O2] is suggested for degradation of existing soluble organics in the wastewater.
Optimum operating conditions were: H2O2 in concentration of 1.6 M/L (one Stoichiometry with COD), 60 mM/L of Fe2+ ions, at pH around 3 and optimal time of 30 minutes. A corresponding residual COD and BOD were 11365 and 4146 mg/l while phenols were completely removed. Results concluded that,
Other data
| Title | Treatment of hazardous refractory wastewater from natural gas and carpet industries | Other Titles | معالجة المواد الخطره والغير قابله للتحلل من المخلفات السائله لصناعة الغاز الطبيعي وصناعة السجاد والموكيت | Authors | Abdelrhman Magdy Abdelaziz Shana | Issue Date | 2017 |
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