Removal of organic halogens (AOX) from municipal wastewater by powdered activated carbon (PAC)/activated sludge (AS) treatment

1997 ◽  
Vol 35 (10) ◽  
Keyword(s):  
Activated Carbon ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Powdered Activated Carbon ◽  
Organic Halogens

Removal of organic halogens (AOX) from municipal wastewater by powdered activated carbon (PAC)/activated sludge (AS) treatment

1997 ◽  
Vol 35 (10) ◽  
pp. 147-153 ◽  
Author(s):  
C. Bornhardt ◽  
J. E. Drewes ◽  
M. Jekel
Keyword(s):  
Activated Carbon ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Activated Carbons ◽  
Treatment Plant ◽  
Volume Index ◽  
Enhancement Effect ◽  
Simultaneous Treatment ◽  
Volatile Solids ◽  
Organic Halogens

The effectiveness of different treatments with powdered activated carbons (PAC) to reduce the AOX-levels in municipal wastewater was investigated in a bench-scale activated sludge (AS) treatment plant. The PAC was added either directly to the aerated basin (simultaneous PAC-treatment), or to a partial stream of clarified effluent, which was treated with PAC in an agitated tank and recirculated to the aerated basin (subsequent PAC-treatment with recirculation). The standard advanced biological treatment reduced the AOX-content by 24%. In the pilot-plant, three types of powdered activated carbons were tested for a simultaneous treatment. The treatment with 100 mg/l PICA PCO Super produced an additional reduction of AOX by 20%, whereas a dosage of 50 mg/l NORIT W-20 showed no enhancement effect, and W-35 led to an additional AOX-removal of about 9%. Also, an improved removal of DOC, NH4-N and PO4-P was observed. In all cases, the PAC addition caused a significantly improved settling of the AS, reducing the sludge-volume-index, and increasing the content of volatile solids of the PAC-sludge. In general, no evidence of a synergistic effect of the PAC addition to activated sludge, nor bioregeneration of the activated carbon, could be observed. This suggests, that the observed effects probably are caused only by simple adsorption.

Fate of Toxic Organic Compounds in Activated Sludge and Integrated PAC Systems

1987 ◽  
Vol 19 (3-4) ◽  
pp. 471-482 ◽  
Author(s):  
W. J. Weber ◽  
B. E. Jones ◽  
L. E. Katz
Keyword(s):  
Activated Carbon ◽  
Activated Sludge ◽  
Organic Compounds ◽  
Powdered Activated Carbon ◽  
Carbon Adsorption ◽  
Powdered Carbon ◽  
Benzene Toluene ◽  
Adsorptive Properties ◽  
Carbon Concentrations ◽  
Toxic Organic Compounds

The addition of powdered activated carbon (PAC) to activated sludge treatment systems to enhance removal of specific toxic organic compounds from wastewater was evaluated. Nine organic compounds encompassing a range of solubility, volatility, biodegradability, and adsorptive properties were studied. Kate and equilibrium investigations were conducted to quantify the removal mechanisms of volatilization, biodegradation, biosorption, and carbon adsorption. Results from steady-state bioreactor studies showed that the addition of less than 100 mg/ℓ powdered activated carbon to the influent did not enhance the removal of the biodegradable target compounds investigated: benzene, toluene, ethylbenzene, o-xylene, chlorobenzene, and nitrobenzene. Significantly improved removals of the poorly degradable and non-biodegradable compounds 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, and lindane occurred at influent powdered carbon concentrations in the 12.5 to 25 mg/ℓ range. Influent powdered carbon concentrations of 100 mg/ℓ effected overall removals of greater than 90%. The addition of powdered activated carbon not only reduced effluent concentrations but also reduced the amounts of the volatile compounds stripped to the atmosphere.

Microbiological Aspects of the Treatment of Joint Oil Refinery and Municipal Wastewaters

1986 ◽  
Vol 18 (9) ◽  
pp. 115-123 ◽  
Author(s):  
O. Petrović ◽  
B. Dalmacija ◽  
D. Misković ◽  
M. Gantar ◽  
S. Gajin
Keyword(s):  
Activated Carbon ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Direct Method ◽  
Oil Refinery ◽  
Coliform Bacteria ◽  
Organic Load ◽  
Microbiological Analysis ◽  
Municipal Wastewaters ◽  
Microbiological Treatment

The bacteriological parameters of both the primary and secondary microbiological treatment of mixed oil refinery and municipal wastewaters have here been analyzed. Primary treatment was performed using activated sludge in a two grade bioreactor and for the secondary treatment, four columns with granular activated carbon were used. The first and the last column were aerated, whereas the two in the middle were without aeration. The ratios of the oil refinery (R) to municipal (M) wastewaters in the mixtures were 85:15, 70:30, 50:50 and 30:70. The microbiological analyses included the total bacterial count (direct method), the number of heterotrophs and oligotrophs with their ratios, number of coliforms, nitrifying and denitrifying bacteria (growing method). Activated sludge as well as microbial community on the activated carbon were investigated by using scanning electron microscopy. Chemical parameters, such as pH, COD, BOD, NH4+, NO2− and NO3− were determined by the standard methods. The performed microbiological analysis approved the validity of the joint oil refinery and municipal wastewater treatment. The decrease of the organic load in purified water ranged from 88 to 96 % (COD estimate) and from 91 to 99 % (BOD estimate) while the removal of individual groups of microorganisms varied from 55 to 99 %. The highest decrease was observed in the coliform bacteria (97 - 99 %). It is worth noting that a decrease in the total nitrogen in the system ranged from 59 to 74 % and that of nitrate from 56 to 61 % after secondary microbiological treatment.

Sign in / Sign up

Export Citation Format

Share Document