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Municipal wastewater was amended with organic garbage leachates at a concentration around 700 mgCOD(soluble)/L and fed to three different anaerobic systems to compare their performance: a down flow fluidized bed (DFFB), an expanded granular sludge bed (EGSB) and a zeolite-packed anaerobic filter reactor (ZPF). The DFFB and EGSB reactors were operated at HRT of 6 and 4 h and the ZPF reactor at 12 and 36 h. Organic loads rate for the DFFB reactor were 2.3+/-0.9 and 4.8+/-1.8 gCOD/L.d, with removal efficiencies around 40% and a methane productivity of 0.2+/-0.03 L/L(reactor).d. For the EGSB reactor, organic loads tested were 2.1+/-0.9 and 4.3+/-1.3 gCOD/L.d, removal efficiencies attained were of 77.6+/-12.7% and 84.4+/-4.9%, respectively at both conditions and total suspended solids were removed in 54.6+/-19.3%, while methane productivity at 4 h HRT was of 1.29+/-0.4 L/L(reactor).d. The ZPF reactor was operated at lower organic loading rates, 1.4+/-0.27 and 0.42+/-0.13 gCOD/L.d and attained removal efficiencies of 48+/-18% and 83+/-8%, respectively, reaching a methane productivity of 0.21+/-0.09 and 0.12+/-0.04 L/L(reactor).d, 83+/-8.0% of total suspended solids were retained in the reactor and as HRT was increased ammonium concentrations increased in 39%. Specific methanogenic activity in all systems was around 0.2 gCOD-CH(4)/gVSS d.

The Mexican petrochemical industry, Morelos S.A. de C.V., is one of the biggest and more important petroleum industries in Mexico and Latin America. It has an activated sludge system to treat its wastewater flow, which is approximately 7,000 m3/d. The wastewater contains volatile organic carbon substances classified as toxics. The old surface aeration system was changed for fine bubble diffusers; however, one major drawback of the new aeration system is that the temperature in the bioreactor has increased due to the compression of the air, which at the compressor exit reaches 85 degrees C. This effect results in the temperature in the bioreactor attaining 32 degrees C during the fall, whereas in the spring and summer, the bioreactor temperature reaches higher values than 40 degrees C. The high temperatures reduce the microorganism activity and cause a higher volatilisation rate of volatile compounds, among other effects, which affect the performance of the biological treatment. This work was performed to obtain a better modelling of the wastewater treatment from the petrochemical industry. The model describes the effect of the temperature on the performance of the biological treatment. The model was obtained from tests that were carried out in laboratory reactors with 14 L capacity, which were operated at different temperatures (from 30 to 45 degrees C), with the same wastewater and conditions as the actual system.