However the actual efuent concen tage of wwtps showed

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Unformatted text preview: range. WWTPs with efficiencies above the upper limit of the presenting a substantial percentage of Concerning facultative ponds (FP), a very high percen- literature ranges. However, the actual effluent concen- tage of WWTPs showed a low performance in terms of trations were significantly above the upper reference COD, TSS and TN, but a good performance in terms of value (poor performance), for practically all constituents. TP and FC. In this case, the only exception was also the mean effluent The anaerobic ponds followed by facultative ponds (AP þ FP) showed good BOD, COD, TP and FC removal Figure 1 | faecal coliform concentrations, which were lower than the reported values. Mean effluent concentration for the six constituents, considering the six treatment technologies. 42 S. C. Oliveira & M. von Sperling Figure 2 | | Performance of wastewater treatment technologies Journal of Water, Sanitation and Hygiene for Development | 01.1 | 2011 Mean removal efficiencies for the six constituents, considering the six treatment technologies. The activated sludge (AS) process presented BOD and COD effluent concentration values closer to the reference value were observed for TP and FC, showing a better performance than that reported in the literature. values. However, considering BOD and TSS removal effi- The UASB reactors showed good BOD and COD ciencies, the performance was below the expected for removal efficiencies and a poorer performance compared activated sludge plants. This can be partially explained with the reference ranges reported in the literature, consid- by the low influent concentrations, which makes the ering TSS, FC and nutrients. achievement of high removal efficiencies more difficult. The performance achieved by the UASB reactors fol- Effluent concentrations systematically below the limit lowed by some form of post-treatment (UASB þ POST) was 43 | S. C. Oliveira & M. von Sperling Table 5 Typical and observed effluent concentrations, and percentage of plants with effluent concentrations higher than the upper value in the literature range | FP AP þ FP AS UASB UASB þ POST BOD (mg L ) 40 to 80 74 to 575 50 to 80 86 to 176 50 to 80 54 to 133 10 to 40 16 to 58 70 to 100 67 to 129 20 to 80 13 to 63 89 96 57 31 30 0 Literature Actual 100 to 200 159 to 1134 120 to 200 342 to 676 120 to 200 213 to 421 30 to 120 35 to 188 180 to 270 147 to 344 60 to 200 61 to 219 82 99 90 27 50 29 Literature Actual 30 to 60 53 to 290 60 to 90 132 to 343 60 to 90 80 to 236 20 to 40 13 to 130 60 to 100 49 to 137 10 to 90 17 to 85 63 95 86 55 40 13 Literature Actual .20 37 to 84 .20 25 to 48 .20 26 to 69 .20 12 to 33 .20 36 to 60 15 to . 30 – 100 90 100 50 100 – Literature Actual .4 4 to 9 .4 2 to 7 .4 4 to 8 .4 1 to 2 .4 2 to 11 1 to . 4 1 to 8 83 64 82 0 60 25 Literature Actual 106 to 107 4 Â 105 to 1 Â 107 106 to 107 2 Â 105 to 2 Â 106 106 to 107 7 Â 104 to 1 Â 106 106 to 107 3 Â 104 to 3 Â 105 106 to 107 4 Â 106 to 7 Â 107 102 to 107 9...
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This document was uploaded on 04/09/2014.

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