الفهرس 
LITRETURE REVIEWOnly 14 pages are availabe for public view
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Abstract
The performance of up-flow anaerobic sludge blanket (UASB) reactor followed by down-flow hanging sponge (DHS) as integrated sewage treatment at four stages - one of them is startup period - has been investigated for 181 days. The combined system was operated at two hydraulic retention time (6, 8 hr.) for UASB and three organic loading rate for DHS (using 4 segments, 3 segments, 2 segments), to optimize the combined system to produce a final effluent quality suitable for safe disposal according to the standards and specifications of treated sewage effluent in law 48/82.
For stage one, there are 2 tested phases to get the better HRT in two HRT’s, where the UASB reactor was operated at 6, and 8hr followed by 4 segments of DHS. The average removal efficiency of UASB reactor working at 6hr for BOD5, CODt, CODs, TSS, VSS, and Oil & grease were 61.4±4.6, 66.5±6, 49.6±9, 66.6±12.6, 65.3±17.2, and 54.4±26% respectively, compared with working at 8hr the average removal efficiency were 70.5±1.1, 69.1±2.9, 59.9±2.2, 76±8.2, 74±14.9, and 62.9±6% respectively.
For stage two, UASB was operated at HRT 8hr, and there are 3 phases to get the better organic loading rate for DHS, the DHS system was operated with 4 segments, 3 segments, and 2 segments respectively. The average removal efficiency of DHS system working with 4 segments for BOD5, CODt, CODs, TSS, VSS, Oil & grease, T.K.N., ammonia, and total phosphorus were 69.5±6.3, 66.9± 7.8, 58.3±5.3, 69.1±11.8, 67.8±13.1, 60±22.1, 36.2±5, 29.7±1.6, and 38% respectively, where as with 3 segments the average removal efficiency were 76.5±4.3, 62.2±18.2, 56.2±19.8, 60.1±6.4, 64.6±5.2, 54.8, 24.4±11, 22.4±4.5, and 29% respectively, and with working with 2 segments the average removal efficiency were 57.4±16.1, 44.7±8.2, 46±3.1, 4±20.5, 6.6±16.3, 21.4, 12.5±5.9, 14.4±5.4, and 22% respectively.
In stage three, an aeration tank has been used to increase DO concentration in the UASB effluent before feeding DHS system. This stage was operated with 8hr HRT for UASB and 4 segments of DHS, The average over all removal efficiency for BOD5, CODt, CODs, TSS, VSS, Oil & grease, T.K.N., ammonia, and total phosphorus were 95±2.3, 90±1.8, 82.5±3.7, 93.2±2.3, 93.7±1.7, 65.8, 54.4±7.9, 47.8±5.4, and 66.4±17% respectively.
However, the residual geometric mean of faecal coliform counts in the effluents of the stages shown above were 8×103, 2.80×105, 2.80×103, 9.8×103, and 3×103 MPN/100ml for stage 1 phase 1 and 2, stage 2 phase 1 and 2, and stage 3 respectively.
The overall efficiency for the best-integrated system achieved with using UASB at 8 HRT, 4 segments of DHS with pre-aeration. The effluent quality of the complete system were 21.3±8.7, 85±20.9, 56.7±9.2, 33±5.8, 19.5±4.9, 13, 34.1±10.4, 63.8±8.1, and 1.5±0.9 mg/l for BOD5, CODt, CODs, TSS, VSS, Oil & grease, T.K.N., ammonia, and total phosphorus respectively.
The results shown that the integrated system of UASB & DHS with intermediate aeration can almost obtain effluent quality comply with law 48/1982 for the disposal into agriculture drains (BOD=60 mg/l, COD=80 mg/l, TSS=50 mg/l)
In general, available data proved that the combined integrated system are appropriate, and applicable options for wastewater treatment.
Key words: Sewage; UASB; DHS; COD; F. coliform; Safe disposal.