Table 2. Removal efficiencies of continuous-flow and batch
wastewater reservoirs.
All results are from real scale reservoirs except
those quoted as “experimental”.
|
Parameter |
Continuous-flow |
Batch 30-50 days |
Sources |
|
BOD |
70 % |
90 % |
Juanico&Shelef (1991) Soler et al. (1991) Juanico&Shelef (1994) |
|
COD |
50 % |
80 - 90 % |
|
|
MBAS (detergents) |
50 % |
90 % |
Juanico&Shelef (1991) Juanico&Shelef (1994) |
|
Nitrogen |
|
70 % – 80 % (1) |
Juanico (1999) Avnimelech (1999) Bahri et al. (2000) |
|
Phosphorus |
< 30 % |
60 % – 85 % (1) |
|
|
10 - 30 % |
Sala et al. (1994) Araujo et al. (2000) (experimental) |
||
|
Faecal coliforms |
90 - 99 % |
99.99 % - total |
Kott et al. (1978) Felgner & Sandring (1983)(experimental) Juanico&Shelef (1991) Juanico&Shelef (1994) Liran et al. (1994) Indelicato et al. (1996) Athayde et al. (2000)
(experimental) |
|
Streptococcus
and Clostridium |
|
total |
Berná et
al. (1986) |
|
Giardia and
Cryptosporidium |
|
99.99 % |
Nasser et al. (2000) |
|
Polivirus I
- Chat |
|
total |
Funderburg et al. (1978) (experimental) |
|
Nematode eggs |
|
total |
Kouraa et al. (2002) Barbagallo et al. (2002) |
|
Heavy metals |
down to background concentration in unpolluted waters (1) |
down to background concentration in unpolluted waters (1) |
Juanico et al. (1995) |
|
Organic micropollutants : -- phthalates -- alkyl phenols -- alkyl benzenes -- hydrocarbons |
60 – 75 % (2) |
|
Muszkat (1999) |
(1): Data from Juanico and Avnimelech are from two deep reservoirs in
series, operated as continuous-flow reactors but with short periods of batch
operation. Data by Bahri are from shallow reservoirs.
(2): Soils irrigated with effluents from reservoirs did no present
accumulation of studied organic micro pollutants. Those irrigated with
effluents from activated sludge plants presented build-up of some organic micro
pollutants.
Table 3. Summary
of the performance of the Ben Slimane plant during the first year of operation.
|
|
|
Raw sewage |
Anaerobic Ponds |
Aerated Lagoons |
Facultative Ponds |
Wastewater Reservoirs |
|
BOD |
design value |
325 |
160 |
80 |
40 |
<
20 |
|
[ mg/l ] |
measured |
|
120 |
70 |
40 |
10 |
|
F. coliforms |
design value |
1E7-1E8 |
1E7 |
1E6 |
1E4 |
< 100 |
|
[MPN/100 cc] |
measured |
|
2E6 |
6E5 |
1E4 |
0-20 |