TABLE 1.

Data from wastewater treatment plants (sewage treatment plants) involved in the study: wastewater treatment processes, numbers of population equivalents (domestic, touristic, and industrial), discharge points, and physicochemical characteristics^a

STP	Wastewater treatment process	Population equivalentb				Discharge point	Physicochemical characteristic (mean value)					Temp range (°C)
		Total	Domestic	Touristic	Industrial		pH (mean value)	TSS (mean value)	BOD (mg/liter) [mean value]	COD (mg/liter)	Cl (mg/liter)
Kairouan (KR)	Oxidation ditch extended aeration activated sludge (low charge)	250,570	238,540	530	11,500	River Oued Laataf to Lake Sabkhet el Kalbia						15−26.4
Influents							7.0 ± 1.0	440	557	1,408	497
Effluents							8.0 ± 1.0	25	26	84	426
Sousse-South (SS)	Conventional activated sludge (medium charge)	325,150	270,968	31,000	23,182	River Oued el Hallouf to sea						15.8−30.1
Influents							7.0 ± 1.0	409	406	800	710
Effluents							8.0 ± 1.0	43	48	117	639
Dekhila (D)	Conventional activated sludge (medium charge)	44,615	31,345	3,080	10,190	River Oued Hamdoun to sea						NAc
Influents							7.0 ± 1.0	348	335	1,040	1,597
Effluents							8.0 ± 1.0	26	23	71	1,216
Sahline (SH)	Oxidation ditch extended aeration activated sludge (low charge)	11,350	0	11,350	0	River Oued Hamdoun to sea						17−29.2
Influents							7.0 ± 1.0	322	369	1,268	587
Effluents							8.0 ± 1.0	13	21	70	489
Jammel (J)	Extended aeration activated sludge (low charge)	83,610	80,430	0	3,180	River Oued el Melah to sea						15.9−29.4
Influents							7.0 ± 1.0	240	270	795	604
Effluents							8.0 ± 1.0	25	30	106	639

^aSTP, sewage treatment plants; TSS, total suspended solids; BOD, biochemical oxygen demand; COD, chemical oxygen demand.

^bPopulation equivalents are expressed in numbers of subjects.

^cNA, data not available.