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Table 2 Two-stage HSSFCW system influent and effluent concentrations (mgL−1) and percentage removal efficiencies shown in brackets

From: Post treatment of anaerobically treated brewery effluent using pilot scale horizontal subsurface flow constructed wetland system

Month

UASB reactor effluent concentration (mean ± SD)

CW1 effluent concentration (mean ± SD)

TSS

COD

TN

NH4–N

TP

PO43−

TSS

COD

TN

NH4–N

TP

PO43−

Jan

274.4 ± 12

614 ± 5.3

101.4 ± 3

74.8 ± 2.2

32.5 ± 2.4

25 ± 1.4

116.4 ± 6 (57.6)

199 ± 3 (67.6)

51.5 ± 5.6 (49.2)

28.3 ± 2.5 (62.2)

18.1 ± 1.1 (44.3)

11.3 ± 2.4 (54.8)

Feb

263.7 ± 5.4

545.7 ± 10

77.4 ± 2.2

51.2 ± 1.8

28.4 ± 1

20.6 ± 0.4

88.8 ± 3.9 (66.3)

161.9 ± 5.8 (70.3)

35.9 ± 6.3 (53.9)

21.1 ± 2.2 (58.8)

14.7 ± 0.4 (48.2)

8.7 ± 0.8 (57.8)

Mar

180.2 ± 1.2

338.7 ± 10

43.6 ± 3.2

30.3 ± 0.8

25.4 ± 2.4

17.3 ± 0.9

51 ± 7.1 (71.7)

73.3 ± 6 (78.4)

18.3 ± 1.3 (58)

9.6 ± 0.5 (68.3)

12.5 ± 1.2 (51.6)

6.8 ± 0.2 (60.7)

Apr

256 ± 2

443.7 ± 5.9

38 ± 1.2

23.1 ± 2.4

33.4 ± 2.9

27.5 ± 1.2

97 ± 4.2 (62.1)

114.2 ± 7.5 (74.3)

15.1 ± 1.3 (60.3)

6.4 ± 1.2 (72.3)

19.9 ± 2.1 (40.4)

13.2 ± 1.5 (52)

May

210.9 ± 6.8

278.2 ± 18

57 ± 3.9

34.7 ± 2.5

42.9 ± 2.9

29.9 ± 1.6

53.2 ± 5.4 (74.8)

57.6 ± 8.4 (79.3)

26.3 ± 1.1 (53.9)

13.4 ± 2 (61.4)

30 ± 1.7 (30.1)

16.7 ± 2.4(44.1)

Jun

212 ± 12

350.2 ± 16

63.3 ± 2.1

44.2 ± 2.3

27.7 ± 2.1

20.1 ± 1.6

61 ± 3.4 (71.2)

89.3 ± 2.4 (74.5)

28.9 ± 2.1 (54.3)

17.4 ± 3.1 (60.6)

15.2 ± 1.7 (45.1)

10.5 ± 0.7 (47.8)

Jul

184.3 ± 5.1

207.3 ± 3.1

29.4 ± 1

20.3 ± 1.6

24.4 ± 3.4

14.4 ± 1

31.3 ± 1.1 (83)

30.3 ± 3.7 (85.4)

13.2 ± 4.5 (55.1)

3.4 ± 0.1(83.3)

12.6 ± 0.9(48.4)

7 ± 0.4 (51.8)

Aug

123.7 ± 5.1

334.5 ± 0.5

25 ± 1.9

17.3 ± 1.6

17.9 ± 3.1

10.2 ± 0.3

35.6 ± 2.7 (71.2)

69.6 ± 2.2 (79.2)

11 ± 1.1 (56)

2.9 ± 0.2 (83.2)

10.5 ± 1 (41.3)

5.6 ± 0.9 (45.1)

Sept

239.3 ± 6.1

383.3 ± 9.9

32.8 ± 1.8

21.7 ± 2

41.7 ± 2

32.9 ± 1.4

93.4 ± 5.8 (61)

108.4 ± 2.6 (71.7)

14.1 ± 2.1 (57)

5 ± 1.1(77)

28.5 ± 5(31.7)

19.4 ± 0.9 (41)

Oct

211.4 ± 2.1

436 ± 2

48.6 ± 7.2

35.7 ± 3

23.2 ± 1

19.6 ± 1.3

66 ± 9 (68.8)

127.4 ± 7.2 (70.7)

21.2 ± 4.2 (56.4)

14.2 ± 1.8 (60.2)

14.8 ± 0.8 (36.2)

10.9 ± 1.3 (44.4)

Nov

177.4 ± 12

313 ± 2.6

34.9 ± 4.6

24.9 ± 3.9

20.3 ± 2.2

12.6 ± 0.3

34.8 ± 2.5 (69.2)

92.3 ± 3.3 (70.5)

13.4 ± 0.6 (61.6)

7.2 ± 1.1 (71.1)

11.6 ± 0.4 (42.9)

7.2 ± 0.5 (44.2)

Dec

200.9 ± 7.4

392.7 ± 3.5

61.3 ± 2.1

45.3 ± 4.5

29.4 ± 1.6

22.6 ± 1.3

69.5 ± 1.7 (65.4)

122.4 ± 9.1 (68.8)

29.2 ± 2.5 (52.4)

16.2 ± 2.5 (64.2)

19.7 ± 0.8 (33)

14.7 ± 1.3 (34.4)

p-value

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

Month

CW2 effluent concentration (mean ± SD)

TSS

COD

TN

NH4–N

TP

PO43−

Jan

50.5 ± 0.5 (56.6)

64.1 ± 7.2 (67.8)

21 ± 1.8 (59.2)

9.1 ± 0.9 (67.8)

4.9 ± 0.5 (72.9)

3 ± 0.6 (73.5)

Feb

35.8 ± 1.8 (59.7)

51 ± 5 (68.5)

14.8 ± 2.2 (58.8)

5.4 ± 0.7 (74.4)

5 ± 0.4 (66)

2.8 ± 0.6 (67.8)

Mar

16.8 ± 2.6 (67.1)

17.4 ± 4 (76.3)

6.8 ± 1 (62.8)

1.8 ± 0.3 (81.3)

4.7 ± 0.7 (62.4)

1.9 ± 0.1 (72.1)

Apr

36.9 ± 2 (62)

43.9 ± 3.3 (61.6)

5.3 ± 0.6 (64.9)

1.1 ± 0.1 (82.8)

4.8 ± 0.9 (75.9)

3.2 ± 0.9 (76.4)

May

13.9 ± 2.7 (73.9)

14 ± 3.4 (75.7)

11.2 ± 1.1 (57.4)

3.1 ± 0.8 (76.9)

14.3 ± 1.2 (52.3)

7.4 ± 1 (55.7)

Jun

18 ± 0.9 (70.5)

29.6 ± 1.5 (66.9)

11.9 ± 1.1 (58.8)

4 ± 1.3 (77)

4.3 ± 0.8 (71.7)

2.9 ± 0.5 (72.4)

Jul

5.3 ± 0.3 (83.1)

7.4 ± 1.3 (75.6)

3.4 ± 0.3 (74.2)

0.9 ± 0.1 (73.5)

2.5 ± 0.9 (80.2)

1.2 ± 0.1 (82.9)

Aug

10.4 ± 0.4 (70.8)

15.2 ± 4.7 (78.2)

2.8 ± 0.3 (74.5)

0.7 ± 0.1 (75.9)

2.7 ± 0.3 (74.3)

1.4 ± 0.05 (75)

Sept

37.5 ± 3.3 (59.9)

38.2 ± 2.5 (64.8)

5.6 ± 0.6 (60.3)

0.8 ± 0.1 (84)

16.3 ± 3.9 (42.8)

9.6 ± 0.3 (50.5)

Oct

22.8 ± 1.9 (65.5)

42.8 ± 1.1 (66.5)

7.4 ± 3 (65.1)

3.2 ± 1 (77.5)

9.4 ± 1.6 (36.5)

5.7 ± 0.2 (47.7)

Nov

18.8 ± 1.3 (65.7)

29.7 ± 3.4 (67.8)

4.8 ± 0.9 (64.2)

1.2 ± 0.9 (83.3)

8.7 ± 0.6 (25)

4.8 ± 0.2 (41.5)

Dec

25 ± 1.9 (64)

39.2 ± 3.4 (68)

12.3 ± 1.3 (57.9)

3.7 ± 1.5 (77.2)

13.3 ± 2.4 (32.5)

9.3 ± 0.9 (36.7)

p-value

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

 < 0.05

EEPA*

 < 50

 < 250

 < 40

 < 20

 

 < 5

  1. *Ethiopia environmental protection authority, EEPA (2003) discharge standards (mgL−1)