Intermittent Sand Filter Performance Treating Lagoon Effluents3

Loading

TSS

VSS

BOD

Rate

Influent

Effluent

Removal

Influent

Effluent

Removal

Influent

Effluent

Removal

Pond Type

ub

(mgd/ac)

(mg/L)

(mg/L)

(%)

(mg/L)

(mg/L)

(%)

(mg/L)

(mg/L)

(%)

Ref.

Facultative

5.8

0.1

13.7

4.0

71

9.2

2.0

78

6.3

1.2

82

Marshall and

0.2

13.7

4.8

65

9.2

2.1

77

6.3

1.3

80

Middlebrooks

0.3

13.7

6.0

56

9.2

2.3

75

6.3

2.0

69

(1974)

Facultative

9.74

0.2

30.3

3.5

88

23.0

1.3

94

19.5

1.9

90

Harris et al.

0.4

30.1

2.9

90

22.5

3.4

85

20.6

2.5

88

(1978)

0.6

34.0

5.9

83

25.9

3.1

88

25.6

4.2

84

0.8

23.9

4.7

80

15.2

1.2

92

2.8

1.8

36

1.0

28.5

5.1

82

21.5

2.5

88

13.5

2.6

81

1.0

24.3

3.7

85

18.6

1.6

91

6.1

2.2

64

Facultative

6.2

0.5

32.4

8.6

74

21.9

3.3

85

10.7

1.8

83

Hill et al.

1.0

32.4

7.8

76

21.9

3.2

85

10.7

2.0

82

(1977)

1.5

32.4

6.4

80

21.9

3.3

85

10.7

2.3

79

Facultative

9.73

0.25

70.7

10.1

86

38.8

6.5

83

20.2

6.6

67

Bishop et al.

0.5

197

15.6

92

155

11.9

92

71.4

9.4

87

(1977)

1.0

108

11.8

89

83.0

8.8

89

34.0

13.0

62

Aerated0

9.73

0.5

158

52.5

67

71.1

1.0

68.7

32.9

52

36.6

Anaerobic

NA

0.1

353

45.5

87

264

0.35

208

46.5

78

162

0.5

194

45.1

77

175

Facultative

9.7

0.2

23.0

2.7

88

17.8

0.4

20.8

3.5

83

18.5

* Results for best overall performing 0.17-mm e.s. filters. b Uniformity coefficient. c Dairy waste.

13.2 81 34.4 5.1 85 Bishopetal.

11.3 69 19.6 11.7 40 (1977) 28.1 84 123 19.5 84 Messinger 35.3 78 108 43.7 60 (I976) 35.7 80 107 67.6 37

TABLE 5.3

Mean Performance Values for Three Full-Scale Lagoon-Intermittent Sand Filter Systems

TABLE 5.3

Mean Performance Values for Three Full-Scale Lagoon-Intermittent Sand Filter Systems

Mt. Shasta Facility

Moriarty Facility

Ailey Facility

Facility

Lagoon

Filter

Facility

Facility

Lagoon

Filter

Facility

Facility

Lagoon

Filter

Facility

Parameter

Influent

Effluent

Effluent

Effluent

Influent

Effluent

Effluent

Effluent

Influent

Effluent

Effluent

Effluent

BOD (mg/L)

114

22

11

8

148

30

17

17

67

22

8

6

Soluble BOD

41

7

4

5

74

17

16

16

17

10

6

5

(mg/L)

TSS (mg/L)

83

49

18

16

143

81

13

13

109

43

15

13

VSS (mg/L)

70

34

13

10

118

64

9

9

87

32

8

6

FC (number/

1.16 x

292

30

<2

4.24 x

290

18

34

2.17 x

55

8

<1

100 mL)

106

106

106

PH

6.9

8.7

6.8

6.6

8.0

8.9

8.0

8.0

7.3

8.9

7.1

6.8

DO (mg/L)

4.8

12.4

5.5

5.3

1.8

10.9

8.3

8.3

6.7

10.2

7.4

7.9

COD (mg/L)

244

100

87

68

305

84

43

43

160

57

32

25

Soluble COD

159

71

64

50

197

67

34

34

82

41

23

16

(mg/L)

Akl (mg/L as

95

75

51

42

436

293

260

260

93

84

76

69

CaCO3)

TP (mg-P/L)

4.68

3.88

3.09

2.72

10.3

4.02

2.8

2.8

4.96

3.10

2.67

2.45

TKN (mg-N/L)

15.5

11.1

7.5

5.2

60

22

12.1

12.1

14.2

7.3

4.1

2.2

NH3 (mg-N/L)

10.8

5.56

1.83

1.76

38

16

9.16

9.16

5.5

0.658

0.402

0.31

Organic nitrogen

4.8

5.6

5.7

3.4

22

(mg-N/L)

N02 (mg-N/L)

0.16

0.56

77

0.020

0.05

N03 (mg-N/L)

0.28

0.78

4.3

4.5

0.05

Total algal count

NA

398,022

144,189

141,305

(cells/mL)

Note: NA = not available.

Source: Data from Russell et al. (1980, 1983).

756,681 32,417 32,417 NA 349,175 21,583 29,360

TABLE 5.4

Design Characteristics and Performance of Facultative Lagoon-Intermittent Sand Filter Systems

TABLE 5.4

Design Characteristics and Performance of Facultative Lagoon-Intermittent Sand Filter Systems

Design Flow (m3/L)

Present Flow

Hydraulic Retention Timea

Filter Dosing

(m3/m2d)a

BOD5

(g/m3)

TSS (g/m3)

NH3-

-N (g/m3)

(% Design)

50%

95%

50%

95%

50%

95%

303

56

93

0.03

9

28

12

41

0.9

4

303

79

70

0.37

6

22

7

29

0.4

1.2

568

48

59

0.47

7

17

11

30

378

66

52

0.37

9

21

11

25

0.9

2.4

568

37

55

0.31

6

17

6

16

1.3

5.4

a Based on design flow rate.

Source: Rich, L.G. and Wahlberg, E.J., J. Water Pollut. Control Fed., 62, 697-699, 1990. With permission.

TABLE 5.5

Performance Comparison of Lagoon-Intermittent Sand Filters with Aerated Lagoons and Activated Sludge Plants

TABLE 5.5

Performance Comparison of Lagoon-Intermittent Sand Filters with Aerated Lagoons and Activated Sludge Plants

Process

of Systems

Mean

SD

Mean

SD

Conventional activated sludge

18

12.8

6.85

14.92

10.53

Step-feed activated sludge

13

10.84

7.68

16.23

16.65

Aerated lagoonsa

6

28

71

50

129

DPMC upgrades'"

3

18

39

13

36

DPMC new

1

14

37

11

31

Lagoon-intermittent sand filter

9

8.35

3.07

9.88

3.84

a One aerated cell followed by a polishing pond.

b Facultative lagoons upgraded to dual-power, multicellular aerated lagoons.

a One aerated cell followed by a polishing pond.

b Facultative lagoons upgraded to dual-power, multicellular aerated lagoons.

Source: Rich, L.G. and Wahlberg, E.J., J. Water Pollut. Control Fed., 62, 697-699, 1990. With permission.

for the system. One spare filter unit should be included to permit continuous operation as the cleaning operation may require several days. An alternative approach is to provide temporary storage in the pond units. Three filter beds are the preferred arrangement to permit maximum flexibility. In small systems that depend on manual cleaning, the individual bed should not be bigger than about 1000 ft2 (90 m2). Larger systems with mechanical cleaning equipment might have individual filter beds up to 55,000 ft2 (5000 m2) in area.

Selected sand is usually used as the filter media. These are generally described by their effective size (e.s.) and uniformity coefficient (U.C.). The e.s. is the 10 percentile size; that is, only 10% of the filter sand, by weight, is smaller than that size. The uniformity coefficient is the ratio of the 60-percentile size to the 10-percentile size. The sand for single-stage filters should have an e.s. ranging from 0.20 to 0.30 mm and a U.C. of less than 7.0, with less than 1% of the sand smaller than 0.1 mm. The U.C. value has little effect on performance, and values ranging from 1.5 to 7.0 are acceptable. Generally, clean, pit-run concrete sand is suitable for use in intermittent sand filters if the e.s., U.C., and minimum sand size are suitable.

The design depth of sand in the bed should be at least 45 cm (18 in.) plus a sufficient depth for at least 1 year of cleaning cycles. A single cleaning operation may remove 1 to 2 in. (2.5 to 5 cm) of sand. A 30-d filter run would then require an additional 12 in. (30 cm) of sand. In the typical case, an initial bed depth of about 36 in. (90 cm) of sand is usually provided. A graded gravel layer, 12 to 18 in. (30 to 45 cm), separates the sand layer from the underdrains. The bottom layer is graded so its e.s. is four times as great as the openings in the underdrain piping. The successive layers of gravel are progressively finer to prevent intrusion of

TABLE 5.6

Lagoon-Intermittent Sand Filtration Performance Data

(e.s. = 0.70 mm; U.C. = 21)

Sand 2

(e.s. = 0.35 mm; U.C. = 14)

Sand 3

(e.s. = 0.37 mm; U.C. = 7.0)

Sand 4 (e.s. = 0.18 mm; U.C.

= 2.7

Filter Influent

Hydraulic Loading Rate

(m3/m2/d)

Hydraulic Loading Rate

(m3/m2/d)

Hydraulic Loading Rate

(m3/m2/d)

Hydraulic Loading Rate

(m3/m2/d)

Parameter

(mg/L)

0.2

1.2

0.2

1.2

0.2

1.2

0.2 1

.2

TSS (mg/L)

Mean

100

18

32

13

39

13

41

13

25

SD

38

9

17

5

12

6

15

4

8

VSS (mg/L)

Mean

86

13

22

9

26

10

27

7

17

SD

32

5

12

4

5

4

9

2

4

COD (mg/L)

Mean

156

79

109

73

105

59

91

48

75

SD

38

21

35

21

31

19

32

12

32

BOD5 (mg/L)

Mean

31

16

20

13

20

11

16

6

14

SD

7

6

7

5

8

4

5

4

7

TKN (mg/L)

Mean

11.6

5.6

7.9

4.6

7.3

6.0

7.0

4.3

7.8

SD

4.2

1.7

3.2

2.1

2.2

2.2

2.8

2.2

Mean SD

Mean SD

Mean SD

TC (number/100 mL)

Mean

Mean SD

Source: Truax, D.D. and Shindala, A., Water Environ. Res, 66(7), 894-898, 1994. With permission.

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