List of Chemicals Produced by Decomposing Straw

Acetic acid 3-Methylbutanoic acid 2-Methylbutanonic acid Hexanoic acid Octanoic acid Nonanoic acid Decanoic acid Dodecanoic acid Tetradecanoic acid Hexadecanoic acid

1-Methylnaphthalene

2-(1,1-Dimethlyethyl phenol) 2,6-Dimethoxy-4-(2-propenyl) phenol 2,3-Dihydrobenzofuron

5,6,7,7A-Tetrahydro-4,4,7A-trimethyl-2(4H)benzofuranone 1,1,4,4-Tetramethyl-2,6-fo«(methylene) cyclohexone 1-Hexacosene 11 Unidentified

Source: Everall, N.C. and Lees, D.R., Water Res., 31, 614-620, 1997. With permission areas, the total containment lagoon should be considered. Performance by these types of treatment is controlled by selecting the time of discharge and can be controlled to produce an excellent effluent (BOD5 and TSS < 30 mg/L).

Where land is limited but resources and personnel are unavailable, it is again best to utilize relatively simple methods to control algae in effluents. Intermittent sand filters, application of effluent to farm lands, overland flow, rapid infiltration, constructed wetlands, and rock filters may serve well. Intermittent sand filters with low application rates and a warm climate will provide nitrification. Land application to farm land will reduce both nitrogen and phosphorus while producing an excellent effluent.

Energy savings with these type processes are substantial, and an excellent effluent can be produced (Middlebrooks et al., 1981). Table 5.19 provides a comparison of expected effluent quality and energy consumption in relatively simple processes up to the most sophisticated used in wastewater treatment. Obviously, many variables must be considered in design, but energy consumption and sophistication must receive due consideration.

TABLE 5.19

Total Annual Energy for Typical 1-mgd System Including Electrical and Fuel

Effluent Quality

TABLE 5.19

Total Annual Energy for Typical 1-mgd System Including Electrical and Fuel

Effluent Quality

Treatment System

BOD

SS

P

N

(1000 kWI

Rapid infiltration (facultative lagoon)

5

1

2

10

150

Slow rate, ridge + furrow (facultative

1

1

0.1

3

181

lagoon)

Overland flow (facultative lagoon)

5

5

5

3

226

Facultative lagoon + intermittent sand

15

15

10

241

filter

Facultative lagoon + microscreens

30

30

15

281

Aerated lagoon + intermittent sand filter

15

15

20

506

Extended aeration + sludge drying

20

20

683

Extended aeration + intermittent sand filter

15

15

708

Trickling filter + anaerobic digestion

30

30

783

RBC + anaerobic digestion

30

30

794

Trickling filter + gravity filtration

20

10

805

Trickling filter + N removal + filter

20

10

5

838

Activated sludge + anaerobic digestion

20

20

889

Activated sludge + anaerobic digestion +

15

10

911

filter

Activated sludge + nitrification + filter

15

10

1051

Activated sludge + sludge incineration

20

20

1440

Activated sludge + AWT

<10

5

<1

<1

3809

Physical chemical advanced secondary

30

10

1

4464

Source: Middlebrooks, E.J. et al., J. Water Pollut. Control Fed., 53(7), 1172-1198, 1981. With permission.

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