Trickling Filter Process

Aerobic attached-growth processes include tricking filters (biotower) and rotating biological contactors (RBC). In these processes, microorganisms are attached onto solid media and form a layer of biofilm. The organic pollutants are first adsorbed to the biofilm surface, oxidation reactions then occur, which break the complex organics into a group of simple compounds, such as water, carbon dioxide, and nitrate. In addition, the energy released from the oxidation together with the organics in the waste is used for maintenance of microorganisms as well as synthesis of new microorganisms.

Table 7 Summary of Wastewater Treatment in the Keebler Company

Parameter

Influent: Design basisa

Influent: Operation5

Effluentb

Flow rate (gpd)

51,200

37,000

-

PH

5.6

6.0

6.8

TCOD (mg/L)

1620

830

65

SCOD (mg/L)

-

290

40

TBOD5 (mg/L)

891

500

39

SBOD5 (mg/L)

-

175

24

TS (mg/L)

756

-

11b

FOG (mg/L)

285

-

3b

TKN (mg/L)

-

2

5

PO4-P (mg/L)

-

3

3

aBased on historical pretreatment program monitoring data.bBased on operation in August 1988. Operational parameters:

HRT=2.8 day; MLSS=3300 mg/L; VSS—2600 mg/L; DO=2.2 mg/L; F/M=0.07 1b BOD/1b VSS • day. Yield=0.32; clarifier overflow rate=118 gpd/ft2; clarifier solids loading rate=5 lb/ft2 • day. Source: Ref. 4.

aBased on historical pretreatment program monitoring data.bBased on operation in August 1988. Operational parameters:

HRT=2.8 day; MLSS=3300 mg/L; VSS—2600 mg/L; DO=2.2 mg/L; F/M=0.07 1b BOD/1b VSS • day. Yield=0.32; clarifier overflow rate=118 gpd/ft2; clarifier solids loading rate=5 lb/ft2 • day. Source: Ref. 4.

Trickling Filter Diagram
Figure 5 Flow diagram of trickling filter for bakery wastewater treatment.

The tricking filter can be used to treat bakery wastewater. Solid media such as crushed rock and stone, wood, and chemical-resistant plastic media are randomly packed in the reactor. Figure 5 shows a typical trickling filter, which can be used for the bakery wastewater treatment. Surface area and porosity are two important parameters of filter media. A large surface area can cause accumulation of a large amount of biomass and result in high treatment efficiency; large porosity would lead to higher oxygen transfer rate and less blockage. A common problem in trickling filter systems is the excess growth of microorganisms, which can cause serious blockage in the medium and reduce the porosity. Typical design parameters and performance data for aerobic trickling filters are listed in Table 8. Keenan and Sabelnikov [14] demonstrated that a biological system containing a mixing-aeration tank and biological filter (trickling filter) was able to eliminate grease and oil in bakery waste. A dramatic reduction of FOG content from 1500 mg/L to less than 30 mg/L was achieved. This system was fairly stable during 20 months of continuous operation.

Waste Management And Control

Waste Management And Control

Get All The Support And Guidance You Need To Be A Success At Understanding Waste Management. This Book Is One Of The Most Valuable Resources In The World When It Comes To The Truth about Environment, Waste and Landfills.

Get My Free Ebook


Post a comment