APPENDIX B

Summary of Pond Characteristics

APPENDIX B Summary of Pond Characteristics

FACULTATIVE AEROBIC ANAEROBIC

Partial Mix Complete Mix High Performance Description Earthen impoundment less Earthen Earthen Dual-power, multi- A deep earthen basin not than 2.5m deep. O2- impoundment in impoundment in cellular systems mixed or aerated. The saturated water at surface which aeration which mechanical (DPMC) designed for organic load exceeds any supports aerobic (mechanical surface mixing introduces maximum BOD naturally occurring biodegradation. Aerobic and mixing or submerged air for BOD removal conversion efficiency. dissolved O2. Degradation anaerobic degradation diffusion) is used to and to suspend takes place anaerobically. processes occur mid-depth. meet O2 needs. No solids. Bottom anaerobic water solids suspended. Performance supports methanogenesis. Performance depends on Performance depends on O2 depends on aeration. aeration. from algae.

Common Controlled Discharge – Plastic curtains - High Performance None known at this Placement - in front of Modifications during winter or peak algal with floats, anchored BIOLAC™ time. facultative lagoon as part growth periods in summer to bottom dividing Nitrogen Removal of design or retrofitted to Hydrograph Controlled lagoons into multiple Nitrification and de- existing system. Release - discharge when cells to improve nitrification. conditions in the receiving hydraulic conditions. stream are suitable. Submerged Plastic Curtains - used as diffusers - baffles to divide lagoon into suspended from cells. flexible floating Floating Plastic Grids - booms which move in supporting the Growth of a cyclic pattern plants to reduce algal growth. during aeration activity. Treats a larger volume with

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each aeration line. Effluent recirculation -within the system to enhance oxygen levels. FACULTATIVE AEROBIC ANAEROBIC Partial Mix Complete Mix High Performance Performance BOD: to <30mg/L 95% of the BOD: to <30 mg/L Not available. TSS: to < 15mg/L. BOD: reduced by 60%; time. 95% of the time with NH3: 90%removal. less in cold climates. TSS: to <100 mg/L. settling at end of NH3: up to 90% removal in system. summer. TSS: to < 60 mg/L. P: up to 50% removal. NH 3: nitrified during Pathogen and fecal summer. coliform removal: varies with temperature and detention time.

Costs See Ch. 8 See Ch. 8 See Ch. 8 See Ch. 8 See Ch. 8

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FACULTATIVE AEROBIC ANAEROBIC Partial Mix Complete Mix High Performance Applicability Raw municipal wastewater Municipal and industrial Municipal and Screened municipal Pretreatment of effluent from wastewaters of low to industrial applications and industrial municipal and Primary treatment medium strength. where space is limited. wastewater in areas industrial wastewater Trickling filters where space is with high organic Aerated ponds Raw, screened or limited. loading. Anaerobic ponds primary settled Biodegradable municipal wastewater. industrial wastewater Biodegradable industrial wastewaters.

Advantages Removes BOD, TSS, Smaller plant footprint Small footprint. Small footprint Treats high organic bacteria and NH3. than facultative ponds. Discharge acceptable Removes BOD, loadings. Low energy requirements. Discharge acceptable under all conditions. TSS and bacteria Produces methane for Easy to operate. under all climatic No ice formation in when used with a energy recovery. conditions. cold weather. settling basin Produces less sludge Effective at than other processes. converting NH3 to Low energy - NO3 . requirements.

Disadvantages Higher sludge accumulation Requires energy input. Agitation must be Solids removal is Large footprint. in cold climates; removal Not as effective at sufficient to suspend greater than other Odors. required. removing N and P as all solids. options. Long retention times. Mosquitoes, other insect facultative ponds. High energy High energy Process may not be vectors, and burrowing Ice formation. requirement for requirements. effective in colder animals may be a problem. Mosquitoes and other aeration and solids Relatively little climates. Odors can occur with spring vectors. suspension. experience with this and fall pond turnover. Sludge removal Increased solids type of system. Larger footprint. required. disposal. Difficult to control or predict Routine maintenance Settling basin needed ammonia levels in winter. and cleaning required to to facilitate solids maintain design aeration separation. rates.

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FACULTATIVE AEROBIC ANAEROBIC Partial Mix Complete Mix High Performance Design Systems with at least three cell in 1.8 - 6 m (6 to 20 ft), 3 Three cell systems > 6W/m3 needed BOD loading rate: Considerations series are recommended. m (10 ft). are recommended. for primary basin, 0.04 -0.30 kg/m3/d and Criteria 1.8W/m3 for (2.5- 18.7 lb /103 Inlet and outlet structure design Submerged diffusion 3.7 Agitation must be settling basin. ft3/d). should maximize volume to avoid to 4 kg O2/kW-hour (6 to sufficient to short circuiting. 6.5 lbs O2/hphour). suspend all solids. Detention Time Detention time: 1- <1.5d. 50d. Typical criteria: Mechanical surface Detention time: 1.5 Loading Rate aerators 1.5 to 2.1 kg < 3d. Not appropriate Depth: 2.4-6m 22-67kg BOD5/ha-d. O2/kW-hour (2.5 to 3.5 for [Deeper is better.] Detention Time lbs O2/hp-hour). The design for CBOD5<100mg/L 25-180 d. BOD removal is Surface area: 0.2-0.8 Depth 1.5m – 2.5m. System should have at based on first- ha. Surface Area 4-60 ha. least three lined cells in order kinetics and series depending on soil the complete mix Minimum freeboard: Average organic loading rate and conditions. hydraulics model. 0.9m. detention time relative to ambient temperature: Detention Times 10 – Liners recommended o 30d [20 days most to prevent seepage. T, C BOD, tdet,d kg/ha/d common]. >15 18-36 ? Surface runoff should 0-10 9-18 ? The design of aerated be diverted from <0 4.5-9 120-180 lagoons for BOD lagoon surface. Maximum loading rate for the 1st removal is based on cell in multi-cell systems relative to first-order kinetics and temperature: the complete mix o hydraulics model. Even T, C BOD, though the system is not kg/ha/d completely mixed. >15 40

<0 16 Ponds should be rectangular with a 3:1 or Lining may be required. 4:1 length to width ratio

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FACULTATIVE AEROBIC ANAEROBIC Partial Mix Complete Mix Design Models Areal Loading Rate Method – Use complete mix Use complete Design based on and Equations Simple to use when impoundment kinetic model. mix kinetics volumetric loading [See Appendix will not be mixed. model. rate, water C for example temperature and calculations] Gloyna Model – Assumes a BOD5 hydraulic detention removal efficiency of 89-90%. time.

Complete Mix Kinetics – Marias See Advanced and Shaw model (also assumes first Integrated Pond order degradation kinetics). System Design [NOTE: This model is not widely (Oswald 1999). accepted as a complete mix kinetic model; assumptions have not proven to be valid for facultative ponds.]

Plug Flow

Intermediate Flow (between complete mix and plug flow) – Wehner-Wilhlem Equation accounts for both biodegradation kinetics and dispersion.

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