Constructed Wetlands

Specific Yield and Specific Retention

What Specific Yield

The porosity of a soil defines the maximum amount of water that a soil can contain when it is saturated. The specific yield is the portion of that water that 1 16 1 8 1 4 1 2 1 2 4 8 16 32 64 128 256 Maximum 10 grain size, mm FIGURE 2.3 Porosity, specific retention, and specific yield variations with grain size (in situ consolidated soils, coastal basin, California). 1 16 1 8 1 4 1 2 1 2 4 8 16 32 64 128 256 Maximum 10 grain size, mm FIGURE 2.3 Porosity, specific retention, and specific yield...

Retardation Factors for Selected Organic Compounds

Material Retardation Factor (Rd) (PCBs) are effectively removed by most soils. Highly soluble compounds such as chloroform, benzene, and toluene are removed less efficiently by even highly organic soils. Because volatilization and biodegradation are not necessarily dependent on soil type, the removal of organic compounds via these methods tends to be more uniform from site to site. Table 3.1 presents retardation factors for a number of organic compounds, as estimated from several literature...

G Land Treatment Systems

Haccp Voorbeeld Visverwerkingsbedrijf

Land treatment systems include slow rate (SR), overland flow (OF), and soil aquifer treatment (SAT) or rapid infiltration (RI). In addition, the on-site soil absorption systems discussed in Chapter 10 utilize soil treatment mechanisms. The process of land treatment is the controlled application of wastewater to soil to achieve treatment of constituents in the wastewater. All three processes use the natural physical, chemical, and biological mechanisms within the soil-plant-water matrix. The SR...

Design and Performance Data from EPA Pond Studies

Epa Dispersion Equation

Organic Loading (kg BOD ha1 d1) Source Data from Middlebrooks et al. (1982) and USEPA (1983). Months Effluent BOD Exceeded 30 mg L The Gloyna method was evaluated using the data referenced in Table 4.2. The equation giving the best fit of the data is shown below as Equation 4.2 despite the considerable scatter to the data, the relationship is statistically significant V 0.035< 2(BOD)(1 .099)LIGHT (35-t 2S0 (4.2) BOD BOD5 in the system influent (mg L). LIGHT Solar radiation (langleys). V Pond...

Summary of Typical Dissolved Air Flotation Performance University of Texas at Austin 1976

Air Floatation And Precipitation

Lubbock, Texas Komline-Sanderson (1972) El Dorado, Arkansas Bore et al. (1975) Logan, UT Stone et al. (1975) Sunnyvale, California Alum (225 mg L) acid added to pH 6.4 Alum (175 mg L) acid added to pH 6.0 to 6.3 a Including 33 pressurized (35-60 psig) recycle. b Including 30 pressurized (50 psig) recycle. c Including 100 pressurized recycle. d Including 25 pressurized (45 psig) recycle. e Including 27 pressurized (55-70 psig) influent. FIGURE 5.6 Types of dissolved-air flotation systems. (From...

Comparison of Field Infiltration Testing Methods

Field Soil Infiltration Test

Water Needs Time Required Equipment Technique per Test (gal) per Test (hr) Required Backhoe or blade See this chapter for details. AEP device See this chapter for Pump, pressure See Crites et al. tank, sprinkler, (2000) for details. collection cans approaches a steady-state condition. This steady-state rate can be taken as the limiting infiltration rate for the soil within the zone of influence of the test. A safety factor is then applied to that rate for system design, as described in Chapter...

OnSite Wastewater Systems

Effluent disposal options for on-site systems range from soil absorption in conventional gravity leachfields to water reuse after high-tech membrane treatment. Individual on-site systems are the most prevalent wastewater management systems in the country. This chapter describes the various types of on-site wastewater systems, wastewater disposal options, site evaluation and assessment procedures, cumulative areal nitrogen loadings, nutrient removal alternatives, disposal of variously treated...

References

Agunwamba, J.C., Egbuniwe, N., and Ademiluyi, J.O. (1992). Prediction of the dispersion number in waste stabilization, Water Res, 26, 85. Benefield, L.D. and Randall C.W. (1980). Biological Process Design for Wastewater Treatment, Prentice-Hall, Englewood Cliffs, NJ. Bhagat, S.K. and Proctor, D.E. (1969). Treatment of dairy manure by lagooning, J. Water Pollut. Control Fed, 41, 5. Boulier, G.A. and Atchinson, T.J. (1975). Practical Design and Application of the Aerated-Facultative Lagoon...

About the Authors

Crites is an Associate with Brown and Caldwell in Davis, California. As the Natural Systems Service Leader, he consults on land treatment, water recycling and reuse, constructed wetlands, biosolids land application, decentralized wastewater treatment, and industrial wastewater land application systems. He received his B.S. degree in Civil Engineering from California State University in Chico and his M.S. and Engineer's degree in Sanitary Engineering from Stanford University. He has 35...

Process Design Land Application

The basic design approach is based on the underlying assumption that, if sludge is applied at rates that are equal to the requirements of the design vegetation, over the time period of concern there should not be any greater impact on the groundwater than from normal agricultural operations. The design loading, based Source Data from Bastian (1993) and Crites et al. (2000). Cumulative Pollutant Loading Rate Pollutant (kg ha) Molybdenum was dropped in 1994 and a new value has not been set. Check...

Table of Contents

Chapter 1 Natural Waste Treatment Systems An 1.1 Natural Treatment 1.1.2 Wastewater Treatment Concepts and Performance Expectations 2 1.1.2.1 Aquatic Treatment 1.1.2.2 Wetland Treatment 1.1.2.3 Terrestrial Treatment 1.1.2.4 Sludge Management 1.1.2.5 Costs and 1.2 Project Chapter 2 Planning, Feasibility Assessment, and Site Selection 11 2.1 Concept 2.1.1 Information Needs and 2.1.2 Land Area 2.1.2.1 Treatment 2.1.2.2 Free Water Surface Constructed 2.1.2.3 Subsurface Flow Constructed 2.1.2.4...

Lem Tec Biological Treatment Process

The LemTec Biological Treatment Process uses the LemTec Modular Cover to completely cover the system rather than a mat to retain duckweed (Figure 4.26). The process is still a lagoon-based treatment process composed of a series of aerobic cells followed by an anaerobic settling pond. Cells in series consist of a complete-mix aerated reactor, a partial-mix aerated reactor, a covered anaerobic settling pond, and a Lemna polishing reactor. The polishing reactor is aerated and has submerged,...

Design and Performance of Early Massachusetts Intermittent Sand Filters

Source Data from the Massachusetts Board of Health (1912) and Mancl and Peeples (1991). FIGURE 5.1 Cross-sectional and plan views of typical intermittent sand filter. (From Middlebrooks, E.J. et al., Wastewater Stabilization Lagoon Design, Performance, and Upgrading, Macmillan, New York, 1982. With permission.) FIGURE 5.1 Cross-sectional and plan views of typical intermittent sand filter. (From Middlebrooks, E.J. et al., Wastewater Stabilization Lagoon Design, Performance, and Upgrading,...

Surface disposal of biosolids

Standards (40 CFR Part 503) for the use or disposal of sewage sludge were published in the Federal Register on February 19, 1993 (Bastian, 1993 Crites et al., 2000 USEPA, 1994a). The regulation discusses land application, surface disposal, pathogen and vector attraction reduction, and incineration. Land application is defined as beneficial use of the sludge at agronomic rates, while all other placement on the land is considered to be surface disposal. Heavy-metal concentrations are limited by...

Hydraulics Of Subsurface Flow Wetlands

Darcy's law, as defined by Equation 7.1, describes the flow regime in a porous media and is generally accepted for the design of SSF wetlands using soils and gravels as the bed media. A higher level of turbulent flow may occur in beds using very coarse rock, in which case Ergun's equation is more appropriate. Darcy's law is not strictly applicable to subsurface flow wetlands because of physical limitations in the actual system. It assumes laminar flow conditions, but turbulent flow may occur in...

BOD Removal

The recommended approach to design for BOD removal in SSF wetlands is the volume-based detention time model, as expressed in Equation 7.13 As Q(lnQ - lnCe) KI(y)(n) (7.13) Average design flow (ac-ft d m3 d). Influent BOD concentration (mg L). Porosity of media (see Table 7.1). The temperature of the wastewater will affect the rate constant according to Equation 7.14 Rate constant at temperature T. 1.1 d-1. Most operational SSF wetlands in the United States have a treatment zone and operating...

Denitrification

Equation 7.16 to Equation 7.21 only account for conversion of ammonia to nitrate and predict the area required for a given level of conversion. When actual removal of nitrogen is a project requirement, it is necessary to consider the denitrification requirements and size the wetland accordingly. In the general case, most of the nitrate produced in a SSF wetland will be denitrified and removed within the area provided for nitrification and without supplemental carbon sources. FWS wetlands can be...

Industrial Wastewater Secondary Treatment

For industrial wastewater with BOD concentrations of 400 to 2000 mg L or more, the organic loading rate is often limiting. The procedure for process design is as follows 1. Calculate the BOD load from the concentration and flow where BOD load is the daily BOD load (lb d kg d) 8.34 is the conversion factor Q is the flow (mgd m3 d) and C is the BOD concentration (mg L). 2. Calculate the land area from Equation 8.10 where A is the field area (ac), and 100 is the limiting loading of BOD (lb ac-d kg...

Performance Data

Mean performance data for 13 BIOLAC systems are shown in Table 4.15, and monthly performance data are available in the USEPA (1990) report. All but the Along the Length of the Clarifier Hopper Bottom FIGURE 4.22 Cross-sectional view of integral BIOLAC-R clarifier. (Courtesy of Parkson Corp., Ft. Lauderdale, FL.) Along the Length of the Clarifier Hopper Bottom FIGURE 4.22 Cross-sectional view of integral BIOLAC-R clarifier. (Courtesy of Parkson Corp., Ft. Lauderdale, FL.) Summary of Average...

Conditions for Facultative Design Comparisons

Q design flow rate 1893 m3 day (0.5 mgd) Ce required effluent BOD 30 mg L T water temperature at critical part of year 10 C Ta average winter air temperature 5 C 4.2.6 Comparison of Facultative Pond Design Models Because of the many approaches to the design of facultative ponds and the lack of adequate performance data for the latest designs, it is not possible to recommend the best procedure. An evaluation of the design methods presented above, with operational data referenced in Table 4.2,...

Nitrogen removal in lagoons

Praxair Danbury

The BOD and suspended solids removal capability of lagoon systems has been reasonably well-documented, and reliable designs are possible however, the nitrogen removal capability of wastewater lagoons has been given little consideration in system designs until recently. Nitrogen removal can be critical in many situations because ammonia nitrogen in low concentrations can adversely affect some young fish in receiving waters, and the addition of nitrogen to surface waters FIGURE 4.27 Praxair...

Volumetric Process Design Model

Ce Wetland effluent concentration (mg L). C0 Wetland influent concentration (mg L). Kt Rate constant at temperature T (d-1). 8 Temperature coefficient at 20 C. Tw Average water temperature in wetland during period of concern ( C). A, Treatment area (bottom area) of wetland (m2). Qa Average flow in the wetland (m3 d) (QIN + QOUT) 2. y Average depth of water in the wetland (m). n Porosity of the wetland ( as a decimal). Note (1) The effluent concentration (Ce) cannot be less than the background...

Thermal Aspects

The actual thermal status of a SSF wetland bed can be a very complex situation. Heat gains or losses can occur in the underlying soil, the wastewater flowing through the system, and the atmosphere. Basic thermal mechanisms involved include conduction to or from the ground, conduction to or from the wastewater, conduction and convection to or from the atmosphere, and radiation to or from the atmosphere. It can be shown that energy gains or losses to the ground are a minor component and can...

Commercial Lagoon Nitrification Systems

Chairs For Marcway Turnouts

Lagoon nitrification systems offered commercially include ATLAS-IS Internal clarifier system by Environmental Dynamics, Inc. CLEAR process SBR variant by Environmental Dynamics, Inc. Ashbrook SBR SBR system by Ashbrook Corporation AquaMat process Plastic biomass carrier ribbons by Nelson Environmental, Inc. MBBR process Plastic biomass carrier elements by Kaldnes North America, Inc. Environmental Dynamics, Inc. (EDI Columbia, MO) offers their Advanced Technology Lagoon Aeration System with...

Climatic Data Required for Land Application Designs

Condition Required Data Type of Analysis distribution Frequency Frequency Assess aerosol risk Length of frost-free period Direction, velocity Evapotranspiration Annual and monthly averages Annual distribution Source Adapted from Taylor, G.L., in Proceedings of the Conference of Applied Research and Practice on Municipal and Industrial Waste, Madison, WI, September chance of flooding in a given year by means of a black-and-white overprint. Other detailed flood information is typically available...

Organism Concentration in Wastewater and Downwind Aerosol

Wastewater Concentration (No. 100 mL) x 106 69.9 7.5 0.8 0.22 0.007 1.1 0.39 0.005 Aerosol Concentration at Edge of Sprinkler Impact Circle (No. m3 of air sampled) 2578 5.6 1.1 0.4 11.3 71.7 < 1.0 1.4 Source Sorber, C.A. and Sagik, B.P., in Wastewater Aerosols and Disease, EPA 600 9-80-078, U.S. Environmental Protection Agency, Health Effects Research Laboratory, Cincinnati, OH, 1980, 23-35. Aerosol particles may be up to 20 im in diameter, which is large enough to transport bacteria or...

Typical Pathogen Levels in Wastewater Sludges

Anaerobically Untreated Digested Pathogen (No. 100 mL) (No. 100 mL) The coarse-textured soils and high hydraulic loading rates used in SAT systems increase the risk of bacteria and virus transmission to groundwater aquifers. A considerable research effort, both in the laboratory and at operational systems, has focused on viral movement in SAT systems (Reed, 1979). The results of this work indicate minimal risk for the general case movement can occur with very high viral concentrations if the...

Municipal Wastewaters

Climate Responsiveness Sketches

Examples of FWS constructed wetlands are presented in Table 6.10. The selection of either FWS or SSF constructed wetlands for municipal wastewaters depends on the volume of flow to be treated and on the conditions at the proposed wetland site. As described previously, the SF wetland, because of the higher reaction rates for BOD and nitrogen removal, will require a smaller total surface area than a Municipal Free Water Surface Constructed Wetlands in the United States Municipal Free Water...

Terrestrial Treatment Methods

Typical design features and performance expectations for the three basic terrestrial concepts are presented in Table 1.3. All three are dependent on the physical, chemical, and biological reactions on and within the soil matrix. In addition, the slow rate (SR) and overland flow (OF) methods require the presence of vegetation as a major treatment component. The slow rate process can utilize a wide range of vegetation, from trees to pastures to row-crop vegetables. As described in Chapter 8, the...

Agricultural Runoff

Nonpoint runoff from cultivated fields adds pollution to receiving water in the form of sediments and nutrients, particularly phosphorus. The Natural Resources Conservation Service (NRCS) has developed a process for treatment and management of these runoff waters. A schematic diagram of the system is shown in Figure 6.5 components include an underdrained wet meadow, a marsh, and a pond in series. An optional final component is a vegetated polishing area. The combined concept is referred to as a...

Process Description

For engineering purposes, wetlands have been described in terms of the position of the water surface. The free water surface (FWS) wetland is characterized by a water surface exposed to the atmosphere. Natural marshes and swamps are FWS wetlands, and bogs can be if the water flows on top of the peat. Most constructed FWS wetlands typically consist of one or more vegetated shallow basins or channels with a barrier to prevent seepage, with soil to support the emergent macrophyte vegetation, and...

Inlet and Outlet Structures

Uniform influent distribution and effluent collection over the full width of each wetland cell in the system are absolutely essential. Uniform distribution is typically accomplished with perforated manifold pipes for both inlets and outlets. The size of the manifold and the orifice diameter and spacing are a function of the intended flow rate. For example, cell 1 at the FWS wetland in West Jackson County, Mississippi, is designed for an average flow of 0.6 mgd (2271 m3 d) and utilizes a PVC...

Aerosol Bacteria and Viruses at Pleasanton California Land Treatment System Using Undisinfected Effluent

Wastewater (number 100 mL) Upwind (number m3) Downwind (number m3) 10-30 m 31-80 m 81-200 m a ND, none detected system where undisinfected effluent was applied to the land. It seems clear that the very low aerosolization efficiencies (E) as defined in Equation 3.27 for sludge spray guns and truck-mounted sprinklers indicate very little risk of aerosol transport of pathogens from these sources, and this has been confirmed by field investigations (Sorber et al., 1984) Composting is a very...

Removal of BOD

As explained in Chapters 4 through 7, the biological oxygen demand (BOD) loading can be the limiting design factor for pond, aquatic, and wetland systems. The basis for these limits is the maintenance of aerobic conditions within the upper water column in the unit and the resulting control of odors. The natural sources of dissolved oxygen (DO) in these systems are surface reaeration and photosynthetic oxygenation. Surface reaeration can be significant under windy conditions or if surface...

Combined Sewer Overflow

Management of combined sewer overflow is a significant problem in many urban areas where the older sewerage network carries both stormwater and untreated wastewater. When peak storm events occur, the capacity of the wastewater treatment plant is exceeded in the past, this condition often led to a temporary bypass and discharge of the untreated CSO to receiving waters. Current regulations now prohibit that practice, and wetlands are being given strong consideration as a treatment alternative for...

Special Site Requirements for Discharge Systems

Proximity to a surface water for discharge, impermeable soils or liner to minimize percolation, no steep slopes, out of flood plain, no bedrock or groundwater within excavation depth Proximity to a surface water for discharge, impermeable soils or liner to minimize percolation, slopes 0-6 , out of flood plain, no bedrock or groundwater within excavation depth Relatively impermeable soils, clay and clay loams, slopes 0-12 , depth to groundwater and bedrock not critical but 0.5-1 m desirable,...

Ground Surface Aspects

The major concerns relate to the potential for the contamination of surface vegetation or off-site runoff, as the persistence of bacteria or viruses on plant surfaces could then infect people or animals if the plants were consumed raw. To eliminate these risks, it is generally recommended in the United States that agricultural land treatment sites not be used to grow vegetables that may be eaten raw. The major risk is then to grazing animals on a pasture irrigated with wastewater. Typical...

Sludge Management and Treatment

Approximately 6.9 million ton of biosolids were generated in the United States in 1998, and about 60 of it was used beneficially in land applications, composting, and landfill cover. It is estimated that, by 2010, 8.2 million tons will be generated, and 70 of the biosolids is expected to be used beneficially (USEPA, 1999). Recycling options are described in various documents (Crites and Tchobanoglous, 1998 Crites et al., 2000 USEPA, 1994a, 1995a,c). Sludges are a common by-product from all...

Metal Removal in Hyacinth Ponds

27.6 g L 457.8 g L 18.2 g l 12.8 g L 0.4 g L 0.8 g L 0.9 g L a Average of three parallel channels, with a detention time about 5 days. Source Kamber, D.M., Benefits and Implementation Potential of Wastewater Aquaculture, EPA Contract Report 68-016232, U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Washington, D.C., 1982. Excellent metal removals have been demonstrated in the type of constructed wetlands described in Chapter 6 and Chapter 7. Tests at pilot...

Sources of Site Planning Information

Natural Resources Conservation Service soil surveys Federal Emergency Management Agency (FEMA) maps National Oceanic and Atmospheric Administration (NOAA) U.S. Geological Survey (USGS) reports and maps Elevations, slope, water and drainage features, building and road locations Soil type, depth and permeability, depth to bedrock, slope Land use, water supply, sewerage systems Climatic data The land area estimates derived in this section are used with the information in Table 2.1 and Table 2.2 to...