Dr. Martin T. Auer MTU Department of Civil & Environmental Engineering Wastewater Treatment

The Clean Water Act ‘fishable-swimmable’ Total Maximum Daily Loads Technology-Based Standards Water Quality-Based Standards Discharge Permits (NPDES) yes no yes POTW Design

Federal Water Pollution Control Act Amendments of 1972 (The Clean Water Act) Technology-based effluent limits Water quality-based effluent limits Total Maximum Daily Loads (TMDLs) National Pollutant Discharge Elimination System (NPDES) Add Clark In A Watershed – Everyone Lives Downstream

Receiving Water Impacts River DO Model Q = 8 C = 0, 250, 100

Michigan NPDES Permit

Treatment Plant Design Design Model C in = 250 k = 0.1 V = 0, 250, 750

Aluminum Forming Battery Manufacturing; Cement Manufacturing; Coil Coating & Can Making; Copper Forming; Dairy Products Processing; Electrical & Electronic Component Manufacturing; Electroplating & Metal Finishing; Explosives Manufacturing; Fruit & Vegetable Processing; Ferroalloy Manufacturing; Fertilizer Manufacturing; Glass Manufacturing; Gum & Wood Chemicals Manufacturing; Ink Formulating; Inorganic Chemical Manufacturing; Iron & Steel Manufacturing; Leather Tanning & Finishing; Meat Products Processing; Metal Molding & Casting; Mining Operations; Nonferrous Metals Processing; Organic Chemicals, Plastic & Synthetic Fibers Manufacturing; Paving & Roofing Materials Manufacturing; Soap & Detergent Manufacturing; Petroleum Refining; Pesticide Manufacturing; Porcelain Enameling; Pharmaceutical Manufacturing; Plastic Molding & Forming; Pulp, Paper and Paperboard Manufacturing Timber Products Processing; Textile Mills Federally-Regulated Non-Domestic Sources

Chemicals Designated as Priority Pollutants (126) AROCLOR 1254 (industrial product; banned) BENZENE (industrial product) BENZO(A)PYRENE (asphalt roofing manufacture) CADMIUM (heavy metal; electric/gas industries) CHLORDANE (pesticide; banned or restricted) CHROMIUM (heavy metal; widely used in industry) DDT (pesticide; banned or restricted) ENDRIN (pesticide; banned or restricted) MERCURY (heavy metal; electric/gas and chemical industries) PENTACHLOROPHENOL (industrial chemical – wood products) TOLUENE (widely used industrial chemical) TRICHLOROETHYLENE (industrial solvent, degreaser)

What’s in wastewater? Waste  human feces and urine  food from sinks  soaps and other cleaning agents  runoff from streets and lawns  industrial discharges

What’s in wastewater? Water  lots of it!  Urinal - 1 gallon per flush  Toilet - 4 gallons per flush  Shower - 20 gallons per use  Overall - 55 gal/person/day

It’s mostly water! There are about 500 parts of waste in every 1 million parts of wastewater; that’s 500 ppm. It’s like trying to find this class at a sold out Packers game! H2OH2O

So what’s the problem? P SNOT: it’s not a pretty picture!

Composition of Domestic Wastewater ConstituentInfluentEffluent Suspended Solids BOD Ammonia Nitrogen Phosphorus Fecal Coliforms All concentrations are mg/L, except fecal coliforms which are colony forming units (cfu) per 100 mL.

Where does it go when you flush the toilet? This is really not something I’ve given a lot of thought to.

Collection Systems

Portage Lake Sewer System Hancock Houghton Franklin Sq. Super 8 MTU M&M Bldg. POTW P P G G G G P Surface; 30” 10’;36” Lake; 48” 20’; 48” Near Surface; 30”

Metcalf & Eddy Diurnal Variation in Wastewater Flow

Metcalf & Eddy Wet-Dry Variation in Wastewater Flow

Preliminary Treatment Overview (plant protection) Bar Rack or Screen or Comminutor Grit Chamber Flow Equalization from pumps or wet well to primary treatment

Preliminary Treatment: Bar Rack

Preliminary Treatment: Screen

Comminutor Preliminary Treatment: C

Preliminary Treatment: Grit Chamber

Preliminary Treatment: Flow Equalization The Henry Fork Wastewater Treatment Facility, Hickory, NC

Bar Rack or Screen or Comminutor Grit Chamber Flow Equalization from pumps or wet well to primary treatment Preliminary Treatment Overview (plant protection)

(Kiely, 1997) Primary Treatment (solids, sedimentation)

Primary Treatment – Design InOut vpvp The critical particle is defined as that particle will be captured prior to exiting the sedimentation tank. This particle, and all particles which settle more rapidly, will be retained. The critical settling velocity, v c, is that of the critical particle.

Primary Treatment – Design The design parameter for primary treatment is the surface overflow rate, which can be shown to be equivalent to the critical settling velocity, InOut

Primary Treatment – Design InOut V c, SOR v p1 The design objective then is to reduce v c (SOR) in order to capture the target particle. v p2 The steeper the slope, the higher the settling velocity

Primary Treatment – Design InOut vcvc v p2 v p1 This is accomplished by manipulating the tank residence time (  ) by changing the surface area (A), The steeper the slope, the higher the settling velocity

(Kiely, 1997) Primary Treatment – Design

Primary Treatment: Rectangular Clarifier

Primary Treatment – Circular Clarifier

Secondary Treatment (biological) Simple carbohydrates (a form of organic matter) are produced by plants through the process of photosynthesis. These are then converted to more complex carbohydrates and other forms of organic matter such as starches, fats and proteins. The sun’s energy, captured during photosynthesis, is stored in the chemical bonds of this organic matter. Organisms (from bacteria to humans) take up and metabolize organic matter to obtain the energy required to support life. In secondary or biological treatment, we utilize microorganisms to remove the dissolved and small particulate organic matter which would exert an oxygen demand if it were released to the environment. The waste (actually organic matter) is simply converted into another form (microorganisms) which can then be separated from the waste stream by settling yielding a clean effluent.

The Microbial Loop in Nature

Microorganisms in Secondary or Biological Treatment Source:

The Microbial Loop in Secondary Treatment

Secondary Treatment: Trickling Filter

Secondary Treatment: Trickling Filter Media Image Source: Wastewater Engineering, Metcalf & Eddy

Secondary Treatment: Trickling Filter Design Hydraulic Load (W h ) 4-10 m 3  m -2  d -1 Organic Load gBOD  m 3  d -1

Secondary Treatment: Rotating Biological Disks

Secondary Treatment: Activated Sludge

Activated Sludge: aeration (mechanical)

Activated Sludge: aeration (diffuser)

Activated Sludge Design: microorganism growth rate In the aeration tank, microorganisms take up food (soluble and particulate BOD) and grow, converting waste to microorganisms. Since the concentration of microorganisms in the aeration take is held constant, the ‘growth’ must be removed or wasted. The rate of sludge wasting (dX/dt) divided by the mass of sludge in the aeration tank is equal to the microorganism growth rate,

Activated Sludge Design: relation to BOD concentration Growth Rate (  ) Food (BOD) As the steady state food concentration in the aeration tank increases, the growth rate increases.

High  Low  Activated Sludge Design: growth phases High BOD Poor settling Low BOD Good settling

Activated Sludge Design: solids retention time The solids retention time (SRT) or sludge age is defined as the average time that a microorganism spends in the aeration tank and is equal to the inverse of the growth rate, Thus, the longer the SRT, the lower the growth rate, the lower the effluent BOD and the better the settling characteristics of the sludge. The design should seek to operate toward the upper end of the range of SRT values (2-20 days) to achieve the best removal.

Activated Sludge Design: food:microorganism ratio The solids retention time or sludge age varies with the rate at which the microorganisms are fed, i.e. the food:microorganism ratio, Low F/M ratios equate to high SRTs and generate the desired effluent characteristics (low BOD, good settling). Since S 0 and Q 0 are fixed and X must be maintained between some bounds, the design parameter becomes V, the volume of the aeration tank. Note, however, that there are practical limits on the volume of the aeration tank, requiring consideration of less ‘optimal’ treatment.

(From Kiely, 1997) Endogenous Growth Log Growth Declining Growth Activated Sludge: design and operation Design Operation

Activated Sludge: Plug Flow Configurations (From M&E) Plug Flow (Conventional)

Activated Sludge: Plug Flow Configurations (From M&E)

Activated Sludge: Plug Flow Configurations (From M&E)

Activated Sludge: Completely Mixed Flow Configurations (From M&E)

Activated Sludge: Completely Mixed Flow Configurations (From M&E)

Secondary Clarifier

Disinfection (UV light)

putrid: in a state of foul decay, as animal or vegetable matter putrescible: liable to become putrid Putrescible

Anaerobic Digestion: Biochemistry

Anaerobic Digestion: Reactors

Sludge Drying Beds

Belt Filter

Centrifuge

Multiple Hearth Furnace

Land Application The Madison Metropolitan Sewerage District provides wastewater treatment to villages towns and cities surrounding the Madison area lakes. Biosolids produced at the MMSD Nine Springs Wastewater Treatment Plant are recycled to agricultural land as a fertilizer and soil conditioner. Biosolids recycling practices are regulated by both USEPA and Wisconsin DNR to ensure that human and animal health are protected.

Recycling The Milwaukee Metropolitan Sewerage District has been marketing its biosolids as Milorganite, a fertilizer and soil conditioner, for over 80 years. Today, 55,000 tons of Milorganite are sold annually. Milorganite is produced by place dewatered sludge cake in massive dryers with a temperature gradient of °F at the inlet and °F at the outlet. This effectively inactivates viral and bacterial pathogens

Lagoons or Oxidation Ponds

Septic Tanks