what is a drawback to higher sludge ages, higher oxygen and lower F/M ratios? When the sun is out these organisms use CO2 from aquatic life to convert nutrients into complex sugars. Facilities in San Marcos and Houston were the first non-experimental activated sludge plants in the world. Constructed wetlands are treatment systems that use natural processes involving wetland vegetation, soils, and their associated microbial assemblages to improve water quality. The activated sludge process is a type of wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa.. Closed Channel Systems for Measuring Flow, Plants over ____ MGD must install instrumentation for continuous flow totalizing, The quantity of oxygen required to partially stabilize the decomposable organic matter in a waste stream, Lists the effluent limitations in TX permits, -Carbonaceous Stage (Conversion of organic carbon to CO2). Contaminants that enter a waterway from a single, identifiable source, Contaminants that enter a waterway from an unidentifiable source, (National Environmental Laboratory Accreditation Conference), Title 6 of TX health and Safety Code CHAPTER 502, the protection of personnel and the laboratory environment from exposure to infectious agents, A combination of facility design and operational practices to protect outside the lab environment from exposure to infectious material. Weir loadings cannot exceed how many gal/day per linear foot of weir at peak flow, for plants with flow 1 MGD or less? Lead to eutrophication of streams and lakes. Everyday wastewater from our homes, schools toilets, businesses and even factories goes down and flows into the City's sewer … Chemical Oxygen Demand. This stage of the feeding process includes many different materials that are given off (excreted) such as carbon dioxide, water, and nitrates. Found a large number of protozoa found after 24 hours of aeration. What is an issue with higher than required DO? -The weight of oxygen consumed per unit of time. Insufficient mixing can lead to _________. Regulation of discharges from point sources of pollution. Great volume in proportion to its weight. clarifier solids loss problems that are not associated with sludge bulking include: -activated sludge has a high volume to weight ratio. The treatment organisms collect waste products to use as their food supply. Destroys or inactivates pathogenic (disease causing) bacteria, viruses and protozoa. treated sewage flowing out of the sewage treatment plant is known as the final sedimentation chamber in the aerated sludge process, Greece can conveniently be removed from the sewage in the They stabilize most of the organic matter, and found mostly in activated sludge floc. Bacteria are the primary worker organisms, usually composing 70-90% of living material present. If failed to remove by skimmer, it will show up in effluent. these particles show in clarifier overflow as ash or pin floc. Sewage sludge is a product of wastewater treatment. in the aeration system, an RAS … Fixed smear is stained with (1) crystal violet, (2) an iodine solution, (3) a decolorizing agent, such as alcohol, and (4) safranine. There are three kinds of sludge: sewage sludge from municipal treatment works, septage pumped from septic tanks, and industrial sludges. The result is how many pounds of excess biosolids are produced per pound of BOD. -4.5 pounds of oxygen required to oxidize 1 pound of ammonia to nitrate. Heavy metals, organic chemicals, Ammonia, chlorine, or chlorinatio by-products, cyanides, phenols, acids, bases. Self-nourishers, which synthesize cell materials from simple inorganic compounds and minerals, and use energy from the sun or chemical reactions. saturation deficit that affect oxygen transfer. Convert nitrate into nitrogen gas while using organic carbon as a food source (Denitrification, occurs in anoxic conditions). -Decant the clarified water, and send it to disinfection. Reduces the shock load on a plant. Shows how organisms respond when a batch food is introduced into their environment. science test. 2.2 Sewage Sludge Incineration There are approximately 170 sewage sludge incineration (SSI) plants in operation in the United States. The sludge resulting from this process represents the next challenge for the water treatment industry, in particular the minimizing of its volume. (both are very rare), Major indicators of healthy activated sludge. will not settle unless trapped by floc. O2/ lb BOD = (Pounds Oxygen Applied/Day) / (Pounds BOD5 removed/day), Oxygen Applied Rates/day (Mechanical Aerators), Oxygen Applied Rates/day (Diffused aeration), ft3 O2/ lb BOD5 = [Million ft3 / day] / [Pounds BOD5 removed /day]. The clump may contain millions of bacterial cells along with the food supply and other solids that may have been collected. 20,000 gal/day per linear foot of weir at peak flow. Their food is the dissolved and suspended organic matter. A PDF of the CWA from the U.S. Senate, as well as a summary, are available. Determines the consistency or repeatability of analytical measurements (Run duplicates to assess precision), A measure of the nearness of an analytical result to the true value. -They use starved intracellular polyphosphate for energy to store soluble COD and release it for energy requirements. The inorganic solid fraction in MLSS is biologically inactive and consists of sand, silt and clay particles or it is minerals that are a necessary part of the cellular matter of the living organisms. It comes from homes, hospitals and businesses – anything flushed or dumped down the drain. Secondary sedimentation to remove suspended matter from the oxidized effluent. the flow is circular around the turbine, so work best in circular basins or rectangular basins with semicircular ends. -Heavier solids will settle and be removed by underflow. What is the typical range of RAS solids concentration? Many complex biochemical reactions must occur for utilization. -Measure of how many gallons of flow pass over the clarifier overflow weir each day (gallons per day per linear foot of weir). Where can you find TCEQ's safety specific information? Ciliated protozoa include free-swimming, stalked and crawling. The longer solids can settle, the concentration will increase. concentrations of bugs, oxygen and food are uniform throughout the AB. -Particles initially settle independently, but flocculate as they descend in the clarifier. Removes solids that readily settle or float, using the force of gravity and the density difference between the water and solids to substantially reduce the solids content of the wastewater. -large populations can lead to poor settling and poor compaction of sludge, causing slime, -spiral-shaped bacteria that have flexible walls and are capable of movement, -Cyanobacter species, blue-green algae. Houston's Northside plant became operational in 1917 (10 MGD). When F/M is high, the rate of deamination exceeds nitrification. Five mechanical systems required to operate an activated sludge plant are: -Mechanical aerator, such as surface aerators, horizontal rotors, jet spargers, or submerged turbine aerators. They take in organic material and DO and convert these materials into new organisms, energy, CO2 and H2O. AB detention time for a Two stage nitrification plant? What role do bacteria play, and what is their % in a WWTP? -TSS (mg/l) = [(ending weight (g) - beginning weight (g)) * 1,000,000] / [mL sample]. -Influent is mixed and aerated while mixing with the RAS. Highlights of the "Ocean Dumping Ban Act of 1988" (S. 2030) as passed by the House and the Senate TITLE I - OCEAN DUMPING BAN ACT OF 1988 (Amends the Marine Protection, Research, and Sanctuaries Act, commonly called the "Ocean Dumping Act"). -MLSS is aerated in a short (40 min- 2 hour) period prior to separation of the solids in the final clarifier. Results when nitrates are converted to Nitrogen gas in the bottom of the clarifier, resulting in bubbles to lift the blanket. (creates supernatant), -Settling occurs as compression on the sludge blanket, due to its density (occurs once sludge blanket has formed), Depends on the area to volume ratio of the particle. If WAS is excess or RAS too little, there may be an insufficient amount of biomass to treat influent, so DO will be very high. Single bacteria are too light and small to settle. Grow individually and do not stick together. Start studying APES Review LAWS + ACTS. (Racetrack, stabilization channels, orbital channels, concentric channels, oval ditch, carrousel units, and multi-channel), -Primary treatment consumes 30-40% organic load. Crawlers dominate over stalked ciliates and fewer predator ciliates are found. The main stages of a typical sewage sludge incineration process are shown in Figure 3.6 and can be divided into four main parts: sludge pretreatment, combustion, energy recovery and cleaning systems. (Higher F/M, bugs are more active in eating, reproducing and growing). -floc on the inside and outside of the floc create an oxygen gradient, due to exposure differences, which result in higher oxygen demand in highlloading times. Mechanisms for transferring RAS from the sludge blanket to the Aeration basin: Return pumps must be capable of pumping ________ of the influent flow. Poor settling, cloudy supernatant high in suspended solids. Heterotrophic bacteria which use NO3 and/or NO2 as an electron acceptor for carbon oxidation. Discovered for nitrification to occur, alkalinity must atleast equal the nitric acid, The second was to keep activated sludge in contact with sewage during aeration, The final condition was to adjust the quantity of activated sludge to the quantity of sewage for maximum nitrification. WHAT IS SEWAGE SLUDGE? Per pound of CBOD, achieve 0.5 lbs of yield (average). Learn sewage with free interactive flashcards. -Swelling or bulging. -temperature, salinity, and surfactants (detergents) affect oxygen saturation concentrations and transfer rate. -used to find out why solids are settling slowly. -Flow retention from RAS, influent and recycle drain. Determined by dividing the oxygen uptake by the concentration of solids in the bottle. Use complete mix aeration basins. -nitrogenous demand is around 80% of CBOD demand. Glycogen Accumulating Organisms. Dead cells become food for living cells that are capable of degrading the components of the dead cells. Plants larger than 5 MGD must participate. In the F/M ratio, what is used as a measure of food (F)? Soluble food is absorbed through the cell wall, Occurs when special organic catalysts (enzymes) break the food products into simpler materials that can be used by the treatment organisms, Growth, Reproduction, and Respiration (Utilization). According to the EPA, how many plants (approximately) are not meeting BOD standards? WAS is sent to an aerobic digester, where solids stay for 15-30 days, then thicken by gravity or centrifugal force (belt press or centrifuge). Activated sludge, fixed film, and pond systems. used almost exclusively in oxidation trenches. Package plants often have a separate sludge holding basin (aerobic digester). This helps trap and filter particles from the water, producing a clarifier effluent free of turbidity. Consists of a flat converging section, a sloping throat with a known width, and a flat diverging section. -Influent is added to the heal of activated sludge left over from the last SBR cycle. using spins to determine the optimum %RAS, -SSCt = [AB conc * 1000]/ Settled volume over x time. What is the difference between Raw wastewater and Fresh wastewater? -Maintain a low blanket by increasing RAS rate. Bacteria, viruses, protozoa and other organisms that are responsible for causing disease in humans and animals. Digester buffering capacity is the ability of an anaerobic digester to resist pH changes and "survival mode". have slime material around the bacterial cells. Here are some examples of pollutants. The membrane component uses low pressure microfiltration or ultrafiltration membranes and eliminates the need for clarification and tertiary filtration. aeration demands for nitrification compared to CBOD removal. Used by microorganisms to make cell components (assimilation and growth) for reproduction (usually simple cell division, sometimes budding) and to produce energy for the chemical reactions occurring in the cell (metabolism). -Quick method to identify the potential for shock loading (high oxygen demand) in a wastewater influent. (Occurs between the draw and fill phases). -below 2 lbs/day/1000 ft3: Limited biological growth. What occurs when oxygen depletion is complete? Not much filamentous to bind flocs. Few microscopic animals. Further testing showed they could decant the supernatant and leave the solids in the tank until sent to wasting system. -The peak flow the clarifier can handle with carrying solids over the weir by hydraulic washout. what must take place before nitrifying bacteria can convert ammonia into nitrite and nitrate? Yeast exists as single, large cells with round, oval, or spindle shapes. (long skinny filament settles slower than small circular particle), Particles settle faster in warm water, which is less viscous and less dense than cold water, The number of gallons leaving the clarifier per square foot per day, The average time in hours that the flow stays in the clarifier, The number of gallons leaver the clarifier per foot of weir length per day, The number of pounds of solids applied to each square foot of the clarifier floor per day. E-Coli is fecal indicator for freshwater and Enterococcus is fecal indicator for saltwater. and/or abiotic processes), sorbed to sludge, or discharged in the aqueous effluent. Degradation results in the creation of breakdown products that can be either more or less toxic than the original compound. Oxidation ditches, many package plants and small activated sludge plants, Extended aeration plant operation (endogenous process), -No primary clarification, one AB per process train, Diffused or surface aeration, no separate digester, Components of Extended aeration package plants. How much suspended solids and BOD does effluent have after the primary treatment process? In activated sludge systems, bacteria are usually in which growth phases? Stationary and endogenous. -Fill: influent is added to RAS, or "heal" in the reactor (reversing the conventional activated sludge process, where RAS is added to raw). very tiny air bubble rising slowly through water has a high ratio of surface area to volume and a long contact time with water. The more surface area exposed, the slower the particle settles. Pin floc is not excessive. Fewer filaments bridge floc together. removed by skimmer, unless trapped by floc which will settle. Also keeps the rate of metabolism low by giving each bug a small amount of food. Used to determine the acute and chronic toxicity of the effluent to aquatic test organisms. 503.8 Sampling and analysis. Build proteins and nucleic acids (DNA, RNA). Microorganism population is too great for the amount of food. air is much higher in concentration than water, so oxygen wants to move to lower concentration. Microscopic animals are in larger numbers. It has been amended several times, most prominently in 1987 to increase controls on toxic pollutants, and in 1990, to more effectively address the hazard of oil spills. Nutrient requirements of the typical bacterial cell: Mass ratio used to assure adequate nitrogen, phosphorus and BOD removal. What solids are wasted when following a correct wasting schedule? -Assess the effect that a permitted wastewater discharge may have on the aquatic organisms in the receiving waters. -Rely solely on kinetic (uptake) mechanism, -Rely both on uptake rate and on ability to denitrify. -Collects the flow as it leaves the clarifier. Sewage sludge is a byproduct of water treatment plants and as you can imagine it’s plentiful. How much screenings and grit are pulled from each MG of influent? Will also affect the efficiency of the clarifier. When food is plentiful, growth and reproduction dominate. It could also be caused by any of the following: Small, fragmented floc (caused by excessively old sludge), Excessive flows (caused by I&I), Absence of protozoa (caused by toxicity or loss of oxygen), Dispersed growth of bacterial cells (during organic overload or start-up condition), approximately 90% of settleable solids, and 35% of the BOD. (Total lb/day BOD) / (Total flow X 8.34 lb/gal). -Biological process when Nitrate (NO3) is split into nitrogen gas (N2) and oxygen (O2) for use in respiration. (clark and gage 1914, 295). Supernatant will be very clear, practically without any visible particles. Hydraulic detention time affect on nitrification. These bacteria usually form when DO or nutrients are insufficient. Often results in solids going over the weirs of the clarifier with treated effluent. floc particles are physically separated and volume increases. The floc structure provides extensive surface for adsorption of food, oxygen and nutrients from the waste water. More solids in the system results in more competition for incoming food. (Thrive in composting). Amount of oxygen required by aquatic bacteria to decompose given load of organic waste; a measure of water pollution. 26 terms. May be passed through or only partially treated. Clean Water Act, from U.S. Senate, 33 U.S.C. Nocardia, Thiothrix, Sphaerotilus, Bacillus, Beggiatoa, Microthrix, Haliscomenobacter, Nosticoida, Leucothrix, Lineola, Flexibacter, Streptothrix, Vitreiscillaceae, filamentous organisms (common blue-green algae), -an exocellular polysaccharide (sugar polymer stored outside the cell) from nutrient deficiency, low DO, high F/M, or toxicity, when bulking is happening in clarifier, _____ RAS rate, -adequate but low MLSS concentrations (high f/m and lower sludge ages), caused by fire fighting foams or other surfactants; also by non-biodegradable detergent use. Advanced treatment processes may be necessary, along with effective industrial pretreatment programs. Heavy metals, acids, bases, pesticides, herbicides, phenolic compounds, and sulfides. Healthy sludge uses oxygen rapidly when food is present, but more slowly when food is absent. AB detention time for a Complete mix plant? Represents to number of milliliters that will contain 1 gram of solids after settling for 30 minutes: is the reciprocal of the SVI multiplied by 100. -The total alkalinity in a water which produces a pH above 4.4 (the M or methyl orange endpoint), and which reacts with mineral acids to produce a neutral salt. occurs during start-up, during young sludge conditions, or following hydraulic washout usually diminishes after several days; toxicity also causes this. (a micron is one-one thousandth of a mm), -Microscope equipped with an ocular micrometer. -Used to determine the activity of the microorganisms and to observe the number and variety of different bugs present. What does nitrogen do in living organisms? Highest form of wastewater treatment that includes removal of nutrients, organic and solid material, along with biological & chemical polishing. Three main types of incinerators are used: multiple hearth, fluidized bed, and electric infrared. reduce the quality of water for drinking, recreational uses, and commercial uses. -Measure of how well the mixed liquor actually thickens in the clarifier. More free bacterial cells. bacteria are very efficient, so not many bugs are required for treatment. Bacteria is storing food and reducing activity to survive. -Effluent quality improves with increasing protozoan populations. Dilute the sewage sample 1:10 and 1:100 in the buffered saline blank. -Combine activated sludge treatment with a membrane liquid-solid separation process. Provide the environment and adequate detention time for biosorption, utilization, and biological stabilization to occur. What is the fastest reproduction rate for bacteria? Floc is relatively large, irregular shaped, and varying density. (More accurate). Reduces specific contaminants, such as suspended solids, ammonia, or phosphorus, to very low levels in order to achieve strict effluent standards or to prepare the water for reuse. Sludge in the final clarifier seems to gain in volume and the sludge blanket slowly rises and finally escapes over the weir. -Waste concentration rate (WCR) : the ratio of weight to volume reflects changes in VSS. The concentration of food, microorganisms and oxygen changes as the flow proceeds down the basin. Or, the SVI30 in mL is divided into the total settleometer volume in mL. -Leads to ashing, clumping, and rising blanket. (lower BOD and TSS) Ex: ciliates, flagellates, and amoebas, Populations of protozoa affect on effluent, -High ciliated protozoans, good effluent quality, -Stalked ciliates: of the genera Vorticella, Epistylis, Zoothamnium, Carchesium, and Opercularia, Flagellates, swimming ciliates and Amoeba Protozoa, -Flagellates: genera Oikomonas, Bodo, and Cercobodo. Bartow and Mohlman found that domestic sewage with 20% RAS could completely nitrify to nitrite then quickly convert to nitrate in much less time (5 hours). -used to estimate suspended solids in samples taken from any part of plant. Temperature's affect on the biological growth curve. Thickening, digestion or stabilization, conditioning, dewatering, Disposal in landfills, application on farm land or forest land, incineration, disposal in lagoons, application for commercial purposes (30 TAC 312). Bacterial counting methods indicate only 3-115% of the mass in a typical activated sludge system is living. Number of cells are constant as they prepare for growth; no multiplication. These regulations adopt the "risk assessment approach" of the United States Environmental Protection Agency (EPA) and regulate land application of sewage sludge on the basis of sewage s… Occur when oxygen levels are very low or absent and nitrate is present, but when anaerobic (septic) conditions have not yet become established. Unsightly algae blooms, nighttime oxygen depletion, and excessive bottom slime growths. grow optimally at very low oxygen levels. Bacteria are single-celled organisms which collect and breakdown organic materials into simpler products that can be used as food or released in to the environment (CO2, H2O, nitrates, phosphates and sulfates). Effects when food is limited to microorganisms? Frothing and foaming are associated with the use of the following: Frothing and foaming have increased due to: Methods to prevent and eliminate frothing and foaming, Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur, Potassium, Iron, trace elements in correct proportions. Common places WWTP microorganisms can originate from? These organisms feed on living bacteria and floc particles. Growth and reproduction slow, activity slows, and organisms die faster than they regenerate. How many parts of alkalinity are needed in the water to stabilize one part of ammonia? Equation for flow weighted composite samples, [Flow at time of sample X Total amount of sample needed] / [number of samples needed X Average flow]. About 2 to 4 times. Coarse or fine screening, Grinding, Grit Removal, Grease Removal, Pre-aeration, Flow Equalization, pH adjustment. Very young developing sludge, high F/M conditions, or nutrient deficiencies. Immediate and adverse effects within a short time of exposure, Gradual effects over a long time of exposure, Ideal temperature range for activated sludge. How are different weighted solids removed from clarifier? Issued by a state agency to achieve acceptable standards. large air bubbles have a low surface area to volume ratio and rise rapidly, which reduces oxygen transfer but increases mixing. Can be physical, chemical, biological or a combination of these. the loss of an electron (gain of an oxidation number). These bacteria stick together to form a strong, small, irregular-shaped clump. Aseptically add 1ml of undiluted sewage in each tube and E.coli young culture to tube 1 and mix the tube contents thoroughly. COD value is typically how much larger than BOD value? The heart of the activated sludge plant, where biological solids must separate by gravity settling, producing clear, clean supernatant. While sewage sludge is usually treated using a standard plan of action, it is extremely important to factor in aspects like the origin of the sewage, the treatment process used to reduce the sewage to sludge, as well as the possible byproducts that can be retrieved from it for further use before choosing a sludge treatment plan. The ratio of the amount of food applied per day to the inventory of biomass in the aeration basin. -if clean water at 20oC is aerated in an open container exposed to 1 atmosphere pressure (14.7psi), the oxygen level will rise till water is saturated with oxygen (9.17 mg/l). A measure of the oxygen-consuming capacity of organic matter present in wastewater. settles rapidly and does not pull smaller particles down, larger and lighter, due to high loading or low solids. -How many days a pound of solids stays in the AB, (30-min settled solids, mL/L X 1000) / (MLSS, mg/L). -Provide solids/liquid separation under quiescent conditions. -Bottom area of the clarifier that holds the settled sludge volume as it is removed by the RAS/WAS sludge flow. Sewage sludge is the solid, semisolid, or slurry residual material that is produced as a by-product of wastewater treatment processes. The general arrangement of an activated sludge process for removing carbonaceous pollution includes the following items: An aeration tank where air (or oxygen) is injected in the mixed liquor. The population of microbes in the treatment plant will shift, favoring the groups that adapt best to the new environmental conditions. -Sulfur Dioxide, Sulfite compounds, activated carbon or hydrogen peroxide is added after the chlorine contact chamber. T. Chalkley Hatton and William R. Copeland concluded that combining the Clark and gage experiments of 1912-1913 with the Manchester experiments of 1913-1914 in a warm laboratory would remove practically all turbidity from sewage, 15-30 mg/L nitrates, form granular sludge which rapidly settles, and reduces the number of bacteria to 96% or more. Moreover, the sludge becomes activated more readily at a temperature of 70F than at 45F. settles gently and uniformly, trapping smaller particles as it settles and compacts. The aeration pattern is altered to add more oxygen into the head of the aeration basin, where it is needed for the rapid biodegradation of waste material and less oxygen at the end of the AB, where only endogenous respiration is occurring. It receives the influent from the primary clarifier and RAS from the secondary (or final) clarifier. They use the oxygen bound in materials like nitrates, sulfates, phosphates and CO2 to supply oxygen for cell growth. - OM present in the sewage sludge is biologically converted to a gas containing 70% methane and 30% CO2 --- Done in an airtight reactor with a floating gas collector --- Methane can be burned for renewable energy and can used to maintain the heat of the building