UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN ACES 11 1 no. /5^<^ ■ ^Ml <■"'■■■' ^ * '^ ^ - - ' Designing and Managing Livestock Waste Lagoons in Illinois I US^A^f # ,y <- 'J u V.J -i^STTQF^li'n--":-'^' by Ted Funk, Georgios Bartzis, and Jonathan Treagust University of Illinois at Urbana-Champaign College of Agriculture Cooperative Extension Service Circular 1326 Designing and Managing Livestock Waste Lagoons in Illinois This circular was prepared by T. L. Funk, Extension Educator, Farm Systems, Cooperative Extension Service, College of Agriculture, University of Illinois at Urbana-Champaign, Jonathan Treagust, and Georgios Bartzis, visiting scholars, Silsoe College, Silsoe, England. Introduction 1 Types of Lagoons 2 Aerobic, anaerobic, and facultative lagoons Anaerobic single-stage versus anaerobic multiple-stage lagoons Design Constraints for Proper Operation 4 Federal, state, and local regulations Loading and sludge accumulation rates Frequency of dewatering Water supply and drainage Species and expected values of manure production Soil and location Finding the Recommended Volume 6 Minimum design volume Livestock waste volume Dilution volume Determining the volume Finding the Right Dimensions 10 Depth Length-to-width ratio Side slopes Other Construction Constraints 12 Designing the earth embankment Designing the inlet and outlet Open channel versus pipe Outlet to next lagoon Designing the pumping system Placement Selecting equipment Operation and Maintenance 13 Starting up Breaking a crust Inspecting the lagoon Removing sludge Testing fertility Controlling odor Dewatering the lagoon Guaranteeing safety Worksheet Examples 15 Bibliography 17 Q(,3o 7 Introduction "^C ^^ ^-fe \ Vfy Growing environmental concerns and stringent laws controlling disposal of animal waste and surface run-off make it more important than ever that today's farmers select the most appropriate waste-handling system. The type of system used will depend on economics, regulation, and the farmer's situation. Local factors such as cost, size and number of animals, soil type, and topography, and external factors such as regulations, climate, and proximity to housing must all be considered. Pit systems store manure until it is returned to the land. However, where land is scarce and leaching levels are high, these systems may present a pollution problem. Composting and the use of additives for decomposition are only convenient in small-scale intensive systems. Livestock waste lagoons, however, not only handle manure in the liquid form for convenience and low labor, they treat and stabilize livestock manure while meeting the requirements of state and federal law. Waste lagoon systems treat and store live- stock manure for disposal onto land. They also store waste water for irrigation and flushing. Systems can be compatible with irrigation equip- ment, and they have reasonable construction costs and minimal fly problems. Livestock waste lagoons do require periodic sludge removal and careful management to prevent the pollution of groundwater and the emission of powerful odors. To avoid problems with odor and sludge, lagoons must be large enough for sludge to decompose biologically. Lagoons must also be loaded gradually and consistently at the start, taking care to avoid overloading. Once in full operation, a lagoon must never be pumped below the minimum design volume. The minimum design volume is the volume the lagoon requires to ensure efficient bacterial action for continuous decomposition of livestock waste manure. Waste treatment efficiency can be improved by weekly agitation, though this can increase odor problems. This agitation can be performed by a tractor-powered lagoon pump. The sides of the lagoon should also be maintained by planting grass and mowing regularly. Types of Lagoons Aerobic, anaerobic, and facultative lagoons A livestock lagoon treats manure as a liquid, the manure having been diluted by wash water and runoff. The lagoon acts as a biological tank, decomposing the waste before it is utilized as a resource in the form of irrigation liquid. The biological reaction is achieved by either anaerobic bacteria (these bacteria are inhibited by oxygen), aerobic bacteria (these bacteria require oxygen), or facultative bacteria (these bacteria decompose the waste, with or without oxygen). To operate successfully, aerobic lagoons require shallow depths and large surface areas because the aerobic process requires huge amounts of oxygen and sunlight. This system is impractical for many farms because large areas of flat land have to be sacrificed to accommodate it. Aerobic lagoons do control sludge and odors better than anaerobic ponds, but they may need me- chanical aerators to do so. Anaerobic lagoons are most commonly used for livestock waste treatment. They can store, dilute, and treat high loading rates of livestock waste rather inexpensively with minimal labor and maintenance. The land area needed to con- struct such a lagoon is also relatively small, making the anaerobic lagoon practical for many operations. Facultative lagoons combine the benefits of anaerobic and aerobic decomposition. In the anaerobic process, some offensive gases may be emitted, leading to odor problems. An aerator can be used to make the top of the lagoon aerobic, reducing odors. ary cells where further treatment occurs through bacterial action and oxidation. In single-stage lagoons, there is no secondary treatment. The advantage of the secondary treatment is that it reduces undesirable odors, and it reduces the possibility that disease may be transmitted when the lagoon water is used for flushing gutters. The design volume required to construct a multiple-stage lagoon is approximately twice that of a single-stage lagoon. Construction costs can be cut by siting the two lagoons side by side so that they share a common wall. Operators often overlook the option of building a secondary cell, but the advantages may far exceed the costs, especially in areas that are close to residential buildings. Operators of single-stage lagoons who wish to benefit from the advantages of multiple-stage lagoons may add a second stage at least 50 percent of the size of the first lagoon. If the water in the second stage is going to be used for flushing, this size may be increased to 75 percent. This will leave the first stage at the minimum design volume and allow water to be taken only out of the second stage (Figure 2). Anaerobic single-stage versus anaerobic multiple- stage lagoons Anaerobic livestock waste lagoons are divided into two categories: single-stage lagoons and multiple-stage lagoons (Figures 1 and 2). In multiple-stage lagoons, the effluent produced in the first stage or cell is transferred to the second- Figure 1. Single-cell anaerobic lagoon Berm Length Safety Volume Emergence Spillway Inlet Pipe Depth Dilution Volume Livestock Waste Volume Minimum Design Volume SKETCH NOT TO SCALE Figure 2. Two-cell multiple-stage anaerobic lagoon Total Volume Inlet Pipe 1st Stage 2nd Stage Trickle Tube Emergence Spillway / Minimum Design Volume Optional Volume For Rushing SKETCH NOT TO SCALE Design Constraints for Proper Operation Federal, state, and local regulations Illinois law does not require a permit for a no- discharge system such as a livestock waste lagoon. Federal law does regulate agricultural pollution; certain laws prevent wastes from entering public waters and others prevent the emission of strong odors. Essentially, the law states that no effluent may be discharged unless the discharge is a result of a specified storm; and to accomplish this, the technology used must comply with the no-discharge limitations where it is economically and technically possible. If the system is built to discharge, a National Pollutant Discharge Elimination System (NPDES) permit is required. Current Illinois laws require that lagoons must be protected against excessive water from floods and storms. The standard used is a one-in-ten-year flood and a 25-year, 24-hour storm. Lagoons must have a "freeboard" or excess capacity adequate for such a storm. The law also prohibits building a lagoon within a ten-year flood plain. A lagoon cannot be sited within one-half mile of a populated area or within one-fourth mile of a nonfarm residence, although there are exceptions to this law. Lagoons must also be built on soil of low permeability, or they must be sealed against contamination of groundwater. Loading and sludge accumulation rates To load a lagoon, fill it with water from one-third to one-half of its total volume. Then add manure consistently and in increasing amounts until the total volume level is reached. While loading the lagoon, never allow the volume to drop below the minimum design volume. Use a highly visible post gauge marked at minimum design volume and safety volume levels so that these stages can easily be recognized (Figure 1 ). It is best to start a lagoon in the spring because warmer weather increases bacterial action; this activity helps to ensure correct operation of the lagoon and minimizes odors. Regular loading of the lagoon — daily or weekly — also protects against undesirable odors. In winter, when temperatures are low and waste decom- poses more slowly, it is best to store or land-apply as much manure as possible to reduce the load on the lagoon. Lagoon loading rates depend on the size, number, and species of animal kept and the latitude of the location. For example, a swine farm located in southern Illinois can load a lagoon with more waste than a farm in northern Illinois with a lagoon that is the same size. Because of this difference. Tables 1, 2, and 3 are provided to help determine the correct volume for central, north- em, and southern Illinois. The sludge accumulation rate of a lagoon varies with loading rates and is difficult to predict. Cattle lagoons accumulate sludge more rapidly than swine lagoons. If the manure contains bedding (bedding has a slow decomposition rate), the sludge accumulation rate will be higher. Measure the sludge accumulation rate at least once a year to assess the lagoon's efficiency. If sludge accumulates rapidly, pump it out and apply it to the land, either by incorporating or injecting it into the soil. Then refill the lagoon with fresh water to its minimum design volume. Frequency of dewatering The volume of water in a lagoon increases con- stantly due to surface runoff, water added from the livestock operation, and direct precipitation. When the lagoon's water line approaches the safety level, pump the lagoon down (dewater it). Some lagoons may need to be dewatered every six months to return them to the minimum design volume. Dewatering controls mineral buildup, prevents overflow, and reduces the amount of sludge. It also provides nutrients to crops. Various types of irrigation equipment can be used for dewatering. This process can cause odor problems, so try to dewater when the wind is blowing away from neighbors. Other factors that influence how often dewatering should occur are salt concentration and soil type. To a certain extent, the soil type of the area where the water is to be pumped affects dewatering. It may not be possible to dewater every six months if the land area is small or if the area is already high in certain salts or nutrients. Soil tests are advisable. Water supply and drainage When starting up a lagoon, allow clean surface water such as roof drainage and rainwater to fill the lagoon to the desired level. After the lagoon is filled to about one-third capacity, there may be a need to divert runoff water to reduce the filling rate. In an anaerobic lagoon, use enough water to maintain the minimum design volume depth. If less water is entering the lagoon because of low rainfall, the lagoon may need to be diluted with clean water to reduce salt concentrations. It is very important that the lagoon does not overflow, so gutter any extra water from roofs of buildings to channel it away from the lagoon. All water added to a lagoon before dewatering is the dilution volume, and for a specific length of time, this volume should be approximately equal to the livestock waste volume (Figure 1). Where surface runoff is inadequate, find a viable source of dilution water, such as water from ponds and wells. Species and expected values of manure production The design of a livestock waste lagoon is influ- enced by the quantity and composition of the manure entering it, which depends on animal species, age, stage of production, and the environ- ment. Published manure production values include not only feces and urine but also average amounts of waste water and other materials that find their way into the waste collection system. For ex- ample, a livestock waste facility for a swine nursery unit may have to handle three to four times as much waste as the actual feces and urine produced due to the large amounts of wash and waste water entering the system. Soil and location Lagoons should be positioned over nearly imper- meable soil that can seal the bottom and side walls. Soil Conservation Service and Cooperative Extension Service personnel can help determine a soil's suitability for lagoon siting. Remove and seal field tile lines that cross the site to prevent the lagoon from becoming a pollution hazard. Avoid sandy sites and sites close to limestone unless the lagoon is lined with clay or soil ce- ment. Liners can be used, but they are initially expensive and difficult to install. Over time, the lagoon seals naturally due to the buildup of animal waste in the form of sludge. When siting a lagoon, remember these important criteria. A lagoon cannot be within 200 feet of a water well unless the well is owned by the lagoon's owner. In this case, the lagoon can be as close as 75 feet to the well, but this situation is not recommended. For convenience, a lagoon should be downhill from the source of manure, and it should be far enough away from streams to prevent pollution. Finding the Recommended Volume A livestock waste lagoon should be large enough for efficient bacterial decomposition of a certain amount of diluted manure over a specific period of time. The total volume required equals the sum of the lagoon's minimum design volume, waste storage volume, and dilution volume. Figures 1 and 2 illustrate these four volume components for properly designed single- and multiple-stage anaerobic lagoons. Minimum design volume The minimum design volume is the volume the lagoon requires to ensure efficient bacterial action for continuous decomposition of livestock waste manure. The liquid level of waste in the lagoon should never drop below the minimum design volume. If this happens, decomposition will be poor and odor problems will occur. Livestock waste volume The livestock waste storage volume equals the total amount of waste produced by the livestock operation for a specific period of time. This volume will depend on whether the lagoon is dewatered once or twice a year. If a lagoon is dewatered once a year, the livestock waste volume will be double that of a lagoon dewatered twice a year. If coarse solids are removed from the liquid manure before it enters the lagoon, the total lagoon design volume can be reduced by up to 25 percent. Either a settling tank or a mechani- cal separator can remove solids from the liquid manure stream,- solids are then available for land application or perhaps composting. Dilution volume The dilution volume for any type of livestock waste lagoon in Illinois should be approximately equal to the livestock waste volume. The dilution volume includes all extra water such as building wash water, spillage from livestock watering devices, feedlot runoff, direct precipitation, and water pumped from a well or stream. Determining the volume Tables 1, 2, and 3 recommend total and minimum design volume for both single- and multiple-stage, one- or two-dewatering lagoons. Use the appropri- ate table for your particular location, and consult the left-hand column of that table for the type and weight of animal kept. Across from this column, find the minimum design volume and total volume values for single- or multiple-stage lagoons that are dewatered once or twice a year. Now find the total volume line, labeled "total," and look for the column that applies to your particular situation. There are two main choices: one or two dewaterings per year and single- or multiple-stage lagoons. The figures give total volume for single-stage lagoons and total volumes for each lagoon in a two-stage system. The number represents the volume of the lagoon in cubic feet; this figure must be multiplied by the number of animals at that given size. For different animals and different weights, all the volumes must be found and added together to give the grand total volume. The minimum design volume is also given as a guide for initial filling of the lagoon and for its pumping down. This figure is found in the row above the total volume labeled "mdv." The total volume does not include the safety volume,- this is taken into account in the dimensions given in Table 4. Table 1. Determining Volume for Lagoons in Central Illinois Weight, One dewatering Two dewater ings Single- Multiple-stage Single- Multiple-stage lb. stage 1st 2nd stage 1st 2nd Swine: cubic feet of lagoon volume ] per animal Nursery pig 35 mdv 48 44 13 48 44 12 total 75 44 40 62 44 27 Growing pig 65 mdv 88 82 23 88 82 23 total 140 82 75 114 82 49 Finishing hog 150 mdv 203 188 53 203 188 53 total 323 188 173 262 188 113 Gestation sow 275 mdv 372 344 97 371 344 96 total 592 344 317 482 344 207 Sow + litter 375 mdv 507 469 132 506 469 131 total 807 469 432 657 469 282 Beef: 500 mdv 750 625 251 750 625 252 total 1,090 625 590 920 625 420 750 mdv 1,125 938 376 1,125 938 378 total 1,635 938 895 1,380 938 630 1,000 mdv 1,500 1,250 500 1,500 1,250 504 total 2,180 1,250 1,180 1,840 1,250 840 1,250 mdv 1,875 1,562 626 1,875 1,562 630 total 2,725 1,562 1,475 2,300 1,562 1,050 Dairy: 150 mdv 264 225 75 263 225 75 total 412 225 225 338 225 150 250 mdv 440 375 125 438 375 125 total 688 375 375 563 375 250 500 mdv 880 750 250 878 750 250 / total 1,375 750 750 1,125 750 500 A 1,000 mdv 1,760 1,500 334 1,755 1,500 500 total 2,750 1,500 1,000 2,250 1,500 1,000 1,400 mdv 2,464 2,100 700 2,457 2,100 700 total 3,850 2,100 2,100 3,150 2,100 1,400 NOTE: mdv = minimum design volume; total = total volume. SOURCE: Values in this table are derived from Design and Operation of Livestock Waste Lagoons by D.D. Jones and A.L. Sutton, 1977. Table 2. Determining Volume for Lagoons in Northern Illinois Weight, One dewatering Two dewaterings Single- Multiple-stage Single- Multiple-stage lb. stage 1st 2nd stage 1st 2nd Swine: cubic feet of lagoon volume per animal Nursery pig 35 mdv 54 50 15 54 50 14 total 85 50 45 70 50 31 Growing pig 65 mdv 100 93 26 100 93 26 total 159 93 85 129 93 56 Finishing hog 150 mdv 230 213 60 230 213 60 total 366 213 196 297 213 128 Gestation sow 275 mdv 422 390 110 421 390 109 total 671 390 359 547 390 235 Sow + htter 375 mdv 575 532 150 574 532 149 total 915 532 490 745 532 320 Beef: 500 mdv 851 709 285 851 709 286 total 1,236 709 669 1,043 709 476 750 mdv 1,276 1,064 426 1,276 1,064 429 total 1,854 1,064 1,015 1,565 1,064 714 1,000 mdv 1,701 1,418 567 1,701 1,418 572 total 2,472 1,418 1,338 2,087 1,418 953 1,250 mdv 2,126 1,771 710 2,126 1,771 714 total 3,090 1,771 1,673 2,608 1,771 1,191 Dairy: 150 mdv 299 255 85 298 255 85 total 467 255 255 383 255 170 250 mdv 499 425 142 497 425 142 total 780 425 425 638 425 284 500 mdv 998 851 284 996 851 284 total 1,559 851 851 1,276 851 567 1,000 mdv 1,996 1,701 379 1,990 1,701 567 total 3,119 1,701 1,134 2,552 1,701 1,134 1,400 mdv 2,794 2,381 794 2,786 2,381 794 total 4,366 2,381 2,381 3,572 2,381 1,588 NOTE: mdv = minimum design volume; total = total volume. SOURCE: Values in this table are derived from Design and Operation of Livestock Waste Lagoons by D.D. Jones and A.L. Sutton, 1977. 8 Table 3. Determining Volume for Lagoons in Southern Illinois Weight, One dewatering Two dewaterings Single- Multiple-stage Single- Multiple-stage lb. stage 1st 2nd stage 1st 2nd Swine: cubic feet of lagoon volume i per animal Nursery pig 35 mdv 42 38 11 42 38 10 total 65 38 35 54 38 23 Growing pig 65 mdv 76 71 20 76 71 20 total 121 71 65 99 71 42 Finishing hog 150 mdv 176 163 46 176 163 46 total 280 163 150 227 163 98 Gestation sow 275 mdv 322 298 84 321 298 83 total 513 298 275 417 298 179 Sow + litter 375 mdv 439 406 114 438 406 113 total 699 406 374 569 406 244 Beef: 500 mdv 650 541 217 650 541 218 total 944 541 511 797 541 364 750 mdv 974 812 326 974 812 327 total 1,416 812 775 1,195 812 546 1,000 mdv 1,299 1,083 433 1,299 1,083 436 total 1,888 1,083 1,022 1,593 1,083 727 1,250 mdv 1,624 1,353 542 1,624 1,353 546 total 2,360 1,353 1,277 1,992 1,353 909 Dairy: 150 mdv 229 195 65 228 195 65 total 357 195 195 293 195 130 250 mdv 381 325 108 379 325 108 total 596 325 325 488 325 217 500 mdv 762 650 217 760 650 217 total 1,191 650 650 974 650 433 / 1,000 mdv 1,524 1,299 289 1,520 1,299 433 total 2,382 1,299 866 1,949 1,299 866 1,400 mdv 2,134 1,819 606 2,128 1,819 606 total 3,334 1,819 1,819 2,728 1,819 1,212 NOTE: mdv = minimum design volume,- total = total volume. SOURCE: Values in this table are derived from Design and Operation of Livestock Waste Lagoons by D.D. Jones and A.L. Sutton, 1977. Finding the Right Dimensions Depth Permissible depth varies widely according to site and location. Table 4 gives four different depths for each volume; build the lagoon as deep as possible w^ithout getting closer than 4 feet to the highest expected water table level. A deep lagoon provides reduced surface area, better mixing qualities, reduced odor emission, and a smaller shoreline for better mosquito control. The depths given include the 2 feet of freeboard needed for the safety volume. Length-to-width ratio After determining the volume of the lagoon and deciding on the appropriate depth, use Table 4 to determine the length-to-width ratio of the inside of the lagoon. For example, if a 350,000- cubic-foot lagoon is to be built 20 feet deep, the dimensions 1 75 feet by 200 feet can be derived by using Table 4. These dimensions were chosen to give a roughly square lagoon. Single-stage lagoons are usually square or circular, while multiple- stage lagoons may be more rectangular (Figure 3). The amount of space available will limit the lagoon's shape; it is important to allow for an 8- foot top width for the berm and space for the outside dry slope in addition to the dimensions derived from the table. Plan well ahead and think about possible extension in the future or adding a second stage if constructing a single-stage lagoon. Side slopes Table 4 assumes inside slopes of 2.5 to 1. Slopes that are steeper than this may require gravel riprap to stop erosion. If a dash appears in Table 4, the lagoon design is not possible because the slopes collide in the middle. Figure 3. Bam, feedlot, and multiple-stage lagoon Clean Water Diversion Flushing Tank ■'^U-'*-?^ Separator Sump Pit and Pump 10 Table 4. Interior Dimensions for Livestock Waste Lagoons Bank slope = 2.5:1; dimensions include 2-foot freeboard; all dimensions in feet, unless otherwise specified. 10 12 15 20 Volume Interior width Interior width Interior width Interior width 1,000s 100 150 200 100 150 200 100 150 200 100 150 200 cuft Interior length 10 46 - - - - - - - - - - . 20 64 50 - 63 - - 63 - - - - - 30 82 60 - 78 - - 77 - - - - - 40 100 71 - 93 68 - 90 68 - - - - 50 117 81 66 109 77 - 103 75 - - - - 60 135 91 73 124 85 70 117 82 70 103 - - 70 153 102 81 139 94 76 130 89 74 114 - - 80 171 112 88 155 103 82 143 96 79 125 - - 90 189 123 95 170 111 88 175 104 84 136 - - 100 207 133 103 186 120 94 170 111 89 147 - - 110 225 143 110 201 129 100 184 118 94 158 104 - 120 242 154 117 216 138 106 197 125 99 169 109 - 130 260 164 125 232 146 113 210 132 104 180 115 - 140 278 175 132 247 155 119 224 139 109 192 121 - 150 296 185 140 263 164 125 237 147 114 203 126 101 160 314 196 147 278 172 131 250 154 118 214 132 104 170 332 206 154 293 181 137 264 161 123 225 137 108 180 350 216 162 309 190 143 277 168 128 236 143 112 190 367 227 169 324 198 149 291 175 133 247 148 115 200 385 237 176 339 207 155 304 182 138 258 154 119 225 430 263 195 378 229 170 337 200 150 286 168 128 250 475 289 213 416 251 185 371 218 162 314 182 138 275 519 315 231 455 272 200 404 236 175 342 196 147 Interior width Interior width Interior width Interior width 150 200 300 150 200 300 Interior 150 length - 200 300 150 200 300 300 341 250 168 290 213 145 254 187 131 223 165 120 325 367 268 180 312 228 155 272 199 138 238 175 126 350 393 287 192 334 243 165 290 211 146 253 184 132 375 420 305 203 356 258 174 308 223 153 267 194 137 400 446 323 215 377 274 184 325 236 161 282 204 143 425 472 342 226 399 289 193 343 248 168 296 213 149 450 498 360 238 421 304 202 361 260 176 311 223 154 475 524 378 249 443 319 212 379 272 183 326 232 160 500 550 397 261 464 334 221 397 284 190 340 242 166 600 654 470 307 551 395 259 469 333 220 399 280 188 700 758 544 354 638 455 297 540 382 250 457 319 211 800 862 617 400 725 516 335 612 431 280 516 357 234 900 966 691 446 812 577 372 683 480 310 574 395 256 1,000 1,071 765 492 899 640 410 755 529 340 633 433 279 11 Other Construction Constraints Designing the earth embankment The top width of the berm around the lagoon should be at least 8 feet. When constructing the berm, allow an extra 10 percent for settling. If possible, the berm should be capped with topsoil and seeded to grass. The outside slope of the lagoon berm should be at least 3 feet of run to 1 foot of rise if animals will be grazing on the land and 5 to 1 if the area is to be mowed by a tractor. A safety volume or freeboard of 2 feet has been calculated into the dimensions in Table 4 to allow for unusually heavy rainfalls such as a 25- year, 24-hour storm. This precaution will usually prevent the lagoon from overflowing. A gravelled slope with a ratio of no more than 15 to 1 should also be included somewhere in the embankment design so that tractors will have access to the lagoon for dewatering, agitating, or mowing. Designing the inlet and outlet Open channel versus pipe. When a lagoon is sited below the source of waste, it is possible to use gravity to feed the lagoon and deliver the waste in either open channels or pipes. Open channels provide easy access for cleaning and have greater liquid-carrying capacity. They do, however, freeze in winter and may add to odor problems. Pipes can be used for a system that collects animal waste in a sump and pumps it to the lagoon. Eight- to 10-inch pipes with cleanouts and rigid joints are ideal to transport the waste. The inlet to the lagoon can be either above or below the water surface. Any inlet should project at least 20 feet into the lagoon and should be sup- ported every 8 feet. It should discharge into at least 3 to 5 feet of liquid depth. If the inlet is above the surface, it may freeze during winter. When it is below the surface, the system requires pressure to work properly and it may require daily cleaning with fresh water in isolated cases to control blockages. Outlet to next lagoon. In a multiple-stage system, the outlet or overflow to the next lagoon should be able to handle one-and-a-half times the peak daily inflow of waste. A typical overflow device is a 6-inch pipe (trickle tube) through the first lagoon's berm. The pipe is tilted 1 foot on an uphill slope so that the liquid enters the pipe I foot below the surface of the first lagoon. The pipe's submerged inlet keeps floating solids out of the second lagoon stage. Locate the trickle tube or outlet pipe as far away from the inlet pipe as possible. A T-tube may also be used to hold floating solids back. Designing the pumping system Placement. In many cases, it is necessary to use a sump pump to either pump the waste to a lagoon that is higher than the source or to pump waste to a site where it can easily be screened. A sump pit is used to collect the waste at a low point com- mon to all the animal confinement areas. A sump pump is placed in this pit to lift the waste to the screen or the lagoon. The sump pit must be large enough for a person to work in, and it should contain a device to close the inlet pipe while work is being done. The sump pit must never be entered until adequate ventilation has removed potentially lethal gases. Selecting equipment.Vse a commercial-grade sewer pump with either an automatic or a manual switch. Automatic switches include flotation, mercury, or pressure switches that are automati- cally activated when the sump pit is full. To minimize salt and crystal buildup problems around the pump and sump pit, a secondary pipe circuit may be included to flush a 30-percent hydrochloric acid solution around the pump to dissolve the salt. Also, use smooth-walled plastic pipes and as few joints and elbows as possible to help reduce salt buildup. Ground pumps correctly to ensure that a voltage differential does not encourage crystalline buildup. 12 operation and Maintenance Starting up Start up new anaerobic lagoons in spring or summer to ensure maximum bacterial reproduc- tion, waste digestion, and stabilization before cold weather. The first stage of the start-up procedure is filling the lagoon with clean water to at least one-third of its total volume. Sources of clean water may be nearby streams, lakes, wells, or directed surface runoff and roof drainage. The second stage of the start-up procedure is to gradually increase manure loading. Start by adding waste at one-fourth of the normal recom- mended loading rate during the first two months. Over the next two months, add half the normal amount; and over the fifth and sixth months, add three-fourths of the normal loading rate. After six months, the lagoon should be ready to receive the full loading rate of manure. Until the lagoon is ready, store the manure or apply it to the land. Odors may occur during start-up. If they become severe, decrease the loading rates or begin the start-up procedure again. Breaking a crust Sometimes solids float on the surface of the lagoon, forming a crust. This crust helps to maintain anaerobic conditions, keep temperature constant, and minimize offensive odors. Odors may be released when the crust is broken during pump-down. The crust should be broken and removed when it becomes more than 1 foot deep. To do this, pump liquid on top of it during agita- tion with a chopper-type pump. Inspecting the lagoon Inspect lagoons regularly to ensure odor control, overflow control, fly control, and proper lagoon operation. Mow grass and weeds around the lagoon's embankment to simplify inspection, decrease the organic loading rate, and discourage flies and mosquitoes. Keep trees from growing on the embankments; their roots may destroy the berm or leave root channels that seep. Use a permanent post gauge in the lagoon to determine volumes and de watering times. Removing sludge Remove sludge when the buildup occupies about one-third of the lagoon's total design volume. Sludge can be removed by using agitation, sludge pumps, a hydraulic dredge, or a dragline. It can then be disposed of with surface or large-bore sprinkler irrigation systems if enough dilution water is used. Semisolid sludge can be hauled with manure spreaders; diluted sludge can be irrigated directly onto land if there is no danger of damaging the leaves of a growing crop. Testing fertility Animal waste is high in nitrogen, potassium, and phosphorus. During lagoon operation, nitrogen is converted to ammonia, leaving a small amount of nitrogen in the sludge. Phosphorus accumulates in the sludge so little is lost; and most of the potassium remains in solution in the lagoon. Take representative lagoon samples regularly and analyze them before pumping the lagoon. Controlling odor Odor is one of the greatest problems associated with livestock waste lagoons. It usually seems stronger in the spring because the organic matter has not been completely digested during the winter. To prevent odor problems, use the correct start-up procedure, add the right amount of dilution water, and decrease the loading rates during winter and early spring. Lime and nitrates can be added, but they are an expensive and temporary solution. Several enzyme products, available as deodorants and disinfectants, can be used to treat lagoon odor. These products can be very costly; test them first by using the recommended dosage in a 5 -gallon container of lagoon liquid. Then prepare an 13 untreated sample of the same size. After a few days, compare the smell of the two samples to assess the product's effectiveness. When the problem is severe, plastic coverings over the lagoon can be an expensive but efficient method of odor control. Aeration equipment — for example, mechanical aerators — are effective, but they are initially expensive, have high operating costs, and require maintenance. Odor problems may be intense during the first two weeks after installation, but they should become less intense after a few months of operation. Dewatering the lagoon Pump the lagoon down to its minimum design volume when the water level reaches or is near the bottom of the freeboard. The type and size of the dewatering irrigation equipment depends on the size of the lagoon and the solids content of the liquid manure. It will also depend on the solids content of the waste water. Thus, the irrigation equipment can vary from 2-horsepower gasoline pumps with 1-1/4-inch black plastic pipe and lawn-type sprinklers to the "big-gun" sprinklers with large nozzles. The big-gun sprinklers require pressures up to 100 pounds per square inch and pumping rates up to 800 gallons per minute. An alternative for medium-sized systems is gated pipe laid on a contour. Tank wagons can transport fluids in capaci- ties ranging from 400 to about 3,000 gallons, but they are more expensive and time-consuming than irrigation systems unless the lagoon's volume is less than about 75,000 cubic feet. Tank wagons are commonly loaded with either cen- trifugal, vacuum, or helical rotor high-capacity pumps; and they can spread the manure evenly on both sides or one side of the wagon. Guaranteeing safety Lagoons are potentially dangerous places. Install fences around lagoons to prevent easy access and place warning signs at intervals around the fence. It is important to ventilate sump pits properly to prevent buildup of lethal concentrations of gases such as hydrogen sulfide, ammonia, carbon dioxide, and methane. Enter a manure pit only after it has been well ventilated. Make sure that anyone entering the pit has a breathing apparatus and that two people are on hand to pull out any- one who collapses. Keep open flames away from sump pits because methane is highly explosive. 14 Worksheet Example Example: A swine producer has 500 nursery pigs and 525 finishing hogs near Urbana. The producer wishes to construct a two-stage anaerobic lagoon that requires two dewaterings a year. The value shown, 82, gives volume of the first stage of a two-stage lagoon for each growing pig. Total will be 500 pigs x 82 cu ft/pig = 41,000 cu ft. Table 1. Determining Volume for Lagoonrin Central Illinois Weight, lb. The value shown, 49, gives the volume of the second stage of a two- stage lagoon for each growing pig. Total is 500 pigs x 49 cu ft/pig, which is equal to 24,500 cu ft. Two dewaterings Single- stage Multiple-stage 1st 2nd Swine: cubic feet of lagoon vaJume per animal Nursery pig 35 mdv 48 44 13 X 44 12 total 75 44 40 62\ s^ 44 27 / Growing pig 65 mdv 88 82 23 88 \82 23/ total 140 82 75 114 |82| 49 Finishing hog 150 mdv 203 188 53 203 188 53 total 323 188 173 262 EM I113I Gestation sow 275 mdv 372 344 97 371 / 344 i total 592 344 317 482 / 344 20^1 Sow + litter 375 mdv 507 469 132 506 / 469 13ll total 807 469 432 657/ 469 282 \ Beef: / 500 mdv 750 625 251 /-SO 625 252 \ total 1,090 625 590 /92O 625 420 \ 750 mdv 1,125 938 376 /l,125 938 378 \ total 1,635 938 895 / ' 1,380 938 630 ] 1,000 mdv 1,500 1,250 500/ 1,500 1,250 504 total 2,180 1,250 l,18c/ 1,840 1,250 840 1,250 mdv 1,875 1,562 616 1,875 1,562 630 total 2,725 1,562 1/75 2,300 1,562 1,050 Dairy: 150 mdv 264 225 75 The value shown, 188, gives the volume of the first stage of a two-stage lagoon for each finishing pig. Total is 525 pigs x 188 cu ft/pig = 98,700 cu ft. 263 338 438 563 878 1,125 225 225 375 375 750 750 75 150 125 250 250 500 1,000 1,400 mdv total 1,760 2,750 1, 1, mdv 2,464 2, total 3,850 2, NOTE: mdv = minimum design volume; total = total volume The value shown, 113, gives the volume of the second stage of a two-stage lagoon for each finishing pig. Total is 525 pigs x 1 13 cu ft/pig = 59,325 cu ft. The total volume for the first-stage lagoon for treating waste produced from 500 growing pigs and 525 finishing hogs would be 41,000 cubic feet + 98,700 cubic feet = 139,700 cubic feet. The total volume for the second stage would be 24,500 cubic feet -1- 59,325 cubic feet = 83,825 cubic feet. 15 Worksheet Example The producer requires lagoons that are approximately 12 feet and 15 feet deep respectively, due to the presence of limestone in the area. Both lagoons should also be roughly square to make maximum use of available space. The volume of the first lagoon is approximately 140,000 cu ft. At a depth of 12 ft, the most square dimensions would be 150 ft by 155 ft. 155 ft appears horizontally across from the required volume. Table 4. Interior Dimensions for Livestock Waste Lagoons Bank slope = 2.5:l,Ndimensions include 2-foot freeboard; all dimensions in feet, unless otherwise specified. -TT 12 15 20 Volume Interior ^ ^idth Interior width Interior width Interior width 1, 000s 100 150 \ 200 100 150 200 100 150 200 100 150 200 cuft Interior length - 10 46 - \ - - - - - - - - - - 20 64 50 63 - - 63 - - - - - 30 82 60 -\ 78 - - 77 - - - - - 40 100 71 - \ . 93 68 - 90 68 - - - - 50 117 81 66 \ 109 77 - 103 75 - - - 60 135 91 73 \l24 85 70 117 82 70 103 . . 70 153 102 81 )A9 94 76 130 89 74 114 - 80 171 112 88 19S 103 82 143 96 79 125 - - 90 189 123 95 17^ 111 88 175\ 104 84 136 - - 100 207 133 103 186\ . 120 94 170\ 111 89 147 - - 110 225 143 110 201 \ 129 100 184 \ 118 94 158 104 - 120 242 154 117 216 \ 138 106 197 \ 125 99 169 109 - 130 260 164 125 232 \l46 113 210 \ , 132 104 180 115 - 140 278 175 132 247 |155| 119 224 \ 139 109 192 121 - 150 296 185 140 263 164 125 237 \l47 114 203 126 101 160 314 196 147 278 172 131 250 \54 118 214 132 104 170 332 206 154 293 181 137 264 ki 123 225 137 108 180 350 216 162 309 190 143 277 ik 128 236 143 112 190 367 227 169 324 198 149 291 1^6 133 247 148 115 200 385 237 176 339 207 155 304 181 138 258 154 119 225 430 263 195 378 229 170 337 200\ 150 286 168 128 250 475 289 213 416 251 185 371 218\ 162 314 182 138 275 519 315 231 455 272 200 404 236 \ 175 342 196 147 300 325 350 375 400 425 450 475 500 600 700 800 900 1,000 For the second-stage lagoon, a volume of 83,825 ft is required at a depth of 15 ft. The figure across from this volume under the 15 ft depth, 143 ft, combined with an interior width of 100 ft, would give the nearest square dimensions. 393 420 446 472 498 524 550 654 758 862 966 1,071 287 305 323 342 360 378 397 470 544 617 691 765 192 203 215 226 238 249 261 307 354 400 446 492 334 356 377 399 421 443 464 551 638 725 812 899 243 258 274 289 304 319 334 395 455 516 577 640 165 174 184 193 202 212 221 259 297 335 372 410 290 308 325 343 361 379 397 469 540 612 683 755 211 223 236 248 260 272 284 333 382 431 480 529 146 153 161 168 176 183 190 220 250 280 310 340 253 267 282 296 311 326 340 399 457 516 574 633 184 194 204 213 223 232 242 280 319 357 395 433 132 137 143 149 154 160 166 188 211 234 256 279 16 Bibliography Ackerman, E.O. 1985. Ten reasons why livestock waste management systems fail. Peoria,IL: Illinois Environmental Protection Agency. 7\merican Society of Agricultural Engineers. 1985. Agricultural Waste Utilization and Management: Proceedings of the 5th International Symposium on Agricultural Wastes. St. Joseph, MI: ASAE. . 1990. Agricultural and Food Processing Waste: Proceedings of the 6th International Symposium on Agricultural and Food Processing Wastes. St. Joseph, MI: ASAE. . 1990. Design of anaerobic lagoons for animal waste management. ASAE Engineering Practice: ASAE EP403.1. St. Joseph, MI: ASAE. Illinois Environmental Protection Agency. 1992. Agriculture related pollution. State of Illinois Rules and Regulations, Title 35: Environmental Protection — Subtitle E: Agriculture Related Pollution — Chapter I: Pollution Control Board and Chapter II: Environmental Protection Agency. Springfield, IL: lEPA. Jones, D.D., and A.L. Sutton. 1977. Design and operation of livestock waste lagoons. Purdue University Cooperative Extension Service publication ID- 120 West Lafayette,IN: Purdue University Cooperative Extension Service Schneider, J.H. 1990. Advantages of multi-cell animal waste lagoons. American Society of Agricultural Engineers paper no. 90-4521. St. Joseph, MI: ASAE. Smith, R.E. 1983. Anaerobic lagoons — design and solids management. American Society of Agricultural Engineers paper no. 83-4068. St. Joseph, MI: ASAE. Soil Conservation Service. 1979. Waste treatment lagoon standards and specifications. USDA-SCS Technical Guide section IV, article 359. Sweeten, J.M., C.L. Barth, R.E. Hermanson, and T. Loudon. 1979. Lagoon systems for swine waste treatment. Pork Industry Handbook PIH-62. West Lafayette,IN: Purdue University Cooperative Extension Service. 17 Helping You Put Knowledge to Work Illinois University of Illinois Cooperative 3' Urbana-Channpaign Extension Service College of Agriculture Urbana, Illinois June 1993 Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. DONALD L. UCHTMANN, Director, Cooperative Extension Service, University of Illinois at Urbana-Champaign.The Illinois Cooperative Extension Service provides equal opportunities in programs and employment. V