Anotec Pig Production And Odours

Livestock farming: A General Overview of Swine Production, Odours & the Anotec ™ Solution Introduction Odours are among the most contentious of issues with regard to a piggery operation. Pig farms generate odours that the surrounding community may find offensive. Odours from a piggery are a complex issue involving processes within the piggery, in effluent collection areas, in storage ponds and manure spreading areas. The factors that contribute to the impact of an odour nuisance on a recipient include the frequency (F) of occurrence of odour impact, the intensity (I) or strength of the odour, the duration (D) of exposure and the offensiveness (O) or character of the odour (Artis 1984, Bulley and Phillips 1980). These terms are collectively described as the FIDO factors. Shed design, effluent collection and disposal systems, and overall piggery management will influence the rate at which an odour is generated. The impact of generated odours will be influenced by the climate and topography. Location, design and good management practices aim to prevent odour problems with nearby residences.

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Let’s Start Off with the Site

A suitable site is probably the most important factor for a successful system. The following points should be noted: •

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Soil type sho uld be light and free draining to avoid damage by tractors and poaching by stock in the winter. Sandy soils on top of chalk or gravel are ideal. Very thin soils that blow or those with very sharp flints should be avoided. Sites should be managed to avoid leaching of organic material and soil erosion that can cause problems in watercourses and on public roads. Annual rainfall should be below 750mm, though this depends on the soil type. Fields should provide natural shelter from the wind if possible and have flat areas for the siting of huts or arks. Fields should have good access for vehicles and be close to staff housing for security. Sites for outdoor sows are normally included in an arable rotation with pigs being moved every year or every other year, depending on soil type, stocking density and the arable management. At least two years should be left before pigs are returned to the same site. Sows can be moved onto stubble or bare soil, but established grass is preferred.

Feeding • •

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Sows are fed in groups with the feed distributed directly onto the ground. Sows are not individually fed, as this is not practical outside. Feed should therefore be spread over as wide an area as possible to help ensure each sow receives an adequate share and to minimise bullying. Common practice is to distribute feed in a line allowing at least two metres per sow. As individual rationing is not possible the average daily feed allowance is often higher to ensure all sows achieve an adequate intake so figures for feed used per so w are higher that those for an indoor herd. Extra feed should be provided in the winter. A good quality cob or ro ll will not break easily under foot and will reduce wastage. Food must always be put on a dry area.

Service Management Most outdoor herds choose one of the following service options: •

Boars may be house in individual paddocks with single sows introduced for service.

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Group serving. Groups of sows are introduced to a gro up of boars at weaning with the numbers of sows equal to the number of boars. They are introduced to the service paddock at intervals abo ut 3 - 4 days over a 2-week period and then the boars are rested for 1 week. Boars operating within this system need to be group reared. Overall boar to sow ratio for the herd is approximately 1:12. "Dynamic" or rotating service group. Sows are grouped together at weaning and fed ad lib. At oestrus they are moved into a large group according to their body size and condition. They are served within the group and stay there for about the first 10 weeks of pregnancy before being remixed into weekly groups. Typically a dynamic service group will contain 30 sows and 3 boars with 3 sows being added and removed each week. Mixing at oestrus helps to reduce aggression as the new sows are attracted to the boars. A "conventional" indoor system using supervised services with sows returned to the field after service.

In all cases boars should be run with groups of sows around 3 weeks after service to detect any returns. Management The management of sows kept outdoors requires different skills than for indoor systems due to the extensive nature of the system and the need to cope with extreme weather conditions. • • • • •

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Skilled staff that are fit and willing to work in all conditions are essential. Access to clean drinking water is essential. Adequate shade and wallows should be provided to avoid heat stress or sunburn in hot weather. Huts should be adequately bedded with straw at all times to ensure a warm dry lying area. Clear sow identification using large plastic ear tags, tattooing or electronic ear buttons is essential to ensure easy management and as a basis for recording performance. In traditional layouts, trailers most easily move sows. This can also be used as a mobile handling pen. Nose rings are often applied to prevent sows rooting and damaging the paddocks, but this practice raises serious welfare considerations. A single ring thro ugh the septum is preferred to reduce replacement requirements. Boars should not be rung. A preventative health programme for o utdoor sows should be drawn up in conjunction with a veterinary surgeon.

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Terminology So that we all know what we are talking about we had better agree on the terminology. The Agricultural Industry is endemic with different words meaning the same thing. Apologies if these are a bit basic for some:

Breeding Herd Sow - breeding female

Feeding Herd

Boar - breeding male Weaner - newly weaned pig Gilt - yo ung female Grower - pig not yet at sale weight Piglet - young pig with mother Porker - pig to be sold for po rk Farrowing - giving birth Baconer - pig to be sold for bacon Service - sow and boar mating Weaning - separation of sow and litter

Materials and Equipment •

Materials and equipment used in the construction of pig houses should not be harmful to the pigs and should be easily cleaned and disinfected.

Ventilation Systems •

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All automatic ventilation systems should include an alarm that gives warning of their failure and a back-up system that provides adequate ventilation in the event of failure. This can be either manual (for example, windows / doors) or automatic (for example, drop out panels). The alarm must be tested at least once per week and must be capable of working if the electric supply is cut off. The back-up system should be checked at least once per week and any faults with the alarm or back-up system must be fixed as soon as possible.

Automatic Equipment •

All automatic equipment, for example, feed augers and ventilation systems should be checked once per day.

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Any faults found with the equipment should be fixed as soon as possible. If the fault cannot be fixed immediately temporary measures should be taken to prevent any distress to the pigs.

Light • •

Pigs should not be kept in permanent darkness. The light provided could be either natural or artificial. If artificial light is provided this should be for a period equivalent to the period of natural light. This is normally between 9.00am and 5.00pm.

Stock Inspection / Sick Pigs •

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To check that pigs are in a state of well being they should be inspected at least once per day. Any pigs suffering distress or pain should be treated immediately. Any sick or injured pigs identified should, where necessary, be isolated in dry bedded pens. To avoid unnecessary pain or distress, veterinary advice should be sought as soon as possible for pigs that are not responding to the stock keeper's care.

Feed and Water • •

Pigs sho uld be fed a diet that is suitable for their weight and age. They should be fed at least once per day and fresh water should always be available in adequate quantities.

Floors •

Floors of pig houses should be smooth but not slippery and designed not to cause injury to the pigs.

Tail Biting •

All pigs, taking into acco unt the environment and stocking density, should be able to obtain straw or other material to satisfy their behavioural needs.

Boar Pens •

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Boar pens should be at least six square metres if they are to be used for living only. A larger pen is required if the pen is also to be used as a service area. Boar pens should be positioned so that the boars can see, smell and hear other pigs.

Teeth and Tails

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Tail docking and teeth clipping should only be carried out where there is or has been evidence of injury to the sow and / or pigs. Teeth clipping should be carried out within seven days of birth.

The Not-So-Simple Problem of Swine Odours For some, the problem seems simple: pigs stink. Why does it take a team of specialists to figure that one out? And the simple answer is, it hasn’t. We kno w, for instance, that a clean pig had about the same amount of body odour as a clean human being. And we know, in general, why the swineodour problem was suddenly finding its way into headlines and public debates. The main questions raised are: What are the primary sources and causes of odours from sw ine operations? How can those odours be reduced or made less offensive?

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The Complexities of Swine Odour How people respond: When we notice an odour from a swine operation, our noses have detected a complex mixture of gases, vapours, and dust. Often, this odorous mixture results as animal manure decomposes anaerobically--that is, when bacteria that do not use oxygen slo wly degrade them. The familiar smell of ammonia and the "rotten egg" odour of hydrogen sulphide gas can both result from anaerobic decomposition. However, the same anaerobic process also releases volatile fatty acids, whose odours people often find more offensive than either ammonia or hydrogen sulphide. In fact, some 150 volatile compounds have been found in swine waste. These compounds result from natural, biological reactio ns and include organic acids, alcohols, aldehydes, fixed gases, carbonyls, esters, amines, sulphides, mercaptans, and nitrogen heterocyclics. Many of these compounds are carried by airborne dust and other particles, some of which, in the confines of a swine house, may also contain pathogens or physical irritants. Odorous mixtures vary with location, the size and type of swine operation, production practices, season, temperature, humidity, time of day, and wind speed and direction. With so many compounds and environmental variables, it is often difficult to determine which compound--or combination of compounds--is giving offence. To complicate matters further, our sensitivities and reactions to odours are, like fingerprints--individual and specific. They are influenced by personal preferences, opinions, experiences, and the varying sensitivities of our olfactory systems. In this way, odour is something like sound: What some people hear as music, other people hear as noise. Whether people think of the odour as music or noise, many of those who live or work near a swine operation would like to turn the volume down. Odours can irritate, anger, or upset us, especially if we associate them with something threatening, unpleasant, or beyond our control.

Sources of Odours In general, the best odour-control system is a well-managed farm. However, many parts of the swine farm produce odours if they are not well managed and clean. Typically, odours from swine operations originate from one or more of the following sources:

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Buildings and holding facilities. If manure accumulates in swine houses or holding facilities, anaerobic decomposition begins and odours intensify. In open lots, uncontained odours from accumulated manure become intense during warm, wet weather. Buildings may also release odours, however, if manure builds up inside. As animals become dirty with urine, manure, and feed dust, their body heat radiates odour. Slatted floors can help separate the animals from manure and urine, but under-floor areas also generate odours unless they are frequently cleaned. There is evidence that collecting and storing manure in water, as in pit-recharge systems, reduces levels of ammonia and hydrogen sulphide gas in livestock buildings. Even so, these systems can release odours as the contents of uncovered pits and tanks are disturbed during pumping and flushing. Every part of a facility's wastehandling system produces odours if it is not kept clean. Many of the volatile fatty acids and other compo unds associated with odour attach themselves to dust. When dust from feed, dander, and other sources is allowed to coat animals, walls, and ventilation systems, virtually every surface releases odours. In a poorly ventilated building, these odours build up, and they may escape in a concentrated dose. Manure storage and treatment. In some countries, most animal wastes are flushed, washed, pumped, scraped, or otherwise removed from swine buildings, usually with water, and stored in lagoons. If lagoons are mature, large enough, and well managed, offensive odours will be reduced. During the start-up phase, which may last a year or more, some offensive odours will be generated until materials and biological processes stabilise. Even in mature lagoons, odours are released if raw wastes are added too rapidly or if a spring warming creates a thermal inversion, lifting material from the deepest strata toward the surface. Lagoon liquid used to flush pits or irrigate land releases a relatively mild odour if it is drawn from the uppermost, aerobic layer of the lagoon. But if pumping disturbs the deeper, anaerobic layers of a lagoon, offensive odours will result. Manure can also be stored as a liquid in concrete or metal tanks, open or covered, and in earthen storage and treatment basins. Without careful design and management, each of these systems generates odours. Land application. Typically, lagoon liquids are removed from lagoons during warm weather when they can be used to fertilize pastures, forests, or crops. But these are the same seasons when heat and humidity can promote the production of odour. If liquids drawn from lagoons have received adequate treatment, odour is not usually a problem during and after irrigation. Generally, because sludges remain in the lagoon for long-term storage and treatment, they are applied to land very infrequently. But when anaerobic sludges are spread across a field, odorous compounds may volatilise rapidly. Until the materials are dry and stable, volatiles rise and move off-site in the wind. Odours usually subside in one to three days, unless humidity is high or the layer of sludge is too thick. If the material is applied in a thin, even layer during dry, breezy weather and early in the day (between 8 a.m. and 2 p.m.),

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much of it will dry before the humidity increases during the late afternoon and evening. On some sites, land application can be managed so that the fields are downwind fro m nearby neighbours. Sludges and liquids may also be injected or incorporated into the soil--an effective but costly alternative to conventional methods. Carcass disposal. For example, a 1,000-sow farrow-to-finish operation may produce over 40,000 pounds of dead pigs annually. In some parts of the United States and Australia, most carcasses are disposed of by landfill, onfarm burial, rendering, or incineration. Decaying carcasses can release offensive odours if they are stored too long for disposal or pickup, or when they are transported. Each of the available options for disposal is problematic. Fees and restrictions on the use of landfills for animal disposal have increased so rapidly that this option is becoming infeasible. Incineration is costly in the equipment, fuel, and maintenance necessary to prevent odour and air pollution. On-site collectio n and burial presents the risk of disease and may threaten water quality, especially in nutrient-sensitive watersheds and in permeable soils near water supplies. In addition, disposal practices other than rendering do not allow for any recovery or reuse of the carcass as a nutrient resource. The swine industry may need new options for disposal. Measures and Thresholds If we assume that eliminating all odours from swine operations is neither practical nor necessary, we are left with a difficult question: How much odour is too much? Recent research indicates that odours outside swine farms are intermittent and often may result from barely detectable levels of compounds--often in the parts-per-billion range. Even so, the human nose is very sensitive, and an odorous compound does not have to be very strong to raise an objection. The extreme variability of sources, causes, environmental facto rs, and human response makes it difficult to measure swine odours or determine some objective limit for odour emissions. The problem is compounded by the fact that an odour's offensiveness does not always correspond to its intensity. For instance, odours produced by agitating anaerobic slurries have been judged very offensive, even at low intensities, while odours ventilated from swine houses have been judged less offensive, even at much higher concentrations. Despite these complications, measures and thresholds are possible and necessary, especially for odour monitoring and correction. In the effort to improve facilities and management practices, measures enable experts to establish goals and bases of comparison and give the formulators of Anotec ™ Odour Control Products (OCPs) an indication of what treatment would be most effective. By using gas chromatography and other sophisticated analytical techniques, it is possible to identify many of the various chemical constituents in an odour sample. Although we get information regarding each individual component and its concentration, the GC analysis does not reveal which of the components or mixtures of compo nents are responsible for the

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odours perceived. Anotec ™ takes the view that an overall significant reduction in the entire concentration levels will result in a lower perceptible odour unit. Olfactometry conducted by using an olfactometer and a human panel gives us a good indication whether the odour control chemical Anotec ™ formulated is suitable. While no standard method has yet been developed for measuring and evaluating swine odours, several techniques have been used to evaluate odours from various kinds of livestock facilities. Because the human nose is the best available odour-detector, most of these techniques involve the human panels discussed previously. Panels evaluating the intensity of an odour typically assign numbers to odours in relationship to their magnitude. Panels ranking odours for their offensiveness usually do so using a numerical scale. Several devices have been used to contain an odour and present it to a panel. The simplest of these uses a cotton swatch. More elaborate tests use instruments such s the scentometer and the olfactometer, both of which dilute pungent air with odour-free air and the odour panel evaluates the different dilutions. A concentration of odorants that can be detected by observers is called the "detection threshold." Each of the methods for assessing odours is expensive and time consuming. Commercially available olfactometers can cost between $AUD15, 000 and $AUD140, 000. An odour panel using these instruments should include up to eight people, each of whom must be selected, trained, and compensated. Such panels may be best suited for helping set the thresholds of certain odorous compounds, or for calibrating the instruments used in odour measurement. But panels may be too costly for use in routine testing and monitoring. While no single method or technology is likely to account for all of the variables affecting our response to an odour, objective measures are nevertheless useful. With them, the swine industry would be able to respond to clear standards, design better facilities, and improve management practices. Anotec ™ also believes that chemical analysis is mandatory when determining the best available formulation for the treatment of all odorous emissions.

A Role for New Technologies Stringent regulations in several European countries have, in some cases, led to waste-management and odour-control systems mo re advanced and elaborate than those in the United States and Australia. However, in Europe, producers generally recoup the cost of those systems in the higher prices paid for pork. In some parts of the world, then, society has been willing to pay more for its food in order to ensure cleaner water and air. For industry, consumers, and government there is a mutual interest in the development of cost-effective new technologies for reducing odour. And the benefits of these technologies are likely to extend beyond odour reduction

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alone. Since most agricultural odour problems are also waste-management problems, their solutions are likely to affect odour and water quality, energy conservation, and nutrient management as well.

The Search for Solutions Measurement of Odours Because of the costs and variables involved in using human panels to measure odour, a number of devices have been tested for their ability to measure odours electronically. Here, in Australia, for instance, scientists are developing an electronic device that senses para-cresol, which is sometimes regarded as an "indicator chemical" in swine odour. In general, however, research in Western Europe supports the general agreement among U.S. scientists that there are no reliable chemical indicators for odours caused by complex biological materials such as manure. In addition, odorous compounds are interactive, not additive, in their effect. That is, the combination of several odorous compounds may create a unique odour and not several odours perceived independently. Even so, the difficulty of measuring odours has not prevented the use of thresholds and standards in Europe, and the European Economic Community is moving to ward a common standardised procedure for the measurement of odour. In Germany, thresholds based on the use of olfactometers have withstood legal challenges. And in the Netherlands, ten certified laboratories apply a standardized procedure for measuring odour - at co nsiderable cost. The Netherlands has also adopted a new "Green Label" code for environmentally friendly housing for animals. To qualify, the facility must not exceed the threshold for ammonia emissions. Anotec ™ has since adopted the Dutch Standard for Olfactometry – Forced Choice Method. While ammonia is neither the only source of odour nor the most offensive, studies in Europe consistently find that measures to reduce ammonia generally do reduce odo urs from other compounds as well. In land application of manure, for example, when Anotec ™ 0307 reduced ammonia emissions by 75% it was found to reduce the overall odour by >98%. The biological sources of ammonia--the digestive by-products of microbes--also yield other odorous compounds. Drying or acidifying animal wastes stops microbial action, preventing the production of odorous compounds. However, when microbial action ceases, so does the reduction and transformation of nitrogen, and thus more nitrogen remains in the wastes. Sources of Odour: Where is it coming from? Recent studies have shown that no two pig farms are the same. Ho wever, it was somewhat surprising to be able to pin point the odour source, or rather the main contributors to the overall odour problem. When investigators compared odours from different pig farms, several trends emerged. Locations at the ventilating fans used with under-floor and tunnel systems yielded the highest levels of odour. Even so, levels measured around the buildings using these systems were generally lower than levels taken

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around roof-ventilated buildings. Lagoons produced levels of odour roughly comparable to those around the houses. Generally, odours were lower around buildings using under-floor or tunnel ventilation than around buildings with roof ventilation. Anotec ™ usually collects air samples for GC analysis and at times samples for Olfactometry. The latter samples are presented to an odour panel, which rate odours by their intensity and characterise each sample using descriptive terms. It was determined that at each of the sampling sites, odours were intermittent. Levels of odours tended to be highest during early morning and evening when air turbulence was reduced and air movement approached laminar (smooth) flow. In most samples, odours at 20 metres downwind from the site were very faint (three to nine times above threshold). On one occasion, however, a constant and invariable wind carried odour directly from a site's ventilation fans to the sampling site 20 metres away. Without eddying currents to dilute and disperse the odour, levels rose to 27 times higher than threshold. It was heartening to see that treatment with the Anotec ™ 0307 formulation; the levels of odorous compo unds detected were extremely low. The analysts had difficulty acquiring samples with enough molecular mass to be analysed chemically (using a gas chromatograph and mass spectrometer). No hydrogen sulphide was detected above 0.5 ppm, the limit of the detection method. At the minute levels sampled, the odorous compounds were unlikely to be toxic to humans. Dietary Amendments: What a great idea! When it comes to odour, not all swine manures are created equal. The odourcausing potential of fresh manure varies among pigs and their diets. Because nitrogen is a key ingredient of ammonia and many other odorous compounds, it is generally true that the higher the nitrogen content of swine manure the greater its potential odour. In general, pigs excrete excess nitrogen when they ingest more protein than they can efficiently use. In some diets, amino acids are not in balance with the animal's requirements. In others, the source of protein used in the feed is poorly digested. Improving the conversion of feed can not only reduce odour but also lower feed bills, which represent about 60 percent of a swine operation's production costs!

Odour-Control Additives Many products are available for allegedly treating or preventing odours in animal facilities, manure storage tanks, and lagoons. Some of these products work and some do not. They are generally found in one of the following categories:

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Masking agents are mixtures of perfumes and solvents used to cover up an objectionable odour with a more desirable one. Counteractants are aromatic oils that cancel or neutralize an odour so that the intensity of the mixture is less than that of it constituents. Digestive deodorants contain bacteria or enzymes that eliminate odours through biochemical digestive processes. For example, sarsaponin can be added directly to lagoons, promoting microbial action. Adsorbents are products with a large surface area that may be used to adsorb the odours before they are released to the environment. Sphagnum peat moss, for example, has been found to reduce odour in some lagoons. Chemical deodorants are strong oxidizing agents or germicides. Germicides such as ortho dichlorobenzene chlorine, formaldehyde, and paraformaldehyde alter or eliminate bacterial action responsible for odour production. Oxidizing agents such as hydrogen peroxide, potassium permanganate, and ozone chemically oxidize odour-causing compounds. Each of these groups has its strengths and limitations. Masking agents and Counteractants, for instance, can be effective in the short-term storage of wastes. However, because these products typically are organic compounds that can be broken down by bacteria, most of them quickly lose their effectiveness in lagoons and tanks. Recently, aggressive marketing has increased the use of digestive deodorants. These products, which contain enzymes or bacteria or both, are advertised for their abilities to break down solids, reduce the release of ammonia, and conserve nitrogen. No one product affects all of the odourcausing compounds possible in swine manure, however. Unless the environments of lagoons and other waste-treatment systems are favourable, supplemental bacteria may die off or fail to reach sufficient numbers to control odour. Of the many products tested in the Netherlands and in Germany for their ability to reduce odours from manure slurries, none has proven reliably effective. Anotec ™ Odour Control Products (OCPs) are formulations based on the chemical analysis of odorous emissio ns and were developed by combining a few of the techniques that have been used over the years. A combination of odour counteraction, adsorption and air scrubbing via a misting system has proven to be the most effective treatment to date. Following is a very basic diagram and description outlining the action of an Anotec ™ molecule and an odour.

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ANOTEC ™ ODOUR CONTROL Mode of Action

Unlike masking agents, Anotec ™ Odour Control physically reacts with the malodour by destroying its intermolecular structure leaving behind the Anotec ™ array, which naturally biodegrades. It has been proven using quality precision instruments that have shown once the Anotec ™ odour control product has been applied, the concentration of the components in the malodour were significantly reduced and / or eliminated. The original malodour cannot reconstitute itself, becoming non-volatile Ideally, Anotec ™ Odour Control should be used where NEW odours are constantly being released or introduced. (i)

(ii)

(iii)

(iv) (v)

Malodour

Anotec ™ Molecule

(iii) & (iv)Anotec ™ Molecule disassociates the malodour molecule rendering it non-volatile. (v)The Anotec ™ molecule then biodegrades naturally.

Anotec ™ Odour Control works as an odour eliminator by combating each individual component within an odorous mix. This is the main reason why Anotec ™ Odour Control has been proven to be superior to any other odour control measures, which favour treating the malodour as a who le or concentrate on one particular constituent - such as ONLY hydrogen sulphide in a sewage gas emission. To date, all testing and removal efficiencies as calculated by the Environmental Science Program, ANSTO, has revealed that Anotec ™ Odour Control is successful in greatly reducing or eliminating malodours in areas such as sewage treatment facilities, rendering plants, ferro us and non-ferrous foundries, cooking facilities (exhausts), bitumen manufacturing, rubber plants, jewellery plating facilities, spray booths etc.

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To maximise the use of Anotec ™ Odour Control, we recommend that a thorough odour audit or investigation be carried out on-site to determine the economic and effective viability of such a treatment. Whilst Anotec ™ OCPs have been proven to be successful in the significant reduction and/or elimination, Anotec ™ maintain that it is advisable that its products are incorporated into an odour management program that includes issues such as housekeeping procedures and even other techno logies such as altering the diet of the livestock. Don’t forget about: Ventilation Research and experience confirm that each of the major carriers of odour (gases, dusts, and vapours) can be controlled, but only with the right ventilation. During winter, when buildings are closed and sometimes heated, producers sometimes hesitate to run the ventilation fans, knowing that heat will escape as the air is exhausted. It is especially in winter that ventilation should be constant. For example, a sow and litter produce about o ne pound of water per hour, or about three gallons a day, in the form of water vapour. Good ventilation helps to prevent condensation, dampness, mould, and the corresponding risks of disease or damage to buildings. It also prevents the build-up of noxious gases formed by the decomposition of stored manure and, in general, improves the environment for workers and pigs. A building's design and ventilation system greatly affect the movement of particles. For example, a building using sidewall ventilation can move large volumes of air, diluting the concentration of particles inside the building as well as in the air exhausted from the building. Ventilation systems that move particles into underfloor pits tend to trap them in the liquids, where they are removed to the lagoon for treatment. In the European countries, climate and environmental regulations dictate a building design and ventilation system somewhat different from those in the United States or Australia. To reduce energy demands, one European system draws air through ducts buried underground. In this system, the ambient temperature of the earth warms the air in the winter and cools it in the summer. (A similar system tested in the foundry industry worked quite well!). An Underslat Ventilation System An underslat ventilation system allows air to enter the building through slots and baffles that are continuous with the eaves, mixes with warm air before reaching the pigs, moves through the slatted floor into flush channels or manure pits, and is drawn through uniformly spaced openings into the plenum, from which it is exhausted. (Source: "Ventilation of Swine Buildings Using the North Carolina Underslat Ventilation System," L. Bynum Driggers. North Carolina Cooperative Extension Service, AG-132.) Properly managed, current technologies for ventilation help reduce odour and provide a more healthful environment for workers and pigs.

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There are also other designs that can improve the quality of the air in pig housing. One of these is the Netherlands Hepaq Environmental Pig House ™, created by Hendrix Feeds and the Plaques engineering firm. In this design, slurry is flushed out of the manure pit several times a day to limit odours and reduce the need for ventilation. In the slurry tank, viscous manure settles to the bottom. From there, it is transferred into storage for processing at treatment plants or application to land. Liquids from the slurry tank are treated by aeration then recycled for use in flushing. Excess liquid is evaporated using ventilation fans and outside air. The companies estimate reductions of 40 to 50 percent in the volume of manure, and 60 to 70 percent in the emission of ammonia, as compared to conventional Dutch systems. Note: separating liquids from solids generally lowers ammonia emissions and reduces treatment costs. Separating liquids fro m manure not only simplifies treatment but also enables the development of useful products. In one European system, for instance, a two-stage separator provides a solid (consisting of 65 percent dry matter), which is composted for use as a potting medium in nurseries. The liquid fraction is used as a fertilizer in hydroponic greenhouses. In Germany, solids are often composted and marketed as fertilizers and soil amendments. This practice has produced so much compost that the supply is exceeding demand. However, in Europe, not all swine wastes are treated on the farm. At some locations, wastes are trucked at producers' expense to remote farms for direct land application. At others, agricultural wastes are trucked to central plants for treatment along with municipal or industrial sludges. Because these plants are under pressure to prevent odour and reduce the volume of wastes applied to land, several technologies have emerged over the last two decades. In Denmark, for instance, one firm is using mechanical vapour compression to evaporate and purify water from industrial and agricultural wastewater. The system, which can separate swine wastes into dischargeable water and concentrated, nutrient-rich slurry, is being tested for on-farm use. The company involved estimates that three forty-foot modular plants plugged into the slurry pipe of a swine facility could process 20 to 30 tons of waste per day. Of course, each of the technologies discussed in this part of the document has some limitations, and some may not prove to be practical for sites locally. Also, while these technologies offer some advantages for odour co ntrol, they do not in themselves reduce the net amount of nutrients that must be managed in the system. Aerobic Treatment, in Brief Aerobic treatment uses air. Anaerobic treatment does not. Most lagoons, manure pits, and other facilities for handling swine wastes are anaerobic, because their submerged materials are not exposed to air. Like many other natural materials, bacteria that use oxygen can oxidise swine manure. These bacteria efficiently transform the manure into a chemically stable material, reducing both pathogens and odour. Some of these aerobic

© Victoria Zavras 2001

bacteria "digest" or oxidize carbohydrates to carbon dioxide and water. Others feed on organic substances and convert nitrogen compounds to ammonium. Still others oxidise ammonium salts to nitrites then nitrates in a process called "nitrification." For the purposes of odour control, the main advantage of aerobic treatment of wastes is that it does not produce the vo latile fatty acids and various other compounds associated with very offensive odours. The main disadvantage of aerobic treatment is that it generally requires power to aerate the materials. A number of researchers have presented evidence that treating swine waste aerobically can lessen its odour. Aeration promotes the gro wth of bacteria that can rapidly degrade phenol, p-cresol, volatile fatty acids, and other compounds. If the solids are first removed, slurries treated aerobically become more stable and produce fewer odours when they are subsequently stored and applied to land. Odour-Control Technologies A number of technologies for reducing odour have been developed for industries using or producing odorous compounds. These include scrubbers, incinerators, adsorbing units using activated carbon, condensers, catalytic converters, and biological filters. Generally, all of these systems incur significant costs in construction, operation, and maintenance, and so they have not been considered practical in swine production. As incentives for controlling odour increase, however, some of these technologies are being tested for use in agriculture. Currently, the least costly technology for removing odours from large volumes of air is the Anotec ™ Odour Control System. The system is identified as the Cirrus Range of engineered systems and is custom built to suit any areas, large or small, indoors or outdoors. The Cirrus system, a scientifically developed misting system, coupled with Anotec’s ™ OCPs, treats the odorous emissions that “scrubs” the malodour. This is turn means that there is a break down of the volatile compounds into their elemental state rendering them nonvolatile and thus non-perceptible to the observers and their neighbours. Anotec ™ OCPs can remove 90 percent or more of volatile organic compounds, creates no secondary pollution, and is efficient in treating low concentrations of odorants (less than 20 ppm). The Anotec ™ range of Odour Contro l Systems is capable of treating large volumes of emissions (such as fugitives) with great success. One rendering operation in So uthern New South Wales, Australia is using five such systems to reduce odour. These systems are treating the air tunnels in the centre of enormous concrete bunkers. Openings in the sides of the tunnels allow air to be forced through and treated at the exit point. These

© Victoria Zavras 2001

systems are not very expensive to construct, and are capable of removing 95 percent of the odours released from the plant. In the past Anotec ™ have tested various Anotec ™ systems for odour control in swine operations, but most of these systems were expensive and were susceptible to dust and clogging. However, the new system has been proven beyond a doubt that it is the most economical and advanced state of the art technology on the market today. In early tests, the system's operation has demonstrated an ability to scrub odour from large volumes of emissions, this in turn has led to the development of various Cirrus systems that accommodate small, medium and large emissions either outdoors or indoors. A similar system was tested in Malaysia using a two-nozzle system for a 600mm wide stack where Anotec ™ and researchers evaluated a pilot-scale system for use in treating the air exhausted from swine buildings. In the study, odorous air passed through a stack whereby the two nozzles treated it right at the exit point. Using gas chromatography and an odour-monitoring device, researchers evaluated the Anotec ™ System’s ability to reduce the levels of odorous compounds and found that there was an overall 95% reduction of the emissions. By its nature, odour is an elusive and complex phenomenon, and any steps we take toward odour reduction will no doubt be complicated by a number of variables. In so me cases, predictive models, both mathematical and physical, may help us account for this complexity and simulate the performance of various technologies before they reach the field. To this end Anotec ™ has been proven to be a wise choice, not merely for its significant effectiveness treating odorous emissions but because it complies with the BATNEEC (Best Available Technology Not Entailing Excessive Costs) policy the company has adopted. Informational: Odours are primarily a subjective response; there are few universally good or bad odours. People react to odours according to their attitudes and previous experience. This factor is usable by livestock operators as they maintain an image of responsibility and productivity. Operators of well-maintained and attractive facilities who have maintained a cooperative public attitude are seldom subjected to odour complaints. Odour frequently becomes an issue along with complaints of water pollution, flies, noise, and other issues when there is faulty site selection, improper facility design, or inadequate management. Compounds emanating from livestock buildings have never exceeded safe air standards and are not hazardous to humans. Under certain situations, such as manure pit agitation, however, dangero us gas concentrations can develop. Odours, therefore, are nuisance pollutants and, like other nonhazardous assaults on the environment, must be regarded accordingly. Important are intensity, duration, and frequency of detection. Within an agricultural community, it seems appropriate that livestock odours be occasionally

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noticed, but nuisance complaints result when intensity or frequency exceeds reasonable limits.

Principles of Odour Control.

Although odours seem mysterious and difficult to manage, the principles of odour formation and control are relatively few and straightforward. For an odour to be detected downwind, odorous compounds must be (a) formed, (b) released to the atmosphere, and (c) transported to the receptor site. These three steps provide the basis for most odour control. If any one of the steps is inhibited, the odour will diminish. Since odorous compound formation is generally the product of biological decomposition, steps to stop odour formation generally inhibit biological activity. Moisture reductio n is the most common technique. By maintaining a manure-covered surface in a dry condition (less than 40% moisture), anaerobic biological decomposition is generally halted; odours are most prevalent immediately following rainfall and when manure surfaces are allowed to remain moist over an extended period. Other inhibitors of biological activity of animal manure include chlorination, pH adjustment, and in nature, temperature control. Although odorous compounds may have formed in manure or manure storage systems, few complaints will be registered unless these compounds are allowed to escape into the atmosphere. The most common means of inhibiting the escape of odorous compounds is covered manure storage tanks. Covering inhibits the interchange of odorous compounds between the liquid surface and over lying atmosphere. Altering the chemical state of the compound of greatest concern may also reduce this interchange. For example, in regions where hydrogen sulphide is a major problem, the addition of lime or other alkaline material will reduce hydrogen sulphide volatility. This procedure should be tried on a small scale; however, to make certain the chemical adjustment will improve rather than worsen the odour problem. Another means of preventing odour is inhibiting transport of manure odour from the production and release site to the area where odour control is necessary. Odour transport has been inhibited in certain locations by the installation of Anotec ™ sprays that scrub the odorous materials from the air, and of barriers that cause more complete mixing of the odorous materials with Anotec ™ OCPs and odour-free air to achieve odour reduction and sufficient dilution. This approach has received only limited application with livestock production odours but is widely used in industry. Odour Control Techniques. Perhaps the most critical and effective means of reducing odour complaints

© Victoria Zavras 2001

occurs in the initial site selection. Although it is difficult to set definitive perimeters beyond which odour will not be a problem, a pork producer must seriously consider odour control as he selects a site. Sites near residential developments, commercial enterprises, and recreational areas are particularly prone to problems. A site may be ideally suited for livestock production in terms of transportation, feed supply, and zoning regulations, but may be inappropriate because of existing or proposed development in the area. There is a general relationship between the perception of odour nuisance, separation distance, and size of a swine production facility. For facilities of 1,000 or fewer animals the incidence of odour complaints is noticeably reduced beyond one-quarter mile. For larger units, separation distances of approximately a half-mile are necessary for adequate protection. Terrain is another factor to consider in site selection. Facilities in a confined valley are particularly prone to have odours drift down the slope with relatively little dilution. Such sites should be avoided if residences or other odour sensitive sites are down slope. Although wind direction is important in evaluating an odour control site, most locations have winds from several directions during the year. The simple location downwind of development is not sufficient. By referring to published data, one can estimate the percentage of time the wind will blow from the odour so urce to the point in question and thereby make a more rational decision concerning site suitability. Where distance alone is used as the criterion, it must be expected that odours can be transported in excess of a mile downwind under appropriate climatic conditions. If these conditions are sufficiently rare and the damage is slight, this might not be an inhibiting factor toward development. The seco nd opportunity for reducing odour problems occurs during the design and construction of a facility. By application of odour control principles, the probability of odour can be minimised. Designing outdoor lots that are well drained, watering systems that do not flow onto the lot surface, and runoff control facilities that are remotely located from areas of odour sensitivity will achieve some odour reduction. In modern, roofed housing units the methods of manure removal from the pens, manure transport, and handling are most important for odour control. Also, animals must be kept clean and dry. Among approaches for accomplishing this are slotted floors, flushing gutters, and frequent pen scraping. Covered storage tanks control odour release from stored manure. Where treatment is required and odour control is important, aerobic systems such as oxidation ditches and floating surface aerators, altho ugh more expensive, are effective to curtail odour emissions. The operation and management of a livestock production facility also offer considerable opportunity for odour control. Maintaining the operating systems is probably most important. Overflowing manure storage tanks, broken scrapers, leaking waterers, and ruptured retention ponds and dikes are among the most common causes of odour complaints.

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Anaerobic swine manure treatment lagoons are of special concern in odour control. Properly designed and managed lagoons are not free of odours but seldom cause an odour problem. However, overloaded or shock-loaded lagoons are more likely to have objectionable odours. Where multiple-celled lagoons are used, it is important that the cell or cells receiving fresh manure not be loaded in excess of the recommendations for your particular area. Anaerobic lagoon odours are most common in the spring and early summer when the water temperature warms and manure accumulated during the winter undergoes rapid decomposition. Another alternative is to add surface aeration sufficient to maintain the lagoon surface in an aerobic condition. Where practical, locate lagoons as far as possible from neighbouring residences, roads, and other odour-sensitive areas. Separation distances are particularly important when anaerobic lagoons are used. One helpful approach is to double the normal separation distances. This may make the selection of anaerobic lagoons inappropriate for larger (more than 1,000 head) facilities in other than the most remote sites. Shielding lagoons from view is also helpful. Disposal techniques and timing are also important for odour control. When manure is applied to cropland, a field downwind of neighbouring residences on that day is important. Morning application is more desirable than late afternoons, which limits drying time. Neighbours are generally most sensitive to odour problems in early evening when utilizing outdoor recreational facilities. When manure disposal is necessary and odour control is critical, immediate incorporation of the manure can effectively minimize odour complaints. Where soil is suitable and neighbours are particularly close, direct soil injection is a valuable technique. Going the full distance The above approaches generally provide great assistance to the livestock producer in coping with complaints of neighbours. When these techniques are not suitable, further steps must be taken. Although some are experimental and have no t received widespread acceptance, they are worthy of consideration. There are alternate waste treatment schemes that can be employed to reduce odour emission. These are generally more expensive but may be justified for larger enterprises or where site conditions or separation distances are such that conventional treatment systems release unacceptable levels of odour. These systems generally require more sophisticated design. Aerobic manure treatment systems are helpful. Most co mmon among these are oxidation ditches, aerated storage tanks, and aerated lagoons. By maintaining manure in an aerobic condition, odorous gas production is markedly reduced. For each of these systems it is important that adequate aeration capacity be provided and that management is sufficient to keep the equipment in top operating condition. Manure solids separation may be practiced ahead of each of these systems to minimize aeration demands. Anaerobic digesters similar to those used in municipal wastewater treatment plants may be used for swine waste treatment. Anaerobic digesters represent

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a significant initial investment and an ongoing operational demand; however, they provide nearly complete control of the odorous gasses being released. Some cost recovery can be effected where it is feasible to use the biogas being produced to an economic advantage. Digesters do not provide complete waste treatment, thus are most commonly coupled with some means of effluent storage, either with or without aeration. Flexible covers have been applied to anaerobic lagoons in situations where odour control is essential. These covers prevent uncontrolled escape of odorous gasses. The collected gasses may be burned or subjected to subsurface soil absorption. Lagoon covers require careful design to avoid premature weather damage and allow convenient gas removal. Odour generation The odour generated from piggeries is generally a result of the decomposition of manure. Odour from freshly excreted manure is generally less offensive than odour released from anaerobically decomposing manure. Decomposition of piggery wastes may occur either anaerobically or aerobically. The compounds produced will depend on the oxygen status of the waste and thus the process involved in the decomposition. Aerobic decomposition occurs under conditions where oxygen is available in the system. Under aerobic conditions, the main decomposition by-products will be carbohydrates, water and other compounds (eg. water soluble, inorganic nitrogen and sulphur based compounds) that tend to produce little odour (Elliot et al. 1978). Anaerobic decomposition occurs where there is no oxygen available to the system. Anaerobic decomposition is a slower and less complete process than aerobic decompositio n. Because anaerobic digestion is less complete, the byproducts yielded are more complex and subsequently tend to be more odorous (Elliot et al. 1978). Some of the by-products of anaerobic digestion, such as ammonia and hydrogen sulphide are strong odours that can be detected for a long distance from the source (Elliot et al. 1978). Other compounds released are odourless, such as methane. Odour dispersion When air carries an odour from the source, dispersion or dilution of the odour occurs. This results in a declining odour concentration with increasing distance downwind of the source. This reduction in odour concentration is dependent on the atmospheric stability at the time. Odour will not disperse and mix on a cold and still night as it would during a windy hot day. The stability criteria explain how such factors as the time of day, clo ud cover and wind speed affect odour dispersion. In simple terms, the lower the stability class (closer to A) the better the odour disperses and subsequently the potential for odour nuisance is less. (See Table next page)

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Pasquill's stability categories [Adapted from Pasquill et al 1983] Wind speed

Day time

At 10m

Night time

Incoming solar radiation

Cloud cover

m/s

Strong

Medium

Slight

Mostly overcast

Mostly clear

<2

A

A-B

B

G

G

2-3

A-B

B

C

E

F

3-5

B

B-C

C

D

E

5-6

C

C-D

D

D

D

>6

C

D

D

D

D

*Where A = best odour dispersion

Air scrubbing with Anotec ™ spraying equipment to reduce odour levels within swine buildings has been studied and is recommended for use most building designers that are unable to control odours within their units by other means. Anotec ™ Odour control chemicals are widely available. Extensive data exists concerning the effectiveness of the formulations in a variety of industries. Anotec ™ has been proven to be effective under specialised conditions; and other formulations have been developed for “routine” or “known” odours. The cost of using Anotec ™ odour co ntrol chemicals is variable depending on the type of formulation and vo lumes required, but generally they are an inexpensive alternative to masking agents or other “odour control” chemicals. Research has shown that “other” Liquid products are quoted at $10-20 per litre and solid forms at $1-15 per 500 gms. Anotec ™ products are available in a concentrated formulation at a cost considerably lower than those mentioned above. It is important that a trial be conducted with the Anotec ™ control chemical to make certain it operates to your satisfaction before you buy large quantities. Anotec ™ wet scrubbing of the exhaust air with its chemicals can significantly reduce odours (66-98%) and is inexpensive. Spraying the

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Anotec Oil Phase product onto the surface of a manure pit, carcass pit or waste pile to keep settled dust from going back into the air has resulted in a 70% reduction in odours.

Anotec ™ Odour Control Additives (OCAs) can be added to deep pits. Field tests have shown approximately a 32% year-round reduction in ammonia emissions by delivering Anotec™ in metered amounts to the pit surface in grow-finish buildings. Anotec ™ has the technology to incorporate other techniques that include perimeter spray systems and windbreaks to disperse the odours and shield the livestock enterprise from direct sight. These and other approaches have been tried and succeeded where odour control is especially critical and the additional cost is justified. An important effort involves being a good neighbour and trying to influence your neighbour’s attitude in a positive way. Practice good public relations by sharing some of the good things from your farm with neighbours. Invite them over for a barbecue!!

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Other ideas and techniques to assist you in your Quest for total odour control management. You can use an odour setback guideline under development at Purdue University to calculate appropriate setbacks. It is when your current facilities appear too close to neighbouring residences that you need to use best management practices and odour-reduction methods as recommended by Anotec ™ to reduce the odour impact of the facility on the neighbours. The table below provides the shortest and lo ngest distances estimated by the odour setback guideline for gestation sows and nursery pigs. These recommended distances were calculated with the maximum factors for building design and management, odour abatement, and land use. The effects of wind frequency and surrounding topography on atmospheric dilution are shown as the extreme cases of worst and best dispersion. Actual distances will depend on site-specific wind characteristics. The model provides setback distances in eight directions from the facility. Call Anotec ™ to arrange for access to the Setback program from Purdue University. Recommended Setback Distances Between Swine Buildings and Residential Areas. Number Of Head

Gestating Sows Dispersion Best Worst

100 500 1000 2000 3000 4000 5000 7500 10000

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Nursery Pigs Dispersion Best Worst

(m)

(m)

(m)

86 193 272 386 472 545 610 746 862

144 321 454 643 787 909 1016 1244 1437

48 106 150 212 260 300 336 411 475

(m) 79 177 250 354 433 500 559 685 791

Separation distance plays an important role in the dispersion of odours from piggeries. Sufficient distance should lie between a piggery complex and the property boundary (or nearest receptor) in order to ensure sufficient odour dispersal when the atmosphere is stable.

Installing vertical stacks or chimneys exhausting above the ridgeline could, in so me instances, better disperse exhaust odour. However, the method is only likely to be successful when houses are located very near the farm causing the nuisance. The tall chimneys are beneficial because of the high airflow rates in the summer and an Anotec ™ Odour Control System treating at the exit point will ensure total and effective odour control. Most importantly though, it is because of the summer months that the chimneys have to be insulated and secured with guy wires. The establishment of an automated meteorological station network to gather high quality data specific to a region.

Schematic drawing of a weather station that will enable high quality meteorological data to be collected and used in odour dispersion modelling applications for intensive livestock industries, as well as in support of research projects gathering emission data and in assessment of odour impact. (QLD Dept of Agriculture).

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Suggested management practices The measurement of odour generation rate and odour intensity is a developing science. The technology for odour measurement has not, in Anotec’s ™ opinion, been developed for its use as a regulatory tool. As such the suggested ideal management practices, as directly quoted from the QLD Dept of Agriculture, are to: Avoid excessive manure build up in piggery buildings and below floor pit areas. Have external open drains that are impervious, with non-earthen base and sides, which are kept clean and dry between uses. Manage ponds to ensure minimal crusting and an even effluent loading that does not exceed the design capacity of the pond system. Incorporate piggery solids (sludge and screenings) into the soil within 24 ho urs of spreading, where practical. Manage and site manure so as to avoid odour nuisances. Advise neighbours in advance of any management practices that may lead to odour nuisances. Other methods of reducing odour complaints The old saying “out of site - out of mind” works very well for piggeries. The planting of trees around existing piggeries or siting new piggeries in a wooded area will make them less obvious to the public and generally reduce the incidence of odour complaints. Properly planted tree buffers also have the potential to reduce odour detection at receptors by dispersing the odour. And, as discussed earlier in this document, it is also advisable to set up lines of communication with neighbours. Many odour complaints arise from disagreements and misunderstanding.

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Some Useful Terminology The standards for the terminology below are identified as ASAE S466, Nomenclature/Termino logy for Livestock Waste/Manure Handling Equipment and ASAE S292.4, Uniform Terminology for Rural Waste Management. The following definitions, also directly relative to lagoon management, have been taken from ASAE S466 and ASAE 292.4 with the permission of the American Society of Agricultural Engineers: Aerobic bacteria: Bacteria that require free elemental oxygen for their growth. Oxygen in chemical combination will not support aerobic organisms. Aerobic decomposition: Reduction of the net energy level of organic matter by aerobic micro-organisms. Aeration: A process causing intimate contact between air and a liquid by one or more of the following methods: (a) spraying the liquid in the air, (b) bubbling air through the liquid, and (c) agitating the liquid to promote absorption of oxygen through the air liquid interface. Aeration unit: A tank or lagoon in which sludge, wastewater, or other liquid is aerated. Anaerobic bacteria: Bacteria not requiring the presence of free or dissolved oxygen. Facultative anaerobes can be active in the presence of dissolved oxygen, but do not require it. Anaerobic decomposition: Reduction of the net energy level of organic matter by anaerobic micro-organisms in the absence of oxygen. Bacteria: A group of universally distributed, rigid, essentially unicellular prokaryotic micro-organisms. Bacteria usually appear as spheroid, rod-like or curved entities, but occasionally appear as sheets, chains, or branched filaments. Biochemical oxygen demand (BOD): The quantity of oxygen used in the biochemical oxidation of organic matter in a specified time, at a specified temperature, and under specified conditions. Normally 5 days at 200C unless otherwise stated. A standard test used in assessing the biodegradable organic matter in municipal wastewater.

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Biogas: Gaseous product of anaerobic digestion that consists primarily of methane and carbon dioxide. Chemical oxygen demand (COD): A measure of the oxygen-consuming capacity of inorganic and organic matter present in water or wastewater. It is expressed as the amount of oxygen consumed from a chemical oxidant in a specified test. It does not differentiate between stable and unstable organic matter and thus does not necessarily correlate with biochemical oxygen demand. Composting: Biological degradation of organic matter under aerobic conditions to a relatively stable humus-like material called compost. Denitrification: The reduction of oxidized nitrogen compounds (such as nitrates) to nitrogen gas or nitrous oxide gas. Detention pond: An earthen structure constructed to store runoff water and other wastewater until such time as the liquid may be recycled onto land. Sometimes called holding ponds or waste storage ponds. Detention time: The time wastes are subjected to a stabilization process or held in storage. Digestion: Usually refers to the breakdown of organic matter in water solution or suspension into simpler or more biologically stable compounds, or both. In anaerobic digestion organic matter may be decomposed to soluble organic acids or alcoho ls and subsequently converted to such gases as methane and carbon dioxide. Complete decomposition of organic solid materials to gases and water by bacterial action alone is never accomplished. Dissolved oxygen (DO): The molecular oxygen dissolved in water, wastewater, or other liquid, usually expressed in milligrams per litre, parts per million, or percent of saturation. Earthen storage basin: An earthen structure usually with sloping sides and a flat floor, constructed to store semisolid, slurry or liquid manure. Also called a waste storage pond. Effluent: The discharge of wastewater or other liquid, treated or untreated. Electrical conductivity: A measure of a solution's ability to carry an electrical current; varies both with the number and type of ions contained by the solution. Escherichia coli (E. Coli): One of the species of bacteria in the intestinal tract of warm-blooded animals. Its presence is considered indicative of fresh faecal contamination. Facultative bacteria: Bacteria that can use either free oxygen or reduced carbon compounds as electron acceptors (as in organic substrates like sugars, starches, etc.) in their metabolism.

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Fertilizer value: An estimate of the value of commercial fertilizer elements (N, P, K) that can be replaced by manure or organic waste material. Usually expressed as dollars per to n of manure or quantity of nutrients per ton of manure. Fixed solids: The portion of the total solids remaining as an ash or residue when heated at a specific temperature and time (usually 61600C or 111 20F for at least one hour). Food to micro-organisms’ ratio (F/M): The weight ratio of biodegradable organic matter (BOD) to micro-organisms. Flushing system: A system that collects and transports or moves waste material with the use of water such as in washing of pens and flushing livestock systems. Grassed infiltration area: An area with vegetative cover where runoff water infiltrates into the soil. Gravity separation systems: Structures, which utilise gravity to collect more dense particulate solids by allowing them to settle out of highly liquid manure. The structure may be of any shape but with a relatively shallow depth. Infiltration rate: The rate at which water enters the soil or other porous material under a given condition, expressed as depth of water per unit time, usually in millimetres per hour. Influent: Water, wastewater, or other liquid flowing into a reservoir, basin, or treatment plant, or any unit thereof. Lagoon: An earthen structure for the storage and biological treatment of wastewater. Lagoons can be aerobic, anaerobic, or facultative depending on their loading and design. Land application: Applicatio n of manure, sewage sludge, municipal wastewater and industrial wastes to land either for ultimate disposal or for reuse of the nutrients and organic matter for their fertilizer value. Leaching: (1) The removal of soluble constituents such as nitrates or chlorides from soils or other material by water. (2) The removal of salts and alkali from soils by irrigation combined with drainage. (3) The disposal of a liquid through a non-watertight artificial structure, conduit, or porous material by downward or lateral drainage, or both, into the surrounding permeable soil. Loading rate: The quantity of material added per unit volume or unit area per unit time. Mechanical solids separation: The process of separating suspended solids from a liquid-carrying medium by trapping the particles on a mechanical screen or sieve, or by centrifugation.

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Sedimentation tank: A unit in which water or wastewater containing settable solids is retained to remove by gravity a part of the suspended matter. Also called sedimentation basin, settling basin, settling tank or settling terrace. Seepage: (1) Percolation of water through the soil. (2) The slow movement of water through small cracks, pores, interstices, of a material. (3) The loss of liquid by infiltration from a canal, reservoir, manure tank or manure stack. It is generally expressed as flow volume per unit time. Settable solids: (1) That matter in wastewater that will not stay in suspension during a preselected settling period, such as o ne hour. (2) In the Imhoff cone test, the volume of matter that settles to the bottom of the cone. Settling basins: A relatively long-term separation structure, larger in size than a settling tank. Solids collection is by mechanical means once the liquids evaporate or have been drained away. Settling tank: A relatively short-term separation structure, smaller in size than a settling basin. The liquid is allowed to fully drain away for solids removal by mechanical means. Solids content: (1) The sum of the dissolved and suspended constituents in water or wastewater. (2) The residue remaining when the water is evaporated away from a sample of sewage, other liquids, or semi-solid masses of material and the residue is then dried at a specified temperature (usually 1030C for 24 h); usually stated in milligrams per litre or percent solids. Static inclined screen: A screen, mounted on an incline, over which manure passes as it flows by gravity from a top head box. The liquid passes through the screen due to its flow momentum and surface tension, while solids continue over and flow off the end of the screen. Surface aerator: A partially submerged impeller whose action results in vigorous agitation and air entrainment. The impeller may be mounted on floats in a storage structure with varying liquid levels or fixed in a constant liquid system. An electric or hydraulic motor coupled directly to the impeller may supply power. Suspended solids: (1) Solids that are in water, wastewater, or other liquids, and which are largely removable by filtering or centrifuging. (2) The quantity of material filtered from wastewater in a laboratory test, as prescribed in APHA Standard Methods for the Examination of Water and Wastewater. Vibrating screen: A circular or square shallow container with a replaceable screen bottom. The assembly is vibrated both vertically and horizontally. Manure flows into the container, where liquids pass through the screen and the solids are collected to the side of the container.

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Volatile solids: That portio n of the total so lids driven off as volatile (combustible) gases at a specified temperature and time (usually 6000C or for at least 1 h). Volatile suspended solids (VSS): That portion of the suspended solids driven off as volatile (combustible) gases at a specified temperature and time (usually 6000C for at least 20 min).

© Victoria Zavras 2001