Intensive animal operations including poultry houses, hog farms, feed lots, and dairies all have large quantities of manure that require handling and treatment. In highly stock enclosed houses, manure/waste accumulation can lead to problems with ammonia (gas form), hydrogen sulfide, and nuisance insects. In addition to acute animal health issues, the animal wastes have high levels of nutrients, organics, and enteric microbes that can negatively impact water quality downstream of the facility.
I have worked with several facilities to see if biological waste treatment techniques can help improve animal health in the high density houses and improve both manure handling and biological treatment. Through several years of studying the natural bioprocesses in the houses and feed lots, there are three main areas where biological waste treatment technologies can be used.
Ammonia & H2S Control in Houses
Manure accumulates on the house floors and rapidly releases ammonia in highly toxic gas form if the pH is above 8.0. The ammonia causes eye and lung irritation that can lead to both higher disease susceptibility and lower weight gain. In addition to ammonia, anaerobic conditions can promote anaerobic bacteria that produce hydrogen sulfide – an extremely toxic gas.
In recent trials, we have used select microbes and enzymes to initiate waste degradation in the house. The microbes have proven effective in keeping ammonia below critical levels (< 25 ppm) and keeping hydrogen sulfide under control. This technology works by initiating the manure degradation in the house a process which also helps lower enteric and pathogenic bacteria on the floors and bedding. It is important to select microbes that are effective at degrading animal wastes, producing extracellular enzymes, and have documented abilities to competitively exclude enteric and other pathogenic species in a working environment.
Manure Solids Reduction/Liquefaction & Fly/Insect Control
While the same microbes are used here as in ammonia control, the process of converting manure solids into liquefied form for pumping into treatment units or ponds. In houses with manure pits, the solids can buildup creating a crust. The crust becomes dry and provides an excellent insect breeding site. Under the crust, anaerobic activity creates odors and hydrogen sulfide. These pits can be treated with microbes to keep the crust from forming and to reduce the tendency of solids to buildup and crust on the pit. The bacteria are applied during pad washing and also through direct spray on the crust surface.
Manure Biological Treatment in Ponds/Lagoons
Following pumping from the houses and pens, the waste liquid is most often treated in ponds or lagoons with mixing/aeration. The goal in these ponds is to reduce the BOD5, ammonia, and fecal coliforms from being discharged. Often these ponds experience solids buildup that reduces residence time eventually compromising treatment efficiency. In this case, we have worked to optimize biological activity and improve mixing to suspend the solids. With the solids better suspended, microbes with high extracellular enzyme production can work to degrade the organic fraction of the solids thereby reducing sludge buildup on the pond bottom. We have often seen 3 – 4 feet of sludge decrease in volume to less than 1 foot during trials. The effectiveness depends upon the percent organic and entrapped water in the sludge along with the amount of mixing.
While we may not give much thought to biofilms, we interact with these microbial colonies everyday. In fact, there are biofilms on faucets, teeth, sinks/counters, and even our most often used appliances. Whenever you have biodegradable organics, moisture, and exposure to environmental bacteria; a biofilm will likely develop. While I usually talk about only waste treatment bacteria and associated biofilms, a recent interesting article appeared in Nature. Researchers at The University of Valencia in Spain examined multiple coffee makers and found a wide range of biofilm microbes. In fact, many of these microbes found are organisms commonly isolated from wastewater treatment plants. Study article appeared in Nature - http://www.nature.com/articles/srep17163.
Usually we consider amoebae protozoa as indicators of poor quality water as many amoebae tolerate low dissolved oxygen and can function well along with flagellates in which F/M ratio is relatively high. Once big exception to this rule is the testate amoebae which are usually much more easily seen in a microscopic exam; as the testate amoeba has a shell surrounding the true amoeboid organism inside the shell.
In wastewater the most common testate amoeba is from the Euglypha sp. (pictured below). This amoeba usually increases in number as soluble BOD falls below 40 mg/L and nitrificaiton is occurring. The testate amoebae population tends to trend upwards with longer sludge ages.
While usually seen with good water quality, the shell can remain visible after the amoebae is dead or inactive. Therefore, we should not rely on testate amoeba as a ideal indicator protozoa. For example, if you see testate amoeba as abundant but do not see activity of ciliated protozoa, there is a need to look further to see if any toxicity or other stress is occurring as the ciliates are much more sensitive to environmental changes than testate amoebae. Below is a photomicrograph of a Euglypha sp. testate amoeba at 400x phase contrast magnification.
Often operators increase MLVSS to decrease F/M to reduce aeration costs. Is this really what happens? Let's look at what happens biologically to derive an answer:
So what is the answer? Look at your system and biomass response to see the best MLVSS concentration for your waste stream. Increasing MLVSS to the far reaches of extended aeration reduces the oxygen consumption per individual bacterial cell but suspending the increased biomass and dealing with endogenous respiration oxygen demand cuts tends to consume the oxygen efficiency that was gained by moving to extended aeration.
In the USA, we often take clean water in rivers, lakes, and beaches as a given. However, even large bodies of water can become contaminated quickly with raw sewage entering the water. Besides the immediate potential for disease, the environment becomes less likely to support healthy animal and plant life. So what can be done to cleanup the water in Rio before the olympics? I would do suggest the following;
AP test: Rio Olympic water badly polluted, even far offshore RIO DE JANEIRO (AP) — Olympic sailor Erik Heil floated a novel idea to protect himself from the sewage-infested waters he and other athletes will compete in during next year's games: He'd wear plastic overalls and peel them off when he was safely past the contaminated waters nearest shore.
Heil, 26, was treated at a Berlin hospital for MRSA, a flesh-eating bacteria, shortly after sailing in an Olympic test event in Rio in August. But his strategy to avoid a repeat infection won't limit his risk.
A new round of testing by The Associated Press shows the city's Olympic waterways are as rife with pathogens far offshore as they are nearer land, where raw sewage flows into them from fetid rivers and storm drains. That means there is no dilution factor in the bay or lagoon where events will take place and no less risk to the health of athletes like sailors competing farther from the shore.
"Those virus levels are widespread. It's not just along the shoreline but it's elsewhere in the water, therefore it's going to increase the exposure of the people who come into contact with those waters," said Kristina Mena, an expert in waterborne viruses and an associate professor of public health at the University of Texas Health Science Center at Houston. "We're talking about an extreme environment, where the pollution is so high that exposure is imminent and the chance of infection very likely."
In July, the AP reported that its first round of tests showed disease-causing viruses directly linked to human sewage at levels up to 1.7 million times what would be considered highly alarming in the U.S. or Europe. Experts said athletes were competing in the viral equivalent of raw sewage and exposure to dangerous health risks almost certain.
The results sent shockwaves through the global athletic community, with sports officials pledging to do their own viral testing to ensure the waters were safe for competition in next year's games. Those promises took on further urgency in August, after pre-Olympic rowing and sailing events in Rio led to illnesses among athletes nearly double the acceptable limit in the U.S. for swimmers in recreational waters.
Erik Rumbaugh has been involved in biological waste treatment for over 20 years. He has worked with industrial and municipal wastewater facilities to ensure optimal performance of their treatment systems. He is a founder of Aster Bio (www.asterbio.com) specializing in biological waste treatment.
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