Technical Data
Many ponds and lagoons become stagnant due to the lack of moving water. A number of methods have been developed to improve water health in these types of water bodies. Most are classified either as aerators or circulators. Aerators utilize a water pump to either force the water into the air to increase oxygen level or to cause air bubbles to rise from the bottom to increase oxygen and provide some water movement. The surface units tend to provide support for the upper 1 ½ feet to 2 feet of the pond and the bubblers provide a limited range of movement in a pond. Circulation is designed to develop movement in the pond by using an impeller or other source to force the water to move from near the bottom of the pond to the surface, thereby circulating water at all levels and providing more water movement. No matter what system is used, it is essential to make the water move in order to let nature provide the essential actions to keep the water quality acceptable.
The movement of the water throughout the pond or lagoon cannot be understated as a primary requirement for good pond health. Circulation provides a good way to provide sufficient oxygen in a stagnant pond and prevents stratification. During the summer months the sun heats the upper levels of water, but as the water depth increases, the lower levels remain cool. The lower levels then become depleted of oxygen as a result of organic decomposition. The surface has direct access to the oxygen and utilizes the natural sunlight to provide photosynthesis of the phytoplankton, which are microscopic photosynthesizing organisms. These organisms are agents for creating organic compounds from carbon dioxide, which sustain the aquatic food chain. They are also responsible for the majority of oxygen development on the earth.
Stratification is a significant threat to fish health by creating a layer or layers of oxygen depleted water. The result is that fish often are forced to live near the top of the pond, which opens the opportunity for birds of prey to harvest the fish as they come to the surface to obtain sufficient oxygen.
The WQS Solution
The HONU® (Hawaiian for turtle) is a circulation system designed to provide maximum efficiency and effectiveness to pond health. The concept of water circulation utilizing nature’s processes, including biology and sunlight, is to clean a pond or lagoon without the use of chemicals. An effective circulation system will gently move the water from near the bottom of the pond or lagoon to the surface forcing anaerobic bacteria to move to the top of the pond to be consumed by good bacteria or die from the photosynthesis process. In addition, elimination of surface algae (blue-green), elimination of odors caused by the dead bacteria in the bottom, increased oxygen, improvement of temperature stratification, and decreased mosquito breeding are some of the benefits associated with a well-designed mechanical circulation system.
| Submitted By: Alchem Laboratories, Boise, Idaho - 2012 | ||
| Biochemical Oxygen Demand (BOD) | ||
| Date | Influent | Discharge |
|---|---|---|
| 3/6/2012 | 59 | 33 |
| 2/8/2012 | 136 | 39 |
| 12/6/2011 | 127 | 23 |
| 11/9/2011 | 98 | 24 |
| 9/8/2011 | 209 | Unknown* |
| 8/3/2011 | 192 | Unknown* |
| 7/13/2011 | 203 | 41 |
| 6/22/2011 | 120 | 32 |
| * System turned off due to lagoon maintenance. | ||
Water circulation systems, such as the HONU®, provide oxygenated water, remove toxic gases such as carbon dioxide and ammonia and transport nutrients throughout the pond or lagoon. One of beneficiaries of this process is the fish population. Fish consume oxygen for vital metabolism in their cells. Water has far less oxygen than in open air and fish require 10 to 30 times more volume of water than shore animals. Therefore, a pond with fish requires oxygen saturation and the elimination of carbon dioxide for effective fish health. In order to accomplish this, it is necessary to have diffusion of gases, which is done by breaking the surface tension on the water. This is a primary function of the HONU®.
Biochemical Oxygen Demand (B.O.D.)
The BOD rate is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material that is present in a water sample with a specified temperature over a specific period of time. Although this is not a precise qualitative test, it is often used as an indication of the organic quality of water. The BOD value is commonly expressed in milligrams of oxygen consumed per liter of sample during a five day period of incubation at approximately 68 degrees Fahrenheit (20 degrees Celsius). It is often used in estimating the organic pollution of water. The higher the BOD, the water is considered to be less healthy. It is considered a conventional pollutant in the U.S. Clean Water Act and therefore is often used to determine the effectiveness of a waste water system.
| Influent | Treated Water | |
|---|---|---|
| BOD (5 day) | 1700 | 141 |
| Total Suspended Solids | 80 | 36 |
| Total Dissolved Solids | 992 | 490 |
| Oil & Grease | 8.46 | 2.73 |
| pH | 5.49 | 7.51 |
| Total Nitrogen (N) | 8.98 | 5.31 |
| Total Kjeldahl Nitrogen | 8.1 | 5.2 |
| Nitrate-N | 0.9 | 0 |
| Nitrite-N | 0 | 0 |
| Phosphorus, Total | 2.4 | 0.87 |
| Soluble Tannic Acid | 68 | 5.2 |
| ATL Accurate Testing Labs, LLC-CDA, ID |
||
Most natural waters contain small amounts of organic compounds. Aquatic microorganisms utilize these compounds as food. The microorganisms living in oxygenated waters use dissolved oxygen to degrade the organic compounds, which release energy used by the microorganisms for growth and reproduction. The population of these microorganisms increases in proportion to the amount of food available and reflects a proportional oxygen demand. These organisms can consume dissolved oxygen faster than it can be replaced. This results in fish and aquatic insects dying due to the lack of sufficient dissolved oxygen.
Tests of waste water lagoons in Cascade, Idaho during 2011 and 2012 indicated an average influent (water entering the waste water lagoon) was between 59 in the early spring of 2012 and 209 in the fall of 2011. The average input was approximately 143 over an eight month test period. The median was approximately 130. The discharge utilizing a WQS system utilizing circulation and a 24” impeller averaged between 23 and 41 (the higher BOD rates were a result of not operating the unit for two months during lagoon maintenance and then starting the unit again). The average BOD rate after treating the lagoon with the system was 32. Only two units were used in the lagoon, which called for at least four units for maximum efficiency. This is a decline of approximately 78% of the BOD in the treated water.
In another test conducted in 2010 on a winery waste water pond located in Walla Walla, Washington, the results were similar in overall effectiveness. The BOD rate at the location of the influent was approximately 1,700 mg/Liter. The sample taken from the pond that was being circulated with a similar circulation system to the HONU® (Circul8) showed a substantial decline in BOD, as well as other important elements. The BOD rate dropped to 141 mg/Liter or 8.3% of the BOD of the water entering the pond.
Also included in this test were additional factors that are important in pond health for these types of waste water systems. Total suspended solids dropped approximately 55%, dissolved solids dropped approximately 51%, the pH increased from 5.49 to 7.51, the total nitrogen dropped approximately 41%, the phosphorous dropped approximately 64% and the Tannic Acids fell from 68 mg/Liter to 5.20 mg/Liter or approximately 92%.
Control of Algae
Algae are generally inherently located in stagnant water and must be managed for good pond health. When algae are managed appropriately, the lagoon or pond productivity increases as oxygen is increased and ammonia is eliminated. Unmanaged algae results in additional BOD to the water and increased Total Suspended Solids (TSS) converting carbon dioxide (alkalinity) into algae carbon.
Algae retain nutrients in their cell structures and when these organisms are eliminated, these nutrients are released and recycled. Algae systems tend to be rather complex. There are three basic types or families of algae: sinking, swimming and floating. The floating algae are associated with the cyanobacteria or blue-green and are generally not palatable to other organisms. This bad taste keeps these floating algae from being consumed by most organisms. These type of floating algae, which is not a true algae, grow with light energy, are slow in development and tend to be very susceptible to aggressive flushing of dead spots. Circulation inhibits floating algae with the continuous non-turbulent wave activity. These continuous waves are like sine waves, continuously passing over the algae causing disruption.
The HONU® provides an effective means to control these floating algae commonly referred to as blue-green algae (cyanobacteria) on the surface of ponds. By moving the water and developing the ripple effect on the surface, the water is converted from a high nutritional zone for blue-green algae to an average zone, thereby decreasing the availability of food for the blue-green algae. The system also stabilizes the water temperature throughout the pond, which directly affects the temperature dependent algae. The blue-green algae clumps are disbursed by the movement of the water making them more susceptible to predators. The moving water also upsets the growth cycle of the blue-green algae due to the changing light associated with the wave action. The result is an inhospitable environment for the blue-green algae. Other algal systems are competing with the blue-green algae, which is not a true algal organism, but a bacterial organism. “Good” algae provide positive support to the pond’s ecosystem. A benthic algae layer in the pond reduces BOD and ammonia. The swirling water separates the gases from the solids, decreasing odors. Essentially, the floating algae die overnight as the water is mixed and becomes healthy. The swimming algae then become dominant on the surface as they obtain more nutrients as the blue-green algae sink and release nutrients.
Impact of Ice on Pond Health
Smaller ponds are impacted during the winter months when ice forms across the surface. During the summer there are normally three layers of water in a pond. The upper level is referred to as the “epilimnion” (warmer) and the lower level is called “hypolimnion” (colder). In between these two levels is a layer called the thermocline, which may or may not exist in a pond or lagoon. This level tends to rapidly decrease in temperature during the fall as the outside temperatures begin to get colder. During the summer months, there is normally very little mixing of the pond. Therefore, there is maximum stratification during these warmer months, impacting the overall health of the pond. During the winter, the stratification is often decreased in early fall as the winds provide a means of mixing the water on a natural basis. In cases of ponds that have little availability of winds, the pond never really has the opportunity to mix and break down the stratifications in the water, thereby impacting the living organisms.
During the colder months the water at the bottom of the pond is generally warmer than the water at the surface. In most cases, water expands as it warms and contracts when it gets colder. This is the case when the outside temperature is at or above 39 degrees Fahrenheit. However, if the temperature is below 39 degrees Fahrenheit, water works in the opposite way, expanding as it gets colder and begins to develop ice. As the pond cools, the denser water goes to the bottom of the pond and the less dense water remains near the surface. Water is most dense at 39 degrees Fahrenheit and begins to decrease in density as it reaches freezing at 32 degrees. Since the denser water sinks to the bottom, the water at the bottom is warmer and remains approximately 39 degrees.
As the pond freezes over, the gases from organic materials such as roots, leaves, microorganisms, etc. are not able to escape. The result is the increase of toxic levels of ammonia and other decomposition gases in the water. This toxicity impacts the quality of life of the fish and other aquatic organisms. In addition, as the ice covers the pond, availability of oxygen is decreased.
Fish are dependent on the oxygen in the water and often as oxygen decreased, they are subjected to a “winterkill”, which is directly associated with the icing over of the pond and the inability to obtain sufficient oxygen for fish survival. Normally, although the pond is iced over, there are plants in the pond that continue to produce oxygen. However, if the ice is covered with snow or does not provide sufficient light through the ice cover for photosynthesis, the plants are unable to produce oxygen for the fish and aquatic insects. The result is that the plants die and begin to decompose, using up more oxygen in the process. If enough oxygen is used up without availability of more, the fish begin to die, leading to more decomposition and oxygen use, continuing the depletion at an accelerating rate.
It is, therefore, prudent for pond health to provide a means of keeping the ice from covering the surface of ponds that are susceptible to “winterkill” and build-up of gases during the winter months that, when the ice breaks up in the spring, allow gases to be released causing odor issues. Circulation provides a good means of maintaining a healthy pond during the winter months by mixing the water and not allowing the ice to form on the surface. Water tends to freeze more slowly in moving water as a result of the energy developed during movement, which is turned to heat and thereby slightly warming the water. This makes it more difficult for the pond to freeze over. In addition, circulation brings the warmer water at the bottom of the pond to the surface further inhibiting ice development. Over the winter months, a system that circulates and mixes the water throughout the pond enhances the overall quality of the pond health, the aquatic life, and the ability to continue to provide sufficient oxygen in the water. In addition, the ability to allow the toxic gases to escape without build-up impacts the potential odor associated with spring break-up.
Mosquito Control
Stagnant ponds are perfect breeding areas for mosquitos. The lack of movement on the surface provides enough tension to support mosquito eggs. If the water is moving (or rippling) due to winds or by another means, it breaks this tension and eliminates the availability of breeding areas. Circulation provides that constant movement and rippling across the surface of the pond, even those not generally impacted by natural wind. This decreases the opportunities for mosquito development in these stagnant water surfaces, thereby decreasing mosquito populations in the area. This is nature’s way of controlling disease and nuisance associated with the mosquito without the use of chemicals. The HONU® provides a gentle mixing action that breaks up the surface tension as the ripples project out from the system in the center of the pond. The HONU® provides a ripple effect extending over 150 feet from the unit in all directions providing a minimum of 300 feet of diameter, with an extension of the ripple effect far beyond the immediate action, thereby severely hindering mosquito breeding opportunities in the pond.
Waste Water Systems
Many smaller rural communities utilize lagoon systems for treating waste water. The lagoons are designed to provide a natural process to clean the discharged water. These systems work well if there are long retention times with low flow rates. Many of these systems have begun to use aerators to add oxygen to the lagoon. These aerators work fairly well until sludge builds up in the bottom of the pond, increasing ammonia build-up, and algae increases or is discharged with the effluent causing increased TSS (Total Suspended Solids), which is a water quality measurement, and occasionally a pH level exceeding desired optimums. The concept in this system is to provide for aerobic activity using aerobes and BOD (Biochemical Oxygen Demand) to produce carbon dioxide and sludge bodies (bacteria). The sludge buildup decreases the Hydraulic Retention Time (HRT), which is the time allowed for pollutants to be removed through settling, absorption, etc. Facultative organisms liquefy (hydrolyze) the sludge bodies. Obligate anaerobes then decrease the liquefied sludge bodies into shorter volatile fatty acids and carbon dioxide. Other acid consuming anaerobes then convert the produced acetic acids and hydrogen into methane and carbon dioxide. These gases then float to the top of the water and are discharged into the air. This is where the primary odor is released and can be quite pungent. The resulting water is then discharged as effluent, presumably as “cleaner” water.
The top of the pond is considered to be aerobic, where sludge is produced and then sinks to the bottom. The middle layer is often referred to as the thermocline and is where the sludge is liquefied. The lower layer of the pond is the anaerobic zone, which converts the sludge to gas. Nature has a way of cleaning the deeper ponds. Each year, ponds “turn over” mixing solids and surface water. This turn over brings the obligate anaerobes to the surface where they are subjected to oxygen, which is toxic to these anaerobes and they die, resulting in an odor. The “turn over” phenomenon does not occur every year. It takes two forces, which are an equal density throughout the pond and the wind. The gentle vortex that is developed with the HONU® provides a continuous action in the pond that supports the natural processes and ensures constant elimination of the gases associated with odor. BOD rates tend to stay lower at the effluent as is evidence in the tests in the Cascade, Idaho community waste water tests in 2011 and 2012.
Summary
Ponds and lagoons have manageable issues that need to be solved in order to maintain healthy water. These include:
- Odors
- Sludge
- Increased BOD
- Increased Ammonia
- Blue-Green Algae
- Low pH
- Icing
The Water Quality Solution (WQS) provides a low maintenance, mechanical device placed on the surface of a water body that employs a circulation system to bring new life to ponds, lagoons and reservoirs thus enhancing utility, healthiness and the value of water. The WQS system is a low cost and simple process that couples vortex induced water circulation with photosynthesis to utilize powerful natural phenomena to treat water. Oxygen deprived water is pulled from near the bottom of the pond to the surface utilizing a carefully engineered vortex, where it can take in oxygen and provides the opportunity for sunlight to energize the many photosynthetic microbes that nature provides. Mixing brings the food to the microbes and the microbes to the food. In the process, odor is reduced while improving water quality and clarity. The WQS circulation and mixing process promotes and maintains conditions that cleanse the water, balances the temperature throughout the pond, reduces pathogens and eliminates mosquito breeding areas while reducing algae. A stagnant stratified system is changed to one that is constantly mixing bottom to top, side to side, thereby building a healthy pond.
Circulation utilizing the HONU® eliminates odors by mixing the water and releasing odor producing gases such as ammonia. Sludge is decreased as the pond water moves, bringing dead and decaying organisms to the surface. The BOD rates decrease to manageable levels. Ammonia and acids are dissipated as they are moved to the surface. In the winter, the ammonia build-up under ice is eliminated as the HONU® ensures that the pond or lagoon is not iced over. In addition, fish kill due to the icing is reduced and the dissolved oxygen levels in the water are greatly improved for fish health. The system eliminates blue-green algae, increases pH, decreases phosphorus and nitrates in the water caused by man-made fertilizers and natural events.
The basic HONU® is approximately 150 lbs. and can be carried by three people. It is six feet in diameter and is powered by a 1 horsepower gear-motor with multi voltage capability for shore power of 120 volts to 240 volts or 3 phase. Circulation is provided with a stainless steel shaft and an 18” aluminum impeller which develop a gentle vortex drawing the water from the lower levels of the pond to the surface. The approximate diameter of the wave action produced by the HONU® is approximately 300 feet, indicating that one unit can cover most small ponds and two units can cover most larger lagoons based on overall size and depth (number of units that may be needed for the best results are determined by the WQS staff). The minimum depth for the HONU® is 2 feet and the maximum depth is approximately 60 feet.
The HONU® is made in America.
