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2 Algae Control and Solids Removal A cleaner lagoon or pond is easier than you think 1 Introduction Total suspended solids (TSS) includes all particles suspended in water which will not pass through a defined filter. High levels of TSS can make the water lose its ability to support a diversity of aquatic life. Adequate treatment is necessary to ensure that TSS is not present at levels of concern in the water. TSS can also result from algae growth (Figure 1). When the lagoon contains adequate nutrients, warm temperature, and enough light, algae will grow. Algal blooms can result in supersaturated oxygen conditions in the daytime and anaerobic conditions at night. It is necessary to remove algae in order to protect the water quality, as well as make disinfection efforts more efficient. Bio-Dome, which is manufactured by Wastewater Compliance Systems (WCS), is a submerged, aerated, fixed-film, bio-reactor. The Bio-Dome technology showed a remarkable impact in reducing the concentrations of TSS and algae in lagoon, as well in the other pond systems. The Bio-Dome system consists of concentrically nested domes that are infused with air from the bottom (Figure 2). They sit on the floor of a lagoon and are completely submerged (Figure 2). As the air and water flows through them, bottom-to-top, beneficial bacteria effectively reduce contaminants in the water. Additionally, the unique design of the Bio-Domes results in a high oxygen transfer efficiency (OTE) with minimum energy input. One key feature of the Bio-Domes is their modular nature which allows for seamless growth with the community in order to meet increased populations sizes, loading, and even more stringent effluent requirements. Bio-Dome has demonstrated the ability to remove 2.16 lb TSS/d/unit. The bacteria that grow inside a Bio-Dome system can efficiently biodegrade TSS, and simultaneously delay the buildup of sludge on the bottom of the lagoon. Page 2

3 Figure 1: Algae growth in Wellsville UT Figure 2: Bio-Domes are positioned on the floor of a lagoon (left hand side) and the aeration patent of Bio-Dome (right hand side) The Bio-Dome system can reduce algae for the following reasons: 1) the airlift action in the Bio- Dome can circulate the algae into areas of less efficient sun whereupon the algae dies off and become the organic source for the bacteria inside the Bio-Dome. Figure 2 is the underside of one of the Bio-Dome units removed from one of the installations. The streaks of green amongst the brown of the fixed-film are the remains of algae that has been sucked into the Bio-Dome. 2) The fixed-film bacteria in the Bio-Dome out-compete with the algae for nutrients, which are used for cell growth. 3) The mixing action of Bio-Dome prevents the single cellular algae from maintaining optimal equilibrium in the water column where it is able to reproduce most rapidly. Page 3

4 Figure 2: Underside of bio-dome shell 2 Case Studies This case studies section includes one installation in a wastewater lagoon, and one installation in a decorative pond. The results from both locations illustrate the effect of the Bio-Domes on the algae and TSS. 3.1 New Castle, VA A full-scale Bio-Dome system was installed in New Castle, VA after obtained the satisfied TSS data from their pilot study. In the past over 5 years, this full-scale system in New Castle s wastewater lagoon has been ensuring the TSS levels much lower than the discharge limit. This upgrade not only make had a system capable of ensuring their compliance with the State of Virginia s NPDES limits, but is able to do so with substantially less operational and maintenance expense. This location demonstrates the successful extrapolation of the data/performance of the pilot study into a design for a full scale system. 1. Initial problems: Craig-New Castle, VA, had a problem with severe algae blooms in their three-cell wastewater lagoon (Figure 3) during the summer months. These algae caused an increase in the amount of total suspended solids (TSS) in their lagoon s effluent. Too much TSS can adversely impact water quality and harm aquatic vegetation and aquatic life, so discharge permits usually have very strict TSS limits. Craig-New Castle was looking for an upgrade to meet their permit limit of 30mg/L monthly average TSS. Page 4

5 Figure 3: Satellite imagery of Craig-New Castle Wastewater Lagoon 2. Solution: Among other upgrade options, the Bio-Dome system was chosen because it was reliable and the most cost-effective alternative. From early August to mid-december of 2011, Craig New Castle worked with WCS to run a pilot study (at the east end of the bank between pond #1 and 3b, Figure 3) in order to test if the process can satisfy the state regulators before the full-scale installation. Water was pumped from the east end of Pond #3b into the tank. Effluent from the tank drained back into Pond #1. The HRT was set at approximately 10 days to mimic the normal HRT in Pond #3b. The results from this pilot study showed the Bio-Dome system was capable of reducing the TSS to levels lower than the permit limits. From late March to June 2012, Craig-New Castle proceeded with a full-scale installation of 52 Bio-Domes into pond #3b of the lagoon along with 200,000 floating bird balls (Figure 4). The Bio-Domes started operating with some operational changes in mid-august of The community was excited by the money they saved for their lagoon s upgrade in both capital investment as well as reduced operating costs due to the small amount of energy required for the Bio-Domes. 3. Results: Pilot Results: The results of the pilot run are shown in Figure 5. With the exception of one sample point when the compressor supplying the aeration to the Bio-Dome quit, the effluent TSS concentration was on average 21.5 mg/l less than the influent. The results of the pilot study were sufficient to convince New Castle and the State that the Bio-Domes were indeed capable of ensuring a TSS level below 30 mg/l in the effluent of the Craig New Castle discharge. Full-scale Results: Figure 6 shows the BOD and TSS concentration in the effluent from Jan 2011 to May Before the Bio-Dome installation (before March, 2012), the average effluent TSS was 25.5mg/L. There were four months of TSS exceeded effluent limitation during that time (Figure 6). The effluent TSS consistently remained lower than the limit since mid-august Page 5

6 The increased performance was mainly due to the loss of algae in the lagoon once the Bio- Domes became fully operational. The average effluent concentrations of TSS decreased to 7.3 mg/l (Figure 6). Installation of the Bio-Dome system into the Craig-New Castle lagoon, resulted in dramatically reduced TSS and algae, and successfully maintains compliance with permit limits with low energy expenditures.! Figure 4: The Bio-Domes location (upper), 52 bio-domes installed in the pond #3b (lower left hand corner), and the floating bird balls in the lagoon. Page 6

7 ! Figure 5: Results of the Bio-Dome TSS Pilot Study Figure 6: BOD and TSS concentration in the effluent from Jan 2011 to May Heber City, UT Recently, Bio-Dome system achieved a significant algae reduction in a one-acre recirculating pond (Heber, UT) without the massive capital and O&M expenses due to its unique design. In 2015 summer, the recirculating pond had a serious algae problem (Figure 2a and b). The owner tried different methods (include a bacteria injector) to control the algae, but they all did not work. Within a few weeks of placing the Bio-Domes in the pond, the algae had greatly subsided Page 7

8 (Figure 2c). Lab results indicated that the conventions of all nitrogen species are almost completely eliminated. After one year of installation, a sustainable ecosystem had developed, and the algae situation was under control in that pond. This summer, the owner is very happy because the kids are back in the pond because the water is maintained clear and healthy. Figure 7: The pond before (a and b) and after (c) the Bio-Domes installed 3 Conclusion The effectiveness of the Bio-Domes and Bio-Shells on reducing single cellular algae concentrations in wastewater lagoons is both visually apparent and numerically significant. After evaluating the performance at our various installations, WCS has come to the conclusion that as long as the bio-reactors have a minimum of 7 days to work on the algae, a reliable and significant improvement can be had in overall TSS levels and in reducing the effects of algae blooms on the water quality. When considered alongside the effective treatment of ammonia, especially under the cold temperature, the WCS s Bio-Domes begin to display an all-around value for improving the water quality of the treated effluent in a wastewater lagoon. If you are interested in learning more about Bio-Domes or would like us to put together a proposal for you, please contact us using the contact information below. If you would like to speak with any of the communities mentioned in this article, please feel free to do so using the contact information found on our website. They have all agreed to answer questions and are more than happy to their facilities. Page 8