Floating Treatment Wetlands For Water Treatment
Floating Treatment Wetlands For Water Treatment
Wastewater Lagoons Nutrient Removal TDS/ TSS
Coastline Floating Breakwaters Prevent Erosion Buffer Sewage and Nutrients From Bay
Sewage Effluent Treatment
Landfill Leachates Results
BioHaven Matrix provides much more surface area than natural floating islands. Circulation enhances the microbes’ capacity to seek out surface area and form biofilm. Surface area is provided by matrix and plant roots. The matrix protects the roots and enables optimum, unimpeded root growth. The symbiosis between plant roots and microbes expands the diversity of microbe species within the root mass. The matrix is constructed of post-consumer PET (polyethylene terephthalate) plastic bottles. Unlike alternatives, PET does not degrade in water and therefore contribute to ongoing nutrient and TSS pollution as would an organic alternative, over time, such as coir. The tensile strength of the matrix filter material is specked at 2,500 pounds. It is very resistant to tearing.
six major plant mechanisms safely enable phyto-technologies to remove, destroy, transfer, stabilize, or contain contaminants: 1) Rhizo-filtration 2) Phyto-extraction 3) Phyto-degradation 4) Phyto-volatilization 5) Rhizo-degradation 6) Phyto-sequestration Floating islands provide educational opportunities
They don’t take up valuable land
Intrinsyx Science Design and Engineering Support Floating Treatment Wetlands Projects Underway City of Loveland CO Foote Lagoon High in Nutrients Fort Collins CO Warren Reservoir Salton Sea CA Seattle WA Rain Gardens City of Oakland Lake Merritt Storm Water High in Nutrients Salt Water Open to Bay
BioHaven® Technology: Nutrient Removal from Wastewater Removal of ammonia, nitrate, total phosphorus, biochemical oxygen demand (BOD) and total suspended solids (TSS) with BioHaven® floating treatment wetlands (FTWs) is summarized in this study. Removal rates were substantially improved for ammonia, nitrate and phosphorus, and slightly improved for BOD and TSS, compared to control wastewater lagoons without FTWs. Since their initial implementation nearly a decade ago, one of the primary objectives of BioHavens from Floating Island International (FII) has been to reduce nutrient levels. Potential applications include waterways degraded by agricultural runoff, ponds and lakes impacted by waterfowl and/or septic systems, polishing of municipal wastewater and even treatment of raw wastewater. Table 1 illustrates ammonia removal at five sites equipped with FTWs. The table includes ammonia concentrations, percent removals and removal rates in pounds of ammonianitrogen removed per year per cubic foot of FTW material.
TABLE 1. FTW AMMONIA REMOVAL Ammonia-N Concentration (mg/L)
Percent Removal
Removal Rate (lb/yr/ft3)
Study MBRCT Tank Test
Influent
FTW
Control
FTW
Control
FTW
Control
149
40
NA
73%
NA
0.4
NA
MBRCT Test Pond
172
22
112
87%
40%
0.9
0.4
Wiconisco
47.8
19.3
25.6
60%
51%
2.5
1.9
Rehberg Ranch
44.1
7.2
18.7
84%
58%
1.3
0.9
Elayn Hunt Correctional Facility
16.0
10.0
NA
38%
15%
5.3
1.8
All five systems presented in Table 1 are variations of wastewater lagoons at different scales. The earliest study conducted by FII researchers for a Montana Board of Research and Commercialization Technology (MBRCT) grant was a small-scale BioHaven which did not include a “control” lagoon. The next three studies included controls, which were parallel lagoons treating the same influent wastewater but without FTWs. The Wiconisco and Rehberg Ranch FTWs are small systems treating average flows of 16 and 12 gallons per minute (gpm), respectively. The Hunt Facility FTW is a full-scale production system in Louisiana treating about 200 gpm. Ammonia removal ranged from 38% to 87% in the five systems. The Rehberg Ranch FTW removed 26% more ammonia than the control lagoon (84% vs. 58%), while the Wiconisco FTW was 9% better than the control. The highest ammonia removal rate, 5.3 lb/ft 3/yr, was measured in the Hunt system, which was installed in 2011. This rate was 194% higher than the control removal rate measured before BioHaven installation. Ammonia concentrations at Rehberg Ranch are illustrated in Figure 1.
Figure 1. Rehberg Ranch - Ammonia
Table 2 illustrates nitrate removal in four studies equipped with FTWs.
TABLE 2. FTW NITRATE REMOVAL
Study
Nitrate-N Concentration (mg/L) Influent FTW Control
Percent Removal FTW Control
Removal Rate (lb/yr/ft3) FTW Control
MBRCT Tank Test
236
5
193
98%
18%
12.8
2.3
MBRCT Test Pond
150
0
78
100%
44%
0.9
0.4
Wiconisco
33.6
2.5
4.1
93%
89%
3.0
2.9
Rehberg Ranch
37.0
2.0
0.9
95%
95%
3.1
2.2
Influent concentrations in Table 2 reflect the nitrate concentrations after nitrification (aerobic conversion of ammonia to nitrate) had occurred. The nitrate removal rates also account for removal of the nitrate-nitrogen that had been converted from ammonia, since this nitrogen is no longer present as ammonia or nitrate in the effluent. For Rehberg Ranch, the nitrate removal rate with the FTW (3.1 lb/yr/ft 3) is substantially higher than the control rate (2.2 lb/yr/ft3) because of higher nitrate concentrations after nitrification.
Figure 2. Rehberg Ranch FTW, July 2010
Figure 3. Mature BioHavens at Wiconisco, 2009
The Rehberg Ranch system, installed in late 2009, is the latest-generation FTW as it includes a pump for circulation and aeration. The Wiconisco system was one of the first full-scale FTWs installed in 2005. The Wiconisco and Rehberg Ranch FTWs treated municipal wastewater, which contained high ammonia concentrations but low initial nitrate concentrations. In all four systems listed for nitrate removal, ammonia was reduced to nearly zero while the nitrate concentrations (including the nitrate converted from ammonia by biological nitrification) were still relatively low after FTW treatment. Denitrification (biological reduction of nitrate to nitrogen gas under anoxic conditions) is the primary mechanism for nitrate removal. Although the Rehberg and Wiconisco FTWs were aerated for ammonia removal, both systems achieved anoxic conditions (and subsequent nitrate removal) in the presence of dissolved carbon in the wastewater, which acts as a food source for denitrifying bacteria. Both the Wiconisco (Pennsylvania) and Rehberg Ranch (Montana) FTWs are located in cold-weather climates, which has traditionally limited biological nitrate removal. Table 3 shows total phosphorus removal in six studies equipped with FTWs.
TABLE 3. FTW TOTAL PHOSPHORUS REMOVAL Phosphorus Concentration (mg/L)
Percent Removal
Removal Rate (lb/yr/ft3)
Study MBRCT Tank Test
Influent
FTW
Control
FTW
Control
FTW
Control
15.9
1.5
NA
91%
NA
0.52
NA
MBRCT Test Pond
13.6
5.2
6.4
62%
53%
0.13
0.08
Wiconisco
8.1
4.7
5.1
42%
39%
0.30
0.26
Yingri Lake
0.93
0.29
NA
69%
NA
NA
NA
Mermaid Pool
0.105
0.065
0.075
38%
29%
0.21
0.16
Elayn Hunt Correctional Facility
0.49 5.1
3.6
NA
29%
20%
1.29
Total phosphorus removal ranged from 29% to 91% in the six systems. BioHavens in the Mermaid Pool, MBRCT and Elayn Hunt studies all improved phosphorus removal by 9% compared to the controls. Efforts are currently underway at FII to further enhance FTW phosphorus removal through biological, chemical and physical mechanisms. Table 4 illustrates Biochemical Oxygen Demand (BOD) decrease in five studies equipped with FTWs.
TABLE 4. FTW BOD Decrease BOD Concentration (mg/L)
Percent Removal
BOD Removal Rate (lb/yr/ft3)
Study
Influent
FTW
Control
FTW
Control
FTW
Control
MBRCT Test Pond
330
230
NA
30%
NA
0.7
NA
Wiconisco
176
17
15
90%
91%
14
14
Rehberg Ranch
218
20
28
92%
87%
6.8
6.5
McLean’s Pit
NA
NA
NA
46%
NA
0.8
NA
Elayn Hunt
587
158
NA
73%
21%
376
46
BOD removal ranged from 30% to 92% in the five systems. Percent removal was impressive with the Wiconisco and Rehberg Ranch FTWs (greater than 90%) but was nearly as good in the control lagoons. The Elayn Hunt system had a lower percent removal than the others but was 5% better than the control. Its BOD removal rate was also 1-2 orders of magnitude higher than the other systems studied.
Table 5 shows total suspended solids (TSS) removal in four studies equipped with FTWs.
TABLE 5. FTW TSS REMOVAL TSS Concentration (mg/L)
Percent Removal
Removal Rate (lb/yr/ft3)
Study
Influent
FTW
Control
FTW
Control
FTW
Control
MBRCT Test Pond
42
3
NA
93%
NA
0.5
NA
Rehberg Ranch
81
37
45
54%
44%
1.5
1.2
McLean’s Pit
NA
NA
NA
89%
NA
0.2
NA
Billings Metra
391
28
NA
93%
NA
159
NA
TSS removal ranged from 54% to 93% with the four FTWs; for Rehberg Ranch (the only study with a control), the FTW improved TSS percent removal by 10% and the removal rate by 25%. The Billings Metra BioHaven had a TSS removal rate two orders of magnitude higher than the other studies; we are waiting for more data to confirm these results. Researchers have estimated that approximately 80% of the FTW efficacy is due to bacteria attached to plant roots and the FTW polymer matrix itself, with the other 20% attributed to nutrient uptake by plants. The plants create the platform for biological activity in a biofilm, while also contributing nutrient uptake and aesthetic benefits. This is illustrated in Figure 4.
Figure 4. Illustration of FTW biological activity Conclusion The need to reduce nutrient levels in wastewater is increasingly critical as rivers, lakes and coastal waters become more nutrient-loaded worldwide. This is the entry point for cutting edge, “green” floating treatment wetland (FTW) technology such as BioHavens. Although traditional wastewater lagoons effectively remove BOD and TSS, their ability to remove nitrogen and phosphorus from municipal wastewater is limited. BioHaven technology enhances these lagoons with the “concentrated wetland effect,” facilitating compliance with increasingly stringent wastewater nutrient, BOD and TSS criteria.
Nutrient Removal with Passive Floating Treatment Wetlands Project Location: Elayn Hunt Correctional Facility, St. Gabriel, Louisiana, USA This case study demonstrates the ability of patented BioHaven® floating treatment wetland (FTW) technology to clean water by substantially reducing nutrient levels. At a wastewater facility in Louisiana, BioHavens more than doubled removal rates for chemical oxygen demand (COD), ammonia and phosphate.
Overview Martin Ecosystems of Baton Rouge, Louisiana, an FII licensee, installed BioHaven floating islands into the Elayn Hunt Correctional Facility oxidation pond in March 2011. The primary objective was to determine whether the islands could remove unwanted nutrients that were periodically creating noncompliance with the facility’s discharge permit. The goal is to have the facility continually achieve and maintain compliance. Location Parameters Environment FTW Size Water Source Installation Date Flow Rate Water Body Depth Water Body Area % Coverage
St. Gabriel, Louisiana USA Studied COD, ammonia, phosphate Municipal wastewater pond Area of 1560 ft2 (145 m2), thickness of 8 inches (20 cm) Elayn Hunt Correctional oxidation pond March 2011 208 gpm (47 m3/hr) 3 ft (1 m) 5.1 acre (20,600 m2) 0.7% of pond covered by BioHavens
The BioHavens installed at Elayn Hunt are passive islands without aeration and were planted with three types of vegetation. Most of the removal efficiency attributed to islands has been found to be due to biofilm attached to both the plant roots and the island matrix itself.
Table 1 shows concentrations of the three parameters of concern before and after BioHaven installation. “Before” data were taken in January and March 2011, while “after” data are the averages of monthly data from April 2011 through September 2012. It is assumed that the higher nutrient concentrations seen post-FTW were also seen periodically before BioHaven installation.
Table 1. Contaminant Concentrations (mg/L)
Parameter COD
Before FTW In Out
After FTW In Out
242
190
587
158
Ammonia Phosphate
14.1 13.9
12.0 11.1
16.0 15.5
10.0 11.0
After BioHaven installation, the average percentage removal has been 73%, 38% and 29% for COD, ammonia and phosphate, respectively. This is substantially better than without the FTWs (52%, 23% and 9%, respectively). Table 2 shows contaminant removal rates before and after BioHaven installation, along with the net removal rates that can be attributed to the islands.
Table 2. Removal Rates (lb/yr/ft3) Parameter COD Ammonia Phosphate Total Phosphorus
Before FTW 46 1.8 1.50 0.49
After FTW 376 5.3 3.95 1.29
Net 331 3.4 2.45 0.8
The BioHaven removal rates are more than double the previous rates for all three parameters and are substantially higher than those measured in other case studies. Based on these rates, FTWs can be sized to remove a given contaminant load (concentration and flow).
Conclusions BioHavens have a demonstrated capability to remove excess nutrients such as COD, ammonia and phosphate, along with total suspended solids and other parameters (data not shown). The total cost of this project was much less than other treatment alternatives, demonstrating that FTWs can help public facilities and private industry achieve and maintain compliance in a cost-effective manner. BioHaven technology can enhance existing waterways with the concentrated wetland effect, facilitating compliance with increasingly stringent wastewater nutrient, BOD/COD and TSS criteria. The Louisiana Department of Environmental Quality provided funding for this project, which is owned and operated by the Louisiana Department of Corrections.
Eliminating Odors Using BioHaven® Technology Project Location: Marton, New Zealand This case study summarizes results of a unique configuration of Floating Island International’s (FII) patented BioHaven® floating treatment wetland (FTW) technology to mitigate wastewater odor. This was the first application of FTWs specifically to reduce/eliminate wastewater odors, which also removed biochemical oxygen demand (BOD) at a high rate. BioHavens have now been utilized to reduce odors, remove nutrients and metals, provide wildlife and fish habitat, and improve aesthetics.
Overview An existing anaerobic pond was receiving municipal wastewater from the City of Marton, plus landfill leachate and other industrial waste streams from a nearby malting company; the odor from this mixture created a major problem. The Rangitikei District Council attempted to mitigate the odor by operating six 10-kW aerators 24/7. In addition to high costs, the community still had to contend with extremely unpleasant odors when the aerators frequently required maintenance.
BioHaven serving as wastewater lagoon blanket After thoroughly surveying the pond to accurately map the concrete wave band around the edge of the pond, Waterclean designed and manufactured a BioHaven system to fit tightly over the pond like a blanket, to “seal in” the odor. The FTW was planted with native sedge, Carex virgata, a resilient species to cope with the harsh environment.
Installation Data Location Parameters Environment FTW Size Water Source
Marton, New Zealand Studied Biochemical Oxygen Demand (BOD) Environment Lagoon 2,770 m2 (29,800 ft2) Municipal wastewater, landfill leachate, and industrial wastewater
Installation Date Flow Rate Hydraulic Retention Time
March 2010 3,000 m3/day (550 gpm) 3 – 3.5 days
Results The “floating blanket” has been an outstanding success, reducing BOD from about 450 mg/L to 85 mg/L, an 81% decrease. This removal rate of 395 g BOD/m2/day has greatly improved effluent quality. Waterclean believes that all wastewater treatment is occurring beneath the island, as the root zones do not penetrate far into the wastewater. The water temperature is a constant 27oC. Most importantly, all objectionable odors have been eliminated from the facility and shutting off the aerators has saved approximately $150,000/yr in energy costs.
Special Features The project is a leading-edge application, as it was the first in the world to use FTWs in this manner. The Rangitikei Council wanted a no-risk situation, which required the Waterclean solution to be successful. The wastewater blanket concept was initially presented to scientists, who agreed that it would work in principle.
Conclusion The Marton wastewater blanket has essentially formed a low-rate anaerobic digestor. It has provided a unique solution by eliminating odor, improving effluent quality (primarily BOD) and reducing operating costs. As of September 2013 (after more than three years in operation), the system is still performing optimally.
Treatment of Landfill Leachate Project Location: McLean’s Pit Landfill, Town of Greymouth, South Island, New Zealand Landfill leachate is being successfully treated with BioHaven floating treatment wetlands (FTWs) in New Zealand. BioHavens installed in a wastewater lagoon improved removal of total suspended solids (TSS), biochemical oxygen demand (BOD) and total nitrogen by 89%, 46% and 40% compared to pre-FTW conditions.
Overview Landfill leachate is a problematic water stream to treat in New Zealand and worldwide. Greymouth is a town of approximately 3,000 people on the South Island. The town identified a need for improved treatment of its municipal landfill leachate, which is a dilute stream because of the area’s extremely high annual rainfall (3.5 m or 140 in). Because of limited funding, lagoon improvements are being implemented in three stages. In Stage 1 (initial results are described below), FII licensee Waterclean Technologies constructed and installed 288 m2 (3100 ft2) of BioHavens to cover approximately 20% of the lagoon surface in half of the lagoons. In Stage 2, another 288 m2 (3100 ft2) will be constructed in the other half of the lagoons. In Stage 3, media for biofilm attachment will be added to the primary treatment lagoon that precedes the other lagoons, along with improved aeration, for enhanced nitrification (ammonia removal). The wetland plants used are Carex virgata and Cyperus ustulatus.
Installation Data
Location South Island, New Zealand Parameters Environment FTW Size
Studied TSS, Total Nitrogen, BOD System Type Lagoon A total of 288 m2 (3,100 ft2); each of three ponds contains eight modules with 12 m2 of surface area
Water Source
Landfill leachate
Installation Date
November 2009
Flow Rate Water Body Depth Water Body Area
Variable, with highest flows in the winter (rainy season) 0.6 m (2 ft) Each pond is 40 m x 12 m (131 ft x 39 ft). There are six ponds, with BioHavens in three of them.
Results Parameters
BioHaven Removal Rate (lb/yr/ft3)
Improvement Compared to Pre-FTW
TSS
0.2
89%
Total Nitrogen
2.4
40%
BOD
0.8
46%
Results Removal of TSS and color has been exceptional, as shown in the results table and first photo. The FTWs are also significantly removing total nitrogen and BOD. Operational data and detailed water quality data are still being collected and analyzed; however, the most recent data indicate that TSS removal has been improved by 89% when compared to pre-launch samples.
Conclusion Although the test is still in its early stages, initial results indicate that BioHaven technology is a viable and effective option for improving the quality of landfill leachate.
Field Test of FTWs’ Ability to Treat Simulated Wastewater Project Location: Outdoor Test Ponds, Shepherd, Montana, USA In an early field study, BioHaven® floating treatment wetlands (FTWs) demonstrated substantial removal of nitrogen, phosphorus, total suspended solids (TSS) and biochemical oxygen demand (BOD). Compared to a pond without FTWs, removal rates were improved by 125% for ammonia and total nitrogen, and 63% for phosphorus. Simultaneous aerobic and anoxic removal of ammonia, nitrate, phosphorus and BOD was measured within a single BioHaven.
Overview The need to reduce nutrient loading from wastewater is increasingly critical worldwide as ecological damage to rivers, lakes and coastal waters intensifies and corresponding costs continue to rise.
The Montana Board of Research and Commercialization Technology awarded a twoyear $300,000 grant to produce and test a BioHaven FTW designed to remove nutrients and other contaminants from lakes, streams and wastewater lagoons. In 2007, the project evaluated the effectiveness of treating full-strength simulated wastewater in three test ponds in a controlled outdoor environment. Pond 1 had no aeration or FTW (control pond); Pond 2 had aeration only; Pond 3 had aeration and an FTW.
Results The BioHaven FTW demonstrated rapid removal of ammonia, phosphorus, organic carbon and suspended solids. It removed phosphorus via bacterial processes at approximately the same rate as suspended algae removed phosphorus via plant growth. Water in the BioHaven pond (turbidity of 26 NTU 1 ) was much clearer than algaechoked water in the control pond (388 NTU). This study demonstrated that FTW performance can be optimized by providing proper conditions for microbial processes.
Conclusion This study provides “proof of concept” that the concentrated wetland effect of BioHaven technology is effective in removing excess nutrients and other contaminants. Its use results in visibly clearer water when compared to ponds without a BioHaven. This case study also demonstrates the critical role microbes play in cleaning water because the test BioHaven did not contain plants.
Installation Data Location Shepherd, Montana USA Parameters Studied Ammonia, phosphorus, TOC, BOD, TSS, turbidity Environment Three lined ponds – 5000 gallons (19 m3 each) FTW Size Water Source
Area of 250 ft2 (23 m2); thickness of 8 inches (20 cm) Simulated municipal wastewater (pond water dosed with liquid fertilizer and organic carbon (molasses))
Test Date July – October 2007 Flow Rate Water Body Depth Water Body Area
Batch system with recycle 4 ft (1.2 m) 455 ft2 (42 m2)
Results (September – October 2007) Parameters
BioHaven Removal Rate (lb/yr/ft3)
Improvement Compared to Control Lagoon
Ammonia
0.9
125%
Total Nitrogen
0.9
125%
Total Phosphorus
0.13
63%
TSS
0.5
NA
BOD
0.7
NA
BioHaven® Technology: Total Phosphorus Removal from Wastewater Total phosphorus removal with BioHaven® floating treatment wetlands (FTWs) is summarized in this study. Removal rates in aerated wastewater lagoons were improved up to 163% compared to control lagoons without FTWs. Since their initial implementation nearly a decade ago, one of the primary objectives of BioHavens from Floating Island International (FII) has been to reduce nutrient levels. Potential applications include waterways degraded by agricultural runoff, ponds and lakes impacted by waterfowl and/or septic systems, polishing of municipal wastewater and even treatment of raw wastewater. Table 1 illustrates total phosphorus removal in six studies equipped with FTWs. The table includes phosphorus concentrations, percent removals and removal rates in pounds of total phosphorus removed per year per cubic foot of FTW material.
TABLE 1. FTW TOTAL PHOSPHORUS REMOVAL Phosphorus Concentration (mg/L)
Percent Removal
Removal Rate (lb/yr/ft3)
Influent
FTW
Control
FTW
Control
FTW
Control
15.9
1.5
NA
91%
NA
0.52
NA
MBRCT Test Pond
13.6
5.2
6.4
62%
53%
0.13
0.08
Wiconisco
8.1
4.7
5.1
42%
39%
0.30
0.26
Yingri Lake
0.93
0.29
NA
69%
NA
NA
NA
Mermaid Pool Elayn Hunt Correctional Facility
0.105
0.065
0.075
38%
29%
0.21
0.16
5.1
3.6
NA
29%
20%
1.29
0.49
Study MBRCT Tank Test
The earliest study conducted by FII researchers for a Montana Board of Research and Commercialization Technology (MBRCT) grant was a small-scale FTW (tank test), which did not include a “control” lagoon. The MBRCT Test Pond and Wiconisco system are relatively small wastewater systems that included control lagoons, which were parallel lagoons treating the same influent wastewater but without FTWs.
Yingri Lake is a lake restoration effort that did not have a “control” condition. Mermaid Pool and Elayn Hunt are the latest studies; the Hunt Facility had by far the highest BioHaven removal rate (1.29 lb/yr/ft3) and the highest “net” phosphorus removal when comparing the FTW and control conditions (1.29 – 0.49 = 0.80 lb/yr/ft3). The BioHaven removal rate is 163% higher than the control rate, which was measured in the same lagoon before BioHaven installation. Total phosphorus removal ranged from 29% to 91% in the six systems. BioHavens in the Mermaid Pool, MBRCT and Elayn Hunt studies all improved phosphorus removal by 9% compared to the controls. Efforts are currently underway at FII to further enhance FTW phosphorus removal through biological, chemical and physical mechanisms. The Wiconisco system was one of the first full-scale FTWs installed in 2005 and treats an average flow rate of 16 gpm. The Yingri Lake system was installed in 2010 and is shown in Figure 1. Mermaid Pool, installed in 2011, treats about 700 gpm in a river setting. Elayn Hunt treats about 200 gpm.
Figure 1. Floating Islands at Yingri Lake, Jinan, China 2010
Researchers have estimated that approximately 80% of the FTW efficacy is due to bacteria attached to plant roots and the FTW polymer matrix itself, with the other 20% attributed to nutrient uptake by plants. The plants create the platform for biological activity in a biofilm, while also contributing nutrient uptake and aesthetic benefits. This is illustrated in Figure 2.
Nutrient Removal in Facultative Wastewater Treatment Lagoons Project Location: Wiconisco Township, Pennsylvania, USA This study describes the first full-scale implementation of BioHaven® technology, a passive floating treatment wetland (FTW) with no integrated circulation or aeration. Removal rates for ammonia, total nitrogen and total phosphorus improved by 32%, 9% and 15%, respectively, compared to the control lagoon, with the BioHavens covering only 2% of the pond’s surface area.
Overview In an effort to comply with The State of Pennsylvania’s nutrient reduction goals for the Chesapeake Bay Tributary Strategy, Wiconisco Township’s supervisors approved a unique solution beyond the limitations of conventional treatment technology. In 2005, the Pennsylvania Department of Environmental Protection’s “Growing Greener: New or Innovative Water and Wastewater Treatment Technology” grants program awarded funding to the Wiconisco Wastewater Treatment Plant to utilize emerging FTW technology to remove nutrients from municipal wastewater. In 2006, three BioHavens from Floating Island International were installed into one of two existing lagoons. Encouraged by initial successes, the Township has added a fourth BioHaven to the system. In March 2009, solar-powered circulation pumps were also installed to efficiently raise water onto the top surface of the BioHavens, providing more active treatment via percolation through the polymer matrix and biofilm.
Results Four years after installation, nutrient removal in the BioHaven lagoon continues to be substantial. The rate of ammonia removal is 32% greater than in the control lagoon, while the rate of total nitrogen removal is 9% higher. The BioHaven lagoon has shown a 15% improvement in phosphorus removal as well. These results are of particular interest considering that the FTWs occupy only about 2% of the lagoon surface area (the FTW size was limited by grant funding available). Additionally, algae control costs have declined, as reduced nutrient levels in the BioHaven lagoon curtail algae growth.
Conclusion Although facultative and aerated lagoons can successfully reduce Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS), their ability to remove nitrogen and phosphorus from municipal wastewater is extremely limited. BioHaven technology enhances these lagoons with the “concentrated wetland effect” to facilitate compliance with increasingly stringent nutrient standards for wastewater effluent.
Installation Data Location Wiconisco, Pennsylvania USA Parameters Studied Ammonia, nitrate, total phosphorus System Type Aerated facultative lagoon FTW Size Three 250 ft 2 (23 m2) FTWs plus one 200 ft 2 (18.58 m ) FTW Thickness: 10 inches (25 cm) Water Source Municipal wastewater from 185 households Installation Date Flow Rate Water Body Depth Water Body Area
January 2006 16 gpm (3.6 m3/hr) 10 ft (3 m) 40,000 ft2 (3,700 m2)
Results (2009 – 2010 Data) Parameters
BioHaven Removal Rate (lb/yr/ft3)
Improvement Compared to Control Lagoon
Ammonia
2.5
32%
Total Nitrogen
2.5
9%
Total Phosphorus
0.30
15%
Cost per lb of phosphorus removed
Phosphorus Removal Costs $3,000 $2,000
Amortized Over 30 Years
$2,460
$2,500 $1,554
$1,500 $1,000 $500 $0
$830 $533 $220
$280
$83
$35
PHOSPHORUS REMOVAL COSTS BMP # 1 2 3 4 5 6 7 8
Description NURP Basin Raingarden Water Reuse/Stormwater Irrigation Wastewater Treatment Plant Alum Treatment Underground Treatment Floating Treatment Wetland (FTW) FTW plus aeration
Cost/lb. $1,554 $2,460 $533 $220 $280 $830 $83 $35
Data for 1-6 are from State of Minnesota Public Works report 8: BioHaven area of 2500 ft2 and thickness of 27 inches 8A: Rate of 0.13 lb/ft3/yr (MSU test pond) 8B: Rate of 0.035 lb/ft3/yr (Wiconisco) Capital costs amortized over 30 years at 5% interest (factor of 0.065)
Wiconisco, Pennsylvania 2013 Estimate Cost: $50,000 ($20/ ft2) Area: 2500 ft2 Thickness: 8 inches Annual O&M Costs: Electricity: $0 Monitoring: $3,900 (1 hr/wk @ $75/hr) Total: $3,900 Annualized Capital + O&M: $7,150 Removal: 87 lb / yr Removal rate: 0.052 lb/ ft3/yr Cost: $83/lb Mermaid Pool, net removal (2011 data) Capital costs are amortized over 30 years at 5% interest (factor of 0.065)
Wiconisco, Pennsylvania 2013 Best Case Estimate –Plus Aeration Cost:
$250,000
Area:
2500 ft2
Thickness: Annualized Capital Cost over 30 yrs: Annual O&M Costs:
27 inches $16,250 Electricity: $1,200 Monitoring: $7,800 (2 hrs/wk @ $75/hr) Total: $9,000
Annualized Capital + O&M: Removal: Removal rate: Cost:
$25,250 731 lb / yr 0.13 lb/ ft3/yr $35/lb
MSU test pond run 34, total (aeration + circulation) Capital costs are amortized over 30 years at 5% interest (factor of 0.065)
