POSTER PRESENTATION ABSTRACT THE UPGRADING OF LAGOON-BASED WASTEWATER TREATMENT SYSTEMS IN NORTHERN AREAS USING HIGH PERFORMANCE AERATED LAGOON-AERATED

ENGINEERED WETLAND SYSTEMS 12th INTERNATIONAL CONFERENCE ON WETLAND SYSTEMS FOR WATER

POLLUTION CONTROL Venice, Italy, Oct. 4-9, 2010

James Higgins1* and Martin Hildebrand2,

1. Stantec Consulting, Mississauga, ON, Canada 2. Nelson Environmental, Winnipeg, MB, Canada

Many smaller communities in Canada and northern US States carry out their wastewater treatment (WWT) using two or more large facultative lagoons. Some of these lagoon-based WWT systems discharge continuously to receiving waters but in most cases discharge is seasonal. The advantage of these systems is that they are simple to build and operate, and require only minimal maintenance and attention. However, increasingly stringent discharge criteria that they cannot meet, especially for ammonia and phosphorus, coupled with the liabilities associated with long term build up of sludge in them are now forcing many communities to consider upgrading them. One promising new method for doing so is to upgrade one or more of the lagoons into a high performance aerated lagoon (HPAL) and to follow treatment in it with treatment in an aerated sub-surface flow engineered wetland (EW) located in a drained part of the one of the cells of the lagoon system. (EWs are a special, advanced, semi-passive kinds of constructed wetlands in which operating conditions are more actively manipulated and controlled than is usual with ordinary CWs. They are very much smaller and much more efficient than ordinary CWs, and are more economic to build and operate than conventional [mechanical] wastewater treatment plants [½ to 2/3 the cost].) The paper will review the design & engineering of three HPAL-EW lagoon upgrade projects along with pilot-scale wetland treatability testing carried out in advance of them during which the kinetic and other scale-up parameters needed to design the full-scale facilities were determined. It will demonstrate that such advanced wetland-based facilities can operate with continuous discharge even under the severest winter conditions while still meeting the most stringent discharge criteria. * Corresponding author jim.higgins@stantec.com

An Environmental Assessment (EA) process is underway aimed at defining a wastewater treatment system to replace/upgrade an existing facultative lagoon-based sanitary wastewater treatment facility (the existing WWTF) of the Town of Northeast Manitoulin and the Islands, ON (NEMI). One alternative being evaluated is to use an Engineered Natural Wastewater Treatment (ENWWT) System and this Design Basis Report (DBR) at the Conceptual Design level presents two options for such a system which will be capable of operating year round even under the coldest winter ambient air temperatures. An ENWWT System for NEMI will involve unit operations for primary treatment (settling, coagulation/precipitation), secondary treatment (biological treatment), tertiary treatment (chemical and physical treatment for phosphorus removal) and disinfection (UV). ENWWT Systems are those where all

or part of the secondary treatment step involves kinds of natural biological treatment, in this case the well-proven gravel bed aerated Submerged Attached Growth Reactor® (SAGR) technology. The purpose of this DBR is to define ballpark sizings and costs for both an ENWWT System which utilizes as much as possible of the existing, lagoon-based WWTF (the Upgrade Case) and, for comparison, one for a new, stand alone ENWWT System (the Greenfield Case) assuming such could be located on a 10 ha designated expansion property just west of the existing lagoons. Rather than the twice-a-year seasonal discharge of the existing facultative lagoon-based WWTF, the new ENWWT System will be designed for continuous discharge to an adjacent municipal drain. For surface discharge, the main contaminants of concern (CoCs) will be dry ditch ones including organics (quantized in mg/L [ppm] as carbonaceous Biochemical Oxygen Demand, cBOD5), suspended solids (quantized in mg/L as total suspended solids, TSS), ammonia (quantized in mg/L as ammonia nitrogen, NH3-N), phosphorus (quantized in mg/L as total phosphorus, TP), and pathogenic bacteria (quantized as the number of colony forming units per 100 mL of an indicator species of bacterium, Escherichia coli, E. coli). Target discharge criteria for either ENWWT System case will be <10/<5/0.05/<100 for TSS/cBOD5/TP/E. coli and non-toxic at >5 mg/L for NH3-N. For the Upgrade Case, the first facultative lagoon of the existing WWTF (Lagoon 1) will be left as is, becoming the ENWWT System’s inlet Sedimentation Pond (Cell 1). (I.e., Lagoon 1 will remain as a facultative lagoon but will add a sedimentation/coagulation unit operation to its function.) Existing Lagoon 2 will be converted from a single cell facultative lagoon into a two-cell high performance aerated lagoon (HPAL) (Cells 2 and 3) by placing a horizontal, (east-west) impermeable floating baffle curtain (barrier wall) across it in the middle and installing an aeration system in it. Effluent from the second HPAL cell will pass out of its southeast corner into two aerated, SAGR cells (Cells 4 and 5) located in part of the existing WWTF’s old, disused Lagoon 3. SAGR effluent will flow to a pair of fluid bed Sand Filters in a Utility Building located on the 10 ha expansion property to the west of the HPAL. Continuous backwash from these filters will be pumped to join influent raw sewage entering Lagoon 1. Sand Filter effluent will be UV disinfected and flow via an outfall/compliance structure to the receiving waters, a municipal drain, Howland Drain #2. The estimated capital cost for this upgrade is $3.0MM. For the alternative Greenfield Case, a new HPAL impoundment containing a new Sedimentation Pond and three partial mix HPAL cells would be excavated from open ground towards the north end of the expansion property. This impoundment would contain two sections, a northern one containing a smaller, inlet Sedimentation Pond and a first partial mix cell of the HPAL separated by a floating baffle curtain; and a southern section containing two more partial mix cells separated by a similar baffle curtain. Effluent from the HPAL would flow south into a pair of SAGR cells located just south of the HPAL impoundment. SAGR effluent would be treated in the same manner as that for the Upgrade Case. The estimated capital cost for this upgrade would be $3.7MM. 2.0 Existing Little Current Lagoon-Based Wastewater Treatment Facilities NEMI’s current sewage system involves gravity sanitary sewers and four pumping stations for a town of about 1850 people, and a pressure sewer from a lift station to the lagoon-based WWTF which is located at a site about one km south of the town (the Site). Currently, there are three lagoons at the Site, of which two (Lagoons 1 and 2) are in use and one (Lagoon 3) is classified as disused. Lagoon 1 in the NE corner of the Site is roughly rhombiodal in shape, has a surface area of about 4.1 ha, and has a design volume of about 62,000 m3. Lagoon 2 is located on the west side of the Site, is rectangular in shape, has a surface area of about 4.5 ha, and has a design volume of about 69,000 m3. Currently un-used Lagoon 3 is south of Lagoon 1, is triangular in shape, has a surface area of about 2.4 ha and has a design volume of about 40,000 m3. It is understood that Lagoons 1 and 2 were recently de-sludged, but Lagoon 3 was not and parts of it are overgrown with vegetation. Maximum water depths in the three lagoons are 1.52m, 1.67m and 1.97m, respectively.(It is noted that these depths are relatively shallow compared to those of many other facultative lagoons, and this may indicated difficult-to-excavate material - i.e., rock - beneath

them). Figure 1 shows the location of the Site, while Figure 2 depicts the lagoons and Figure 3 shows their layout. Figure 1: Little Current Lagoons Location

Figure 2: The Little Current Facultative Lagoons

Figure 3: Little Current Lagoons Layout

As may be seen from Figure 1, the receiving waters for the existing lagoon-based WWTF, Howland Drain #2, runs east then south through various ditches into Howland Drain #3 to the southeast and thence into the Strawberry Creek Wetland which in turn discharges into Lake Huron. The existing WWTF is discharged in Spring and Fall into Howland Drain #2 and has a design retention time of 180 days. Phosphorus removal is provided by the surface distribution of ferric sulphate during open water periods.

Discharge criteria for the existing WWTF are <25/<30/<1 mg/L for BOD5/TSS/TP under amended C of A No. 3-0059-78-006, dated October 1993. There is no ammonia criterion. 3.0 The ENWWT System For either the Upgrade Case or the Greenfield Case, an ENWWT System will involve an inlet Sedimentation Pond; a HPAL; SAGR cells; fluid bed Sand Filters and UV disinfection. The HPAL partial mix cells will be aerated using fine bubble diffuser tubing suspended in the water near the bottom of each cell, and receiving air from blowers via floating laterals on the cell water surfaces. Where two HPAL cells occupy any impoundment, they will be separated by impermeable floating barrier curtains. Water flow through these floating barrier curtains will be via openings in them. The aerated lagoon process will be such as to maximize aerobic digestion thereby minimizing organic sludge production. The main purpose of the HPAL (and its upstream Sedimentation Pond) will be to remove most of the sewage's TSS and cBOD. Water exiting from the HPAL will be divided into two streams in a concrete Splitter Box located in the northern berm of the SAGR impoundment which will contain two SAGR cells in parallel. This Splitter Box will use adjustable weirs to divide the SAGR influent stream. The two SAGR cells will be surrounded by and separated from each other by earthen berms with 3:1 outside slopes and vertical (1:1) inside walls supported by wood framing. Berm tops will be 3m wide. Each cell will be filled with 15mm washed and screened gravel substrate, overlain with a 0.2m thick layer of insulating mulch. Freeboard above the mulch will be 0.7m. The dry-surfaced SAGR cells will not be vegetated. Influent will enter each of the SAGR cells via two perforated inlet distributors in distribution chambers oriented perpendicular to flow, one for summer operation and one for winter. Water being treated will move through the SAGR cells horizontal sub-surface flow (HSSF). Treated effluent will be collected in a perforated outlet distributor pipe at the base of the substrate gravel at the downstream ends of each SAGR cell, and flow from it into small concrete control structures on the downstream berm. Each of the control structures will contain a swivel riser pipe which will allow the setting of the water level in the upstream cell. Nominal wastewater retention time in each SAGR cell will be 20 hours at design flow rate, were the cell to operate alone. While each SAGR cell will be able to treat the entire flow alone, normal operation will be with both operating. The SAGR cells will be designed for zero organic sludge formation. The SAGR cells’ main purpose will be to reduce ammonia nitrogen to non-toxic levels whatever the loading or temperature. ENWWT design temperatures will be 0.5 ºC in winter and 25 ºC in summer, and the system will be designed for continuous discharge, 12 months a year at a projected average sanitary sewage flow rate of 1,100 m3/d. Influent sewage alone may not contain sufficient alkalinity (~10 mg CaCO3/mg NH3-N) to allow complete nitrification in the SAGR Cells. To increase feedstock alkalinity to the required levels, a chemical dosing system for 50% NaOH addition and a caustic storage tank will be part of the ENWWT System design addressed herein. Effluent from the SAGR cells will flow into 2-pass FeCl3-dosed, vertical, fluid bed Sand Filters located in a Utility Building located to the west of the HPAL. The purpose of the Sand Filters will be to reduce phosphorus to negligible levels (<0.05 mg TP/L) and polish the treated wastewater. (For the purposes of the Conceptual Design, it will be assumed that the technology used will be the BluPro® type supplied by Bluewater Technologies, but there are other similar kinds available.)

Blowers for the HPAL and the SAGR cells also will be located in this Utility Building along with their control panel. Also found in the Utility Building will be ferric chloride and caustic tankage; chemical injection equipment for FeCl3 and NaOH which will be delivered to the Site periodically by truck; a backwash pump and the Sand Filters’ separate air blower; an effluent flow meter; an autosampler; and electrical equipment. A new power line from Highway 540 will connect to a transformer on a pad beside the Utility Building to provide electrical power to the ENWWT System. (The attached ECEs allow for this power connection but not for any upgrade of power lines along Highway 540, should such be required.) A paved access road will run SW from Highway 540 to the west side of the new Utility Building where a paved parking lot and chemical truck unloading area will be built. Should the client wish, the Utility Building can be expanded to include a Site office. (Costs for this are not included in the ECEs.) Sand filter effluent will flow through UV disinfection equipment located either in the Utility Building or alongside of it. Continuous backwash from the sand filters plus caustic to adjust sewage alkalinity will be pumped back from the Sand Filters to join the influent sewage stream entering the Sedimentation Pond. Treated effluent from the UV disinfection unit will flow to the outfall/compliance structure and into Howland Drain #2. All flows in the ENWWT system will be by gravity except the pumped sand filter backwash. Appropriate Engineers Cost Estimates (ECEs) have been prepared for each case and are summarized below. These are available in detail separately (as are more detailed design calculations). Capital costs in ECEs at this Conceptual Design phase may be assumed to be ±30%. The costs of design & engineering, project management, commissioning, land, surveying, geotechnical studies, power distribution system upgrades, lift stations and pressure sewers and their auxiliaries (screens, power, etc.) are NOT included in the costs presented in the ECEs. ENWWT System design will proceed through this Conceptual Design phase (approximately 30% design completion) to a subsequent Detailed Design phase which will involve 50%, 90% and 100% design completion before Tender documents are prepared.

4.0 Design Bases Overall CoC design bases for the Project are as follows: Table 1: Design Bases Influent Effluent Temperature (ºC) 0.5 & 25 - pH (unitless) 8 - TSS (mg/L) 200 <5 cBOD5 (mg/L) 200 <5 NH3-N (mg/L) 35 <5 & non-toxic TKN (mg/L) 40 5 TP (mg/L) 8 0.05 E.coli (CFU/100 ml) 107 <100 Influent sewage CoC values were selected after reviewing actual published data in Ontario Clean Water Agency (OCWA, the operator of the existing lagoon-based WWTF) 2008 and 2009 Monthly Process Data Reports, and averaged for typical municipal sewage. Raw sewage flow rates for the existing lagoon-based Little Current WWTF averaged 925 m3/d in 2008 (range 302 – 6,644 m3/d) and 1,012 m3/d in 2009 (range 421 – 3,252 m3/d). For Conceptual Design purposes, precipitation will be assumed to be equal to evapotranspiration so that that effluent flow of a new ENWWT System (Qo) will approximately equal influent flow (Qi). As is normal in natural wastewater treatment systems involving large impoundments that function as equalization ponds, the new Little Current ENWWT System will be designed to treat the average flow rate of sewage rather than the anticipated peak flow rate for which a conventional mechanical WWT plant would have to be designed if equalization were not available. Accordingly for either case, the design raw sewage flow rate will be set at 1,100 m3/d, an average flow rate anticipated for the future for NEMI. It is assumed that the proposed compliance criteria of Table 1 will be acceptable to NEMI, the local Conservation Authority and to the Ministry of the Environment, which will grant a Certificate of Approval amendment based on them. It is assumed that pre-treatment of the raw sewage occurs at the lift stations in NEMI. For the new ENWWT System, primary treatment will occur by mixing continuous backwash from the tertiary treatment Sand Filters with influent screened raw sewage pumped from the existing lift station in NEMI. Mineral sludge will accumulate in the inlet Sedimentation Pond, both from the influent raw sewage and from precipitated ferric phosphate and ochre in the sand filer backwash as well as from precipitation/coagulation reactions because of excess ferric chloride in the backwash. For the Greenfield Case, the relatively small inlet Sedimentation Pond will require periodic de-sludging, but for the Upgrade Case the recently de-sludged large Lagoon 1 (which would function as the Sedimentation Pond for that case) would probably not require de-sludging for a considerable period. The following table presents expected design bases for the main CoCs for primary treatment. Table 2: Primary Treatment Design Bases Influent Raw

Sewage Effluent from Sedimentation

Pond into HPAL TSS (mg/L) 200 50

cBOD5 (mg/L) 200 95 NH3-N (mg/L) 35 28 TP (mg/L) 8 4 E. coli (CFU/100 ml) 107 ~103 The above effluent values are conservative and assume that 75% of the influent suspended solids (150 mg TSS/L) will be removed in the Sedimentation Pond (Lagoon 1 for the Upgrade Case and a much smaller eastern corner of the northern portion of a new HPAL impoundment for the Greenfield Case), and with these precipitating solids, about 60% of the organics (~105 mg cBOD5/L), 20% of the ammonia (~7 mg NH3-N/L), 30% of the phosphorus (~2 mg TP/L) and 60% of the E.coli will be associated, and thus also will be removed. In addition, about 2 mg TP/L of the influent dissolved phosphorus will precipitate out in the Sedimentation Pond due to excess ferric chloride in the Sand Filter backwash. Precipitated phosphorus in the backwash from the tertiary treatment Sand Filters (which will be continuously recycled) will settle out in the Sedimentation Pond and will amount to about 6 mg TP/L. About 4 mg TP/L of phosphorus (largely dissolved phosphorus compounds) from the raw sewage will be found in the Sedimentation Pond effluent. The HPAL will remove organics in the raw sewage (200 mg cBOD5/L) down to 25 mg/L in the effluent from its third cell. It will operate at water temperatures as low as 0.5 ºC and as high as 25 ºC. The following table presents expected CoC design bases for the cells of the HPAL. Table 3: HPAL Design Bases Influent from Sedimentation

Pond Effluent from HPAL

TSS (mg/L) 50 15 cBOD5 (mg/L) 95 25 NH3-N (mg/L) 28 28 TP (mg/L) 4 4 E. coli (CFU/100 ml) 103 103 Some nitrification might occur in the HPAL but its main purpose will be to remove cBOD5 down to 25 mg/L or lower so that heterotrophic bacteria do not compete with the nitrifying bacteria in the downstream Aerated EW cells. For Conceptual Design purposes it will be assumed that no nitrification occurs in the HPAL. The HPAL would have two partial mix cells for the Upgrade Case and three for the Greenfield Case. Effluent from the HPAL will pass into the SAGR cells whose sizing will be for worse case conditions, reducing ammonia nitrogen in them to below 5 mg/L at a water temperature of 25 ºC in summer, and below 100 ppb of molecular ammonia in winter at a water temperature of 0.5 ºC. The following table presents expected CoC design bases for the two SAGR cells. Table 4: Design Bases, SAGR Cells Influent from HPAL Effluent to Sand Filters TSS (mg/L) 15 10 cBOD5 (mg/L) 25 10 NH3-N (mg/L) 28 <5 summer, < 100 ppb

molecular ammonia in winter TP (mg/L) 4 4* E. coli (CFU/100 ml) 103 <103

*Initially the SAGR cells will remove part of the influent phosphorus by sorption and plant uptake but after a few seasons they will saturate with it, and influent phosphorus to the SAGR cells thereafter will roughly equal effluent phosphorus from them. Phosphorus removal and final filtration of treated water from the SAGR cells will be carried out using the Sand Filters. Final disinfection of the wastewater exiting the Sand Filters will be carried out using the UV Disinfection Unit. The design bases for these final treatment steps will be as follows: Table 5: Design Bases around Sand Filters and UV Influent from SAGR Cells Effluent to Discharge TSS (mg/L) 10 <5 cBOD5 (mg/L) 10 <5 NH3-N (mg/L) <5 <5 & non-toxic TP (mg/L) 4 0.05 E. coli (CFU/100 ml) <103 <100 4.0 Upgrade Case For the Upgrade Case, the design of the ENWWT System will be as described in Section 3 except that existing Lagoon 1 would become the ENWWT’s inlet Sedimentation Pond (Cell 1). Essentially, this impoundment would be left as is. Effluent from it would flow by existing piping to existing Lagoon 2 which would be divided in half and converted into a two-partial mix cell HPAL (Cells 2 and 3) using an impermeable floating baffle curtain across its middle. Water depth in the Upgrade Case’s HPAL would be 1.67m. (This is dictated by the existing lagoon’s water depth, and can be compared with a proposed 4.6m depth in the Greenfield Case’s HPAL [see below] which would be excavated in the expansion area. The larger size of Lagoon 2 will compensate for the lower water depth.) The Upgrade Case’s HPAL cells will not be lined as the existing clay liner in Lagoon 2 is assumed to be suitable for the new situation as well. For the Upgrade Case, HPAL aeration air will be provided by two 40 HP PD blowers, capable of providing 600 SCFM at 4.1 psig. Standby will be provided by the SAGR standby blower. Retention time in each of the approximately 33,000 m3 volume HPAL partial mix cells will be about 30 days (60 days total) Effluent from the HPAL will flow into the two parallel aerated SAGR cells (40m wide by 60m long, 2,400 m2 surface area per cell) (Cells 4 & 5) located towards the western end (see Figure 3) of currently un-used Lagoon 3, part of which will be drained to accommodate them. The SAGR cells will be surrounded by earthen berms made from borrowed material it is assumed will be available on the Site. Displaced sludge and vegetation currently occupying the bottom of Lagoon 3 in the location proposed for the SAGR cells will be removed and placed in the remaining, undrained eastern part of the lagoon. The SAGR cells’ substrate will be 1.4m thick. Water level in the SAGR cells will be set at 1.27 m, just below the gravel surface level. Liner will only be placed on the sides of the SAGR cells, not on their bottoms where it will be assumed that the existing Lagoon 3 liner will suffice. Aeration air for the two SAGR cells will be provided by two 40 HP PD blowers (one operating, one standby) each capable of providing 730 SCFM at 3.7 psig. HPAL and SAGR blowers will be located in the Utility Building which it is assumed can be located alongside and to the west of the HPAL (old Lagoon 2). HPAL and SAGR blowers will be cross-connected so that only one standby will be needed. Effluent from the SAGR cells will flow into the Sand Filters whose effluent will be UV disinfected before discharge into Howland Drain #2.

Blowers, sand filters, chemical tanks, UV disinfection equipment and other infrastructure will be located in the Utility Building and it might also house an office and a lab, although these options are not covered in the Upgrade Case ECE. (Also, an alternative location for the Utility Building might be just near the SE corner of existing Lagoon 2 between it and the SAGR cells. This option would require less SAGR aeration piping but might have logistical and cost disadvantages. This could be evaluated during Detailed Design.) The following sketch shows the process flow for a new ENWWT for Little Current for the Upgrade Case.

The following sketch shows the layout of a new ENWWT for Little Current for the Upgrade Case. Figure 5: Upgrade Layout Drawing

The estimated capital cost to construct the Little Current ENWWT System under the Upgrade Case is $3.0 MM. The following table provides more detail on this ECE estimate. Table 6: Estimated 30% Design Capital Cost Breakdown, Upgrade Case Cost Category Capital Cost

($K) Percent

Mobilization and Demobilization 12.7 0.5 Site Preparation 74.0 2.4 Construction 166.7 5.5 Buildings/Structures 218.6 7.2 Equipment 1,579.9 51.9 Materials 671.9 22.1 Amenities 41.1 1.4 Sub-Total 2,765.0 90.9 Contingency (10%) 276.5 9.1 Total Capital Cost Estimate 3,041.4 100.0 The capital cost estimate of Table 6 assumes a tendered construction contract contractor profit margin of 10% which includes contractor project management, site supervision, bonding, markups, contractor profit, and other unspecified contractor-related costs (e.g., its costs for administrative overheads, site

office, communications, client liaison, etc.). The above capital cost estimate does not include the costs of design & engineering (i.e., the costs of preparing this Conceptual Design and the subsequent Detailed Design), any activities associated with preparing and dealing with construction tenders, any activities associated with licencing & permitting or the EA, activities associated with startup & commissioning, or activities associated with construction supervision. The following table presents the estimated annual Operating & Maintenance costs (O&M) for the Greenfield Alternative (±50%). Table 7: Estimated Annual O&M Costs for the Upgrade Case Cost Category O&M Costs

($K/yr) Labour 79.9 Monitoring 32.5 Maintenance 12.0 Energy 1.5 Chemicals 24.0 Miscellaneous 1.0 Total 151.4 The above costs assume a full-time operating staff of one person, supervisory time at 10% and 30% salary burdens and do not include any markup by a contract operator (e.g., OCWA). Higgins, J.P., Wallace, S.D., Walters, M., Smith, S., Dummond, L. & Mihail , A., 2010a, Developing Engineered Stormwater Wetland Technology to Better Manage Stormwater Runoff Quality, paper to be presented at 12th International Conference on Wetland Systems for Water Pollution Control, Venice, Italy, Oct. 4-9, 2010. Higgins, J.P., Langan, J., & Hildebrand, M., 2010b, The Upgrading of Lagoon-Based Wastewater Treatment Systems in Northern Areas Using High Performance Aerated Lagoon-Aerated Engineered Wetland System, poster to be presented at 12th International Conference on Wetland Systems for Water Pollution Control, Venice, Italy, Oct. 4-9, 2010. Higgins, J.P., Wallace, S.D., Minkel, K., Wagner, R., & Liner, M., 2010a, The Design and Operation of a Very Large Vertical Sub-Surface Flow Engineered Wetland to Treat Spent De-Icing Fluids and Glycol-Contaminated Stormwater at Buffalo Niagara International Airport, paper to be presented at 12th International Conference on Wetland Systems for Water Pollution Control, Venice, Italy, Oct. 4-9, 2010. Wootton, B., Walters, M., Higgins, J.P., Hussian, I., & Blowes, D., 2010, The Integration of an Advanced Phosphorus Removal Technology into an Engineered Wetland System, poster to be presented at 12th International Conference on Wetland Systems for Water Pollution Control, Venice, Italy, Oct. 4-9, 2010.