The purpose of this project: is to evaluate the use of an Aerated Fluidized Bed Reactor (aerated-FBR) combined with Constructed Wetland Treatment (CWT), for reclaiming dairy lagoon wastewater effluent (DLWE). A two- step approach is proposed whereby (a.) ammonium-nitrogen (NH4-N) and orthophosphate (PO4-P) are extracted by precipitation of struvite (MgNH4PO4·6H2O) using an aerated-FBR; (b.) nitrate-nitrogen (NO3-N), total suspended solids (TSS) and dissolved organic carbon (DOC) are removed by CWT to produce irrigation waters. The aerated-FBR-CWT method will reduce livestock farm operation costs by recycling nutrients as struvite fertilizer and reclaiming DLWE as irrigation water
Changing of experiment set-up from swine and dairy farm to dairy only, and expanding work over two growing seasons:
The original proposal for GNE-158 aimed to evaluated the aerated-FBR + CWT set-up both in a dairy and swine farm. During the process of placing the CWT pools at site one, Fulper dairy farm it became apparent that relocating the experiment is not feasible. For this reason, a change of experiment outline was made for conducting the experiment only at the dairy farm site. The rational behind this approach is that since the overall nutrient content, BOD and TSS were significantly higher for dairy site, conclusions from this work will include the treatment needs required for swine wastewater treatment.
Our group is interested in validating this assumption and will look into future study opportunities to optimize this approach to the treatments needs of swine and other livestock wastewater types.
In addition, the duration of the study was extended from one to two research seasons (season I, season II), season I took place through 2018 and season II will take place through March-September 2019.
- Assessment of DLWE properties to determine aerated-FBR-CWT requirements:1. Assessment of DLWE properties to determine aerated-FBR + CWT requirements. The study location: Fulper farm, Hunterdon County. An on-site study will characterize the DLWE, including TSS, BOD and nutrient content, in order to design the most suitable CWT
- Produce struvite fertilizer for crop production by recycling nutrients from DLWE: The aerated-FBR will be used to recover OP and NH4-N from DLWE by induced precipitation of struvite, to be recycled on-site as fertilizer. The measurement of success for aerated-FBR treatment is >70% PO4-P removed with >60% struvite content in the precipitated salt for DLWE.
- Implement CWT to meet primary treatment water discharge requirements: While traditional DLWE treatment does not contribute to farm water balance, CWT can reclaim the bulk of effluent water for irrigation by removing remaining nutrients and contaminants. The current standard for primary effluent treatment is 30/30 mg/L BOD/TSS. CWT will need to reduce the BOD/TSS concentrations accordingly if the water is to be reused. The assumption is that if a consistent and stable CWT system can be constructed to remove nutrients, BOD/TSS requirements can be attained by expanding the system in a series of CWT structures. The measurement of success for CWT is therefore meeting the effluent discharge requirements, making treated DLWE usable for crop
- Industry outreach: Dissemination: The aerated-FBR-CWT method will be promoted by hosting on-site tours of the treatment facility for local producers, high school students and researchers at the RU-NB farm site, and by attending agronomy expo
- STEM outreach: Undergraduate student research: To encourage more students to engage in STEM-related sustainability research, undergraduate students will be directly involved in the project. These students will be supported by National Science Foundation (NSF) Research Experiences for Undergraduates (REU), and Garden State-Louis Stokes Alliances for Minority Participation (GS-LSAMP) programs at Rutgers University-Newark (RU-N). The students will conduct on-site research at the RU-NB farm, compile reports, and present results at local conferences.
- Scientific and public outreach: Publication and presentation: Findings will be published in scientific peer-reviewed journals as part of Mr. Rabinovich’s doctoral dissertation. Results will be presented at national meetings, such as the American Chemical Society (ACS) meetings. Presentations at local events will inform the general public.
Environmental challenges of DLWE:
Dairy cows generate ~20 gallon/day-animal (gal/d-a; estimated for Holstein cow) of DLWE(1), with high concentrations of dissolved nutrients and other components. DLWE is the sum of flush effluents from milking parlors, yards and stalls which is stored in wastewater lagoons. High levels of PO4-P, NH4-N and TSS generate harmful BOD(2), and decompose into contaminants such as NO3-N(3). The common treatment practice is applying DLWE onto fields as fertilizer using cannon sprinklers or spraying vehicles(4). DLWE can impact agricultural soil, groundwater and surface water, and its odor can be a nuisance. The high NH4-N content in DLWE is converted into NO3-N by nitrification, resulting in nitrate contamination of groundwater through leaching. Particulate PO4-P is susceptible to aeolian transport which introduces it to open water sources and contributes to eutrophication.
Sustainability issues being addressed:
Many livestock farms also grow a portion of their livestock feeding crops on site, and maintaining soil fertility is a significant component of operation costs. Spraying DLWE over crop fields is an acceptable, but less sustainable approach to waste disposal. Moreover, in events of high rainfall and rising groundwater table, the constant need to dispose the lagoon effluent can be costly in and labor-intensive.
In addition to environmental problems, the spraying method for disposing DLWE also presents agronomic disadvantages. Non-composted DLWE is a lower-grade fertilizer compared to compost and mineral fertilizers with regards to nutrients chemical stability and provides an imprecise nutrient application(5). The higher volatility and bioavailability of NH4-N, compared to PO4-P in soils often results in excess P application to meet the crop N demand, or the need for additional fertilizer. In addition, excess water is applied via spraying. Therefore, DLWE spraying has low water preservation and fertilizer application efficiencies.
Aerated-FBR-CWT reclaims key nutrients, PO4-P and NH4-N, as struvite fertilizer and produces treated water for targeted irrigation. The 1:1:1 ratio of N:P:Mg distinguishes struvite as a PO4-P, NH4-N and magnesium (Mg) a macronutrient(6). Application of Mg benefits the soil structure, reducing swelling and the exchangeable sodium ratio in clay soils(7). Production of struvite combined with irrigation water maintains the regional mass-balance of these resources as less fertilizer and water are required from outside the farm resource-cycle.
Reclamation of DLWE:
Preliminary work used a bench-scale aerated-FBR to reclaim struvite from swine and dairy lagoon wastewater. Results showed 64% PO4-P removal for dairy. P removal was achieved through Mg addition and increasing the pH to 9. Solids collected from aerated-FBR are mostly struvite (60-55%), mixed with calcite (CaCO3). Use of CWT to treat wastewater is well established with two major treatment concepts of submerged and open water flow, with variations depending on local climate, fauna and biota. The research group is currently working on testing an adaptation to dairy CWT treatment that aims to reduce both TSS and BOD levels in LWE to meet 30 mg/L discharge standards.
Through the first work season of the current pilot project through 2018, A 40-Liter pilot scale aerated-FBR and three CWT pools, ~3000-Liter each, were placed at the Fulper farm site. The aerated-FBR was tested and modified to meet the needs of continuous operation. An open code farm management software was implemented into the reactor microcontroller and evaluated. The CWT were populated with native wetland plants and their viability was tested in the present of effluent from the aerated-FBR outflow.
Economic impact of aerated-FBR-CWT:
The economic impact of implicating the aerated-FBR + CWT method is currently under review and will be make public at the conclusion of 2019 experiment season.
- Herbert, N.; Stettler, D.; Zuller, C.; Hickman, D. Agricultural waste characteristics. National engineering handbook. Part 651, Agricultural waste management field manual; 210–VI–AWMFH; U.S. Department of Agriculture, Natural Resources Conservation Service: Washington, DC, 2008; https://www.wcc.nrcs.usda.gov/ftpref/wntsc/AWM/handbook/ch4.pdf (accessed Jan, 2019).
- Sharpley, A.; Jarvie, H. P.; Buda, A.; May, L.; Spears, B.; Kleinman, P. Phosphorus Legacy: Overcoming the Effects of Past Management Practices to Mitigate Future Water Quality Impairment. Environ. Qual. 2013, 42, 1308-1326.
- Van Es, H.; Sogbedji, J.; Schindelbeck, R. Effect of manure application timing, crop, and soil type on nitrate leaching. Environ. Qual. 2006, 35 (2), 670–679.
- Sharpley, A. N.; Daniel, T.; Gibson, G.; Bundy, L.; Cabrera, M.; Sims, T.; Stevens, R.; Lemunyon, J.; Kleinman, P.; Parry, R. Integrating P and N Management in BMPs. Best management practices to minimize agricultural phosphorus impacts on water quality; ARS–163; U. S. Department of Agriculture Agricultural Research Service: Washington, DC, 2006; 20-30.
- Chai, L.; Kröbel, R.; Janzen, H. H.; Beauchemin, K. A.; McGinn, S. M.; Bittman, S.; Atia, A.; Edeogu, I.; MacDonald, D.; Dong, R. A regional mass balance model based on total ammoniacal nitrogen for estimating ammonia emissions from beef cattle in Alberta Canada. Environ. 2014, 92, 292-302.
- Rabinovich, A.; Rouff, A. A.; Lew, B.; Ramlogan, M. V. Aerated Fluidized Bed Treatment for Phosphate Recovery from Dairy and Swine Wastewater. ACS Sustainable Chem. Eng. 2017 6 (1), 652-659.
- Latifi, N.; Rashid, A.S.A.; Siddiqua, S.; Horpibulsuk, S. Micro-structural analysis of strength development in low-and high swelling clays stabilized with magnesium chloride solution—A green soil stabilizer. Appl. Clay Sci. 2015, 118, 195-206.
- https://github.com/kizniche/Mycodo (Accessed Jan, 2019).
- Roadcap, G.S.; Kelly, W.R.; Bethke, C.M. Geochemistry of extremely alkaline (pH> 12) ground water in slag‐fill aquifers. Groundwater, 2005, 43 (6), 806-816.
In order to meet the project objectives, the performance of the two-step aerated-FBR- CWT approach is evaluated in pilot scale at on dairy fam site. This treatment includes applying struvite recovery, followed by contaminant removal for wastewater. Dairy lagoon wastewater effluent (DLWE) includes all the liquids generated in the farm yard, stalls and milking parlor by livestock and maintenance procedures. These are drained to a separation pool with a two-chamber cell connected by an overflow canal. The bulk of the solids sink to the bottom of the first cell, while effluent overflows to the secondary cell. From there the effluent is drained into the storage lagoon.
The two-step treatment method uses aerated-FBR + CWT (Figure 1) applied in a continuous flow canal system. DLWE is pumped into the aerated-FBR and from there, the outflow will be directed into the CWT canal for primary wastewater treatment.
Assessment of the DLWE chemical properties was done to determine DLWE treatment requirements using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Ultraviolet Visual (UV-Vis) spectroscopy, quantifying major ions and dissolved nutrient content.
The acescent of TSS is done using gravimetry with 1.5 µm glass fiber filters, in accordance with EPA method 160.
Preliminary assessment of DLWE at farm, acquired using colorimetric analysis (Hach DR 3900) and ICP-OES (Agilent 5110), are presented in Table 1.
DLWE nutrient removal using aerated-FBR:
Effluent from the lagoon is prefiltered using 55 gallons, ¾” rock matrix filter using submerged seepage pump and then pumped into the aerated-FBR reactor with a peristaltic pump. (Figure 2) The rock matrix filter is constantly filled where a floating pump switch shut the pump off when the filter is full. A drain valve is used to empty the filter for maintenance and biofilms removal periodically. Maintenance is done by applying one gallon of concentrated bleach and flushing the reactor/ filter system several times to remove bleach traces.
The reactor pH and effluent temperature are logged using a raspberry Pi microcontroller. The Raspberry pi system use MyCodo software(8), an open code platform that allow to collect data and apply agricultural environment control. The Mycodo feedback setting collect analogical sensors data such as pH, oxidation reduction potential (ORP), temp (T), etc. using data isolation mount with appropriate digital signal convertors (Atlas scientific). The Mycodo program then govern power relay system to adjust pH in the aerated-FBR to meet nutrient recovery needs using a peristaltic pump (Fisher Scientific FH100).
Figure 2: Aerated-FBR placement at dairy farm research site
Figure 1.1: The components of the pilot scale aerated-FBR
Figure 1.2: Reactor system placement
Figure 1.3: Input of DLWE into the aerated-FBR
Figure 1.4: Micro-controller set-up
Nutrients recovery is facilitated by the precipitation of struvite from LWE to remove PO4-P from DLWE. The struvite mineral is made up of Mg(2+), PO4(3-) and NH4(+) ions in a 1:1:1 ratio. Struvite precipitation can be described by the following reaction:
Mg2+ + NH4+ + PO43- + 6H2O = MgNH4PO4·6H2O
Struvite has a low solubility product with Ksp=10-13.26, indicating that mineral dissolution is low, contributing to its properties as a slow-release fertilizer. For DLWE both the Mg (~0.01M) and PO4-P (~0.0015 M) concentrations tend to be consistently lower than NH4-N (~0.033M), making them the limiting factor for struvite formation. Another factor affecting struvite formation is the high calcium concentration of DLWE that can promote the formation of other PO4-P minerals such as hydroxylapatite (Ca5(PO4)3OH). This results in an inferior fertilizer with regard to P availability in soil solution due to the extremely low solubility of hydroxylapatite (log Ksp= -44.33) compared to struvite. Adding supplementary Mg to the effluent as magnesium chloride hexahydrate (MgCl2*6H2O) can promote the formation of mostly struvite salts and reduce the apatite content, while adding potassium(K) PO4-P (K2HPO4) could remove excess NH4-N. The rate of precipitation is also driven by pH, where the reaction time, represented as hydraulic retention time (HRT), is the time required for nutrient removal to reach treatment goals at pH 9. The pH of lagoon DLWE ranges from 7.5-8, depending on the depth of the lagoon, DLWE type (open lagoon, closed tank) and the time of year. To meet the pH 9 requirements in the aerated-FBR, the pH can be increased by carbon dioxide stripping with aeration and the addition of sodium hydroxide (NaOH) titration.
The aerated-FBR is a small field size reactor with a 40-liter volume. The reactor will be housed near the DLWE source in the farm operational area, receiving power supply from the nearby farm facility. A peristaltic metering pump (Masterflex) will be used to load DLWE into the reactor. At an inflow rate of 10 gallons/hour the aerated-FBR will have ~60-120 minutes HRT allowing enough time for precipitation, and the ability to treat up to 240 gallons of DLWE per day. The main chamber will generate the bulk of struvite crystallization as incoming DLWE becomes saturated and interacts with struvite colloids. For initial struvite nucleation, 0.1g/L (4 g/reactor-run) of fine-grained struvite powder will be added as seeding for struvite crystal nucleation, acting as a template for crystal growth and precipitation. In order to supersaturate struvite in the DLWE, alkaline conditions are required. Aeration at a 45 cu.ft. air per cu.ft. DLWE-hour will be used to raise pH up to ~pH 8.5 by CO2 stripping, using a linear diaphragm air compressor (Thomas). To further induce precipitation, and maximize removal of NH4-N, 0.25 N NaOH, 1 M MgCl2*6H2O and/or 1 M K2HPO4 solutions will be added using three Fisher brand peristaltic pumps based on experimental treatment. The pH will be measured in the reaction chamber using an inflow Cole-Palmer pH electrode. The main chamber has an overhead mixer (Arrow 1200) with a PTFE coated mixer shaft and a 4-inch blade, generating a circular flow to promote crystallization and generate suspended particles, preventing struvite sedimentation on the reactor walls. A narrow-slit passage connects the continuous flow stirred-tank reactor chamber (CSTR) and fluidized bed (FB) chambers in the aerated-FBR. The FB conical prism reduces the DLWE flux from an average of 20 cm/min at the entry slit, to an average 2 cm/min at the point of exit. As the struvite particle velocity slows, they cease to be suspended and vertical settling transports crystals downward. This circular motion separates the salt solids from the effluent leaving the reactor, allowing the crystals to undergo an extended growth period. When the crystals reach a reasonable particle size (~0.125 inches), they can be easily separated from smaller particles by reducing the mixing speed and collection from the valve at the reactor base. The fluidized bed formation is tuned by adjusting the mixing speed of the overhead stirrer. Minerals harvested from the aerated-FBR will be air-dried in incubation at 95 oF for 72h and analyzed with X-ray diffraction (XRD; Bruker, D8) and ICP-OES (Agilent, 5110) to determine their elemental and nutrient contents. Additional analysis using simultaneous thermal analysis (STA) and evolved gas analysis (EGA) will evaluate the thermal stability of fertilizer solids collected from
aerated-FBR (Netzsch Perseus STA 449 F3, coupled with Bruker Alpha FTIR). Such analysis will compare thermodynamic factors such as enthalpy of ammonia emission and mass loss rates between collected struvite and commercial fertilizers.
DLWE primary treatment with CWT:
CWT allows microbial, flora, chemical and mechanical processes to remove contaminants from DLWE. Our CWT system (Figure 3) will use a three-cell setting, based on the Environmental Protection Agency (EPA) CWT manual, combined with recommendations for LWE-CWT tested by Agricultural Research Organization (ARO) in Israel, for dairy farms. The CWT cells are series in a column of canals and consist of Free Water Surface (FWS) and Vegetated Submerged Bed (VSB) cells settings (Figure-2). The HRT requirement for each cell is two days, for a total HRT of six days. Each CWT cell consist of wood beam frame with plywood support and 45-micron synthetic rubber (EPDM) liner for effluent containment. The total DLWE mass in the CWT is the total volume times the cell porosity. For our assessment, we will use recommended porosity values of 0.7, 0.3 and 1 for the FWS (emerged plants), VSB (submerged flow with plant cover) and open FWS (submerged plants). Our three-cell canal combined size is 1.2 m (4 ft) wide, 0.6 m (2 ft) deep and 12 m (40 ft) long. The total pore volume of the CWT canal is ~5800 L, and with a DLWE intake of up to 908 L/day (240 gallons) coming from the aerated-FBR, will meet the 6-day HRT needs. The CWT cells are placed on an operational space near the aerated-FBR.
Figure 3: CWT placement
Three pools are connected with overflow canals, where effluent enters the VSB pool (1) then the FWS pools (2,3). The pools have a 2-1” height difference, ensuring flow direction from pool 1-3 despite soil compaction under CWT weigh.
CWT cell 1: Vegetated Submerged Bed (VSB): The first CWT cell is VSB cell (Figure 4) filled with local river pebbles (non-carbonate rock), roughly 1-3 inch in diameter. The top 6 inches of the cell are sandy loam / pea pebble with vegetated wetland plants. The flow of DLWE through the cell serve two purposes: a. remove BOD and TSS by sorption/ metabolism of biofilm activities; b. allows for aerobic respiration to lower pH of effluent coming from aerated-FBR at ~pH 9.
Figure 4: Outline of VSB placement
Figure 4.1 Construction of VSB pool: Liner of EPDM, with sand base later and DLWE insert point in 0.5-inch PVC pipe
Figure 4.2 DLWE insert point is covered with 3/8” crashed roch, this allow better TSS retention and ease of access to effluent entry point for maintenance
Figure 4.3: VSB pool is filled with 1-3” rocks and covered with sand and crashed rock mixture. Plants in figure are smooth cordgrass and swamp rose mallow.
A combination of salt tolerant plants is evaluated for the VSB, including: Hibiscus moscheutos (Swamp Rose Mallow); Spartina (Smooth cordgrass); Alkali bulrush; Inland saltgrass; Alkaline milkweed; Scirpus validus (soft stem bulrush) and Juncus effusus (common rush). Following season I of this study (2018) the swamp rose mallow and smooth cordgrass showed promising vitality response and after consultation with wetland specialists (Pineland Nursery, NJ; aquascapes unlimited, NJ; Granite seeds, CO; river refuge seeds OR) the above plants are cultivated to ~2-5 ft size in our research nursery prior to field placement. For the purpose of this study a population establishment observation will access which plants species retains vitality over the experiment period. The parameters we will monitor are overall survival rate, growth and stress symptoms (leaf bleaching, dwarfish plants, survival rates).
CWT cell 2-3: Free Water Surface (FWS): the FWS is a fully vegetated water pool with a 6-inch turf soil bed to support salt / pH tolerant emerging water plants: Phragmites australis (common reed), Typha anagustifolia (Narrow Leaf Cattails), Pontederia cordata (Pickrel Rush), Acorus americana (Sweet Flag) and populated with floating Lemna minor (Duckweed) plants. Lemna cover of the water surface creates mildly anaerobic conditions needed to promote flocculation, sedimentation, adsorption and the anaerobic reactions that degrade nitrate.
The CWT discharge is through a 0.75 inch flexible PVC tube at the base of the rear wall of cell three. By adjusting the height of the outflow tube end, the water level in the CWT canal and outflow rate can be regulated.
To evaluate the efficiency of aerated-FBR-CWT, samples of DLWE effluent will be analyzed prior and after treatment. The quality of fertilizer produced at the FB-reactor will be evaluated based on the struvite content in the fertilizer. Prior to this study, ICP- OES analysis will be used to quantify the ionic content of nutrients and pollutants. DLWE samples will be taken twice a week at 8am and 4pm over a two-month period at each site, to account for fluctuations in CWT operation with thermal and fauna activity. Samples will be taken from DLWE at entry to the aerated-FBR, entry to the CWT and outflow from the CWT, for a total of 192 samples. Each sample will be filtered to separate solids with 0.45 micron filter and acid digested prior to analysis. Treated samples will be analyzed in duplicate for COD, NH4-N, NO3-N using DR3900 spectrophotometer (Hach) analysis kits and in triplicate for PO4-P, using ICP-OES (Agilent). TSS analysis of samples will be done by evaporating in a furnace at 105 deg-C. The pH and effluent temperature at the FB-reactor entry, and the CWT entry and outflow will be measured at the time of sampling.
Evaluation of CWT plants phytotoxicity values for DLWEs pH, salinity and nitrate:
In order to get an improved prediction of how well CWT plants can be established in DLWE treatment, we will test the effect of alkaline pH, Mg salinity and MO3-N on narrow leaf (NL) Cattail- a hardy model CWT plant. NL-Cattail in 1” plugs were purchased from a nursery (aquascapes unlimited, NJ) and revived from dormant conditions in grow chamber under ~500 µmole-photon/m2s fluorescent light (216w, 6500k, 12h/day at 3 ft). During the experiment growth period, lighting will be adjusted to 1000 µmole-photon/m2s.
For each treatment (pH 8-10, Mg 0-20mM, NO3-N 0-50 mM) Plants will be grown in 10 L bath. Growth parameters will be evaluated through the 4-week grow period and by compering biomass and elemental composition of harvested plants.
Evaluating phosphate availability for struvite-calcite fertilizer recovered from DLWE
Phosphate response in turf grass (Kentucky blue turfgrass) will be compared between struvite-calcite fertilizer recovered from DLWE and commercially available fertilizers. treatments will evaluate the effects of phosphate source, calcite application and Mg, on plants growth over a 42-day period. Turfgrass plants are sensitive to P availability with short growing cycle and of commercial interest, making them a suitable model plant. These plants also require calcite application in most soils, making them a suitable plant for testing the struvite-calcite fertilizer.
Plants will be grown in 3.5” pots with low P soil (sand) and medium P soil (sandy loam field sample), where soil are pre-mixed with equal N, P, K, calcite, Mg applications for the different fertilizers sources. For each pot, leachate and nutrients extracted from soil sample and plant biomass are analyzed for elemental composition using ICP-OES.
Evaluation of aerated-FBR+ CWT through season I of field work:
Through the calendar year of 2018, the setup of aerated-FBR operated at the Fulper Farm site. There were several challenges with running aerated-FBR reactor and CWT pilot design that require some fixing, mainly with influent intake setting and effluent pH entering the CWT.
Problem 1: Excessive foaming in reactor mixer due to aeration, solution was to rebuilt the reactor top and install a sealed bearing stirrer guide (Universal Stirrer Guide, Cowie) for the reactor mixer shaft.
Problem 2: Constant clogging of influent intake. Pumping of lagoon effluent was constantly clogged by biofilms and debris. Solution was to install a prefiltration device made of a 55-gallon barrel filled with crushed rocks. A sewage pump fills the barrel and the aerated-FBR pump from the filtered effluent collected in the barrel. This set up tend to create biofilms inside the barrel, so it is cleaned periodically with 5 gallon of bleach and washed with DLWE to remove bleach traces.
Problem 3: pH of effluent entering the CWT. Through the beginning of the growth season the pH in the CWT pools was going from 9 to ~8 in the first SVB (rock matrix) pool, but towards the end it went up and at the peak of the summer it went as high as pH 10 in the end of august. This suggest transition to anaerobic conditions and was followed with pH of free water surface pools going as high as ~9 with regression in wetland plants growth.
Outline for season II of CWT testing:
The CWT will be further evaluated over the period of season II through March-August 2019 where 1st CWT pool will remain a VSB pool and 2nd,3rd pools (FWS) will both be populated with emerging plants (in season I, 3rd pool was populated with submerged plants)
The stages of evaluating CWT treatment are:
Stage 1: Raw DLWE remediation: Untreated DLWE is pumped directly from the lagoon into the CWT to evaluate the use of CWT for TSS, BOD removal
Stage 2: Combined aerated-FBR + CWT with air sparging(9) application for the VSB (pool 1) to lower DLWE pH. Air sparging is the process of pumping air into soil aquifers. In wetland treatment of alkaline wastewater this process showed to lower pH form pH12 to pH ~8 over a 24-76h HRT period. The function of air sparging is to promote aerobic respiration that release CO2 to form carbonic acid and lower the groundwater pH. To achieve an effective air sparging, 30 l/min air will be pumped into the VSB effluent point of entry.
Stage 3: Combined aerated-FBR + CWT with air sparging and the addition of bacillus licheniformis microbial treatment. The soil bacteria bacillus licheniformis is used in wastewater treatment to improve flocculation that remove TSS, overall nutrients removal and BOD consumption. The alkaline pH tolerance (optimum ~8, tolerate pH 9) make it a suitable candidate for inoculation in the VSB pool. Sample of bacillus licheniformis (Bio-Cat) is commercially available and licensed to field use. Dry bacteria are revived in yeast extract/ salt broth, grown to 5-gallon media and used to inoculate the VSB pool.
Stage 4: Combined aerated-FBR + CWT without air sparging. Test the vitality and performance of CWT without measures for pH reduction.
Education & Outreach Activities and Participation Summary
The finding from 2018 season were presented at:
- Poster session presentation at the Our Farm Our Future national SARE and NCAT, ATTRA meeting, Saint Louis Missouri on April 2018.
- Two on-farm tours (July, September 2018) at Fulper farm (NJDEP, General public field day). First farm tour included members of the Bureau of Environmental Analysis, Restoration and Standards and local NRCS personnel (~8 participants). Second farm tour included local members of the farming community, NJDEP, Academic faculty from Rutgers, NJIT and CCNY and USDA personnel (total ~25 participants).
- A national meeting of the American Chemical Society (ASC) through an oral presentation session (Fall 2018) with ~15 researchers from the environmental and geochemical research community.
- Princeton agricultural society October meeting 2018. Ongoing work was presented to ~25 members of the Agricultural society.
- Environmental engineering course at City College of New York (Dec 2018), work was presented to a class of 35 college students.
Research work from aerated-FBR is being processed into a scientific publication, to be published after the conclusions from season-II.
Technical training materials:
- A training tutorial webinar is currently being produced to assist implementing the microcontroller developed for GNE-158 into general agricultural sustainability practices.
- A best management recommendations document is currently being prepared for applying aerated-FBR and CWT for DLWE treatment.
Follow up research collaboration:
- Study looking into the application of aerated-FBR fertilized in tropical soils, Universidade Federal de Viçosa, Brasil.
- Study looking into P response with turf grass for aerated-FBR solids, Rutgers Agricultural extension, New Brunswick NJ.
Project outcome will be updated throughout season II of field work (March-August 2019)