2017 Onsite Wastewater Mega-Conference Concurrent Session Abstracts Tuesday, October 24, Track: Technical Nitrogen

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1 2017 Onsite Wastewater Mega-Conference Concurrent Session Abstracts Tuesday, October 24, 2017 Track: Technical Nitrogen 8:20 AM 9:10 AM Nitrogen Removal Using Saturated Up flow Woody Fiber Media Larry Stephens Nitrogen in raw wastewater is predominately in the forms of organic nitrogen and ammonia. Well-developed aerobic treatment processes biologically convert these forms of nitrogen to nitrates (nitrification), the oxidized form of nitrogen. After this first step, biological nitrogen removal requires the reduction of nitrate to elemental nitrogen gas (denitrification) that is released to the atmosphere. This step requires the wastewater containing the nitrate to pass through an environment low in dissolved oxygen with a food source (in the form of carbon) for denitrifying bacteria. Aerobically treated wastewater does not normally have enough remaining carbon to support a bacterial population. There are other ways that have been used to accomplish denitrification, but this research utilizes an inline, up-flow, anaerobic reactor/filter to accomplish nearly 100% denitrification. After the nitrification, the wastewater is introduced to the bottom of the up-flow denitrification reactor using a pump controlled by a programmable timer. In this way, the feed pump can be adjusted from time to time to maintain the desired flow and contact time in the reactor. The media in the reactor is shredded bark mulch. This media serves two functions: 1) Serve as a carbon source for denitrifying bacteria; and 2) Provide surface area for denitrifying bacteria to attach themselves. Previous research has shown that shredded bark is a good material for this purpose. The reactor is an up-flow reactor to provide a saturated, anoxic environment forcing the bio-culture to utilize the oxygen attached to the nitrate molecules and release nitrogen gas to the atmosphere. Results of a year of operation shows the ability to reduce the total nitrogen content of domestic wastewater to less than 5.0 mg/l. These pilot study results have led to a community system design to handle flows in excess of 100,000 GPD. 9:10 AM 10:00 AM Frosting on the Cake - Passive Nitrogen Removal Dennis Hallahan Nitrogen has long been the nemesis for the decentralized industry. However, over the last years has seen a boon of technology development within the decentralized industry to address the nitrogen conundrum. Manufacturers have developed nitrogen treatment systems for smaller scale systems that are based upon the larger scale centralized treatment systems. The majority of the technologies

2 are mechanical in nature and therefore require higher levels of operations and maintenance than the typical conventional decentralized system consisting of a tank and a drain field. There are passive methods of treating nitrogen that may offer lower operations and maintenance. A passive system method of nitrogen removal has been studied at the University of Waterloo over 30 years ago. This technology has been licensed commercially on large scale. Then following the same path as the more complex, mechanical nitrogen treatment technologies, the passive system is being scaled down to the singlefamily home level. The state of Florida went to great lengths to study passive systems. In 2008, the Florida legislature provided funding to develop cost-effective, passive strategies for nitrogen reduction that can be incorporated into a conventional system. The Massachusetts Alternative Septic System Test Center (MASSTC) has studied the passive system as well and due the layering of material has labeled the system as Layer Cake". The presentation will briefly summarize past research of passive systems, review the benefits and negatives of the passive system, and present data from new field research. The cost of sewering has risen dramatically over the previous decades. The costs of decentralized systems are falling giving the numerous offerings in the marketplace, the future looks bright for onsite. 10:30 AM 11:20 AM Reducing Nitrogen Loadings in the Chesapeake Bay Using an Economical, Low-Impact Sewer Solution: A Case Study in South Kent Island, MD Julie Barown and Todd Mohn Community leaders on South Kent Island (SKI) in Queen Anne's County, Maryland, had serious concerns about public health and the environment due to the large percentage (70%-90%) of failing septic systems on the island. Affected areas have high groundwater and poor soils, which facilitate the delivery of nitrogen to the Chesapeake Bay. The County, the Maryland Department of Planning, and the Maryland Department of the Environment had to find an effective way to address this problem and the technical issues related to onsite sewage disposal, Smart Growth requirements, anti-growth concerns, alternatives in proposed sewer system designs, affordability, and state funding requirements. They established the South Kent Island Wastewater Sub district and began researching solutions. County staff investigated public sewer collection systems nationwide to select an appropriate technology for this unique island peninsula. Estimated project capital and operation and maintenance (O&M) costs were reduced significantly by choosing a septic tank effluent pumping (STEP) low-pressure sewer system. Installation began in Though SKI doesn't fall within a Priority Funding Area, the district qualified for state funding due to the failing septic systems. The project strikes a balance between solving a significant, long-standing public health problem and allowing a limited amount of infill development. This project will reduce nitrogen loading into the Chesapeake Bay by an estimated 17,300 pounds per year, far exceeding nitrogen reduction from alternative OSDS systems. That reduction will help the County reach ~33% of its septic system goal for the Chesapeake Bay Watershed Implementation Plan. SKI's project will affect over 2,000 existing/future EDUs. It's become a model statewide for addressing the technical, legal, political, and financial conflicts that arise during septic system remediation projects. This presentation will discuss the planning process, required policy actions, regulatory actions, technical design, estimated O&M costs, and the current installation process for the project. 11:20 AM 12:10 PM The Role of Decentralized Wastewater Systems in the Revival of the Chesapeake Bay Claude Goguen

3 We will discuss the how the waters of the Chesapeake Bay became an environmental crisis and how the surrounding states came together to try to solve the problem. One of the strategies was to incorporate advanced nutrient removal technologies in septic 1:40 PM 2:05 PM Cost-Effective Cluster & Individual Systems Achieving Effluent Total Nitrogen 3+/- mg/l and Total Phosphorus <0.10 mg/l Pio Lombardo This presentation will discuss cluster and individual passive wastewater systems achieving effluent Total Nitrogen (TN) of 3+/- mg/l that have been operating for 10+ years in MD, VA, NC, FL, MA, NY & CA. The costs, footprint, O&M requirements, and effluent quality of fifteen (15) installations throughout the U.S. will be described. The treatment performance evaluations will include data collected by regulatory agencies evaluating the systems. Applications will include individual residential and cluster systems serving residential and commercial developments. 2:05 PM 2:30 PM Cost-Effective Groundwater Treatment using PRBs to Achieve Site Net 100+% Nitrogen Removal and Watershed TMDL Compliance Pio Lombardo This presentation will discuss actual and proposed installations of permeable reactive barriers (PRB) for groundwater nitrogen removal to achieve site net 100+% nitrogen removal and watershed Total Maximum Daily Loads (TMDL) compliance. Nitrogen removal performance data as independently measured by the Woods Hole Marine Biological Laboratory for PRB that has been operating for 12+ years on Cape Cod will be presented. Planning design and nitrogen removal of PRBs that has been operating for 2 years for septic plume nitrogen removal will be presented. Two projects, located in NY and CT, in which the PRB has been designed, and are expected to be systems around the bay. This presentation will contain information on those systems and the contribution they made to the progress so far. operational by October 2017 will be described. The design procedures of site characterization and PRB sizing will be discussed, along with costs and permitting. Costs will be normalized and stated as capital, annual O&M and Life Cycle Costs on an equivalent residential unit (EDU) basis. The results of a PRB feasibility study for TMDL compliance for a Pond watershed on Martha's Vineyard will be presented. The study determined that PRBs could technically achieve TMDL compliance at a life cycle cost of approximately 10% of the cost of sewering. 2:30 PM 3:20 PM Development of a Nitrogen Sensor for On-Site Systems Christopher Clapp The on-site industry has been and continues to be challenged with costly sampling from health department to health department across the country that can last from one year up to 5 five years and with as little data as one unit to up to twenty or more. This sampling is costly and can cost a manufacturer or the local installer anywhere from $100 to upwards of $800 per sample per month. Additionally, as more and more municipalities see the promise of on-site treatment, and they begin to look to this method for complying with TMDLs, they will need reliable data to justify all claims that they are meeting their standards. With those concepts in mind the EPA, The Nature Conservancy on Long Island, and InnoCentive, launched a technology challenge in the fall of 2016 to create a sensor that could be installed within a treatment unit that could reliably measure nitrate, ammonium and total nitrogen and telemeter that information. The proposed sensors had to be accurate within 1mg/l, last up to 10 years, require maintenance as

4 little as once per year, and be cost effective at around $1000 per unit installed. The challenge was divided into phases the first of which was an Ideation phase where solvers" were to propose the technical concepts as to how they would solve such a challenge. A total prize allotment of $50k was awarded out to 3 top finishers and 4 honorable mentions of the 18 submissions the challenge received. The challenge then moves to a prototyping and proof on concept phase where solvers will have the opportunity to put their ideas into practice. It is believed a successful sensor will help the industry move to market faster and with better data while giving regulators and the public a sense of confidence that their actions are having the intended response. Ancillary benefits may include notifications to service providers to respond to emerging problems before they become emergencies and other industry uses such as agriculture and turf management. 3:40 PM 4:30 PM Agricultural Mineral Soil Additives for Passive Nitrate Removal & Phosphorus Removal Using Low Energy Electrochemistry Christopher Jowett Following recent work of other researchers, we have experimented with autotrophic denitrification using the agricultural minerals, limestone and natural sulphur, in a submerged, up-flow configuration, termed the 'Waterloo NOx-LS'. Historical reports of problems using sulphur were likely due to incorrect design or use, and our present testing has determined design configurations and maintenance frequencies, revealed geochemical reactions and demonstrated sustainable performance. Case Study: Nitrate-rich Waterloo Biofilter effluent from a school + community center in Ontario was passed through a 210 L submerged upflow NOx-LS (limestone + sulphur pastilles) unit followed by a limestone chip 'polishing filter' in a 22- month field test. Samples of influent and effluent were taken twice monthly and analyzed for ph, dissolved oxygen (DO), temperature, cbod, TSS, TKN, NO2,3-N, sulphate, and alkalinity. Different hydraulic loading rates (HRT) of 8-34 hours were used. Removal of 94% TN is obtained overall, including the low HRT periods with high TN effluent. With the low TKN = 1.7 mg/l, values of TN = 3.6 mg/l were attained overall, with 2.2 mg/l TN for HRT > 10 hours, and 1.0 mg/l TN for HRT > 15 hours, down from an average TKN = 66.9 mg/l in raw sewage. Essentially all NO2,3-N is removed to non-detectable with HRT > 10 hours, but substantial NO2,3-N breaks through at HRT < 8 hours. The cbod increased from 4.5 to 9.3 mg/l in the NOx-LS effluent, irrespective of HRT, with ph and TSS remaining similar at ~7 units and ~3 mg/l respectively. The NOx-LS effluent is polished to cbod = 4.4 mg/l in a subsequent filtration module. Pore waters were sampled periodically with suction lysimeters to see the evolution of biochemical reactions as the nitrate-rich water migrates up through the reactive media. SEM photographs determined that severe solution pitting occurred in the inlet area of the media, as expected, with less pitting further along the flow path. Nitrate was effectively depleted within the first 20 cm at HRT > 12 hours.

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