230 likes | 323 Views
Upper Neuse Water Quality Monitoring Plan Stakeholder Meeting February 9, 2012. Onsite Wastewater Subcommittee Status Report. Sub-Committee Members. Steve Bristow, Chair (Wake Co. Health Dept. ) Steven Berkowitz (DHHS OWPB) Nancy Deal (DHHS OWPB) Mary Giorgino (USGS)
E N D
Upper Neuse Water Quality Monitoring PlanStakeholder Meeting February 9, 2012 Onsite Wastewater Subcommittee Status Report
Sub-Committee Members Steve Bristow, Chair (Wake Co. Health Dept. ) Steven Berkowitz (DHHS OWPB) Nancy Deal (DHHS OWPB) Mary Giorgino(USGS) Mandy Hall (DWQ Surface Water Protection Section) Reginald Hicks (City of Durham Environmental Services) Kathryn Hobby (Wake Co. Environmental Services) Bob Jordan (Durham Co. Health Dept.) Tom Konsler (Orange Co. Health Dept.) SushamaPradhan(NC State University) Maverick Raber(Durham City Stormwater)
1. Process • What you’ve been doing and how you got here. What have most of your discussions focused on? What were your biggest questions or concerns? How did you decide to tackle the issue(s)?
1. Process (continued) • Solicited by the Chair and specifically expressed by subcommittee • Formed the basis of our Research questions • Unknowns – gaps in knowledge base • Definitions • Whether DSFs should be covered by us • Monitoring requirements for Sand Filters • Added member with expertise
Onsite/decentralized systems • Jurisdiction over systems in NC is a regulatory distinction • Surface dispersal: DWQ Surface Water Protection • Subsurface dispersal: DHHS OWPB and LHD • Systems in both categories collect, treat and disperse wastewater at or near the point of waste generation • We decided to include sand filter systems that are designed to discharge in our discussions • They were not addressed elsewhere
Conventional subsurface gravity system Source Distribution Box Drainfield Septic tank with effluent screen Aerobic Soil
Subsurface pressure-dosed gravity system Source Pressure manifold Pump Tank Drainfield Pressure regulating valve Aerobic Soil Septic Tank with effluent screen
2.Monitoring Design Guidelines • Update on the progress of prioritizing your objectives and determining which Monitoring Design Guidelines (research questions) to pursue. • Identify gaps in knowledge data base • Identify ongoing research efforts • Gather existing data • Support ongoing research
2.Monitoring Design Guidelines (continued) • What studies have you decided on? How far along in developing them are you? • Literature search is ongoing • Drafted our research questions • How many did you choose? Why? • 3 – keep it simple!
Development of Research Questions Based upon • Subcommittee questions, which reflected gaps in the knowledge database
Development of Research Questions Based upon NSAB Questions as related to Onsite Wastewater: 1. What is the sensitivity to N&P generation/loading to various septic system failure rates? • We must know the load from malfunctioning systems as well as the rate of malfunction.
Development of Research Questions Based upon NSAB Questions 2. How do various maintenance practices for septic systems affect N&P generation/loading? • We must know the nature and frequency of maintenance activities.
Development of Research Questions Based upon NSAB Questions 3. What kinds of septic system improvement (density, failure rate, performance, local conditions, type) can change N&P generate loads? • Again, we need better numbers on loading!
1. What is the fate and transport of N&P from functioning subsurface onsite wastewater treatment systems? • Site and system variables for nutrient fate and transport: • Geology/soil type (Triassic vs Slate belt vs Acid crystalline) • System type • Conventional • Pressure dosed gravity to conventional or other trench • Low pressure pipe • Advanced pretreatment (media filters and RWTS) • Other • System age • Use and maintenance • Density
2. What is the N&P loading from malfunctioning subsurface onsite dispersal systems? • Note: malfunction is defined in .1961. Realistically, field assessment would conclude “malfunction” if any of the following were found: • Surfacing effluent or backpressure (upon probing trenches) • Effluent backup in tank headspace/home that cannot be attributed to blocked pipes
3. What is the N&P loading from sand filter systems? • Site and system variables for N&P loading: • Geology/soil type (Triassic vs Slate belt vs Acid crystalline) • System type • System age • Use and maintenance • Density
Next steps • Surveys • Literature searches • Support ongoing research • Optical Brighteners as indicators • 319 project • Source identification • Other
3. Opportunity for Feedback • Share areas of confusion. • Are you struggling with some aspects? • Are there questions you would like to ask the group and get feedback on? • Would you like recommendations for someone to solicit as a resource? • Do you think there is overlap with another group?