Overview of Wastewater and System Types

1. Source Distribution Box Drainfield (soil treatment area) Septic tank with effluent screen Soil Overview of Wastewater and System Types NC Certified Subsurface Systems Inspector School

2. Characterizing wastewater • What’s in it? • How much is there? • What are the consequences of inadequate treatment?

3. Composition of Domestic Wastewater Toilet Laundry Bathing Kitchen Garb. Grinder Misc

4. Organic material Waste from plant or animal sources • Can be dissolved, a solid or a liquid • Broken down and consumed by microbes (aerobes and anaerobes) • As it decays, dissolved oxygen is depleted • Measured as BOD5

5. Inorganic material • Stable compounds • Not easily broken down by microorganisms • Minerals, metals, dissolved salts • Sand, silt, cadmium, copper, lead, zinc, sodium • Residential flows have low metal content • Stormwater, inflow and infiltration • Cracked pipes, leaky manhole covers

6. Solids Total solids Any suspended or dissolved material Organic or inorganic Settleable solids Heavier suspended particles that settle out during preliminary treatment

7. Solids (cont.) Total suspended solids (TSS) Solids that don’t pass through filter paper Mixture of organic and inorganic particles Total dissolved solids (TDS) Solids that pass through a filter Minerals, salts, metals, ions

8. TSS impacts on treatment High levels lead to clogging Reduce efficiency of treatment system Block or plug distribution pipes Seal off and plug voids in soil and filters

9. Fats, Oils, and Grease(FOG) Animal or vegetable-based FOG Residential kitchens Degradable by microorganisms Petroleum-based FOG Industry/automotive repair Bath oils, moisturizing cream, tanning oils Not readily broken down by microorganisms

10. Environmental impacts of FOGs Adds to thickness of septic tank scum layer Clog pipes, treatment systems, drainfields Collect and harden on surface, trap trash, plants and other materials Cause foul odors and attract insect pests FOG

11. Rhinovirus – common cold Clostridium in septic tank Pseudomonas in drainfield Influenza virus E. coli 0157H7 Staphylococcus Pathogenic organisms

12. Pathogenic organisms • Disease-causing organisms • Bacterial, viruses, Helminths (worms), protozoa • Comfortable in human digestive system • Conditioned to living in low oxygen conditions • Difficulty surviving in air-filled environments

13. Health impacts Pathogens can cause disease in humans Typhoid Cholera Dysentery Hepatitis Salmonellosis Poliomyeilitis

14. Bacteria • Extremely common in sewage • Microscopic, single celled organisms • Found naturally • Host cell not needed for reproduction • Some are pathogenic – indicator organisms – Fecal Coliforms

15. Fecal coliform Indicator microorganism Cultured in standard tests to indicate contamination Measured as colonies/100 mL

16. Infectious dose and persistence

17. Nutrients Essential for growth of living organisms • Major nutrients • N, P, K • Secondary nutrients • Mg, Ca, S • Micronutrients • Cu, Zn, Mn, Mo, B

18. Nitrate (NO3-) Blue baby syndrome – methemoglobinemia Bloodstream is starved of oxygen May also be problematic to older adults Linked to miscarriages, birth defects, cancer Health impacts

19. Eutrophication: nutrient enrichment of surface waters Can occur naturally Accelerated by inefficient or incomplete wastewater treatment Algal blooms, depletion of dissolved oxygen Fish kills and harm to other wildlife Surface scum, increased odor, insects Increases cost and difficulty of drinking water purification Freshwater-phosphorous; Marine – nitrogen Environmental impacts of excess nutrients

21. Metals Inorganic chemical compounds NOT often found in residential wastewater Present in vitamins in very low amounts Stable and resistant to decomposition Some essential for animal & plant nutrition At higher levels some can be highly toxic

22. Persistent organic chemicals Stable organic compounds Slow to decompose; can persist in soil and groundwater for years Many are synthetic Not usually found in residential wastewater unless homeowner flushes something they shouldn’t Solvents & household cleansers Paint Medical products

23. Source • The user • The amount of flow • Everything that goes down the drain

24. Wastewater Loading • Quality • Organic Load • Quantity • Hydraulic load

25. WASTEWATER QUANTITY • Daily Flow • Design • Actual • Flow Estimates • People served • Square Footage • Peak Flows • Daily - Runoff Period • Weekly • Seasonal

26. Wastewater Treatment Processes • Physical • Chemical • Biological • Aerobic • Anaerobic

27. Point vs. non-point sources • Point source • Can identify the source • Non-point source • Source is less clear

29. Introduction to Onsite Wastewater Systems

30. Parts of a subsurface system • Source • Collection systems • Primary treatment or Pretreatment • Advanced treatment • Disinfection • Distribution • Dispersal

31. Source • Flow • Constituents

32. Flow • Design daily flow • Based upon projected flow from facility • Bedrooms, seats, people • Actual average daily flow • Varies considerably • Average daily flow >70% of design is a red flag

33. Collection Systems • A collection system • gathers wastewater from sources • conveys it to treatment system • components may include: • sewer lines, force mains, manholes, pumps, holding tanks • Types of collection systems • Gravity • Pressure • Combined

34. Primary treatment components • Typically, a septic tank

35. Advanced treatment components • Some type of aerobic treatment ATU’s Media Filters

36. Disinfection components • May be required to reduce pathogen levels UV Light Chlorine

37. Distribution components Pressure Manifold D-box

38. Dispersal components • Trenches • Beds • Low-pressure pipe (LPP) • Drip dispersal

39. Basic Types of Onsite Wastewater Systems used in North Carolina

40. Basic Gravity System Components Source Drainfield or Soil Treatment Area Distribution Box Septic tank with effluent screen Soil

41. X-section of conventional trench

42. Innovative Trench components: Gravelless Systems

43. Shallow placement drainfield Drainlines and Gravel Suitable Fill Aerobic Soil Water Table

44. Areal Fill (“Mound”) drainfield Trenches Suitable Fill Aerobic Soil Water Table

45. Installation of mound

46. Source Pressure manifold Dosing Tank Drainfield Soil Septic Tank with effluent screen Pressure-dosed gravity

47. Manifold in Vault

48. Long manifold on flat site

49. Basic LPP System Components Source Manifold Dosing Tank Turn up LPP Laterals Aerobic Soil Septic Tank with Effluent screen

50. Sleeved pipe