Advanced Onsite Wastewater Treatment Overview

Transcription

1 Advanced Onsite Wastewater Treatment Overview Chippewa County Annual Septic Installers Conference 2015 Dave Cotton, P.E. MDEQ Onsite Wastewater Program

2 What is wastewater Domestic Wastewater Black Water Gray Water Commercial Domestic High Strength Process Water Storm Water

3 Why do we care about onsite wastewater management Protection of Public Health Protection of the Environment Cost, cost, cost Jobs

4 How do we manage WW Centralized Planned as a quality of life right Decentralized Once thought to be temporary Recognized as long-term solution

5 What is in wastewater Biodegradable organics Total suspended solids Nutrients Pathogens Inorganics

6 What is in wastewater Biodegradable organics Total suspended solids Nutrients Pathogens Inorganics Biochemical Oxygen Demand = BOD5 (mg/l) = 350 mg/l f = 140 mg/l (out) = 800 mg/l to = 2,500 mg/l = 100 mg/l to = 20,000 mg/l Secondary treatment = 30 mg/l

7 What is in wastewater Biodegradable organics Total suspended solids Nutrients Pathogens Inorganics Total Suspended Solids (mg/l) = 350 mg/l f = 70 mg/l (out) = 200 mg/l to = 300 mg/l Secondary treatment = 30 mg/l

8 What is in wastewater Biodegradable organics Total suspended solids Nutrients Pathogens Inorganics Nitrogen = TN Phosphorous = TP TN = 65 mg/l ftp = 10 mg/l TN= 180 mg/l TP= 25 mg/l Low impact Treatment Level TN = 10 to 20 mg/l * TP = 1 to 3 mg/l

9 What is in wastewater Biodegradable organics Total suspended solids Nutrients Pathogens Inorganics Dysentery, hepatitis, gastroenteritis, typhoid fever, Bacteria Viruses Millions of pfu/100 ml

10 Constituents are Removed Through Biological processes Chemical processes Physical processes

11 Factors Affecting Removal Organic loading Hydraulic loading Hydraulic retention time Flow configuration Temperature ph

12 Factors Affecting Removal, cont. Oxygen availability Grease and oil Inorganic solids (kitty litter, etc.) Toxins (cleaners, poisons) Medications/antibiotics

13 Components of WW Treatment Collection Treatment Disposal/Dispersal It is a resource not a waste

14 WWTP treatment

15 On-site Treatment Sewer Line = Collection Septic Tank = Primary Treatment Treatment & Dispersal = Process Treatment + Recharge

16 Septic Tank Primary Treatment Watertight and Structurally Sound Residency Time = Primary Treatment Differential Settling Sinkers and Floaters

17 Soil Based On-site Treatment

18 Soil Based Treatment

19 Soil Based Treatment

20 A Problem Lot Size - The house fits, how about the septic?

21 A Problem Lot Size Fast Food how about the septic?

22 On-site Advanced Treatment Treatment

23 Most Common Treatment Processes Pond treatment processes, lagoons (facultative, anaerobic) Suspended growth, extended aeration (ATUs) Attached growth, packed bed filters (textile, sand, peat)

24 Pond Treatment Processes Large, shallow earth basins with large land area requirement Incorporates natural processes involving both algae and bacteria Sedimentation and contact time used to reduce constituents

25 Suspended Growth, Extended Aeration Microorganisms are suspended in liquid Microorganisms metabolize organic matter to CO 2, H 2 O, and cell mass Process generates activated sludge

26 Attached Growth Aerobic microbes attach and grow on media Wastewater flows across a zoogleal film created by microbes Microbes extract and digest soluble organic matter from the wastewater

27 On-site Advanced Treatment Treatment BOD5 <30 mg/l

28 On-site Treatment Dispersal Remember 2 Functions Conventional Treatment need 3 to 4 feet of unsaturated soil. With advance treatment polish and get rid of liquid - can the site move water away today so more can come tomorrow?

29 Maintenance of WW system Centralized Trained and Certified Operator Decentralized Historically out of sight out of mind!

30 All Systems Need Maintenance Septic Tank System Look at septic tank at least every 5 years Pump systems Check pumps and controls every 5 years Treatment Units Per manufacture and at least one a year Some times monthly or weekly

31 Where is the Oversight Infrastructure Approval of technology Oversight of lifetime maintenance Monitoring of performance Enforcement Who is the best Responsible Management Entity?

32 Contact Information Dave Cotton MDEQ Onsite Wastewater Program