On-Site Wastewater Conditioning System for Phosphorus Removal An Interim Report NALMS Chris Mikolajczyk, CLM, Princeton Hydro, LLC Paul Sutphen, BS, MS, Clear Lake Technology, LLC

Lake Impairment July 1950 – lake clarity 12 feet vs 4 feet July 2014 Culver Lake is a eutrophic water body and is P limited Phosphorus loading from septic represents a significant source of nutrient loading from the watershed

Design Objectives of Waste Water Conditioning System Contain phosphorus and other contaminants within septic tank Adaptable to all tank and field on-site systems No ground disturbance or alteration required to existing system Simple, reliable, and relatively low cost Condition wastewater in proportion to household phosphorus regardless of numbers in household

Septic Tank Effluent Sampling Results Before dosing with alum pH Cond TP = 9.8 –11, avg mg./l PO4(P) = , avg. 7.8 mg./l TSS = , avg. 66 mg./l E. Coliform = 2.49 million/100ml. Avg. H2O consumption 70 gpd (2 member household) Phosphorus/person= 1.17 gr./day (30% org./70% inorganic.) After dosing with alum pH Cond, TP 3.9 mg./l ( 63% red.) PO4(P) 0.6 mg./l (92% red.) TSS = 18-62, avg. 38 mg./l (42% red.) E. Coliform = 23 thousand/100ml. (99% red.) Alum dose range mg./l. Alum use approx. 4 gal./yr./person Alum cost approx. $22/yr./person

Summary of Findings and Next Steps Developed a system for conditioning waste water A 1000 gallon Septic tank functions well as a clarifier Significant removal of phosphorus, coliform and TSS 30 gal. tank of liquid alum would last > 2 years/2 persons Next Steps Continue to monitor sludge accumulation to determine optimum septic tank pumping frequency Continue testing of a black/grey water two tank system More information at clearlaketechnology.com

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