A COMBINED REED BED AND FREEZING BED

FILTER FOR SEPTAGE TREATMENT AND

REUSE IN COLD CLIMATE CONDITIONS

C. Kinsley, K. Kennedy, A. Crolla

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Introduction

• Septage - accumulated sludge in septic tanks

• ~1.2x106 septic systems in Ontario (860 000

m3/yr) • 60% applied directly to agricultural land

• 40% co-treatment at WWTP

• Ontario Ministry of Environment is committed to

phasing out the land application of untreated

septage

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Reed Beds• Variation on drying bed

design

• Sludge is dewatered and composted in one step

• Plants provide many benefits: • roots create drainage pathways

• plant movement and growth breaks sludge cake

• plants absorb water from sludge

• oxygen transfer to the plant roots assist in the stabilization and mineralization of the sludge.

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Combined Reed Bed-Freezing Bed Field Study

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Reed Bed Filters Unplanted Filter

Experimental Variables• Solids Loading Rate (42-144 kg TS/year)

• Hydraulic Loading Rate (1.9-5.9 m/year)

• Planted vs unplanted

• Season (T, Precip)

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Treated Effluent Irrigation

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Plant Development

Experiment 1: Effect of SLR on Drainage

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Experiment 1: Effect of SLR on Drainage

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Experiment 2: Effect of Plant Growth on Drainage

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Design Loading Rate

• Subtract ponded water from May-Nov from hydraulic

loading.

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Year Design Hydraulic Loading Rate (mm/d)

SF RB1 RB2

2007 8.4 8.5 9.5

2008 8.4 8.2 8.8

2009 10.8 7.1 8.1

Avg. ± SD 9.2±1.4 7.9±0.7 8.8±0.7

Design Hydraulic Loading Rate = 8.6±0.7 mm/d or 2.9 m/y or 75 kg/m2/y

Experiment 3: Effect of Hydraulic Load on Drainage

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Filtrate Quality

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Significant effect of Period for COD, TSS, TN and TP was observed

(P<0.05), while no effect for Year (P>0.05) was observed.

Dewatered Sludge Quality

• Similar nutrient and solids content to solid dairy manure

• Metals and E.coli meet biosolids standards

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Acknowledgements

• Ontario Ministry of Environment

• Canadian Water Network

• René Goulet Septic Tank Pumping

• Canada Mortgage and Housing Corporation

• Eastern Ontario Water Resources Committee

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Thank you!www.orwc.uoguelph.ca