Vermicomposting toilets, an alternative to latrine style microbial composting toilets, prove far superior in mass reduction, pathogen destruction, compost quality, and operational cost.
Composting toilets aim to recycle excrement into safe, stable humus. Preceding this, low costs, low risks, and mass reduction should be ensured. Source separating vermicomposting toilets (SSVCs) outperformed mixed latrine microbial composting toilets (MLMCs) in all categories. MLMCs: incurred ten times greater operational costs; created 10x more operator exposure; employed no proven pathogen reduction mechanism since solid end-products averaged 71,000±230,000CFU/g (fecal-origin) Escherichia coli and 24±5% total solids, consistently failed NSF/ANSI Standard 41; failed to reduce volatile solids compared to raw fecal matter; increased total contaminated dry mass by 274%, and produced alkaline end-product (8.0±0.7) high in toxic free ammonia (Solvita® 2.6±1.5). SSVCs have low maintenance costs and risks; adequate worm density for pathogen destruction (0.03±0.04g-worm/g-material); reduced E. coli 200±244CFU/g in neutral (7.4±0.3), stable (60±10% volatile solids), and mature (4±0 Solvita® NH(3)) end-product.
University of British Columbia, Department of Geography, 1984 West Mall, Vancouver, BC, Canada V6T 1Z2. geoff.hill@geog.ubc.ca
Geoffrey B
GB
Hill
Susan A
SA
Baldwin
D000818:Animals; D004926:Escherichia coli / Q000302:isolation & purification; D006801:Humans; D009835:Oligochaeta; D012987:Soil; D014038:Toilet Facilities / Q000191:economics
D012987:Soil