Evaluation of Solvita compost stability and maturity tests for assessment of quality of end-products from mixed latrine style compost toilets

Journal Article · Mon Jul 15 04:00:00 EDT 2013 · Waste Management

DOI:https://doi.org/10.1016/J.WASMAN.2013.03.021· OSTI ID:22300369

Baldwin, Susan A. ^[1]; Vinnerås, Bjorn ^[2]

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1. Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, B.C., Canada V6T 1Z3 (Canada)
2. Swedish University of Agricultural Sciences, Box 7032, SE-750 07 Uppsala (Sweden)

Highlights: • Solvita® stability and maturity tests used on composting toilet end-product. • Solvita® ammonia better suited in evaluation of feedstock suitability for vermicomposting. • No clear value of Solvita® stability test due to prevalent inhibition of decomposition by ammonia. - Abstract: It is challenging and expensive to monitor and test decentralized composting toilet systems, yet critical to prevent the mismanagement of potentially harmful and pathogenic end-product. Recent studies indicate that mixed latrine composting toilets can be inhibited by high ammonia content, a product of urea hydrolysis. Urine-diverting vermicomposting toilets are better able to accomplish the goals of remote site human waste management by facilitating the consumption of fecal matter by earthworms, which are highly sensitive to ammonia. The reliability of Solvita® compost stability and maturity tests were evaluated as a means of determining feedstock suitability for vermicomposting (ammonia) and end-product stability/completeness (carbon dioxide). A significant linear regression between Solvita® ammonia and free ammonia gas was found. Solvita® ranking of maturity did not correspond to ranking assigned by ammonium:nitrate standards. Solvita® ammonia values 4 and 5 contained ammonia levels below earthworm toxicity limits in 80% and 100% of samples respectively indicative of their use in evaluating feedstock suitability for vermicomposting. Solvita® stability tests did not correlate with carbon dioxide evolution tests nor ranking of stability by the same test, presumably due to in situ inhibition of decomposition and microbial respiration by ammonia which were reported by the Solvita® CO{sub 2} test as having high stability values.

• OSTI ID: 22300369
• Journal Information: Waste Management, Journal Name: Waste Management Journal Issue: 7 Vol. 33; ISSN WAMAE2; ISSN 0956-053X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AMMONIA
AMMONIUM NITRATES
CARBON DIOXIDE
COMPOSTING
HYDROLYSIS
RELIABILITY
STABILITY
TOILETS
UREA