US EPA

2996327 

Journal Article 

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

Hill, GB; Baldwin, SA; Vinnerås, B 

2013 

1 

Waste Management
ISSN: 0956-053X
EISSN: 1879-2456 

33 

7 

1602-1606 

English 

23647950 

10.1016/j.wasman.2013.03.021 

WOS:000321166600005 

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 CO2 test as having high stability values. 

Composting toilet; Human feces; Solvita; Ammonia; Maturity; Stability