Next Article in Journal
Current Developments and Challenges in the Recycling of Key Components of (Hybrid) Electric Vehicles
Previous Article in Journal
Recycled Shredded-Tire Chips Used As Support Material in a Constructed Wetland Treating High-Strength Wastewater from a Bakery: Case Study
Article Menu

Export Article

Open AccessArticle
Recycling 2016, 1(1), 14-24;

Sanitizing Fecal Sludge for Reuse Using Wood Ash as an Additive

Department of Environmental Health and Sanitation Education, University of Education, Winneba, P.O. Box M40, Mampong-Ashanti, Ghana
Office of the Vice Chancellor, University of Energy and Natural Resources, P.O. Box 214, Sunyani, Ghana
Author to whom correspondence should be addressed.
Academic Editor: Michele Rosano
Received: 11 September 2015 / Revised: 15 October 2015 / Accepted: 15 October 2015 / Published: 20 October 2015
Full-Text   |   PDF [431 KB, uploaded 21 December 2015]   |  


Wood ash has been widely used as an additive for excreta from dry compost toilets to sanitize it for reuse. However, there is dearth of quantitative information about its efficiency in sanitizing partially digested sludge from wet onsite sanitation systems. This paper presents findings of a series of two experimental studies to assess optimum wood ash dosages required to raise the pH of partially digested fecal sludge to sanitizing levels (pH > 11) in a tropical climate. The study monitored the variation of pH of the sludge containing between 0 (control) and 180 g of ash per litre of sludge. Average initial pH and total solids of the sludge were 7.79 and 72 g/L respectively. Generally, the magnitude and rapidity of pH spike was correlated with the ash dosage (r = 0.988) and was statistically significant (p = 0.0015; Fcrit = 2.3157) among all dosages. Drastic increase in pH (from 7.81 to 11.60 ± 0.07) was recorded in the first 24 h for ash dosages between 140 g/L and 180 g/L, whereas dosages below 140 g/L had pH values less than 10. The difference in variation of pH between the first 24 h and the successive 24 h was statistically significant (P(T ≤ t)two-tail = 0.00; tcrit = 2.09). On the average, 97% of the overall pH increment within a 48-h monitoring period occurred in the first 24 h for the 140–180 g/L ash dosages. The optimum ash dosages are 7–15 times higher than reported lime dosages but ash provides a cheaper alternative than lime for recycling plant nutrients. Further studies on pathogen inactivation efficiency are ongoing. View Full-Text
Keywords: wood ash; fecal sludge; pH variation; excreta; reuse; sanitize wood ash; fecal sludge; pH variation; excreta; reuse; sanitize

Figure 1a

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Monney, I.; Awuah, E. Sanitizing Fecal Sludge for Reuse Using Wood Ash as an Additive. Recycling 2016, 1, 14-24.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Recycling EISSN 2313-4321 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top