There is a growing need for decentralized wastewater treatment systems that support small abattoirs. Constructed wetlands (CW) are a potential solution; however, research on this subject has been limited to warm climates. Therefore, a research/demonstration site was established at a small-scale abattoir in Great Village, Nova Scotia, Canada. At the site, a 58.5-m2 two-celled surface flow CW with Typha latifolia was constructed. On average, the abattoir produced 0.75 m3of wastewater per animal slaughtered (a mixture of cattle, pigs, and lambs) with an annual inflow of 124 m3 and high monthly variability. The residence time of the CW (during the growing season) was determined by a tracer test to be 111 d, and the active volume of the system was 89%. Overall, mass removals during two years of continuous monitoring were BOD5 (95%), TSS (72%), TDS (81%), TP (88%), SRP (97%), TKN (87%), and TAN (87%). The average E.coli level in wetland effluent (88 CFU 100 mL -1) was below the regulatory limit of 200 CFU 100 mL-1, although 13% of samples exceeded this value. Treatment efficiencies were generally higher during the growing season than the non-growing season.
- Constructed wetland
- Decentralized treatment system
- Water quality
ASJC Scopus subject areas