Aquaculture solids management using a combination of sand/gravel or unwoven fabric bed with Lolium perenne Lam as a plant biofilter.
OBJECTIVE
This work is an evaluation of the efficiency of a sand-gravel or unwoven fabric bed system and Lolium perenne Lam as plant biofilter in the reduction of solids and nutrients removal from aquaculture discharge water.


METHODS
The first step consisted of the collection of wastewater in the tank and the distribution at three different hydraulic loading regimes (0.5, 1, 1.5 L/hour) to the different experimental systems. The second step was to evaluate the performance of the different systems. The first system consisted of a bucket filled with a substrate of sand/gravel (20 cm in depth), on the bottom of which was a 80 mesh/inch2 of nylon (S1); the second was similar, but was planted with Lolium perenne lam (S2); the third was planted with a grass plate consisting of 7 layers of unwoven fabric planted with L perenne (S3).


RESULTS
The second system showed the best performance in reducing solids as well as in nutrients (TN, TP, and COD) reduction. The removal rates for TS, TN, and TP were negatively correlated with the loading regimes, with 0.5 L/hour being the most efficient and thus taken as the reference.


CONCLUSIONS
Solids management using a sand/gravel substrate as bed culture and Lolium perenne L. as plant biofilter has proved to be an efficient technique for solids reduction with low operating cost. This grass plays an important role in wastewater eco-treatment by absorbing dissolved pollutants (TAN) as nutrients for its growth.
Nduwimana
André
A
Institute of Agricultural and Bio-Environmental Engineering, College of Biosystems Engineering and Food Sciences, Zhejiang University, Hangzhou 310029, Zhejiang, China.
Yang
Xiang-Long
XL
Wang
Li-Ren
LR
D017756:Aquaculture; D005374:Filtration / Q000379:methods*; D008129:Lolium / Q000378:metabolism*; D012822:Silicon Dioxide
D012822:Silicon Dioxide