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Removal of organic and inorganic compounds from landfill leachate using reverse osmosis
Talalaj, I. A.
Abstract
The main objective of this work was to evaluate
an effectiveness of removing organic and inorganic
pollutants from landfill leachate in a long-term reverse
osmosis (RO) study. Investigations were carried out during
the first year of RO exploitation since February till September
2013. Over 20 parameters were analysed both in
leachate and permeate samples. In the first 1-year operation,
the treatment performance was feasible for most of
analysed leachate pollutants. The average removal rate of
chemical oxygen demand (COD), electro-conductivity,
ammonia nitrogen (N-NH4+), total inorganic nitrogen,
cyanides (CN-), iron (Fe) and chlorides (Cl-) reached 97,
97.2, 98.7, 99, 93, 97.6 and 98 %, respectively. A smaller
reduction rate—of 83 and 86 %—was obtained for sulphates
(SO4
2-) and sulphides (S-), what is the result of
sulphuric acid addition before treatment process in order to
decline a pH to a value of 6.0–6.5. Boron was eliminated
only by 81 % due to easy transportation through the
membrane uncharged species of boric acid B(OH)3, which
predominate in leachate. Average reduction of nitrites
(NO2
-) and nitrates (NO3
-) was 63.8 %, which is the
result of inhibition NO2
- oxidizers by nitrous acid and
relatively low ratio of biochemical oxygen demand and
COD (BOD/COD). The obtained permeate quality does not
meet the Polish discharge standards for S-. It is also
foreseen that the concentration of N-NH4
+ in maturate
leachate will increase in the next years.
Keywords
Landfill leachate; Pollutants; Reverse osmosis; Treatment
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