poster - International Conference of Agricultural Engineering

annual rainfall is 1,382 mm and the rainy season is concentrated between October and
March (1,048 mm), representing 75.8% of the total annual rainfall. The driest period occurs
between June and September (SENTELHAS et al., 2009).
The sewage originated from installations of FEAGRI/UNICAMP (bathrooms, laboratories and
kitchen) present characteristics of domestic effluents. In the sewage treatment plant (STP)
there is a box for the separation of the coarse material which is conducted to the Partitioned
Anaerobic Reactor (PAR) and afterwards to the Subsurface Flow Constructed Wetlands
(SFCW), with average dimensions of 3,17mx1,68mx0,53m, and useful volume of
approximately 1.150 liter for each CW. The substratum used was gravel of size 1 and
ornamental plants Heliconia psittacorum (CW1) and Cyperus altenifolius (CW2). The
plantation of the macrophytes was in December 2008. The monitoring of water quality was
done in two periods: before pruning (BP) at the beginning of May till Mid-August 2009, when
pruning occurred, totaling 8 days monitoring. The sampling of affluent and effluents was
done on an hourly scale (from 09:00 till 18:00 h, every hour). The flow was regulated
manually, from the ball valves, in the morning before the first sampling. The flow
measurements were performed by the volumetric method (direct measurement) (CALIJURI
et al., 2009). The water collection for the analysis was made just after the flow
measurements, being one affluent sample to the CWs and a sample for each effluent of
CWs. The analysis of water quality parameters was done in a specialized lab, according to
the methodology of Standard Methods (APHA, 1998).
The calculus for the amount of variables was made by the multiplication of the concentration
from each input and output variable by the effluent flow of input and output referring to each
day. The efficiency of daily retention for the amount of each variable was obtained by the
difference between the daily amount of input and the daily amount of expected output divided
by the daily amount of input, times 100.
The variables analyzed for the water quality were: Ammonia nitrogen (NH³ + ), Nitrate (NO -3 )
and Total Phosphorus (TP).
3. Results and discussion
The characterization of the PAR effluent can be observed at Table 1. The average values
were obtained from the hourly collected samples, afterwards integrated in the daily scale,
corresponding to the sampling days during the period monitored.
Table 1. Average values and standard deviation of the principal characteristic of the effluent
after anaerobic baffled reactor (ABR), and affluent of the CW.
Sewage pH EC DO water temp NH³ + NO -3 TP
effluent 7.9 ± 0.2 966.6 ± 151.0 2.06 ± 2.1 22.5 ± 1.8 41.0 ± 15.8 1.7 ± 0.4 3.4 ± 0.7
PAR
pH Hydrogen potential; EC Electrical Conductivity (µS.cm -1 ); DO Concentration of dissolved oxygen (mg.L -1 );
Water temperature (ºC); NH³ + ammonia nitrogen (mg.L -1 ); NO -3 nitrate (mg.L -1 ); TP total phosphorus (mg.L -1 ).
Table 2 shows the minimum and maximum affluent concentrations during the total period
under study. The affluent concentration of NH 3+ varied from 24.8 to 76.9 mg.L -1 . Authors like
CALIJURI et al. (2009) and SOUSA et al. (2000) worked with domestic sewage and affluent
averages of 43 mg.L -1 and 43.9 mg.L -1 , respectively. As for NO -3 the variation was of 1.1 to
3.0 mg.L -1 , MAZZOLA (2003) worked with domestic sewage and affluent concentrations of
NO -3 which varied from 0.4 to 1.3 mg.L -1 . The affluent concentration for TP during the period
studied varied from 2.2 a 5.2 mg.L -1 . WU et al. (2010) and ZHANG et al. (2007) worked with
domestic sewage and an average affluent concentration of TP 4.1 and 4.4 mg.L -1 ,
respectively. SILVA and ROSTON (2010) report an average affluent concentration of 5.1
mg.L -1 in wash water at the milking parlor. The results found corroborate with the above
mentioned authors.