15 n:nd 35°C (
t: Zasabianca-Ck?assaHIgi, s with mertime production cmr VdliCh er-level period of rivers: receiving environment is “t’e~j vulnerabie to the waste~at~r~~ the resistance of loaded a~~o~~~~ effluents ( ~2fti ,~t al., 1981 CopeIli et al., 1982) and its -known ability for wastewater treatment ( 1989; Sate & Kondo, 19
besvieen water hyacinth, “,ichhornia .,I SoEm, ~WZSproduced CM paperir, a 1 hectare lagoon, as a finishing is paper desci-ibes the evolufioa of the cu&ture (cover area, biomass production). The available space was covered up to 60% within four months with an average production C$ 466 g d. wt d--I m -‘. At she beg~~~~i~g,the culture was restrained by the efiuent foam atzQ thus, an initial biomass of 100 kg fresh weight was necessav for its development. The lack of available space restrai~~ed the coveting speed of the lagoon c$‘er 40% coverage. The harvest of the water hyacinth~~ 220 ions j+esh weight, was cam’ed out during the ,fij?h ~~~~t~ and was very di.cult because of the e~~ta~g~erne~tof the plants. So, harvesting had to be carn’ed out in order to reduce the plant cover sye)rn 50 to 2570~ when ~~a~~estil~gwas still ea5y but teatYneni was still ejjkierzt.
process has already been tested in the Tartas for two years in pilot mnks with a short retention time (l-2 days). A re 40% of n&d solids (SS), 35% of C 21% of was obtaiaed with 0 g lK3 of SS, INKIt g TIP3 of taining and 274i45 g nl-3 of
crassipes, large-scale producstay effkenr., Eandes, France.
In France, papm-industry effluents are me of the strongest sources of pollution. In t Tartas factory produces yearly 140 0 Daste from the use of 700 000 tons @or cellulose e tion, 36 000 rn3 of wastewaters recess (cleaning, first whitening a&aline extraction) flow daily through an aerated pm of 8.1 ha before being discharged into the environment. However, this treatment is not sufficient and the s, Eichhornia crassi.es (Mart.) Solms, was suggested as a finishing treat oints were in favour of this proces
eqerature
scale
culture
of E.
crassipes
091 paper
industq
WZiSlCWat~rS.
(Fig. I> of !+I !~eciares (depth w rate 901 m3 K ’ and a retention time of aboilt 13 ays) was constit ideal bat LX(with 18 aerators and four ers) md ree plug-flow reactors p1; with, respectively, and 2 aerators), which allowed an axtensio e retention time. e bottom of the aerated and tire divisions meen the three plug-flow reactors were made of plastic sheets. The ideal baclmix received the anaerobic
varies 35
phngs of the water ~~~owi~g to the !ast flow reactor were carried out over 10 days in easurements
on
c&Jtflow
(1509m3ii’)
I Aerated 1 ideal
pond
backmix
+
(8.!ha 3
5 water-mixers 27 aerators
plug
300000 flow
m3) ~~~~~~~~
*
-
Scale
:
700 m
o
consumed after an ~~c~batio~ of five days at 20°C. The suspended solids (SS) were obtained by Htration through a glass filter, grad weighing. Total dissolved nitrogen a (Sri were measured by calorimetry by sons, 1943). The wea er data were provided e Tartas factory), Mete0 France-Dax (20
Scheme of the wastewater treatment of paste paper factory of Tartas. Aerated pond with water hyacinths as final treatment in the last plug-flow reactor. OutP,ow from aerated lagoon plus small lagoon.
t from the process at a temperature a pH of 7; at the outlet, the temperat
of 32°C
effluent were, respectively, 27°C Goma, 1992). Two 1’7 m3 concre units (84 x 34 m: depth 05 m) situated under a greenhouse were fed with the outflowing water and used for the winter conservation of the plants. 13 May 1992, an initial biomass of water hyaci s (100 kg fresh weight, that is to say coming from the pilot-plants, was implante last plug reactor (P3). The final project pIa onal small lagoon of 4.7 ha, now use an a for bioxide effluent from whitening, as a pond with water hyacinths after its Iinking to the aerated pond, into which will pour all the effluents. The area covered by plants in P3 was estimated monthly by photographs taken from factory roof. This last plug-flow rea trarily divided into six areas to facilitate estimation (Fig. 2). Monthly, random water hyacinth samplings (five repeated samples) were carried out with a square-metre frame in a 100% covered area, in order to measure the biomass density. The total biomass was estimated by multiplying the total surface covered by water hyacinths and the bio density. Between two sampling dates, the prod~ct~Q~ as calculated according to the formda _z! where BO is the biomass at time to 1-B,)/(t,t,), and Pa the biomass at time tI and expr d.wt e coverere total biomass were talc duction and surface cover and were expressed in days and tons, respectively. On 45 October 1992, th an ha,rvested final biomass was mecanically
The
weighed.
to October,
us, 75*0*3
the cha
mg 1-l.
a exceeded
was necessary to implant
2n
T
15°C only in July and
‘initial
minimal biomass’
mainiy a uring the second stage [area plants. 0 to 6000 m2 corresponding to 25 artment area), the total biomass area increased similarly; the culture was and a pro by both develop ants. During the thn stage (over
the tetal biomass. The growth was
tion of the covered
JUIY
August
September
October
Sunshine periods (hours per month) and average minimum ) maximum temperatures (&ix, La&es) over the 150 dayysof the experiment.
Fig. 3.
of water ~~aci~tbs) where the peri as an an%ifoam barrage and allowed the e central part of the inoculum. The final harvest, 220 tons fresh weight, was carried out in ). It was very difficult to perOctober ~mbricatio~ and the height of form bet the plants (some reached 1 m high). This harvested sented only 0.05% of that of the pine yearly in the factory. Over this five erage calculated production was 55.2 which corresponds to a biomass 324 days. The harvest was spread as a fertilizer in neariy maize fields.
l&ion of the covered area, of the wet-weight total calculated biomass the beginning of the cuhure water hyacinth slowly grew and the ~rod~~ct~~~ was low (5 g dwt d-l m-“1. ween .the 30th and the 120th day, which corrended to the hottest months (June, July and August), the growth was higher, with a mean production of 97.5 g d.wt d-j m-‘. During these three months, the meat doubling times of covered area and biomass were, r After the 120th hyacinths occupied of the P3 area. rate of increase of
the 156th day, when harvesting occurred, the total ated biomass was 260 tons fresh weight. se three stages the culture, plants was plo against the 5. During the stage (area covering increased quicker than
50
Time (days) (a) Evolution of the covered area; (b) biomass ?er czovered square metre; and (c) total biomass.
Fig. 4.
Fig. 5.
“Covered area in squax-em&es anti total biomass.
3x
d), the total biomass increased
quicker than he vegetation covering and thus production was mainly caused by vertical growth of the water hyacinths,
The values of the producti ere comparable to those obtained in the pilot t ma2) for a covering of 25-1 water retention time of 1 or 2 d Chassany 8t Goma, 1991). These production data were better than those obtained under similar conditions on other types of low-ammonium effluents (wastewaters: 51 g d.wt dd’ m-’ with a load of 15 mg 1-l of NIL,-N and a retention time of five days) or with higher loads (carcass treatments, hi- 1 mp2; pectin effluent; 41 g d.wt dd’ pig manure; 45 g d.wt dd’ mP2 with 100 NE&-N with retention times of 20 days) bianca-Chassany et al.) I992). The environmental parameters which acted on the water hyacinth production were as follows. At i beginning of the culture, the foam was growth. The production peak corresponde air temperature peak and arose when the covere area was 20% and all other conditions were suitable (nitrogen and phosphorus in excess, free space, averurn temperatures up to WC, aver temperatures up to 25°C). After this, re remained the determining factor ct al., 1981; Center usk, 1984; Reddy & Tucker, assany, 1985). by plants over 60% of t was mainly total, production greatly decreased r hyacinths. caused by vertical growth of the Three facts could have explained this: the decreasin temperature, the lack of available space an physiological state of the plants which limite shoot production. The final harvest has to be done before the water surface is covered. It is suggested, fore, that before the final harvest, some inter arvests (I or 2) are made during the increa f the growth curve of the culture, bringing covering from 50 to 25%.
AC
De C~~a~~a~~~-C~~~~~~y, M-L. &LGoma, G. (1991). !?re-
niers r&dtats
sur 1’Cpuration par Etchhomia mmipes
d’effiuents papetiers (Usine de Tartas, Lam&s, France). C R. Acad. Sci. Paris, III, 312, 579-85. De Casabianca-Chassany, M-L. (1992). Traitements des effluents industrials, er! particulier des effluems papetiers par ~i~h~Qrn~~ cmssipes, Ie jacinthz d’eazh performance du procCdC. ReteMs Bq7~% en GCnie &es De Casabianca-Chassany, M.-L., oonne, C. b”- Basse?es, A. (1992). Eichhoinia crassipes systems on three ammolmiu-m-containing effluents (pectin. carcass-treatstes and manure): pr~ductioai and gurificatisn. ehnol., 42, 95-3 01. D (1978), Upgrading stabilization pond effluent hyacinth culture. 1. Whter PoEi Confml Fed., 5, 833-45. Fonade, C. & Goma, 6. (19923. Nouvelle aptrock du lagunage a&C et da nii-iange dans les grams hassins. Rdcents Rq@s en C&G.e des P~ocd~ks, 20, 9%2 08. Reddy, K. EL & Tucker, 1. C. (1983). Productivity and nutrient uptake of water hyacinth ~i~~~Q~~~~ ~mssipes~ I. Efkct of nitrogen source. Econ. Rot., 37, 237-a7. eddy, K. R. & Debusk, W. I?. (1984). Growth characteraquatic Culrured in istics of EEKXOphJE,)lteS nutrient-enriched water: 1. Water hyacinth, water lettuce, and pennywort. _&on. Bat., 3 . Et., Agami, M. & Tucker, 3. C. (1989). IdhiReddy, ence of nitrogen supg)iy rates on growth 2nd nutrient
water hyacinth (Eichhor~ia cracsipes) piants. .) 36, 33-43. ICondo, T. j1981). iomass ,production of
S
This study was realized under t du Pin de I’IJsine de Tartas C mps, Nei-ou and Goma and Chave
Research Center of deaux Talence for their help.
from
the
water hyacinth and its ability to emsve morgank minerals from water: I. Effect of the concentration of of plant growth and nuiriculture solution on the ra i 257-07, cnt uptake. Japaiz J. Ecol., ~~~vert~~, B. C. & MC ~ W. C. (1981). Energy from vascular plants wastewater treatment systems. &on. Bot. s 35. 224-32.