Eutrophication is a serious environmental job originates from extra alimentary burden in H2O organic structures. Health jobs can happen where eutrophic conditions interfere with imbibing H2O intervention ( Bartram et al,1999 ) .Luxuriant growing of micro and macrophytes is one of the issues associated with eutrophication that has many socio-economic deductions in add-on to unbalancing the ecosystem construction and map. Biogas from H2O hyacinth biomass by biomethanation is a possible solution to work out the job in an environment friendly manner. In the present survey anaerobiotic digestion of H2O jacinth was conducted in lab graduated table anaerobiotic bioreactor system.. Regular analysis of the operational parametric quantities was done to closely supervise the public presentation of the system. Microbial community analysis of the ALBR and UASB were done by metagenomic approach.Quantitative analysis of the hydrolytic enzymes cellulase, xylanase and pectinase and amylase in ALBR and UASB were done and showed positive correlativity with protozoon count.
Cardinal words: Water jacinth, ALBR, UASB, Biomethanation, Protozoa
Introduction
Water jacinth ( Eichornia crassipes ) is an aquatic weed making socio economic jobs like hinderance to H2O conveyance, yachting, fishing and about all other H2O activities. Water hyacinth mats degrade H2O quality by barricading photosynthesis, which greatly reduces O degrees in the H2O. This creates a cascading consequence by cut downing other submerged life such as fish and other plants.I T besides form a microhabitat for a assortment of disease doing vectors like mosquitoes, snails etc. Recovering value added merchandises like biogas from H2O hyacinth biomass by anaerobiotic digestion is a positive attack to turn to the issue in an environment friendly manner.
MATERIALS AND METHODS
In the present survey anaerobiotic digestion of H2O jacinth was conducted in lab scale bioreactor unit. Water jacinth was collected from the contaminated H2O beginnings, Veli lake and Parvathy puthanar in Thiruvananthapuram Dist. The workss were transported and maintained in 4.5 M3 capacity H2O armored combat vehicle adjacent to Environmental engineering lab in NIIST.
Plant biomass was subjected to different pre-treatment stairss and digestion surveies were done in batch experiments to acquire maximal biogas production. Different pretreatments like mechanical suppression, chopping, alkali hydrolysis and acerb hydrolysis were tried. The volatile fatty acid coevals, alkalinity production and biogas generated were monitored to measure the public presentation.
Based on the biogas output in batch experiments, surveies were extended to lab scale uninterrupted bioreactor system. Two separate systems were tested for the digestion procedure. In one attack, a two phase system was tested ( hydrolytic and biomethanation phases in separate reactors ) and in the 2nd attack a individual phase reactor was tried. The public presentation of both the systems in footings of biogas output was compared. The bioreactors were operated under different organic burden rates ( OLR ) to optimise the public presentation. Volatile fatty acid ( VFA ) , Chemical O demand ( COD ) , MLSS, VSS etc. was invariably monitored to measure the public presentation of the system. The slurry features after digestion were done for possible manure application. Quantitative analysis of the hydrolytic enzymes such as cellulase, xylanase, pectinase and amylase in the anaerobiotic reactor was analyzed and the enzyme activity was correlated with microbic communities in the reactor to understand the functional importance of different micro-organisms in the intervention procedure. Molecular finger printing technique was adopted to follow the community construction and diverseness in the intervention
RESULT AND CONCLUSION
Among different pre-treatment attacks tried, mechanical suppression of H2O hyacinth biomass resulted in faster digestion and higher biogas output ( Graph 1 ) .
Between the two systems tried, the dual phase system produced an mean 0.409L biogas /g VS within 6 yearss, meanwhile, individual phase system produced same measure of biogas in 37days, from 2 kilograms wet weight of biomass. So in individual phase system clip continuance for the complete digestion of the biomass is about 6 times higher than dual phase system.
Among the different OLR ( 7, 11, 14 19 kilograms COD/m3.day ) tried, maximal methane production was obtained at an OLR of 11 kilograms COD/m3.day ( Graph 2 ) .
Without any external buffering agents or pH regulators, pH of the influent from ALBR and wastewater from UASB was found to be between 6.2-7.2. Alkalinity of the reactor was maintained between 20 -30 meq/L. Volatile fatty acid ( VFA ) of the reactor was high during initial twenty-four hours and was reduced on subsequent yearss. Assorted spirits suspended solids ( MLSS ) and Volatile suspended solids ( VSS ) of the reactor sludge were 21g/l and 12.5g/l severally.
Activity of cellulase, xylanase, pectinase and amylase during the digestion procedure showed a similar form ( Graph 3,4 ) . From the 2nd twenty-four hours, enzyme activity showed a similar patternand after 9th twenty-four hours it started to diminish.
The chief Protozoa nowadays in the system were Menoidium, Cyclidium, Metopus, Colpoda, Rhyncomonas and Bodo ( Graph 5 ) . In anaerobiotic environments, Protozoas are chiefly responsible for the biological methane production owing to their physiological association with endosymbiotic methanogens ( van Bruggen et al. , 1983 ) . A important correlativity was observed between protozoon count with enzyme activity ( Graph 6,7 ) and biogas production ( Graph 8 ) in the reactor, bespeaking the functional function played by Protozoa in the digestion procedure. Ciliates of the genus Metopus have shown to be rigorous anaerobiotic beings populating in many anoxic home grounds including Marine deposits, municipal landfills, anoxic paddy Fieldss and anaerobiotic reactors ( Finlay and Fenchel, 1989 ) .Metopus showed a positive correlativity with gas production and enzyme activity ( Graph 9 ) . Denaturing Gradient Gel Electrophoresis for the archeal community analysis of ALBR and UASB showed a different community form
Features of the slurry after digestion had a Entire Kjeldahl Nitrogen of 8.70 % and entire phosphoric of 0.78 % and presence of minerals bespeaking its likely usage as manure.
Figures
Graph 1: Biogas yield from H2O jacinth digestion after different pretreatment
Graph 2: Methane production from the reactor at different OLR
Graph 3: Showing the activity of cellulase, xylanase pectinase and amylase in the unfastened ALBR.
Graph 4: Showing the activity of cellulase, xylanase, pectinase and amylase in the UASB
Graph 5: Diverseness of the Protozoa present the digester
Graph 6: demoing correlativity between celluase activity and protozoon count
Graph 7: demoing correlativity between pectinase activity and protozoon count
Graph 8: demoing correlativity between gas production activity and protozoon count
Graph 9: screening positive correlativity between gas production and Metopus count
