The Performance Of Zincremoval From Wastewaters By Using Sulfur Packed Bioreactor

Classification of heavy metals is still under discussion and can be ambiguous yet any components having generally higher densities than water and normally happening fundamentally in earth's crust can be characterized as heavy metals.The most wellknown precedents incorporate zinc(Zn),arsenic(As),lead(Pb),nickel(Ni),mercury(Hg),manganese(Mn),copper(Cu),and cobalt(Co).The vast majority of the heavy metals are known to be lethal at various dimensions to human health,and high exposure to them can be deadly.Research has demonstrated the impact of heavy metals to be cancer-causing including failure of organs,nervous breakdown,and long haul can cause death.Induction to heavy metals can be either by means of air,water or food.In numerous zones heavy metal pollution of water streams is additionally affected by the human exercises,for the most part by mining,vehicle pollution,and utilization of heavy metals containing mixes utilized in the industries.The EGSB framework utilizes granular sludge,which is portrayed by great settling characteristics and a high methanogenic activity.Due to the high settle capacity of the sludge,high up-flow fluid velocity,for example surpassing 6m/h,can be applied.These high fluid velocities,together with the lifting action of gas developed in the bed,lead to a slight extension of the sludge bed.Furthermore,because of that,great contact among sludge and wastewater is accomplished in the reactor,prompting altogether higher loading possibilities contrasted with ordinary treatment systems.In this study we investigated the biological treatment technique to remove heavy metals from wastewater by using sulfur packed EGSB bioreactors and batch tests at the scale of laboratory experiments,the relationship between biological reduction of sulfur and removal of heavy metals(Zn)was conducted in an expanded granular sludge bed(EGSB)reactor.Two lab-scale EGSB reactors have about 5 cm diameters of each column,one having sulfur powder as a carrier and other having sulfur particle as carrier.The sludge used in sulfur packed EGSB is derived from Wencheng wastewater treatment plant having 36.8g/L total Suspended solids(TSS)and 23.5g/L volatile suspended solids(VSS).Sulfur and acetate were used as electronic acceptor and donors,while sulfide and carbon dioxide are the end products from the sulfur reduction and acetate oxidation.Afterwards Sulfide produced reacts with the heavy metal in the medium to form precipitation.Synthesized medium comprises of sodium acetate anhydrous 1g/L,ammonium chloride 0.1g/L,potassium phosphate 0.1g/L,calcium chloride 0.1g/L,magnesium sulfate 0.1g/L,caustic soda 1.5g/L and trace elemental solution1ml/L and hydraulic retention time(HRT)is 2 days.In reactor with sulfur powder as carrier the steady concentration of sulfide and acetate were 70mg/L and 380mg/L in the effluent,however for reactor with sulfur particle as carrier the steady concentration of sulfide was 40mg/L and acetate concentration was 280mg/L.Meanwhile,the concentration of zinc in both reactors was 3.125mmol/L and 5.375mmol/L however removal rate of heavy metal was 100% for both reactors.In the batch tests,the concentrations of sulfide in 8.48g/L of sulfur powder and sulfur particles were 350mg/L and 400mg/L respectively.In second stage for acetate concentration,for reactor with sulfur powder the concentration was 600mg/L and 550mg/L for sulfur particles.Removal of zinc was 100% at the inlet of 3.125mmol/L and 9.375mmol/L of Zinc but slight reduction of 10% on 18.750mmol/L was detected.Moreover,we can change different parameters to examine efficiency of microbial community as well as removal rate of heavy metals.Changing of different parameters may comprise in change in HRT,pH values,temperature and quantity of heavy metals in certain amount.