Study On Bamboo Carrier For Contaminated River Water Restoration

With the development of cities, lakes and rivers have suffered serious pollution. Theproblem of increasing eutrophic water bodies is making researchers to develop economicaland effective technologies much further for water body remediation. In this paper, abiofilm carrier made of bamboo was developed, which was source widely, crafting cheap,free of pollution. Laboratory-scale reactors filled with bamboo carriers were used to treatthe badly contaminated Huxi River. The main contents and conclusions are as followings:（1） Compared with plastic suspension ball carrier, the performance of biofilm reactorfilled with bamboo carrier was studied during start-up phase and stable operation phase.As part of the start-up phase, the reactor system was inoculated with activated sludge fromwastewater treatment plant. Results showed that bamboo carrier was microbial beneficial,and start-up phase shorten. At stable operation phase, the removal rate of COD_CrandNH₃-N were above74%and80%respectively, while the effluent COD_Crand NH₃-Nconcentration could reach class Ⅲ of the National Surface Water Standard in the reactorfilled with bamboo carriers; however, the removal rate of COD_Crand NH₃-N werevulnerable to feed water quality in the reactor filled with suspension ball carriers. Themicroscopic inspection pictures showed that there were more adhesion microorganisms onbamboo carriers, which demonstrated the higher biological activity of the biofilm.（2） Batch experiments were conducted on the bamboo carriers from the biofilmreactor in order to determine the effect of nitrogen and phosphorus removal. The resultsclearly indicated that the best operation states were anaerobic for3hours, aeration for4hours, and sedimentation for30minutes. The different DO values had great impact on theremoval of contaminants in the reactor, and an interval value of4⁵mg/L proved to be thebest for the polluted river restoration. Higher nitrate concentration in the influent wasfound inhibitive to phosphorous release at the anaerobic phase, leading to low efficiencyof TP removal. The nitrate concentration should be restricted to below0.87mg/L, so as toget high efficiencies of TP removal; otherwise cultivation of denitrifying phosphorusremoving bacteria was proposed. （3） In the restoration of polluted river water, the bamboo carrier reactor inoculatedwith predominant phosphorus removal bacteria was testified to be limited in theimprovement of phosphorus removal, on account of restricted volatile fatty acidconcentration. Moreover, the bamboo carriers inoculated with predominant phosphorusremoval bacteria did not improve the removal rate of COD_Cr, and the removal of ammonianitrogen showed no distinct difference, by contrast of the same carriers inoculated withactivated sludge from wastewater treatment plant.