Research On Influence Of Metabolites And Biodiversity Caused By Trace Quantity Heavy Metal In SBR

As the emissions requirements of industrial wastewater containing heavy metals continue to increase in China, collection of industrial wastewater and integrated treatment has become a trend. More and more attention has been paid to biological treatment technologies of wastewater containing heavy metals. Heavy metals pollution has a strong representation of heavy toxicity and can directly affect normal microbial activity, result in the death of a large number of active microbial. The effect on activated sludge is destructive and irreversible. In this research we choose a representative study of Cu²⁺ and Ni²⁺ as objects, focus on the sequencing batch reactor(SBR) with different concentrations of trace Cu²⁺ and Ni²⁺, observe how microbial metabolites, activated sludge characteristics and biodiversity changes.Extracellular polymeric substances(EPS) concentration in the reaction with Cu²⁺ severely impulse in the beginning, then result in the late adaptation. EPS steadily decline in the concentration of small magnitude. Stable range of the EPS in the latter period has inversely proportional to the concentration of added Cu²⁺. Ni²⁺ contained raw water is far less strongly than the impact caused by Cu²⁺ on EPS. Dosing of Cu²⁺, Ni²⁺ to the reaction system will cause a decline in short term, do not induce reduction of soluble microbial product(SMP). Tolerance of SMP for Cu²⁺ in the early reaction is more obvious, but not long maintained, often fluctuate in the later reaction. The impact on SMP caused by Ni²⁺ contained raw water is sustainable. The effect on SMP caused by Ni²⁺ contained raw water is within a small range, but Cu²⁺ contained raw water cause large fluctuations.Cu²⁺ enhances activated sludge settling immediately after dosing, but the effect Ni²⁺ enhancing activated sludge settling is not obvious. Flocculation effect is enhanced by a weak variation range when the concentration of Cu²⁺ is between 1mg/L to 2mg/L. The Ni²⁺ concentration between 1mg/L to 5mg/L may reduce SVI, and the decline range decrease with enhanced concentration. 3.5mg/L, 5mg/L Cu²⁺ contained raw water seriously damage the function of the COD removal at the end. Ni²⁺ contained raw water whose concentration is between 1mg/L to 5mg/L have little effect on the effluent COD and removal rate can be basically maintained at 85%. Microbial metabolites adsorption of Cu²⁺ in raw water is not monotonic. When the influent concentration of Cu²⁺ is 3.5mg/L, it is the highest adsorption efficiency of activated sludge. When the concentration of Ni²⁺ is between 1mg/L to 5mg/L, Ni²⁺ can be partly chelated by activated sludge, far less than the rate of adsorption of chelated Cu²⁺.Raw water with different Cu²⁺ concentration conditions may result in the demise of particular bacteria in activated sludge. Addition of Cu²⁺ add toxic effects, and also promote the growth and proliferation of some special microorganisms, even make them become the dominant flora. Raw water with added Cu²⁺ will reduce the richness of microbial populations, but the variation is more complicated. The diversification of bacteria with Ni²⁺ contained raw water is more complicated, difficult to summarize with a simple proportional relationship. The effect on bacteria similarity in the Ni²⁺ contained raw water is much more greater than Cu²⁺. Dosing of Ni²⁺ contained raw water can produce inhibition of microbial populations in richness, SDI increase with the increasing Ni²⁺ concentration.