Non-ferrous Smelting Lime And Purification Of Waste Water Biological Agents Depth Processing

Wastewater produced from the nonferrous metal factories contained a lot kinds of metals with high concentrations. The lime-neutralization is used to treat the wastewater in almost 95% of the factories. The effluent contains high cadcium and micro heavy metals, it causes the waste of both metal resources and water resources, and influences the safety of drinking water. It is of importance to study on the novel technique for deeply treatment of lime-neutralization-purified wastewater to resolve water resource crisis and improve sustainable development of non-ferrous industry.For the deeply purification of the lime-purified water the bio-formulation B was made and reserached, and the technique of "biological adsorption-decalcification" was put forward. Based on the properties of heavy metals in purified water, after characterization and adjustment using addition agent H, bio-formulation B is designed and developed with the main composition of the waste activated sludge from municipal sewage treatment plant, which contained a lot of functional bacteria with high efficiency. The technological conditions of treatment of heavy metal containing wastewater with lower concentration were optimized, which is 25℃, pH value 8-10, reacting for 1h, and no significant effect of temperature has been observed in the test, while other factors exerted important influence on the sorption process. Little effect of dosage of activated sludge on the adsorption of Cu²⁺, more effects on the adsorption of Zn²⁺ and Cd²⁺ have been observed. It was also researched that the heavy metal ion adsorption was a parabolic relationship with pH. The Cu²⁺ is removed firstly.The system of bio-formulation B and artificial zeolites was used to removing the calcium from wastewater. Effects of parameters such as pH value, temperature, reaction time and sorption duration on removal rate of Ca²⁺ and pH value were studied in detail. The results indicate that solid-to-liquid ratio is an important factor on the removal of Ca²⁺, still pH value and temperature have obvious influences on the process, reaction time has little effect on removal rate of Ca²⁺ after reacting for 10 min. The removal rate of Ca²⁺ increases with increasing the solid-to-liquid ratio at 25℃, initial pH value 8.04, reacting for 1 h., 80.38% of the initial Ca²⁺ amount (solutions containing 801.6mg/L) is removed under the condition of solid-to-liquid ratio 3: 100, the terminal concentration is 157.31mg/L. The increase in temperature is advantageous to removal of Ca²⁺, the removal rate of Ca²⁺ rises from 77.30% to 90.71% with the temperature enhancing from 20℃to 45℃. Removal rate of Ca²⁺ reaches 74.96% in 10min with lengthening reaction time, also the removal rate slowly rises. The effect of pH value on removal of Ca²⁺ is complicated. The compound of artificial zeolite and waste activated sludge plays the role of better buffer effect on pH change, terminal pH value is between 6.5-8.5, being satisfied with the national discharge standard. According to the IR of artificial zeolite, the Ca²⁺ is removed by chemical biosorption.The system of bio-formulation B and Na₂CO₃ used to deeply purification-decalcification controlled freely was combined. Biosorption behaviors of heavy metal ions, such as Cu²⁺, Cd²⁺ and Zn²⁺, were carried out using waste activated sludge as adsorption material, and effects of parameters, such as pH value, temperature, reaction time and sorption duration, were studied in details. The results indicate that the removal rates of Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺ with low concentration are 96.47%, 80%, 90%, 50% respectively adsorbed by waste activated sludge. The optimum conditions were obtained through experiment with the heavy metal removing and decalcification using bio-formulation B and Na₂CO₃ individually. Under the optimum conditions the continuous experiments were carried on, the concentration of Cu²⁺, Pb²⁺, Zn²⁺, Cd²⁺, and Ca²⁺ can satisfy the Water Quality Standard for Drinking Water Sources(CJ3020-93). The reusing-rate reached to 100%, or realized zero draining. The operating cost was 0.84yuan/m³ under the scale of 32m³/h, the operating cost only was 0.53yuan/m³ under the scale of 1000m³/h.The adsorption model of the heavy metal ions by bio-formulation was built. In single heavy metal ion system, the sorption process of Cu²⁺,Zn²⁺ and Cd²⁺ are in accordance with Freundlich model. According to the Zeta potential during the process of lime-purified effluent using bio-formulation B and Na₂CO₃ waste liquid, there was the same precipitation effect without PAM. The mechanism of treatment of heavy metals and decalcification by bio-formulation B were researched by the modern test and analytical method, such as XRD, IR and so on. The reaction product was mainly crystalline solid CaCO₃ both using two kinds of waste liquid. It has been identified that there are a lot of functional groups and chemical bonds, such as -C=O, -OH, existing in the bio-formulation B. Because of the adsorption of heavy metal and the alkaline media of wastewater, their peaks intension and positions changed. During the treatment of lime-purified water, the heavy metals were deeply removal through the functions of adsorption, complexing, precipitaion, ion-exchange by the bio-formulation B and its metabolite. The Ca²⁺ was removed with addition of Na₂CO₃, and the concentration of Ca²⁺ could be controlled freely.The water reusing research was carried out, according to the water quality comparison between the bio-formulation deeply treatment purified water and the common using water, the bio-formulation deeply treatment purified water just a little high of cadcium, in the first stage the average concentration will be about 489.165mg/L in the zinc electrolyte. There is no negative effluent of the existence of heavy metals, and the organic substance is too little to influence the smelting system, so the deeply treatment water can be reused 100%.