Technology And Mechanism On Simultaneous Silicon-remain Cooking In Bamboo Pulp Based On Extended Delignification

Papermaking waste water contains large amounts of suspended solids,organic and inorganic salt such as calcium and magnesium particle, papermakingwastewater reuse will cause pollution matter accumulation, fouling,electrochemical corrosion problems in the circulatory system back after use. Inorder to reduce or eliminate these wastes （mainly among the dissolved solids）on equipment and pipeline corrosion and fouling, at the same time in order to getbetter quality of reuse water, further reduce the unit product consumption, theneed for paper-making wastewater deep treatment to remove more difficult saltsand organic compounds.First of all, the water quality of reuse water and scaling objects are analyzedin paper waste water recycling system. With the increase of cycle number,organic compounds, inorganic ions, the electrolyte and other pollutants inpapermaking wastewater are in the accumulation of different levels. Scalingobjects are analyzed in the chemical method and by ICP-AES. The results showthat the pollutants are accumulation of inorganic-based, while the inorganiccalcium carbonate in the sediments of the main.Fly ash are waste residues generated by the power plant, which containslarge amounts of soluble aluminum and iron salts. It is soluble in the wastewaterand can produce iron salts and aluminum salts of inorganic coagulant. It hasbetter removal capacity for suspended matter, chroma, metal ion and chemicaloxygen. In addition, treatment of papermaking wastewater by fly ash, fly ashwaste turn into treasure, and become an effective resource to achieve the purposeof conserving natural resources. It is effective for ultrafiltration andmicrofiltration to remove suspended matter, organic matter, colloid, reverseosmosis has better removal efficiency for the removal of calcium, magnesium and other inorganic ions in the wastewater, desalination and high efficiency.Therefore, Therefore, fly ash as a pretreatment process, lime softeningcombination of coagulant and microfiltration/ultrafiltration+reverse osmosis，these two methods as the main process, the papermaking wastewater arefurtherly treated.Secondly, the use of fly ash to pretreat wastewater, the main influence factorsof coagulation experiment are analyzed, including coagulant, coagulation timeand pH value of wastewater, optimization of process parameters. In the neutralcondition, the optimum adding amount of fly ash is15g/100mL,200r/minstirring speed, stirring1H, can get the best treatment effect. At this point, theremoval rates of COD_Cr, color and SS in wastewater were respectively62.1%,90.5%and86.2%, effluent COD_Cr, chroma and SS were290.1mg/L,76and118.7mg/L.After fly ash treatment，papermaking wastewater are treated with saturatedlime and PAC and PAM, saturated lime20ml, the aluminum content in the PAC30%0.4ml/L and1g/L PAM2.5mg/L are added, effluent COD_Crandcolor, SS, hardness in turn are128.6mg/L,20degrees and26mg/L,657mg/L.At this point, the removal rates of COD_Cr, color, SS, hardness in wastewaterwere respectively55.4%，74.6%，79.3%，51.6%.After fly ash treatment，papermaking wastewater by sand filtration into themembrane. Microfiltration of effluent turbidity in0.1⁰.25NTU, SS0⁵mg/L, COD70⁹5mg/L, chroma is9¹5PCU, operation results show that,microfiltration membrane can effectively remove suspended solids and colloidalimpurities in waste water. Ultrafiltration experimental studies have shown thatultrafiltration membrane operating pressure should be controlled in the range of0.04⁰.1MPa, so that it has good film properties, the pressure within theeffluent suspended solids in3mg/L, turbidity below0.07NTU, chroma is4¹0PCU, COD average in53.2mg/L. The reverse osmosis membrane waterconductivity was reduced by2⁴.35ms/cm to70⁹0μs/cm, more than99%ofthe average rate of desalination, hardness removal efficiency up to99.5%.Finally, the treatment effect and cost of the main process of the experimentare analyzed. The results show that the lime combined with the coagulant PACand PAM coagulation method on hardness removal efficiency is51.6%, other pollutant removal efficiency are less than55percent. The waste water treatmentcost is1.52yuan per ton; microfiltration/ultrafiltration+reverse osmosismembrane, on the pollutant removal efficiency of95%, The waste watertreatment cost is2.16yuan per ton. Comprehensively analyzed, fly ash aspretreatment process, microfiltration/ultrafiltration+reverse osmosis as themain process, the papermaking wastewater are furtherly treated with goodoverall efficiency.