Phosphate Removal Performance And Operational Characteristics In Crystal Seed Media Filter Treating Drainage Of Seawater Utilization

At present, the situation of China’s coastal water environment quality degradation andwater shortages have become a serious bottleneck restricting to the economic and socialdevelopment of the coastal cities. Development of new water sources to solve the problem ofshortage of water resources has become a major economically developed coastal regionsaround the corner. Using sea water as the city life miscellaneous water （mainly seawaterflushing） and seafood processing industry is an effective way to alleviate the situationshortage of water resources in coastal areas. Traditional biology, chemistry, and adsorption ofphosphorus removal method phosphorus removal from wastewater in the sea, there are manyshortcomings, and they can not achieve the recycling of phosphorus. The crystallization ofmagnesium ammonium phosphate could remove phosphorus and recovery of phosphorusresources from wastewater. Crystallization removal can not only solve the problem of floodEnteromorpha along the coastal cities, but also can solve the shortage of phosphorusresources.Therefore, in order to explore the use of magnesium ammonium phosphatecrystallization process seawater using wastewater feasibility crystalline phosphorus removal,the operating conditions of the experiment, the filter model reactor as the basis of filterfiltration process control. By examining slag, the steel slag matrix composites seed filter, slagand slag-based composite seed filter aqueous phosphorus removal kinetic characteristics,compared to four filter phosphorus removal performance and its crystallization effect, selectthe best crystal the species; emphasis on the hydraulic retention time （HRT, hydraulicRetention time）, pH value, aeration process operating conditions such as the amount ofphosphorus removal reactor performance were investigated by the operating conditions of thesystem analysis of magnesium ammonium phosphate crystallization phosphorus removal ofseed filter view to explore the long-running and highly efficient and stable conditions, providethe basis for engineering practice.The study results showed that the dosing seed crystal can shorten the induction period ofthe crystallization process. Dosing the seed crystal can be achieved not only induce andpromote the crystallization reaction, can also be used as the phosphorus recovered carrier. Compare the five filter the slag matrix composite the seed filter has the strongest phosphorusremoval capacity. Slag based composite filter medium in a certain alkaline conditions, thehydration activity of the active mineral is excited prompt phosphate concentrate in the form ofmagnesium ammonium phosphate crystals, thus achieving the efficient removal ofphosphorus.Different seed crystal filter crystalline reaction product is different to the compositionand morphology of ammonium magnesium precipitation. Precipitation generated by the slagmatrix composites seed filter mesh15．881°、16．484°、21．493°、27．099°、31．989°、33．306°.Etc. characteristic diffraction peaks consistent with those reported to generatemagnesium ammonium phosphate precipitation in the slag matrix composites seed Biofilter.In contrast, slag, slag, slag matrix composites seed filter and quartz sand phosphorus removalperformance was not as good as the the slag matrix composites seed filter the crystals formedafter XRD characterization and analysis, the slag matrix composite filter media in a certainunder alkaline conditions, the hydration activity of the active mineral are excited promptphosphate concentrate in the form of magnesium ammonium phosphate crystals, thusachieving the efficient removal of phosphorus. After screening to determine this experimentto take the slag matrix composites seed filter.Seed filter alkalinity release by the hydraulic retention time （HRT）. With the hydraulicretention time, the release of the seed crystal filter to the increase in the number of thealkalinity, the pH value increased, the alkaline environment required for the reaction providesa crystallization; hydraulic residence time, increasing the ammonium ion, magnesium ion,phosphate reduce the activation energy of the contact ion collision probability, the seed filtermedia to enhance the effect of phosphorus adsorption, so that the formation of magnesiumammonium phosphate precipitation increased, the crystal formation, thereby promoting thethe crystalline reaction, improve the efficiency of phosphorus removal. When HRT=90min,the best effect, so the hydraulic retention time （HRT） for90min.The pH value determines the morphology and activity of various composed ofmagnesium ammonium phosphate ion to achieve a balance in the water exist. pH mayinterfere with the activity of NH4+and PO43-, when the dropwise addition of sodium hydroxidesolution to improve the water sample pH=8.5, the solubility of the phosphorus concentration in the water sample gradually decreases, and eventually reach equilibrium, the maincomponent is MgNH₄PO₄precipitated at this time. So, the seed of the slag matrix compositefilter influent pH was adjusted to8.5. This can reduce the cost of NaOH Pharmacy, puremagnesium ammonium phosphate, can also be appropriate to reduce the effluent pH.Using aeration methods can improve the original pH of the water, adjusting thegas-water ratio for the crystallization process to create a suitable alkaline environment.Aeration not only saves the added drug dose, but can also provide agitation, increased mutualcollisions between ions. When the aeration is excessively large, the filter media within thereactor a certain amount of agitation, and adhered to the surface of the crystals in the filter off,influence the effect of the removal of phosphorus;, and will cause wear between the filteraffect the subsequent formation of crystals attached, so select the aeration gas-water ratio of10.The aeration synergistic plus soda can effectively improve the pH value of the slagmatrix composites seed filter effluent, thereby improving the efficiency of phosphorusremoval, effluent phosphorus concentration decreased. When the hydraulic retention time of90min, adjust the air-water ratio of10through the air compressor, the slag matrix compositesseed filter plus alkali adjust pH=8.0, and the effluent pH=9.56can meet magnesiumammonium phosphate crystallization reaction chemistry requirements.Take aeration synergistic plus resulting precipitate most of the magnesium ammoniumphosphate crystals, and the peak is high, the degree of crystallization is very good, goodrecycling value. The crystals have a orthorhombic crystal structure, Ordering rules andcompact structure, typical MAP precipitated crystal structure, seen from the EDS FIG peakare O, Mg and P, MAP main constituent elements, while adjusting the pH in the aeration Thecrystalline product obtained in the value of the condition is relatively pure magnesiumammonium phosphate.