Study On Preparation Of Hydroponic Phosphate Fertilizer From Wastewatre With The Method Of Biological Phosphorus Accumulation & Supplymentary Carbon Source Induced Phosphorus Recovery

The shortage of phosphorus resources and the shortage of soil resources are two major problems in today’s society.In order to solve the problem of efficient recovery of phosphorus resources from sewage and the possible shortage of phosphorus resources in agricultural production,it is necessary to study the methods of efficient storage and recovery of phosphorus from sewage and form compound phosphorus fertilizer suitable for new type of facility agriculture.This study was based on the Biological Bio-nutrient Removal-Carbon regulation and Phosphorus Recovery（BBNR-CPR）system.In order to establish a new way of biological phosphorus accumulation and efficient phosphorus recovery,the effect of phosphorus recovery solution on vegetable（Pakchoi）hydroponic culture was studied by the means of biological enrichment of phosphorus from simulated domestic sewage and formation of phosphorus recovery solution.In this paper,the effects of different types carbon sources on nitrogen removal,phosphorus accumulation,microbial community,phosphorus recovery liquid composition and the fertilizer efficiency of BBNR-CPR system at different temperatures were studied.The composition of nutrient elements in phosphorus recovery liquid was analyzed,and the preparation and fertilizer efficiency of hydroponic composite phosphate fertilizer were studied.The nutrient composition of Hydroponic phosphate fertilizer formula（HPFF）was optimized by referring to commercial Hydroponic solution formula,and the Hydroponic fertilizer formula was compared with commercial Hydroponic solution.Finally,the formula of hydroponic phosphate fertilizer was improved to develop the formula of hydroponic phosphate fertilizer suitable for the low temperature growth of Pakchoi.The main achievements:（1）The results of batch experiments showed that Cu²⁺did not appear in the supernatant when the concentration of influent Cu²⁺was lower than 2mg/L,and had almost no inhibitory effect on biofilm nitrogen and phosphorus removal.Adjust the composition of recovered carbon source to form a new type of carbon source as the supplementary carbon source for P recovery,（1）（Potassium propionate,90%Potassium propionate+10%glycine）,（2）Potassium propionate phosphate recovery solution,PP-PRS),and（3）Glycine containing phosphorus recovery solution（Gly-PRS）.The results showed that when the supplemental carbon source was changed from sodium propionate to potassium propionate,the average concentration of phosphorus recovery liquid in BBNR-CPR reached 44.79mg/L,and the phosphorus recovery efficiency was increased by 26.5%compared with that of sodium propionate.At this time,the relative abundance of GAOs in the biofilm of BBNR-CPR decreased by 10%,and Acinetobacter spp.increased to 3.24%.Norank＿f＿norank＿o＿Run＿SP154 spp.,norank＿f＿PHOS＿HE36 spp.,norank＿f＿A4b spp.,Flavobacterium spp.and other bacteria related to nitrogen removal increased.When the supplemental carbon source used in the phosphorus recovery process of BBNR-CPR reactor was adjusted to 90%potassium propionate+10%glycine,the concentration of phosphorus recovery solution reached 54.29mg/L and the recovery efficiency reached 41.04%.However,the simultaneous nitrification and denitrification effect and denitrification efficiency of phosphorus accumulation stage were reduced by 31.08%after using the supplemental carbon source to recover phosphorus.In addition,the candidatus competibacter spp.abundance of denitrifying glycan bacteria in biofilms of BBNR-CPR was reduced by 21.09%.Due to the inhibition of nitrogen removal,the relative abundance of bacteria associated with nitrogen removal（norank＿f＿＿norank＿o＿＿Candidatus＿Moranbacteria spp.,fied＿f＿＿comamonadaceae spp.,and Candidatus＿Nitrotoga spp.）decreased,while those associated with biological phosphorus accumulation（Dechloromonas spp.,Pseudomonas spp.,Acinetobacter spp.）increased.（2）According to the growth effect of Pakchoi after application,the supplementary carbon source type in the phosphorus recovery process of BBNR-CPR reactor was adjusted to optimize the operation effect of the reactor,and the composition of phosphorus recovery liquid recovered from BBNR-CPR reactor was optimized,and the nutrient composition of phosphorus recovery liquid was adjusted to form the hydroponic compound phosphate fertilizer（HPFF）formula:The phosphorus recovery solution（PP-PRS）was diluted 4 times,and 550-600 mg tetrachronal calcium nitrate,15-20 mg magnesium sulfate heptahydrate,150-250 mg of ammonium sulfate were added to each L PP-PRS.In addition,the absorption rate of ions in nutrient solution(Ca²⁺、Mg²⁺、K⁺)increased after the HPFF application,among which,the absorption rate of Ca²⁺increased significantly（1.59%）,which was higher than 86.26%of the commercial group.The HPFF and Hoagland formula were used to cross-test,and it was found that the chlorophyll and carotenoids in the cultured Pakchoi leaves had little difference in the growth period of 30 days,and there was no statistical difference in the growth indexes between of the two groups at their harvest.（3）At the third stage of hydroponic culturing,the phosphorus recovery solution（Gly-PRS）was diluted 5.5 times.After adjusting the elements of calcium,sulfur and nitrogen（Supplementary ammonium sulfate:15-20mg/L,calcium nitrate tetrachloride:450-500mg/L）,Low temperature resistance hydroponic phosphate fertilizer formula（LTR-HPFF）was successfully developed.The results showed that the growth indexes of Pakchoi cultured by LTR-HPFF were the best,and the chlorophyll content and carotenoid content of the Pakchoi cultured by LTR-HPFF were better than the control group.Compared with the control group,the absorption of Mg²⁺and phosphorus were increased by 23.18%and 38.22%respectively by applying the LTR-HPFF as the supplementary carbon source for P recovery from BBNR-CPR reactor.At low temperatures,the electrical conductivity in the hydroponic solution of Pakchoi was found to increase.Compared with the control group,using the LTR-HPFF as hydroponic compound fertilizer slowed down the increasing trend of electrical conductivity.