Study On Enhanced Biological Phosphate And Autotrophic Nitrogen Removal In Wastewater Treatment By A Sequencing Batch Biofilm Reactor Of Luffa Cylindrical Sponger(LS-SBBR)

Discharges of phosphate and nitrogen in the effluent from wastewater treatment plants was becoming the primary factor of eutrophication, and the effluent standards were more and more strict. There are various of novel biofilm wastewater treating bioreactor were developed with simple configuration, low sludge production and effective of phosphate and nitrogen removal. Nowadays the biofilm bioreactor rebecome one of the important research aspect in enhanced biological phosphate removal(EBPR).For its netting-like fibrous vascular structural system, the natural fiber, Luffa cylindrical sponge (LS), was utilized as the biofilm support media in a sequencing batch biofilm reactor (LS-SBBR). Experiments on enhanced biological phosphate and nitrogen removal were carried out to disposal the municipal wastewater and metaphase-later landfill leachate with LS-SBBR. Moreover, comparative effect of denitrifying phosphate removal in LS-SBBR and side-stream MBR with gravitation filtration system (GS-MBR) was developed both in lab scale experiments, with comparative experiments on the effect of phosphate uptake in aerobic and anoxic conditions. Investigation of the operational stability with LS-SBBR during the municipal wastewater treatment and the disposal effect of landfill leachate as well as its influence factors under completely autotrophic nitrogen removal over nitrite process (CANON) were implemented simultaneously with the experiments.For its porous biological structural speciality, SBBR with Luffa cylindrical sponge media accomplished biofilm forming in less than a week in the light of the operation mode in the experiment of minucipal wastewater treatment, followed an average removal of COD, NH₄⁺-N, TP and TN were 71.18%, 85.01%, 58.19% and 64.45%, respectively. At the following operation period, Nais elinguis appeared in the LS-SBBR system, thus induced reduction of the thickness of biofilm and the removal rate of COD decreased to 56.11%. At meantime, TN and TP were released obviously, the releasing rate of TP and TN was 92.92% and 33.45%, respectively, in the appearance of Nais elinguis. While the grazing of Nais elinguis did not influenced the ammonia oxidation and could strengthened it to an extent, NH₄⁺-N removal was enhanced from 85.01% to 95.56% in this operation period. The performance of domestic wastewater treatment in LS-SBBR was resumed through discharging excess Nais elinguis. The average nutrient element concentration of nitrogen and phosphorus of Luffa cylindrical sponge was 0.3646% and 0.0646%, respectively, while after the experiment these values decreased to 0.0378% and 0.0238%, respectively, in average. However, the releasing extent of nitrogen and phosphorus from Luffa cylindrical sponge fibers, contrasted to the domestic wastewater disposal under its influent and effluent frequently, as well as organic components, could be eliminated from LS-SBBR system according to research results .LS-SBBR and GS-MBR had realized dentrifying phosphate and nitrogen removal under anaerobic-aerobic-anoxic operational mode in comparative biological nutriment removal tests. Quantity of phosphate uptake in anoxic period to aerobic was 39.97% in LS-SBBR while the value was merely 7.12% refer to the GS-MBR. The feebleness phosphate uptake of GS-MBR was the lack of PHB in anoxic period, thus weakened the absorption of phosphate and the anabolism of polyphosphate.Completely autotrophic nitrogen removal over nitrite (CANON) was observed in the two-staged sequencing batch bioflim reactor (SBBR) in the experiment of landfill leachate treatment with coagulating pretreatment. The experiment results indicated that the most suitable condition for CANON process was as follows: the volumetric loading of NH₄⁺-N was 0.104 kg NH₄⁺-N/(m³Â·d), the SBBR system temperature above 30℃, DO 1.29mg/L, the free ammonia nitrogen 7.2mg/L, and the accumulation rate of NO₂^--N 48.90%. When the influent loading rate of NH₄⁺-N of the first SBBR reached steadily at 0.229 kg NH₄⁺-N /(m³Â·d), the averaged COD removal was 64.04%, meanwhile the NH₄⁺-N removal increased to 72.45%.