Study On The Treatment Efficiency Of Membrane Bioreactor To Micro-pollutants Nh₃-N And HA

The membrane bioreactor(MBR)、MBR with homemade iron oxide coated sands(IOCS) are used to study the micro-polluted source water treatment which contains little NH3-N and HA. In the prophase the composite domesticated method is used to domestic activated sludge. And explores and analyzes the sludge floating、sludge disintegration、sludge bulking and so on. The emphasises are the waterquality indicators like CODMn、turbidity, ammonia、UV254、 UV410and membrane fouling situation. The results are shown as followed:1. The result of MBR technology for micro-polluted raw water is stable and good. MBR is alternative to the conventional treatment process. MBR with IOCS can improve the water quality and system operation stability.(1) Before dosing IOCS, the water indicators like CODMn、turbidity, ammonia、 UV254. UV410are2.29mg/L、0.1NTU、0.54mg/L、0.072cm-1、0.005cm-1in average. The average removal rate is49.6%、98.8%、82.2%、38.6%、79.9%.(2) After dosing IOCS, the CODMn、turbidity、ammonia、UV254、UV410removal efficiency can achieve57.9%、99.3%、84.9%、58.2%、80.1%in average. Removal rate are increased by8.3、0.5、2.7、19.6、0.2percent than that without IOCS.2. The composite domesticated method is used to domestic activated sludge in the slightly polluted raw water which is in the oligotrophic state. The methods like increasing the raw water、shorting HRT (1h instead of3h)、extending SRT (3months instead of1month)、adding IOCS (2g/L)、adding nutrients (flesh sludge and glucose) and so on are taken to make the sludge adapt to the poor nutrition water.3. During the MBR operation, MLSS、HRT、pH are chosen as the impact factors to make the orthogonal test. The effect order of the experimental result is MLSS>HRT>pH. The best operating parameters of MBR are MLSS=1.5g/L, HRT=3h, pH=7.5.4. The physical cleaning、acid cleaning、alkali cleaning, sodium hypochlorite cleaning are used to renew the membrane. The membrane flux ratio is recovered by30.84%、1.9%、 2.3%、28.15%respectively. The membrane flux ratio reaches96.35%of maximum. It is almost fully restored. The effect of acid cleaning and alkali cleaning are not obvious. The organic fouling and Gel layer fouling are the main membrane fouling.5. IOCS is the attachment points of activated sludge with its large surface area、strong adsorption capacity and ion exchange capacity.It can gather the organics in the poor nutrition water and improve the properties of the mixture in the reactor. While reducing the membrane burden, IOCS improves the water quality and the system operation stability of MBR.