Treatment Of Starch Wastewater Using Anaerobic Sequencing Batch Reactor

Anaerobic biological treatment technology is a wastewater treatment technology which has high processing load, low energy consumption; low sludge production and can produce methane gas energy etc. With the increasing emissions of high concentration organic wastewater, anaerobic reactors are widely used in high concentration organic wastewater treatment. A variety of anaerobic reactors were developed gradually. Starch wastewater has strong biodegradability as a high concentration organic wastewater, dealing starch wastewater with the new anaerobic reactors gradually becomes a hot research.Anaerobic sequencing batch reactor(ASBR) as the third generation of the anaerobic reactor, with its provincial investment, operational flexibility, stability, efficiency and other advantages, has attracted more and more attention. But its long start-up time and formation of small particles of sludge limited the promotion and application of the technology. In this experiment, artificial preparation of starch wastewater was used as matrix to start-up by self-made ASBR reactor,thus exploring the operation conditions of high concentrations of starch wastewater treatment,Exploring ways of quick start-up of ASBR and seeking for highly efficient methods which are stable,disposable,reasonable and economic to treat starch wastewater with high concentration.In start-up tests of ASBR reactor, secondary clarifier sludge and UASB anaerobic sludge were inoculated in two same ASBR reactors A and B respectively. At the conditions of constant temperature of 35 ℃, no stirring, no additives and some alkalinity, using the method of increasing the COD concentration and reducing hydraulic retention time to domesticate sludge and start up the reactor gradually. When the influent COD concentration was 5000 mg/L and volumetric loading was 5.16 g/(L ? d), the COD removal rate of A and B reached 86.0% and 91.7% respectively; the sludge achieved granular sludge, sludge concentration of A and B reached to 21.6 g/L and 24.5 g/L in the final respectively, the diameters of sludge had reached 1.1 mm and 1.4 mm. Illustrated by the granular sludge and the operating state, A and B started up successfully and experienced 75 d and 61 d respectively, fast start-up of the ASBR were both achieved.The test was continued to treat high concentration starch wastewater by using A. Increasing influent COD concentration from 5000 mg/L to 10000 mg/L, the volume load became 10.1 g/(L ? d). In this process COD removal rate are volatile. Through changing the influent wastewater volume load eventually into 8.1 g/(L ? d), COD concentration were 8000 mg/L, the removal rate up to 92.8%, p H value fluctuated between 6.8 and 7.2. After a month of efficient and smooth operation, the s ludge particle s ize of the reactor reached 3-5mm, sludge concentration was 21.84 g/L, the maximum sludge settling velocity was 46 m/h, the average gas production reached 402 L/kg COD, when dealing with a high concentration of starch wastewater ASBR reactor achieved an efficient and stable operation, and cultivated a kind of good performance granular sludge.In summary, when the ASBR were used for starch wastewater treatment, the reactor could form a good performance granular sludge after the successful started-up. The reactor showed good working condition when treating high concentrations of starch wastewater. The experiment provided a theoretical basis when ASBR was applicated in industrial practice, and it has great significance to reduce the cost in the high concentration of starch wastewater treatment.