Submerged membrane filtration system using reciprocating membrane

1. A reciprocating submerged membrane filtration apparatus comprising:

a membrane tank comprising a submerged membrane and configured to intake influent wastewater to be treated, the influent wastewater being filtered through the submerged membrane to produce treated water;

a reciprocation apparatus configured to move the submerged membrane to create an inertia force which shakes foulants off from the submerged membrane under oxygen-deficient conditions;

an anaerobic digester configured to biologically treat influent wastewater containing an organic compound by anaerobic digestion under anaerobic conditions to produce sludge and to feed a supernatant above the sludge to the membrane tank; and

a high-rate digester disposed upstream of the anaerobic digester and configured to mechanically agitate influent wastewater containing an organic compound in a mixer, to heat the influent wastewater by a sludge heater to produce intermediate sludge and to feed the intermediate sludge to the anaerobic digester, in which the high-rate digester comprises a two-stage anaerobic digester together with the anaerobic digester.

2. The reciprocating submerged membrane filtration apparatus of claim 1 , wherein the submerged membrane comprises a microfiltration (MF) membrane or an ultrafiltration (UF) membrane.

3. The reciprocating submerged membrane filtration apparatus of claim 1 , wherein the submerged membrane is configured to be reciprocated back and forth at a frequency of 2 Hz or less and an amplitude of 10 mm or more.

4. The reciprocating submerged membrane filtration apparatus of claim 1 , wherein the submerged membrane is configured to be reciprocated back and forth at a frequency of 1 Hz or less and an amplitude of 30 mm or more.

5. The reciprocating submerged membrane filtration apparatus of claim 1 , wherein the submerged membrane is configured to be reciprocated back and forth at a frequency of 0.5 Hz or less and an amplitude of 40 mm or more.

6. The reciprocating submerged membrane filtration apparatus of claim 1 ,

wherein the submerged membrane is reciprocated back and forth at a frequency of 0. 2-0.5 Hz, and

wherein a flocculant inlet is disposed upstream of the membrane tank so that both flocculation by a flocculant and filtration occurs in a single membrane tank.

7. The reciprocating submerged membrane filtration apparatus of claim 1 , further comprising a recirculation line configured such that a portion of the treated water discharged from the membrane tank is mixed with the intermediate sludge discharged from the high-rate digester and is introduced into the anaerobic digester.

8. A reciprocating submerged membrane filtration apparatus comprising:

a membrane tank comprising a submerged membrane and configured to intake influent wastewater to be treated, the influent wastewater being filtered through the submerged membrane to produce treated water;

a reciprocation apparatus configured to move the submerged membrane to create an inertia force which shakes foulants off from the submerged membrane under oxygen-deficient conditions:

an anaerobic digester configured to biologically treat influent wastewater containing an organic compound by anaerobic digestion under anaerobic conditions to produce sludge and to feed a supernatant above the sludge to the membrane tank;

a high-rate digester disposed upstream of the anaerobic digester and configured to mechanically agitate influent wastewater containing an organic compound in a mixer, to heat the influent wastewater by a sludge heater to produce intermediate sludge and to feed the intermediate sludge to the anaerobic digester, in which the high-rate digester comprises a two-stage anaerobic digester together with the anaerobic digester; and

a selenium reduction tank disposed upstream of the submerged membrane tank and configured to biologically treat wastewater containing selenium oxide under anoxic or anaerobic conditions to produce intermediate treated water and to feed the intermediate treated water to the membrane tank.

9. The reciprocating submerged membrane filtration apparatus of claim 8 , further comprising:

a flocculant inlet configured to introduce a flocculant to the intermediate treated water produced in the selenium reduction tank before the intermediate treated water is fed into the membrane tank; and

a recirculation line configured to recover a portion of the produced treated water discharged from the membrane tank and to recycle the recovered treated water to the selenium reduction tank.

10. A reciprocating submerged membrane filtration apparatus comprising:

a membrane tank comprising a submerged membrane and configured to intake influent wastewater to be treated, the influent wastewater being filtered through the submerged membrane to produce treated water;

a reciprocation apparatus configured to move the submerged membrane to create an inertia force which shakes foulants off from the submerged membrane under oxygen-deficient conditions;

an anaerobic digester configured to biologically treat influent wastewater containing an organic compound by anaerobic digestion under anaerobic conditions to produce sludge and to feed a supernatant above the sludge to the membrane tank; and

a recirculation line configured to recover a portion of the treated water discharged from the membrane tank and to recycle the recovered treated water to the anaerobic treatment tank.

11. The reciprocating submerged membrane filtration apparatus of claim 10 , wherein the submerged membrane comprises a microfiltration (MF) membrane or an ultrafiltration (UF) membrane.