1. A method for cleaning a porous polymeric membrane contained in a tank of a wastewater treatment plan including a membrane bioreactor, the method comprising:
introducing a first cleaning solution including a chlorine-based oxidizing agent selected from the group consisting of chlorine, hypochlorites, chlorites, chlorates, perchlorates, and chloramines to a tank containing the membrane;
contacting at least a portion of the membrane with the first cleaning solution for a first time period;
introducing a second cleaning solution including a reducing agent directly to the tank containing the membrane and the first cleaning solution after the first time period has elapsed, the second cleaning solution neutralizing an oxidizing residual of the first cleaning solution and forming an acid species from a reaction between the first cleaning solution and the second cleaning solution;
soaking at least a portion of the membrane with the acid species for a second time period; and
discharging a solution including the acid species from the tank after the second time period has elapsed;
adjusting the pH level of the discharged solution including the acid species;
introducing the discharged acid species into a head of the wastewater treatment plant; and
mixing the discharged acid species with an incoming wastewater flow into the wastewater treatment plant.
2. The method of claim 1, wherein the membrane is a hollow-fiber membrane.
3. The method of claim 1, wherein the oxidizing agent is selected from the group consisting of sodium hypochlorite and monochloramine.
4. The method of claim 1, wherein the reducing agent is selected to neutralize the oxidizing residual from the oxidizing agent.
5. The method of claim 4, wherein the reducing agent is selected from the group consisting of bisulphites, metabisulfites, sulphites, and thiosulfates.
6. The method of claim 5, wherein the reducing agent is selected from the group consisting of sodium metabisulfite, sodium thiosulphate, and sodium bisulfite.
7. The method of claim 1, wherein the second cleaning solution further includes an enhancing agent.
8. The method of claim 7, wherein the enhancing agent is a surfactant or a chelating agent selected from the group consisting of polycarboxylic acids and salts thereof.
9. The method of claim 7, wherein the enhancing agent is selected from the group consisting of citric acid, a salt thereof, ethylenediaminetetraacetic acid (EDTA), a salt thereof, oxalic acid, and a salt thereof.
10. The method of claim 7, wherein a concentration of the enhancing agent is between 0.01 wt % and 1.0 wt %.
11. The method of claim 10, wherein the concentration of the enhancing agent is 0.5 wt %.
12. The method of claim 1, wherein a concentration of the oxidizing agent in the first cleaning solution is between 0.01 wt % and 2 wt %.
13. The method of claim 12, wherein the concentration of the oxidizing agent in the first cleaning solution is approximately 0.1 wt %.
14. The method of claim 12, wherein a concentration of the reducing agent is between 0.01 wt % and 2 wt %.
15. The method of claim 14, wherein the concentration of the reducing agent is approximately 0.15 wt %.
16. The method of claim 1, wherein the first time period is at least about three hours, and wherein the second time period is at least about two hours.
17. The method of claim 1, wherein the membrane is cleaned at ambient temperature and pressure.
18. The method of claim 1, further comprising recirculating at least one of the first cleaning solution and the acid species in the tank.
19. The method of claim 1, further comprising filtering at least one of the first cleaning solution and the acid species through the membrane from an outside wall of the membrane to a lumen of the membrane.
20. The method of claim 1, further comprising soaking the membrane in the first cleaning solution.
21. The method of claim 1, further comprising air scouring the membrane while contacting the membrane with at least one of the first cleaning solution and the acid species.
22. The method of claim 1, wherein the second solution is introduced while backwashing the membrane.
23. The method of claim 1, wherein the first cleaning solution targets organic membrane foulants, and wherein the acid species targets inorganic membrane foulants.
24. A method of facilitating cleaning of a porous polymeric membrane in place, the porous polymeric membrane being contained in a tank of a wastewater treatment plant including a membrane bioreactor, the method comprising:
providing a first cleaning solution including at least one chlorine-based oxidizing agent selected from the group consisting of chlorine, hypochlorites, chlorites, chlorates, perchlorates, and chloramines and a second cleaning solution including at least one reducing agent; and
providing instructions to:
contact at least a portion of the membrane with the first cleaning solution in a membrane tank for a first time period to target organic membrane foulants;
introduce the second cleaning solution directly to the membrane tank including the first cleaning solution after the first time period has elapsed, a mixture of the first cleaning solution and the second cleaning solution forming an acid species from a reaction between the first cleaning solution and the second cleaning solution;
recirculate the acid species through the membrane; and
contact at least a portion of the membrane with the acid species for a second time period of at least about two hours to target inorganic membrane foulants;
discharge a solution including the acid species after the second time period has elapsed;
adjust a pH level of the discharged solution including the acid species;
introduce the acid species into a head of the wastewater treatment plant after the second time period has elapsed; and
mix the acid species with an incoming wastewater flow into the wastewater treatment plant.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A stringed musical instrument for producing music sound comprising:
an instrument body having a longitudinal direction and a lateral direction;
at least one string stretched in said longitudinal direction over said instrument body;
a connector connected between one end of said instrument body and one end of said at least one string; and
a tailpiece unit provided at the other end of said instrument body, and including
a tailpiece connected to the other end of said at least one string, a tail wire connected at one end thereof to said tailpiece and keeping said tailpiece spaced from said instrument body,
a fastener made of a certain sort of material less influenced in variation of humidity rather than wood and securing said tail wire to said instrument body, and
a blindfold supported by said instrument body and preventing said tail wire and said fastener from eyes of users.
2. The stringed musical instrument as set forth in claim 1, in which said instrument body has a center stem without a hollow space serving as a resonator and a framework connected to said center stem.
3. The stringed musical instrument as set forth in claim 2, further comprising a vibration-to-electric signal converter so as to convert vibrations of said at least one string to an electric signal.
4. The stringed musical instrument as set forth in claim 2, in which said electric signal is converted to electric tones fallen within a compass same as the compass of an acoustic violin.
5. The stringed musical instrument as set forth in claim 2, in which said electric signal is converted to electric tones fallen within a compass same as the compass of an acoustic viola.
6. The stringed musical instrument as set forth in claim 1, in which said instrument body has plural plates defining a hollow space serving as a resonator for enlarging loudness of tones produced through vibrations of said at least one string.
7. The stringed musical instrument as set forth in claim 6, in which said at least one string and other strings produces acoustic tones fallen within a compass same as an acoustic violin.
8. The stringed musical instrument as set forth in claim 6, in which said at least one string and other strings produces acoustic tones fallen within a compass same as an acoustic viola.
9. The stringed musical instrument as set forth in claim 1, further comprising a chinrest supported by said instrument body, and said chinrest and said blindfold have a unitary structure.
10. The stringed musical instrument as set forth in claim 1, in which said instrument body has a center stem made of wood, and
said fastener includes
a saddle plate made of said certain sorts of material and formed with at least one hole and at least one threaded hole,
at least one wood screw driven into said center stem for pressing said saddle plate to said center stem and
at least one bolt driven into said at least one threaded hole for pressing said tail wire to said saddle plate.
11. The stringed musical instrument as set forth in claim 10, in which said tailpiece is provided over a major surface of said center stem, and said tail wire extends from said tailpiece through an end surface of said center stem to another major surface of said center stem, wherein said saddle plate is pressed to said another major surface by means of said at least one wood screw.
12. The stringed musical instrument as set forth in claim 11, in which said blindfold extends from a space over an area of said major surface where said tail wire extends through over said end surface to a space over an area of said another major surface where said saddle plate is pressed.
13. The stringed musical instrument as set forth in claim 1, in which said instrument body has a center stem made of wood, and
said fastener includes at lest one wood screw driving into said center stem for pressing said tail wire to said center stem.
14. The stringed musical instrument as set forth in claim 1, in which a player rubs said at least one string with a bow so as to give rise to vibrations of said at least one string.
15. A tailpiece unit used for a stringed musical instrument, comprising:
a tailpiece connected to an end of at least one string of said stringed musical instrument;
a tail wire connected at one end thereof to said tailpiece, and keeping said tailpiece spaced from an instrument body of said stringed musical instrument;
a fastener made of a certain sort of material less influenced in variation of humidity rather than wood, and securing said tail wire to said instrument body; and
a blindfold supported by said instrument body, and preventing said tail wire and said fastener from eyes of users.
16. The tailpiece unit as set forth in claim 15, in which said fastener includes
a saddle plate made of said certain sorts of material and formed with at least one hole and at least one threaded hole,
at least one wood screw driven into a wood piece of said instrument body for pressing said saddle plate to said wood piece and
at least one bolt driven into said at least one threaded hole for pressing said tail wire to said saddle plate.
17. The tailpiece unit as set forth in claim 16, in which said tailpiece is provided over a major surface of said wood piece, and said tail wire extends from said tailpiece through an end surface of said wood piece to another major surface of said wood piece, wherein said saddle plate is pressed to said another major surface by means of said at least one wood screw.
18. The tailpiece unit as set forth in claim 17, in which said blindfold extends from a space over an area of said major surface where said tail wire extends through over said end surface to a space over an area of said another major surface where said saddle plate is pressed.
19. The tailpiece unit as set forth in claim 15, in which said fastener includes at lest one wood screw driving into a wood piece of said instrument body for pressing said tail wire to said wood piece.
20. The tailpiece unit as set forth in claim 15, in which said blindfold is an extension of a chinrest supported by said instrument body.