Abstract: This gas production system includes: a gas production device having a reactor forming a flow path for a treatment target gas, a first electrode and a second electrode to which voltage is applied, and a catalyst layer provided in the flow path and containing a catalyst; voltage generation means for generating voltage to be applied to the first electrode and the second electrode; and gas supply means for supplying the treatment target gas to the gas production device. The voltage generation means has frequency setting means for setting the frequency of the voltage in accordance with the treatment target gas, plasma generated between the first electrode and the second electrode is applied to the catalyst layer, and the treatment target gas is reformed to obtain a product gas.

Abstract: A gas production system which applies plasma to a catalyst in a reactor and reforms a supplied source gas and a supplied oxidant gas to produce a product gas, includes: gas ratio change means for changing a ratio between the source gas to be supplied to the reactor by source gas supply means and the oxidant gas to be supplied to the reactor by oxidant gas supply means; and plasma generation means for generating the plasma to be applied to the catalyst. Thus, formation of highly reactive chemical species on a catalyst surface is efficiently promoted, whereby the yield of the product gas and energy efficiency are improved.

Abstract: This gas production system includes: a gas production device having a reactor forming a flow path for a treatment target gas, a first electrode and a second electrode to which voltage is applied, and a catalyst layer provided in the flow path and containing a catalyst; voltage generation means for generating voltage to be applied to the first electrode and the second electrode; and gas supply means for supplying the treatment target gas to the gas production device. The voltage generation means has frequency setting means for setting the frequency of the voltage in accordance with the treatment target gas, plasma generated between the first electrode and the second electrode is applied to the catalyst layer, and the treatment target gas is reformed to obtain a product gas.

Abstract: A method for cleaning a filter membrane in which at least 2 types of cleaning water containing oxidizing agents are prepared, and the filter membrane is cleaned using the cleaning water in an ascending order of the oxidizabilities of the oxidizing agents. Moreover, an apparatus for cleaning a filter membrane of the present invention comprises a means for cleaning the filter membrane using at least 2 types of cleaning water containing oxidizing agents, and the filter membrane is cleaned using the cleaning water in an ascending order of the oxidizabilities of the oxidizing agents. The method and the apparatus for cleaning a filter membrane can efficiently remove polluting substances adhered to a filter membrane while reducing the amounts of oxidizing agents and water to be used, and can maintain the filtration performance for a long period of time.

Abstract: A water treatment system includes: an aeration tank for converting wastewater containing organic substances into sludge-laden treated water by aerobic treatment; an ozone supply unit for feeding ozone into the sludge-laden treated water drawn out from the aeration tank; and a bubble detector for detecting the condition of bubbles produced by reaction between the fed ozone and the sludge. The ozone treatment is controlled by utilizing as an indicator for sludge volume reduction effect the increase rate of bubbles detected by the bubble detector, so that the water treatment system is able to vary the amount of ozone feed depending on the conditions of water treatment.

Abstract: A water treatment system including: a biological treatment stage for treating an organic wastewater by an action of a microorganism; an ozone gas producing stage for generating ozone gas; a sludge transferring stage for withdrawing and transferring a part of the microorganism-mixed liquid in the biological treatment stage; an ozone treatment stage for bringing ozone into contact with the part of the microorganism-mixed liquid transferred; and a treated liquid returning stage for returning the treated liquid after the ozone treatment from the ozone treatment stage to the biological treatment stage. Undecomposed aggregated microorganisms after the ozone treatment are separated and concentrated, and an ozone treatment is selectively applied to the aggregated undecomposed microorganisms thus separated and concentrated.

Abstract: A method for cleaning a filter membrane in which at least 2 types of cleaning water containing oxidizing agents are prepared, and the filter membrane is cleaned using the cleaning water in an ascending order of the oxidizabilities of the oxidizing agents. Moreover, an apparatus for cleaning a filter membrane of the present invention comprises a means for cleaning the filter membrane using at least 2 types of cleaning water containing oxidizing agents, and the filter membrane is cleaned using the cleaning water in an ascending order of the oxidizabilities of the oxidizing agents. The method and the apparatus for cleaning a filter membrane can efficiently remove polluting substances adhered to a filter membrane while reducing the amounts of oxidizing agents and water to be used, and can maintain the filtration performance for a long period of time.