NOVELTY - System for wastewater treatment with intermittent aeration and low power consumption comprises: a device for pretreatment of wastewater, which includes pumps (25) that suck the wastewater, which has been sifted through a fine and coarse grid (22), and gravel is stored in a chamber (19), the pre-treatment device has a measuring device and flow control, valves and control.    USE - The system is useful for wastewater treatment (claimed).    DETAILED DESCRIPTION - System for wastewater treatment with intermittent aeration and low power consumption comprises: a device for pretreatment of wastewater, which includes pumps (25) that suck the wastewater, which has been sifted through a fine and coarse grid (22), and gravel is stored in a chamber (19), the pre-treatment device has a measuring device and flow control, valves and control, these pumps (25) are controlled by electro levels which emit a signal to a programmable logic control (PLC) device for pump control, level and flow rate of liquid, the liquid is pumped to the treatment device, or upflow anaerobic sludge blanket (UASB) device, which is the digester sludge; aerobic treatment device consisting of an air diffusion equipment or fine bubble diffusers (1) which are fed by a blower (9) which blows air to them and operate intermittently and bias, noting an high density of diffusers in the aerobic zone, where optional that the region would be deeper than other areas, an agitator (8), both the agitator and the blower is controlled by time using a PLC, the agitator operates after broadcasters stop, energy applies also to avoid sedimentation of sludge in the aeration tank. Then the water passes to a settling tank (3) which separates the liquid from the mud, this is achieved by a chamber that stores the sludge within the settling device, with the objective of implementing a more homogeneous sludge suction, at the bottom of the sedimentation chamber is a ring (30) which serves to absorb the mud by a pump (14), this pump has the characteristic of being calculated to prevent the pressure is not excessive; through some pipes the pump moves sludge treatment team using a solenoid valve (10), and sends the excess sludge, the device of anaerobic digestion of sludge using another solenoid valve (IG), this UASB device (21) digests by anaerobic bacteria, using energy for digestion, which are a suspended blanket or granules, this UASB device comprises input tubes (6), to break into the sludge, and going from the bottom up using a pipe (5), at the top, have an accumulation chamber biogas can be burned when ascending, to avoid damage to the atmosphere, the burning system is controlled by PLC, and in that part also has a separate sediment unit to obtain anaerobic sludge fluid. The liquid sludge is not removed by the thirst feeders (3) the settler at the top has a groove and a sawtooth wire screens along with cream, which allows the fluid does not have cream or mud and is transferred to coil tubing, or disinfection chamber (15), which is responsible for giving residence time to the disinfectant, the disinfectant is served by a metering pump, and controlled by PLC, optionally may have a transducer for controlling the concentration of disinfectant. An INDEPENDENT CLAIM is a method for wastewater treatment with intermittent aeration and low power consumption comprising: (a) Pre-treatment as a process, which is designed to remove sand from 0.2 cm, but leave smaller grains of sand, removing all non-biodegradable particles, then into the lift station, the residence time is less than or equal to 20 minutes; (b) Water is pumped to a water treatment equipment, such treatment varies depending on: If the biological oxygen demand (BOD) concentration for five days is 300-1,000 it comprises: aerobic, anoxic, and facultative aerobic phases, has hydraulic residence time of 4 hours to 3 days, the anoxic phase, which is a function of nitrogen content in the wastewater in question, but which is calculated based on a safety factor of 1.5-2.5 times the theoretical time, that time could be 3 additional hours, up more than 3 days; if the concentration of BOD measured for five days, is 300-10,000, the system also comprises an anaerobic initial phase comprising launching from UASB system as unit after pumping, with residence time up to 24 hours, or up to 5 days. Under these conditions the UASB system has dual function, one unit of the other as grinding sludge digestion system, then the sludge is transferred to a unit of the UASB type, in case of low load, where sludge is digested, with efficiencies ranging up to 90% of volatile suspended solids, the remaining liquid is taken up by the aeration system; within the UASB system, organic sludge are gradually replaced by fixed suspended solids, which must be purged at 7 years, or when the ratio of volatile suspended solids (VSS)/total suspended solids (TSS) is less than 0.1. The treated liquid is settled by the retention times of 10 minutes to 2 hours, the time of purging by bomb inside the settler chamber is not greater than 4 hours. The purge volume varies as the content of the influent BOD, by purging so locating the bacterial mass in logarithmic growth phase and not growth phase is usually seasonal and operates, but must ensure the contents purge time sludge within the system in the order of at least 5 ml/L of Imhoff cone measured at up to 900 ml/L, given that low concentrations of sludge, and low temperatures can cause foam, preferably in domestic wastewater ranges 300-850 ml/L of sludge. The purge must ensure that the bacteria are in log phase; (c) the sewage sludge bleed excessively or are purged to a system which degrades UASB sludge anaerobically, forming a phase-shifted to the system and it would be a phase-only anaerobic sludge purge; (d) the effluent is disinfected for less than 1 minute for ozone or up to 30 minutes in the case of chlorine.    DESCRIPTION OF DRAWING(S) - The drawing shows the side view of the system for wastewater treatment.    Fine bubble diffuser (1)    Input tubes (6)    Solenoid valve (10)    Pump (14)    Disinfection chamber (15)