A round meander septic tank includes an elongate baffle that divides the interior space of the tank into two semicircular chambers. Untreated wastewater is introduced to the first chamber through an inlet located near the first end of the baffle. The wastewater flows through the first chamber to a portal at the second end of the baffle and passes through the portal into the second chamber. A wastewater outlet from the tank is located in the second chamber near the first end of the baffle. Wastewater passing through the portal flows through the second chamber to the outlet and out of the tank. The baffle and the shape of the septic tank increase the distance that the wastewater must flow from the inlet to the outlet as compared to a rectangular meander tank with a single baffle.

Tertiary wastewater treatment wherein a tank is divided into a primary separation chamber, an aerobic chamber, and a clarifier chamber. Media are preferably disposed in the aerobic chamber and most preferably, the media can be contained in one or more porous containers. A recirculation path is preferably provided between the aerobic chamber and the primary separation chamber. In one embodiment, the recirculation between the two chambers can be powered by an air lift pump.

Disclosed is a process for treating wastewaters including at least one step of aerobic biological treatment of the wastewaters in a biological reactor (3), as well as a step of ozonation during which ozone is injected into one or more circuits (1, 6) arranged to transport a respective fluid into the biological reactor (3). Also disclosed is a device relating thereto.

Described herein are attached growth reactor systems which increase nitrifying bacteria biomass through a variety of means during warm weather. As a consequence, the attached growth reactor system contains sufficient nitrifying bacteria biomass to remove ammonia from wastewater in cold to moderate climates. In one example, there are two attached growth reactors into which wastewater is distributed discontinuously. Specifically, wastewater is transferred to the first attached growth reactor for a first period of time and then is transferred to the second attached growth reactor for a second period of time during warm weather which effectively doubles the nitrifying bacteria biomass in the system. During cold weather, approximately half of the wastewater is applied to each reactor simultaneously.

A tank is disclosed as having a tub therein that divides the volume of the tank into an anoxic chamber inside the tub and an equalization chamber outside of the tub. The anoxic chamber anoxically treats wastewater while the equalization chamber equalizes fluctuations in wastewater influent as well as provides a holding space for wastewater if power to the tank is cut off. The tank can be part of a system for treating wastewater, such as one with an anaerobic tank having an anaerobic chamber for anaerobically treating wastewater, an aerobic/filtration tank having a filtration sub-tank therein that divides the volume of the tank into a filtration chamber inside the sub-tank and an aerobic chamber outside of the sub-tank. The aerobic chamber can aerobically treat wastewater while the filtration chamber has a membrane unit for filtering wastewater.

Membrane bioreactor (2) for treating of sewage that includes a first and second bioreaction vessel (4, 6). The first bioreaction vessel (4) includes a first vessel wall (14) for enclosing an internal first vessel space. The second bioreaction vessel (6) includes a second vessel wall (26) for enclosing an internal second vessel space. The first vessel wall (14) includes a convex first peripheral vessel wall part and a first inner vessel wall part (22). The second vessel wall (26) includes a convex second peripheral vessel wall part and a second inner vessel wall part (30). The first vessel wall (14) and the second vessel wall (26) are mechanically connected to each other by means of a vessel connection structure (90). The vessel connection structure (90) positions the first and second peripheral vessel wall parts relative to each other during the treating of sewage.

Described herein are attached growth reactor systems which increase nitrifying bacteria biomass through a variety of means during warm weather. As a consequence, the attached growth reactor system contains sufficient nitrifying bacteria biomass to remove ammonia from wastewater in cold to moderate climates. In one example, there are two attached growth reactors into which wastewater is distributed discontinuously. Specifically, wastewater is transferred to the first attached growth reactor for a first period of time and then is transferred to the second attached growth reactor for a second period of time during warm weather which effectively doubles the nitrifying bacteria biomass in the system. During cold weather, approximately half of the wastewater is applied to each reactor simultaneously.

The invention comprises an improved venturi apparatus and method of use.

The invention relates to a method for carrying out biological purification of wastewater with the aid of activated sludge, in which the wastewater is introduced into a tank for phosphor elimination (P tank), then into an activated sludge tank (B tank) and then into at least one sedimentation and recirculation tank (SU tank), in which a number of operating cycles are carried out, including a sludge return phase, a recirculation phase, a pre-sedimentation phase and a draw-off phase (S phase, U phase, V phase, and A phase respectively), wherein the method further includes the elimination of settleable solids of the inflow, the storage of the produced primary and excess sludge and the reduction of the rising of the water level in the wastewater purification system by using an additional tank (S tank), wherein the S tank is hydraulically connected with the P tank, the P tank with the B tank, and the B tank with the at least one SU tank, wherein the wastewater is first introduced into the S tank, then into the P tank, then into the B tank and subsequently into the at least one SU tank, wherein in the S phase the thickened activated sludge is introduced from the at least one SU tank into the P tank, in the U phase the volume of the at least one SU tank is mixed, in the V phase the activated sludge is settled, and in the A phase the treated wastewater is flowing out of the system and wherein the settled sludge of the S tank is transported from time to time to another special treatment plant.

Described herein are attached growth reactor systems which increase nitrifying bacteria biomass through a variety of means during warm weather. As a consequence, the attached growth reactor system contains sufficient nitrifying bacteria biomass to remove ammonia from wastewater in cold to moderate climates. In one example, there are two attached growth reactors into which wastewater is distributed discontinuously. Specifically, wastewater is transferred to the first attached growth reactor for a first period of time and then is transferred to the second attached growth reactor for a second period of time during warm weather which effectively doubles the nitrifying bacteria biomass in the system. During cold weather, approximately half of the wastewater is applied to each reactor simultaneously.