0001 The present invention relates to an environmentally affirmative trench system treating effluents from soil covered biological septic tanks for decomposition of household sewage.

BACKGROUND OF THE INVENTION 0002 1. Field of Invention 0003 The present invention relates to a more environmentally affirmative trench system treating household sewages from a soil covered multi-step biochemical septic tank. Secondary contamination of the underground water by the wastewater soaked out of the trench is minimized. Additional oxygen for the microorganisms in the soil, decomposing impurities in the wastewater, is supplied from bottom of the trench. 0004 2. Description of the Prior Art 0005 Many of previous U.S. Patents teach various methods of treating wastewater from septic tanks. U.S. Pat. Nos. 5,707,513; 5,645,732; 4,971,690; 4,826,601; 4,824,572; 4,100,073 teach to use simple filters and chemical treatments. 0006 U.S. Pat. No. 4,895,645 to Zorich teaches the use of a closed multi chamber multi media biological filter tank between the septic tank and the drain field with a complex control system. U.S. Pat. No. 6,264,838 to Nivens teaches a method of a complete synergetic on site wastewater recycle system. The system consists of multi step biological septic tank of conventional type, a rock/plant filter, a dosing chamber, a shallow horizontal flow pulsed planted aggregate filter, and effluent holding tank. The system does not use power. The materials of construction are natural. However, the impervious membrane isolating the shallow aggregate filter from the soil can block the air permeation to the surrounding soil and makes it rot destroying the biological environment in the soil. 0007 The last two technologies utilize biological methods. They are very complex for a normaal house wastewater treatment. They are environmentally imperfect.

SUMMARY OF THE INVENTION 0008 It is the object of this invention to provide a more simple and environmentally affirmative system treating the wastewater from multistage biological septic tanks. The system is simple in design and operation, economical to construct, operate, and maintain. 0009 FIG. 1 is a schematic plane geometry showing the layout of the system. The structure is buried underground. Garden grass and flowers are planted on the soil to provide a pleasant view, adequate for installaton in a normal house yard. No instruments consuming power are used. 0010 System of this invention utilizes pottery pipes, U shaped polyolefin half pipes, soil, stone chips and local plants for the microorganisms living in the area. 0011 The invention provides all the synergistic artificial conditions to naturally treat the waste water to produce an effluent clean enough to be used as household water for toilet, car washing and garden sprinkler while using no artificial chemicals, and no treatment method step requirng frequent maintenance.

BRIEF DESCRTIPTION OF THE DRAWINGS 0012 FIG. 1 is the schematic plane geometry showing the lay out of the system. 0013 FIG. 2 is the cross sectional view of the pottery pipe trench system. 0014 FIG. 3 is the cross sectional view of air supplying pipe surrounded with rock filter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 0015 FIG. 1 is the schematic plan geometry showing the lay out of the system of this invention. Sewages treated in the soil covered biological septic tank (100) are distributed to the pottery trenches (300) by distributor (200). Another porous pipes (400) buried under the pottery trench (300) in transversal direction, surrounded by rock filter, supply the air for microorganisms in the soil and reserve the overflowed wastewater. Effluents are sampled for evaluation at the sampling port (500). Two sets of trenches are installed in series to meet the over flow of the wastewater. 0016 FIG. 2 is the cross sectional view of the pottery piped trench system. When wastewater is introduced into the pottery pipe (303), the water soaks out of the pottery (302) through the pores at the wall. Then the water diffuses into radiational direction by the capillary permeation through the pores in the rock filter (301). Water soaked out to the bottom direction of the pottery pipe (302) is blocked by the U type polyolefin half pipe (305) and captured in the sand layer (304) filling the pipes. The water captured in the sand layer (304) diffuses upper direction by a capillary permeation. No pumps are needed to deliver the water to the effluent end. Water soaked out of the pottery tubes is absorbed by the root of the plants (108) in the soil (107). Impurities in the water are used as fertilizer for the plants and food for microorganisms in the soil. 0017 FIG. 3 is the cross sectional view of air supplying porous pipe surrounded with rock filter. Rock filters (404) with pores (402) are layered on the meshes (405) and pottery pipes (403) are installed. One side of these porous pipes is exposed to the air from above ground. The roles of these porous pipes are: 1) to supply air to the microorganisms living in the soil (107); and 2) to reserve the overflowed wastewater. 0018 Combination of the above mechanisms endowed by the structure of this invention enables non power driven waste water treating system easy to install, maintain and economic. Environmentally affirmation is another strong point of this system.