 on level plots. There are several commercial trickle or drip irrigation systems avail- able. One particular limitation of this type of system when used with wastewater is that particles in the wastewater and algae grow- ing inside the distribution pipes both tend to plug up the small holes or "injectors" in the pipe. For this system, both disinfection and sand filtration are virtually mandatory. Shallow subsurface irrigation means that the water is distributed through a buried distribution system which is shallow enough that the water is available to plants which have established root systems. For this technique, the primary design consideration is the disposal of sewage effluent, and irrigation is a secondary consideration. Nei- ther aerobic treatment nor filtration nor disinfection is necessary. However, root crops should not be grown for human consumption using this system. CONVENTIONAL SYSTEM MODIFICATIONS age effluent throughout the year. Aerobic treatment should be pro- vided if, during the irrigation season, anyone (including yourself) lives downwind within several hundred yards. The sand filter is optional. Its function is to cleanse the effluent to the point that very few solids are present. This results in less clogging of the irrigated surface with particles in the effluent, and results in less disinfectant being needed because small particles tend to use up disinfectant rapidly. Dosing chambers are necessary whenever the effluent must be lifted to the next step in the disposal process. If an aboveground sand filter is used, the effluent must be lifted to its surface. If the discharge from the septic tank or sand filter is below the ground surface, the discharge will have to be lifted up to the level of the irrigated plot. Although the effluent from an aboveground sand filter could be left to dribble out onto the plot, uneven distribution would result. The design presented assumes the more efficient method of peri- odic dosing and submerging of the plot. This requires a dosing chamber. An alternative 