Tree roots and copper sulphate
http://www.ehow.com/how_2173711_control-tree-roots-sewer-lines.html
http://www.drainsandplumbing.com/sewerdraincleaning.html
Once you have the information on location and depth of the sewer line where the roots are, you can use an earth auger to drill a 2.5 inch diameter hole in the ground above where the roots are in the sewer line. First, make sure there are no other utility lines where you plan to drill-call the electric, gas and cable company to make sure you have a free and safe access.
You'll also want one or more lengths of 1.5 inch PVC pipe and a means of cutting it to the right length. You will drill straight down toward the sewer pipe, stopping when you get to a place 24-30 inches above the sewer line. You don't want to go too far down, because the solution you're going to pour into the PVC pipe should go into the soil above the sewer line. Cut the pipe to the length of the hole, and attach a threaded female adapter with a plug onto one end of the pipe. Once you have the hole drilled, put the pipe into the hole, and if it needs trimming to lie flush with the ground (and below the grass so you can't run over it with the lawn mower), pull it out again and cut a little off the bottom until it fits just right. If you have a lot of roots in the lines, or a root that extends a long way through or near a line, you will probably want to insert a PVC pipe at each trouble point and every 6 feet or so along the line of trouble.
Now comes the big fun: take off the plug at the end, and pour copper sulfate into the pipe until it's about half full of the crystals. You can buy copper sulfate at feed stores, nurseries and some old fashioned hardware stores. When the PVC pipe is half full, pour hot water into the pipe until it tops up and runs over a little bit. The copper sulfate is dissolved in the hot water, and starts to run into the soil around the ground. Tree roots hate copper sulfate, and will turn away. The ones in the sewer line will die.
http://www.drainsandplumbing.com/sewerdraincleaning.html
Once you have the information on location and depth of the sewer line where the roots are, you can use an earth auger to drill a 2.5 inch diameter hole in the ground above where the roots are in the sewer line. First, make sure there are no other utility lines where you plan to drill-call the electric, gas and cable company to make sure you have a free and safe access.
You'll also want one or more lengths of 1.5 inch PVC pipe and a means of cutting it to the right length. You will drill straight down toward the sewer pipe, stopping when you get to a place 24-30 inches above the sewer line. You don't want to go too far down, because the solution you're going to pour into the PVC pipe should go into the soil above the sewer line. Cut the pipe to the length of the hole, and attach a threaded female adapter with a plug onto one end of the pipe. Once you have the hole drilled, put the pipe into the hole, and if it needs trimming to lie flush with the ground (and below the grass so you can't run over it with the lawn mower), pull it out again and cut a little off the bottom until it fits just right. If you have a lot of roots in the lines, or a root that extends a long way through or near a line, you will probably want to insert a PVC pipe at each trouble point and every 6 feet or so along the line of trouble.
Now comes the big fun: take off the plug at the end, and pour copper sulfate into the pipe until it's about half full of the crystals. You can buy copper sulfate at feed stores, nurseries and some old fashioned hardware stores. When the PVC pipe is half full, pour hot water into the pipe until it tops up and runs over a little bit. The copper sulfate is dissolved in the hot water, and starts to run into the soil around the ground. Tree roots hate copper sulfate, and will turn away. The ones in the sewer line will die.