Collapse, spread lime, backfill and tamp, septic tank with gravel and dirt for proper disposal Cover area with grass seed and straw once tank is properly disposed 5-17-23 Arrived today to collapse the old septic tank. We got all equipment unloaded and began work on crushing the old septic tank. We then covered it with lime and began backfilling tamping as we went. We then graded out the yard. We then spread seed and straw to complete the job.