"Large-diameter graveless pipe (LDGP) system" means an ISDS where the effluent conduits are pipes that are at least 10 inches in diameter with perforations throughout their circumferences, wrapped in non-woven fabric material separated from the pipe by an intermediate layer, and embedded in sand, such that the biomat interface is formed on the inside of the non-woven fabric.
N.H. Admin. Code § Env-Wq 1002.40
(See Revision Note at chapter heading for Env-Wq 1000) #9086, eff 2-9-08