... , classification Suitable to 15-600 persons IMO MARPOL 73/78 ST series sewage treatment plantApproved by CCS, EC, NK, DNV, ... -600 personsIMO MARPOL 73/78ST series sewage treatment plantSerial products ST are imported the advanced technology HMWORTHY, ENGLAND. Serial product STL ... and manufactured by ourselves based on plants imported. These plants ST and STL make use of two steps bio-chemistry and ...