Packaged STP. Packaged STP Plant in Bangladesh. Package STP is a System where it can install where limitation of space and wide application of Package STP in commercial and residential both sectors. Now a day Packaged Sewage Treatment Plant is widely using Building, school, community area, industry and large commercial space. Package STP is also available in semi- automatic and fully- automatic models, Package STP Plant requires less space and civil work for installation and erection. It treats the sewage waste in order to make it safe for disposal in the environment. In the final stage, treated water generated can be used in gardening, flushing and washing.