According to China's National Economic Industry Classification and Codes (GB/4754-2011), the National Economic Industry Classification: A Agriculture, forestry, animal husbandry and fishery; B Mining; C Manufacturing; D Electricity, heat, gas and water production and supply; E Construction; F Wholesale and retail trade; G Transportation, warehousing and postal services; H Accommodation and catering; I Information transmission, software and information technology services J Finance; K Real Estate; L Leasing and Business Services; M Scientific Research and Technical Services; N Water, Environment and Public **** Facilities Management; O Residential Services, Repairs and Other Services; P Education; Q Health and Social Work; R Culture, Sports and Recreation; S Public **** Management, Social Security and Social Organizations; T International Organizations
Which D4620 Sewage treatment and its reuse
refers to the treatment and disposal of sewage sludge, and reuse activities after purification
Sewage treatment plants fall into this category.