STP Treatment Plant Guide | Sewage Treatment Plant and Sewage Treatment Basics :root --maxw:980px; --accent:#0b6fbf; --muted:#556; --bg:#f7fbff; --card:#ffffff; --radius:12px; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif; color-scheme: light; html,bodyheight:100%;margin:0;background: