处理 ('to process / handle') +
厂 ('factory / plant'). Almost never used alone — it pairs with what's being processed:
污水处理厂 (sewage treatment plant),
垃圾处理厂 (waste processing plant),
食品处理厂 (food processing plant).
处 here is read chǔ (3rd tone), the verbal reading; 4th-tone chù means 'place'.