① Recorded every day and all records are kept
② Recorded every day but some records are not kept
③ Recorded every day but records not kept at all
④ Recorded every day but unclear whether records are kept
⑤ Some operation results are not recorded
⑥ Operation results not recorded at all
⑦ Unclear whether operation results are recorded
⑧ Not applicable(there is no wastewater treatment system)