Proceedings

Abstract
Southern Water has chosen to install on-line monitors for all their permitted outfalls from wastewater treatment works (WTW). This includes turbidity at all sites and ammonia and ortho-phosphate depending on permit conditions.

On-line monitors are used to remotely troubleshoot process issues, thereby targeting Operational
effort, optimising the wastewater treatment process and reducing non-productive site visits. This proactive response to trends has maintained good effluent quality in the face of tightening final effluent quality standards.  15 minute means from the on-line monitors are compared to trigger levels based on permitted concentrations to generate alarms for site Operations. Daily means are derived and Process Scientists categorise the reasons for exceedences of triggers. A relationship has been found between the sum of Total Suspended Solids (TSS) plus Biochemical Oxygen Demand (BOD) and turbidity which is used to predict a turbidity trigger related to the TSS and BOD permits.
A Process Exception Report is automatically emailed to selected recipients. The Exception Reports
promote a proactive response to process deterioration and Exception Reasons are used to generate
Management Reports.