Sussex County Municipal Utilities Authority (NJ)—Composting Monitoring and Reporting

SCADA System for Controlling Composting with LabVIEW

Treatment plant sewage sludge is dewatered and then composted in piles at the Sussex County Municipal Utilities Authority (SCMUA) waste treatment plant near Hamburg, NJ. Composting is done in closed buildings, each building contains 6 large piles of compost (windrows). The windrows are fed fresh air under pressure via an under floor PLC controlled air distribution system. The NJ State EPA requires monthly reporting on the plant’s composting operations.

The composting control in each building is handled by a single, dedicated, PLC. The PLC measures windrow temperature and individually controls the air flow to each windrow. SCMUA management required a computer based system that would perform the following tasks: continuously acquire and log data from the PLC; serve as an operator interface for monitoring and controlling the PLCs; automatically create the monthly EPA reports.

A LabVIEW based SCADA system was created for SCMUA by using Process Automation's generic SCADA Tool Kit for LabVIEW as the starting platform for software development. The system provides remote supervisory control, monitoring, and EPA reporting for, 5 RS-485 linked Mitsubishi PLCs that control compost pile temperatures. The system continuously collects temperature data from 31 RTDs and aids in preparing monthly compliance reports for the New Jersey EPA. The efficient Data Historian compressor in the PAC SCADA system was able to compress two years of temperature data, acquired once per minute from each RTD, into 360 kb of disk space.

 

SCMUA Temperature Trend.

 

SCMUA Temperature Report.

 

A shot of the plant.