Project introduction

Project background

Shiweitou wastewater treatment plant was built in 1999. The capacity was 100000 m3/d in the first period. The service covers Xianmen local island and whole east part. The capacity will be increased by 100000 m3/d in the second period of the project. The effluent quality achieves level 1 B standard given by “Discharge standard of pollutants for municipal wastewater treatment plant” (GB18918-2002). Dewatered sludge is transported and centralized disposal after reduction. The project is the Fujian Province and Xiamen city Key construction projects, while also be considered as the special Performance Evaluation of government energy-saving and ejection-decreasing tasks.

Reconstruction and extension project uses the technics of “energy-saving multi-model A2/O chemical phosphorus removal assisted with oxidation ditch” and other advanced techniques, which has the advantages of good landscape, high environment quality, good effect of energy saving, high reliability of system running. Large amount of optimizing design is accomplished targeting to the key technics control of the instrument and automated control system. The production management system combines the production equipment management with the processing control, with the object to decrease the energy cost and improve the operation efficiency.

System structure

The whole automated control system consists of parts as follows:

Production monitoring system: to configure the data server, Ethernet switch, production management computer, printer, UPS, production operation management software, LED monitor etc. to connect with equipment monitoring automated system network by central monitoring computer and achieve the share of production process information. The administrate computer is able to real-time browse the equipment running status all the plant and local scene.

Industrial real-time control system: the water plant consists of 8 suits of local PLC control stations of the first period and 4 suits of local PLC stations, server, operator station upper computer and dual-level control network. The backbone network is a fiber industrial Ethernet network in the communication speed at 100M CBR. The lower layer is an industrial control network and local bus etc. to locally control the connection between sub-station PLC and remote IO station and local equipment. The interface is coaxial cable or twisted pair.

CCTV system: the CCTV system is configured to monitor different process section of the plant and the plant wall security. The duty officer is able to see the plant production and security status in the central control room at any time.

Instrument system

Online instrument uses 4~20mA DC electrical signal connecting with PLC system. The instrument inspects parameters including NH4-N, PH, ORP, DO, turbidity, level and pressure etc.

Network structure

System function

Automated system obeys the principle of “advanced, open, reliable and practical”. Instrument follows the principle of “necessary, advanced and practical, convenient maintainability”. On the basis of fully consideration to the wastewater treatment process features and practical demands, the design aims to build a modern wastewater treatment plant with advanced technics and achieves the object of “workshop unattended and less duty officers”.