污水处理厂

CSI’s dependable,automatedmonitoringhelps make Nevada site a sure winner
Building an innovativewater treatment facility

Silver Springs is a small community near Reno inwestern　Nevada.  As with many small towns with septic tanks,fecal coliform　is appearing in drinking water wells.　To counteractthis problem, SilverSprings has built a new waste　water　treatmentfacility with aerated　lagoons.  The Silver Springs projectis　innovative in that it sends the treated,　aseptic water tofarmers for reuse in　irrigation rather than releasing the　waterunused into a river or back to　the groundwater via aninfiltration　system.　Another innovative aspect is that the　systemis set up so that the necessary　parties can control and monitorplant　operation and retrieve archived data　remotely. Operators and engineers　access the computer remotely to con-figurethe system and provide updated　software and CR10X programs.　The newfacility consists of head-works with a spiral drive andagitator,　controls for grit removal and screening, three lagoons, aclarifier, two　sand filter beds, a chlorine contact　basin, and atreated water effluent　storage pond.

A　number of pumps circulate water and　activated sludge whileaerators operate in　three of the lagoons on a rotating basis.　TwoCR10X dataloggers with AM416multiplexers monitor status andflow　throughout the plant.  Each CR10X/AM416 monitors thestatus of the head-works lift spiral and agitator, theclarifier　arm, the traveling bridge filters, aerator/blower motors,pumps, and door intruder　switches.  The dataloggers monitorpulse　and 4-20 mA　signals representing pump　speeds and flow ratesat various points in　the system as well as a small weather stationon the top of the control building.　An SDM-CV04 current outputmodule　allows one CR10X to control the speed of　chlorine dosing andactivated sludge　movement in proportion to plant flow.　Each CR10Xuses an SDM-CD16ACrelay driver to control pumps and a valve.　Theeffluent storage pond level is measured using a pressuretransducer.  The　dataloggers automatically turn off theirrigation effluent pumps in the event of　freezing temperatures,excessive wind　speed, or low storage pond level. After　shutting down the pumps, the dataloggers　call the irrigationdistrict to notify them.

One CR10X uses a COM300 for voice　synthesizer alarmcallouts.  The irrigation　district can restart the effluentpumps over the COM300 telephone modem by　listening to voicemessages on pond level and weather conditions, then pressing phonekeys to turn the pumps on remotely.　The other CR10X is connected toa　computer in the facility office via an ethernet connection (NL100network inter-face.)  The dataloggers share significant　datavia a serial link using control ports.　Thus, real-time data andcontrol are avail able both on the computer monitor and　over thevoice modem.　Campbell Scientific’s LoggerNet soft-ware communicatesover the network link　to retrieve data from the CR10Xs and dis-playit on a monitor in the facility office.　Grapher, part of theControl Panel　LoggerNet client, allows graphical trend-ing ofreal-time or historical data from the　LoggerNet data cache. LoggerNet’s Baler　client periodically retrieves historicaldata　over the network.  The data is imported　into MS Accessusing Visual Basic for　Applications (VBA) scripts and is usedto　generate monthly reports required by the　EPA.  Datacritical to these reports are　retained for months in the CR10Xsincase of communications or computer　problems.

An electrician wires “half the plant” into　onecompact CR10X-based system.

Rather than releasing the water unused,irrigation pumps at the Silver Springs site provide treated,aseptic water to area farmers for agricultural use.

Clarifier arm is monitored by the CR10X.  Ifhigh-torque is detected, a voice call-out is initiated.

Traveling bridge filter status and failuresare　monitored by the system.

An RAS pump variable frequency drive iscontrolled by　the CR10X system.

The CR10X can call out voice alarms forhead-works high-levels or agitator/lift spiral failures.

Magnetic flow meters　generate a pulse output thatis　tallied by the CR10X.  Flow　rates and total gallons arecalculated from the counts.