General considerations
3.4 The Ohio River Valley Water Sanitation Commission (ORSANCO} System
The Ohio River Valley Water Sanitation Commission is an interstate compact organiza- tion charged with the responsibility for co-ordinating water pollution control activity in the Ohio River basin. Approximately 18 million people live in the basin and the economic activity is comprised of metallurgical, mining, chemical, industrial, and electrical energy production. The treated waste loads from municipal and industrial sources are large and for effective pollution control a rather complex information system has been developed to assist the Commission in its activities.
3.4.1 The ORSANCO information system
The O R S A N C O water-quality, robot-monitor system consists of three separate but integrated components: a group of electronic analysers combined with a transmitter, a telemeter interrogator and receiver, and a data-logger and transcriber (Cleary, 1967).
The analyser component with its transmitter is a self-contained unit that can be located at any point along a stream. A s river water circulates through the unit, the cells containing the electronic sensors respond to changes in quality. These changes are converted into electrical impulses for relay to ORSANCO headquarters in Cincinnati.
The telemeter component in Cincinnati is connected with the analyser units at river locations by means of a leased telephone-wire circuit. At a predetermined interval (every hour at present), the telemeter interrogates each monitor station in sequence, and then stands by to receive a report on the quality characteristics being measured. Signals received through the telemeter circuit actuate data-logging devices. O n e of these is a transcriber that automatically types the information received on a tabulation sheet. This provides a visual record of quality data. At the same time, a paper-tape punch is also activated; it codes the data in a form that can be fed into an electronic digital computer, which is programmed to perform a variety of evaluation processes.
In 1965, the ORSANCO monitor network consisted of four integrated components:
(a) seventeen Water Users Committee manual stations operated on a voluntary basis by the managers of municipal and private water works; (b) eleven manual stations operated under contract arrangements with the United States Geological Survey; (c) thirteen robot-monitor units installed and maintained by ORSANCO, ten of which relay data directly to headquarters and three record information only at the site; and (d) fifteen sampling points for periodic assay of radioactivity in water, in river sediment and biota, and in fish, operated under contract with the Potamological Institute of the University of Louisville.
3.4.1.1 M a n u a l versus automatic monitoring
The robot monitors complement the manually operated components of the network.
Each has merits that cannot be duplicated by the other. The robot monitors perform tests continuously and maintain day and night vigilance. They produce data routinely, rapidly, and economically, but sensors are not yet available for direct measurement of alkalinity, fluorides, hardness, iron, manganese, nitrates, or phosphates. Only a manned station can provide data on bacteriological conditions and threshold-odour values. However, manual monitoring is costly and time-consuming.
3.4.1.2 Data compilation a n d appraisal
Operating the network constitutes only one phase of river-quality surveillance. Evaluating the data with respect to current and prior conditions is the fundamental aim of the pro- gramme. Items of data, like bricks, have only limited usefulness until they are arranged in some orderly fashion. T o give meaning to the hundreds of thousands of items of analytical information assembled each year, ORSANCO has devised a variety of numerical tabula- tions, graphical representations, and appraisal summaries.
Numerical tabulations have been designed to consolidate in a standardized form on a single sheet all quality and related flow data for an entire year at each monitor station.
In addition, each sheet contains information on location of the sampling point, size of drainage area above the point, the number of years of record, and details on flow com- putation and analytical methods. From time to time these sheets are collated and published for general distribution.
Following installation of the robot-monitor system, which has vastly increased the amount of data to be compiled and analysed (the robots alone supply some 50,000 items annually), a programme for electronic data processing was placed in operation. A m o n g other things this has facilitated the annual publication of an appraisal of river-quality conditions and trends.
The volume of data from the robot-monitor system is of such magnitude that manual processing is physically and economically impossible. It would take 150 man-years to produce manual summaries of data collected during the course of one year showing daily averages, maximums, minimums, and standard deviations for all quality characteristics at all stations. By way of contrast, the cost for computer time to produce the kinds of summaries indicated for data collected in 1964 was $4,200.
Examples of systems adapted to different countries
3.4.2 Cost of monitoring
Collection and laboratory analysis of river samples by conventional methods is a costly procedure. For a single sample the cost of measuring only five constituents is at least $10;
if analyses are made for thirty constituents, the cost may go as high as $120. These costs force control agencies to limit the number and duration of their sampling programmes for the assessment of stream conditions.
With respect to the cost of operating the manual component of the O R S A N C O monitor network, the accompanying tabulation provides an annual summary and the dollar value of the data. The ‘value’ placed on the data represents what the actual cost would be if ORSANCO had to fund analytical services equivalent to those contributed by the Water Users Committee at no charge, and if O R S A N C O had to pay the entire cost of services shared by the Geological Survey.
No. of data Out-of-pocket ‘Value’ ‘ Value’
items expenses of data per item
Water users
(17 stations) 31,570 $ 2,664 $71,376 $2.26
USGS
(I 1 stations) 9,900 $10,000 $20,000 $2.202
28 stations 41,470 $12,664 $91,376 $2.20
This accounting shows that the value attached to each item of data averages $2.20. When ORSANCO funds devoted to the project are matched against value received it becomes apparent that the Commission acquires the equivalent of $7.22 of data for each dollar it contributes. The value of data received from each of the twenty-eight manual stations averages $3,000 annually.
The cost of data acquisition using the robot-monitor network may be judged from the following analysis based on experience with the thirteen-station system.
Amortization expense (assuming a seven-year life of equipment and a
$17,000
Operation and maintenance $14,000
Leased-circuit rental $ 6,000
Total annual expense $37,000
4 per cent interest rate on a total investment of $136,000)
This system produces around a half-million items of data per year. Thus, the cost per item averages $0.075 as compared with $2.20 for the manually operated stations. In brief, for those quality characteristics that can be measured automatically, the cost on the average is only about 3% per cent that of manual sampling and analysis.
3.4.3
In 1965 the Commissioners of ORSANCO requested a staff appraisal of the robot monitor system with respect to these questions: Is the system serving the purpose for which it was developed? What specific contributions to pollution control practice have resulted or can be expected from operation of the system? T o what extent is expansion of the system merited? Is it adaptable to the needs of other pollution control agencies? The answers provided may be summarized as follows.
The purpose of the monitor system is to provide information on quality conditions on a continuous, around-the-clock basis. This goal has been attained and sections of the Ohio River and certain tributaries have been placed under 24-hour vigilance.
One measure of the contribution made by automatic monitoring to pollution control management may be expressed in terms of economies realized in the collection of water-
Appraisal of the robot monitor
quality data, as discussed above. Without the automatic system it would not be feasible to monitor streams in a region such as the Ohio Valley on a twenty-four-hour basis.
In terms of specific application, the robot monitor is being used to study cause-and- effect relationships with regard to quality changes, to minimize the effects of spills and accidental discharges on downstream water uses, and to implement the tailoring of waste treatment practices to river-quality conditions. In brief, it can be said that the essential contribution lies in the opportunity it provides to apply a system type of operation to water quality management problems. Usefulness and versatility of the system will be increased as field stations are added and equipment for measuring additional quality characteristics is developed.
3.5