What are the key features and characteristics of trade waste monitoring points? Get all the information you need right here.
For trade waste purposes a monitoring point is defined as the location within the site of a particular industry that contains all the facilities and equipment necessary for us and the industry to adequately monitor the trade waste being discharged to the wastewater system.
Essential features of a monitoring point
The specific features of a monitoring point will vary depending on the industry, but a monitoring point will always include a sample point, as follows:
- New installations. A sample point with a minimum diameter of 100 mm and a water seal of 300 mm to provide access to the waste stream for sampling using an automatic sampler. Refer to the typical drawing Trade waste monitoring point – HX33 20-00.
- Existing installations – these will be assessed on a case-by-case basis. Existing disconnector gullies (DGs) may be accepted.
Additional features which may be required
Depending on the situation, one or more of the following items may be required:
- Power outlet: A 240V, 10Amp AC power outlet (adjacent to and within 2 metres of the trade waste sample point, and located above ground, at a maximum height of 1500 mm, to provide power for the sampling machine).
- Flow metering device: One or more approved flow metering devices, with no bypasses.
Depending on the application, one of the following options may be used.
- Use of main and/or sub water meters – the number of meters is to be minimised, preferably to 1 meter. The trade waste volume will be taken as 100% of the metered volume. In addition, with this option the customer must be prepared to take hourly meter readings when we are performing composite sampling to determine effluent quality.
- Use of an effluent flow meter – details on the requirements for effluent flow meters are specified in Trade waste flow metering.
- pH sensor – A pH sensor with a 4–20 mA output for connection to a data logger with a minimum range of 1–14. The pH sensor is to be separate from any monitor/controller used with dosing to adjust pH. The calibration of the pH sensor is to checked and adjusted as required at a suitable frequency to ensure that the pH reading is always accurate to within 0.3 pH units.
- pH visual display: A visual display for a pH sensor with a minimum range of 1–14.
- Temperature sensor: A temperature sensor with a minimum range of 0–80oC.
- Temperature visual display: A visual display for a temperature sensor to read in degrees Celsius with a minimum range of 0–80oC.
- Data logger: See below for general installation requirements.
- Other: Monitoring devices with visual displays as specified.
Irrespective of the particular facilities we require, all monitoring points must comply with the following:
- Location – discharges from all process areas and/or treatment facilities are to be directed through a single monitoring point located within the property boundary.
- Connection – the connection from the trade waste stream may only connect to the property sewer conveying domestic wastewater downstream of the monitoring point.
- Security – all facilities and instrumentation, both permanent and temporary, are to be secure against accidental or deliberate damage.
- Accessibility – the monitoring point and all its components are to be unobstructed and readily accessible at all times. Monitoring points are not to be located in driveways or parking areas, however it should be possible to drive a vehicle to the area immediately adjacent to the monitoring point for servicing, inspection and sampling purposes.
- Water Corporation access – access by our staff is to be maintained at all times.
The following items, applicable with relevant instrumentation, may also be required:
- Visual displays – the visual displays, 240V AC power outlet, and flow meter pulse output plug are all to be within 2 metres of the sampling point and above ground. Access to these fixtures must be unobstructed.
- Labels – a permanent label is to be fixed on the front of the display or inside the cabinet indicating:
- the units of the totaliser output are in whole kilolitres
- the instantaneous discharge rate is displayed in litres per second; and
- the pulse output rate is 1 pulse per 100 litres.
- Enclosure – if located externally, all visual displays and the chart recorder are to be enclosed in a waterproof outdoor cabinet to Australian Standard AS 193922, Table III-3 and Table II-6 or equivalent standard, with a transparent window to allow viewing of displays. The cabinet is to be protected from direct sunlight in areas of high temperature. The top of the cabinet is not to exceed 1500 mm above ground level and the bottom of the cabinet is not to be less than 600 mm above ground level.
Enclosure lock – if the location of the cabinet is not secure from interference or damage, then a secure lock is to be provided and 2 two keys to the cabinet supplied to us. In this situation the 240V AC power outlet and the flow meter pulse output should also be made secure against interference or damage.
Power supply – the power supply to any monitoring instrument must have its own circuit separate from all other powered facilities on the site, and be direct wired through an on/off switch to the equipment. The on/off switch is to be lockable to guard against the equipment being inadvertently switched off. The keys are to be held by an appropriate responsible person.
Calibration – prior to discharge of any trade waste, a Trade waste monitoring system commissioning report (F 1-8-2) is to be submitted to our Commercial & Industrial Services section.
2 “Degrees of protection provided by enclosures for electrical equipment (IP Code)” Australian Standard AS 1939-1990. An enclosure meeting the specification of Table 11-6 is dust-tight, and one meeting Table 111-3 is secure against spraying water.
Data loggers are to comply with the following requirements.
Connection – directly connected to the measuring instrument.
Labels – the scale for each parameter being recorded is to be clearly displayed on the front of the logger.
Displays – capable of displaying the instantaneous reading for whatever parameter is being monitored. Where the data logger has a totaliser built in, the recorder display is to show the total and instantaneous flow rates thereby avoiding duplication of displays when linked to a flow meter.
Display format – all built-in displays are to be in digital format with a minimum of 6 digits. The displays are to have battery backup and password protection. Where displays are showing flow, the display is to be in whole kilolitres (1 digit is to represent 1 kilolitre). The totaliser is to be clearly marked as displaying in kilolitres. Instantaneous flow rates are to be displayed in litres per second, with a minimum indication of 1 decimal point (0.1 litres per second). The indication is to be clearly marked.
Logger span – the span must be set so that peaks and troughs in the record are shown within the calibrated range.
Annotation – the data logger shall be regularly annotated for date, time and channel inputs.
Historic data – data loggers are required to have enough internal memory to store data for up to 6 months, or other period as directed and available for inspection by our officers.
Although only one variable may be logged when the data logger is initially installed, future logging requirements are to be anticipated. Consequently a data logger capable of logging up to 3 variables simultaneously should be considered.
Other requirements for data loggers include event logging and alarm generation, however the need will depend on the waste being monitored, and will be determined by Water Corporation.