Accurate, automatic and direct control of your wastewater samples
Respirometric methods provide direct measurements of the oxygen consumed by microorganisms from an air or oxygen-enriched environment in a closed vessel under conditions of constant temperature and agitation. Carbon dioxide produced metabolically by the bacteria is chemically bound by the potassium hydroxide solution contained in the seal cup in the bottle.
The result is a pressure drop in the system, which is directly proportional to the BOD value and is measured by the BOD sensor.
The BOD level is then displayed directly in mg/l. The BOD values are stored automatically in the sensor memory in regulary intervals and can be called up on the large-format display at any time without the need for time-consuming conversion using factors. This means that test series that end on a Sunday can be evaluated during the following week without any problem. Measurement series can be stored on USB stick/SD card or transfered via USB cable to evaluate the datas on a computer.
The measurement period is user-selectable between 1 and 28 days to suit the application. While short measurement periods are useful for scientific applications, standard BOD measurements typically extend over a period of 5 days – and manometric determination of OECD, for example, generally takes place over a period of 28 days.
Measuring ranges and sample volumes
The BOD level of a sample depends on the quantity of organic matter present, which can vary considerably. The Lovibond® BOD measuring system BD 600 is therefore calibrated for the various sample volumes and the corresponding measuring ranges listed in the table below. The overall measuring range of the system is 0 – 4000 mg/l. For all measuring ranges, BOD is shown directly in mg/l.
Evaluation of measurements
The BD 600 measuring system records a measurement once every hour, independent of the length of the measuring period. This way the quality of the series of measurement can be evaluated in an early stage. Current values and stored values may be called up at any time. Stored value can be displayed numerically or graphically. The table/ graph below illustrates an example of BOD5 evaluation. The development of BOD over a period of five days is easily seen.
The complete BD 600 measuring system
In addition to the BOD unit for measurement and storage of BOD levels, the Lovibond® BD 600 BOD measuring system includes sample bottles, measuring sensors, non-wearing inductive stirring system, overflow measuring flasks for metering of sample volumes, nitrification inhibitor and potassium hydroxide as an absorbent.
Inductive stirring system
The microprocessor-controlled Lovibond inductive stirring system is non-wearing and maintenance-free. In other words, there are no moving parts in the system.
At regular intervals, the magnetic stirring rods are accelerated and slowed down again, taking them up to maximum speed and back down again. This ensures the centralization of the stirring rods. Stirring rods that move away from the centre of the bottle are re-centered quickly and reliably.
The inductive actuation system guarantees maintenance-free operation (no need to replace drive belts or burnt-out drive motors) for many years.
Delivery Content: BD 600, complete unit with 6 sensor heads and control unit with batteries, Inductive stirring unit with power supply, 6 sample bottles, 6 rubber gaskets, 6 magnetic stirring rods, 1 overflow flask, 157 ml, 1 overflow flask, 428 ml, 1 bottle, 50 ml potassium hydroxide solution, 1 bottle, 50 ml nitrification inhibitor solution, 1 instruction.