Water Treatment Equipment

Deep Bed Filter Column

The Deep Bed Filter Column is a clear acrylic unit with flanged end pieces to allow easy access. Plain tubes also penetrate the medium through the wall to transmit pressure to a manometer system. The medium is supported on a corrosion resistant gauze mesh below which is packed 1kg of 10mm Ballotini to ensure good wash water distribution. Slotted sampling tubes inserted through the wall penetrate into the media, and are fitted with control valves so that suspension samples can be taken isokinetically. 
The column can be operated as a pressure filter up to 1 barg. The service system supplied comprises a pump, sump tanks, flow controller, Rota meter, control valves, tubing, sampling tubes and bank of water differential manometers .
These sampling and manometer probes are located at 20mm depth intervals, but staggered in position, over 0.8m depth. Consequently, complete profiles of concentration changes in the suspension and of pressure variation can be measured during filter operation.

Aeration Unit

The Aeration Unit comprises an open tank equipped with a paddle stirrer. A variety of diffusers is included. The dissolved oxygen content of the water in the tank is measured by means of an oxygen electrode and dissolved oxygen meter. The equipment consists of a base and backboard standing on four rubber feet. Mounted on the base is the clear acrylic water tank which has a capacity of 24.5 liters. On the front of the tank is a depth scale and at the base a drainage tap. The lid of the tank is partially removable to allow filling. On the fixed part of the lid are mounted the stirrer motor, stirrer and clamping positions for the temperature probe, oxygen probe and aerator tube. Air is supplied by an electrically driven pump through a control valve and flow meter to a diffuser, adjustable for position, within the tank. The meter supplied gives an additional direct reading of water temperature. Air is supplied to the tank by means of a pump with filter and silencer assembly is controlled by a valved flow meter discharging through the aerator tube. Three diffusers, sparger tube, treble airstone and single airstone, may be separately attached to the aerator tube. Operating from internal batteries, the meter may be used for field trials independently of the apparatus. Variable speed adjustment of the stirrer paddle provides different levels of turbulence in the tank. The oxygen/temperature meter is mounted on the backboard with the connecting leads to the appropriate probes.

Demonstration Of Dissolved Air Flotation

Flocculation chemicals can be added to the rawwater in order to improve the flotation of the contaminants. The diatomiteprovided is suitable as a contaminant. Flotationprocesses are used to separate solids from a liquid. The flotation process mostcommonly used in water treatment is dissolved air flotation. The suspension tobe treated is placed in a tank. A pump transports the raw water, whichenters the flotation column via a vertical pipe. The air dissolves in the water under pressure. Part of the waterflows back to the pump via a bypass. The other part of the water enters apressure vessel filled with Pall rings. The height of the supply linecan be adjusted. The pressure vessel ensures asufficiently long dwell time to dissolve the air and to separate undissolvedair. A water circuit with pump is connected to the flotationcolumn. Two compressors supply air to the water circuit on the suction side ofthe pump. 
The water then enters the flotation column from below via a valve. This causesa sudden drop in pressure to almost atmospheric pressure. The contaminants rise up in thecolumn together with the air bubbles. At the upper end of the flotation column,the contaminants enter a circulating channel. Since the solubilityof air increases with increasing pressure, the excess air forms small bubbles.The air bubbles accumulate on the contaminants.

Features:
Transparenttank for observing the processes
Mechanicalwater treatment

Model Sedimentation Tank Experiment

For hydraulic tracer and visualization studies, an accurate dye injection system is provided. A known volume of dye solution is injected just before the entry to the settling tank. 
Water is taken from the laboratory mains supply and is fed to the settling tank via a flow meter. For studies of sedimentation, a slurry is prepared in a sump tank and pumped via a specially designed flow meter to join the fresh water stream just before entry to the settling tank.
This may be comparatively analyzed by the Imhoff cone technique or more accurately by drying and weighing.The sump tank is continually agitated by a flow sparge device to prevent settling of solids during an experiment. A well-mixed slurry of known concentration and flow enters the tank uniformly under an inlet weir. 

Ion Exchange Apparatus

A conductivity meter connected to the outlet of the second ion exchange bed gives a continuous indication of the progress of demineralisation. The apparatus is supplied with typical commercial cation and anion resins. 
Union couplings permit the tubes to be removed from the manifolds and interchanged for softening/demineralisation experiments.
Two vertical transparent tubes mounted on a backboard contain the cation and anion resins. A manifold arrangement at the inlet and outlet to the tubes allows the flow configuration to be changed to simulate the cycles involved in the operation of a deioniser.
Regenerant and test or wash solutions contained in separate sumps are selected by a traversing tube and delivered to the apparatus by pump through a control valve and flow meter. Effluent may be fed to a sump tank and treated water collected in bottles for tests on hardness, conductivity or dissolved solids.

Flocculation Test Apparatus

A bench-mounted framework incorporates facilities for six tests to be carried out simultaneously. The glass flocculating vessels stand on a translucent base which is illuminated from below. Each flocculating vessel incorporates a stirrer paddle driven by a variable speed drive. The paddle assemblies are easily withdrawn for removal and cleaning of the test vessels.
The tests serve to indicate the optimum chemical dosages for removal of turbidity and color, including such parameters as pH adjustment, and the supplemental use of activated carbon. Jar tests, furthermore, yield a wealth of qualitative information on the rate of agglomeration as a function of energy input (paddle speed), the settle ability of the floc formed, the clarity of the supernatant water (which might be related to the subsequent length of filter run).
Analysis of a water or waste preparatory to the design of a treatment sequence often involves coagulation and flocculation tests, 'Jar tests', in the laboratory.
Jar tests are routinely used for the control of plan operations and are performed by treatment plant operators.
Coagulation and flocculation tests may be used, in conjunction with other tests, to study basic processes including, for example, the kinetics of reaction and the removal of trace constituents from aqueous solution.
A digital timer can be set to count down from 1 to 99 minutes. After count down the paddles stop and an alert sounds. 
The paddle shafts are made of stainless steel to resist corrosion. Paddle speed is accurately maintained by electronic feedback control. A digital display clearly indicates the speed which is fully variable. Alternatively, the use of two adjustable presets allows repetition of pre-selected speeds.

Anaerobic Digester

The anaerobic digester comprises two 5 litre upward-flow packed bed reactors with feed rate and temperature control facilities to allow steady, continuous operation at up to seven litres per day over periods of many days.
The temperature of each reactor is controlled by an electric heating mat wrapped around the external wall. The temperature distribution within each reactor is maintained to ±0.5°C. Reactor temperatures may be separately set at any desired value in the range ambient to 55°C.
The reactors may be operated in series or parallel. The flow rates to the vessels are set and controlled by calibrated peristaltic pumps. A buffer vessel between the reactors permits discharge of excess flow from the first reactor when the second reactor is operated in series but at a lower flow rate.
Liquid and gas sampling points are located at all strategic points around the reactors. Non-return valves and liquid seal syphon breaks are included in the process pipework to ensure each reactor operates at a constant volume without the ingress of air or the danger of accidental syphonic action.
The equipment is mounted on a vacuum formed plastic base with an integral drain channel to cope with spillages and wash down.
The gas off-take from each reactor is taken to a volumetrically calibrated collector vessel operating by water displacement. The collected gas can be exhausted from the vessel and the volume re-filled with water during a run without breaking the liquid seal. A constant head, liquid seal device ensures that the gas pressure in the reactor is maintained at a constant value throughout the test run.

Filterability Index Apparatus

A simple measure of whether the liquid is filterable is useful to enable assessment of filtration as an appropriate process, if so what type of pre-treatment and filter media are required. The use of deep beds of porous granular media to filter liquids to improve their clarity is widespread in municipal and industrial practice. Other liquids are filtered through granular media in the processing of beverages and food products for example. Predominant is the filtration of drinking water and industrial water, although the filtration of sewage as a tertiary stage of treatment is increasing. Although the normal methods of chemical and physical analysis such as suspended solids content, turbidity, color etc. may, with experience, indicate whether a suspension is filterable, they give no direct measure of this property.
The Filter ability Index Unit utilizes a bed of granular material, normally sand, which can be chosen by the investigator to suit his own purposes. The measurements taken with this apparatus enable a filter ability number to be calculated which has significance in deep bed filter performance.
A number of measures of filter ability have been proposed, using woven micromesh, lint pads or membrane filters, which have application where these materials represent, or are identical to, the filter media to be used. However none of them is representative of porous granular filter media, such as sand, consequently they are not applicable to deep bed filtration.
The Filter ability Index Unit is not intended for filter design purposes. That requires pilot filter column equipment such as the Deep Bed Filter Column. However preliminary assessment of pre-treatment processes, and possible filter media with the Filter ability Index Unit will reduce the amount of testing required with pilot filter columns. 

Aerobic Digester

The equipment consists of a ten litre reactor vessel mounted on a vacuum formed plastic base, with a liquid feed pump, air supply and instrumentation for monitoring and controlling the process.
The porous liner is removable for cleaning, and a spare liner is supplied.
Waste water is drawn from a floor-standing feed tank (not supplied) by a DC motor driven peristaltic pump. Rotational speed and thus flow rate, are accurately set by a ten-turn potentiometer. The pump delivers the feed to the reactor vessel through a transparent lid.
The cylindrical wall of the reactor is made from a porous plastic material to retain the suspended solids while allowing treated water to pass through to the outer, annular exit chamber. This design allows the essential features of the aerobic treatment process to be studied without the distractions of having to settle the solids adequately enough for external recycle - a well known laboratory problem.
Air is supplied at a measured rate by a small compressor, and discharges into the base of the reactor via a spider-arm dispenser, designed to prevent blockages as well as to produce sufficient bubbling for stirring and reaction. 
Discharge is by gravity to a floor-standing product tank (not supplied).
The reactor temperature is maintained by a 3-term controller which varies power to an immersion heater within the vessel. Any temperature between ambient and +35deg C may be selected, the best conditions being a few degrees above the diurnal maximum in the user's laboratory.
The liquid level in the reactor is maintained at a constant value of 5-10 litres, by an adjustable overflow device connected to the outer annular chamber of the vessel. 

Permeability Fluidisation Studies Apparatus

A bed of granular medium (usually sand, but other materials can be used such as Ballotini or anthracite) is placed in a readily demountable tube through which water can be made to flow in either a downwards or upwards direction.
The test section tube and all tubing connections are transparent so that operation can be observed and the presence of air bubbles easily detected. All metal fittings are corrosion resistant.
Pressure drop across the bed can be measured either by a 0.5m length water differential manometer or a 0.5m length Mercury manometer (see recommended accessories), depending on the magnitude. Valves are fitted for isolation of various parts of the circuit, together with air release valves.
Flow from a laboratory tap passes through a constant head tank, which also allows air bubbles to be released, and is controlled by hand with a needle valve. The rate of flow is indicated by a variable area meter.
No power connections are required and the whole apparatus can be lifted and transported by one person. Test material (Ballotini) for the packed bed is supplied but Mercury for the manometer is not included. 

Sedimentation Studies Apparatus

The simplest type of sedimentation is the settling of a dilute suspension of particles which have little or no tendency to flocculate. In these circumstances, the prediction of clarification rates and their scale-up to plant design is relatively straightforward. 
Sedimentation is a process used widely in the clarification of water and waste water. Particles settle from suspension in different ways, depending on the concentration of the suspension and the characteristics of the particles.
Information from batch tests for such systems forms a vital part of the search for the optimum design and operation of industrial sedimentation tanks. The Sedimentation Studies Apparatus allows demonstration of these different characteristics for any chosen sediment/water system. For higher concentrations where inter-particle effects become significant and where agglomeration may take place, different regimes of settling rate occur, known as 'zone' settling A. 
Five equal sized glass cylinders are mounted vertically on a backboard incorporating measuring scales. Solutions containing different amounts of suspension can be placed in the cylinders and the differences in sedimentation rate observed by measuring the changes in height of the various solid/liquid interfaces with respect to time. Each of the cylinders may be removed from the board for washing, filling and mixing of the solid particles. 
The whole apparatus is bench-mounted and provided with back lighting. An accurate balance (not supplied) is required for weighing the solids. 
The equipment includes the following accessories necessary for a self-contained facility: stop clock, three plastic beakers of 2 litre capacity, specific gravity bottle.