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IGON

Iron & Manganese in Groundwater

Many boreholes the world over are contaminated with Iron Oxide deposits in one form or another either from conversion of dissolved iron salts from the water or by the action of certain naturally occurring bacteria which thrive in an iron-rich environment.

The contamination will take the form of rust-red deposits which will gradually block pump impellers and waterways, together with any rigid piping within the well system and downstream, causing loss of flow due to reducing bore and increased surface friction. The tell-tale signs will be readily apparent when a pump is lifted from the bore but diminishing flow from the system in-situ should suggest that iron fouling could be a problem.

A brown / black colouration to the contaminant will indicate the presence of Manganese Oxide contamination which is similar to Iron Oxide contamination in most respects – and will generally occur in conjunction with it. Manganese will not be mentioned separately hereafter in these notes and all references to Iron and its treatment can be taken as referring to Manganese equally

Surface Symptoms

If water from the pump appears to be crystal clear yet takes on a brown tinge after standing for a while it contains dissolved ferrous ( Fe2+ ) salts which are oxidising to the insoluble ferric ( Fe3+ ) form. With less oxygen available below ground this process will be very gradual at the level of the pump but a hard, rusty, layer will slowly build on hard surfaces and start to choke waterways.

Should the water be rusty & cloudy looking on start-up and have an unpleasant smell there will be Iron Related Bacteria at work in the depths. These grow as an orange slime while also oxidising the ferrous salts into ferric solids which will, again, cause acute blockage of the water passages.

Each borehole is, of course, different but many iron affected wells will suffer both direct oxidation & bacteriological contamination to some degree.

I-GON has been formulated to remedy this problem.

I-GON : Description & Availability

I-GON is supplied as a crystalline powder containing a powerful, naturally occurring, chemical which will combine with the Iron Oxide deposits to form a solution which can be pumped from the borehole. I-GON will not react with or damage any metallic or man-made material generally used in borehole pumps or pumping systems.

Normally available from stock in re-sealable 10kg plastic tubs, I-GON can be supplied in smaller quantities or in bulk if required.

Safety Precautions

I-GON is supplied as a crystalline powder containing an organic acid so should be treated with the appropriate caution.

Whilst I-GON is in its dry state an operative should wear a dust mask & close-fitting goggles or helmet-mounted visor together with acid-proof gloves. Extreme care should be taken to avoid any contamination of other exposed areas of skin, hair or clothing - especially in windy conditions. To avoid splashes when recirculating the freshly prepared solution a waterproof suit and boots should be worn in addition.

As with all chemical handling it is better to look a fool wearing too much protective equipment than to assume the substance is as innocuous as it looks and suffer the consequences later.

In rare cases, where the borehole is in a very confined space, carbon dioxide released during the I-GON reaction could build up to a potentially dangerous level so measures should be taken to artificially ventilate any such enclosed area – air quality should then be monitored continuously.

Site conditions may, of course, impose specific hazards to anyone working at a particular location so personnel should endeavour to ensure that they are cognisant of potential risks at all times. ( Proquip Direct Limited cannot be held responsible for any accident or injury resulting from the misuse of I-GON products outwith the guidance offered in these Instructions for Use - nor for any accident or injury, howsoever caused, not directly related to the use of said products.)

Setting up the Site

Cleaning the borehole can take up to 48 hours depending on the severity of the contamination so an appropriate time slot must be identified beforehand.

The pump should be turned off and isolated electrically before carrying out any modifications to the system. There’s no need to remove the pump from the well but it may be necessary to disconnect and raise the headworks, with a crane or other lifting tackle, to gain access to the top of the borehole. ( Ideally an access port will have been provided in the wellhead but this is rarely the case.)

Provision should be made to recirculate the water ( I-GON solution ) from the wellhead back into the top of the borehole during cleansing rather than discharging by the normal route – this can be by flexible hose from a convenient pipe joint or by purpose-made connection. ( Any of the normal pipe run incorporated in this circuit will, of course, benefit from the cleansing action of the solution.)

At the primary rinsing stage the reaction product will be flushed from the borehole so an effluent tank must be provided to receive this, capable of taking 5 or 6 times the water capacity of the well.

Occasionally, the use of I-GON can dislodge loose material above the pump and this can cause difficulties in withdrawing the unit. Raising the wellhead from the ground slightly before applying the chemical will allow the pump to be worked up and down later in order to ease any blockage.

Cleaning the Borehole with I-GON

I-GON should be fed directly into the bore, either in its dry form or as a slurry, and should be allowed half an hour to dissolve as it settles through the water. ( See below for the appropriate dosage for each well.) The pump should then be reconnected and run for at least an hour, recirculating the resulting solution through the wellhead and back into the borehole to ensure all surfaces are treated. The pump can then be turned off and the solution left to act for up to 48 hours – alternately continued recirculation will speed the cleansing action significantly.

I-GON Dosage

At ambient temperature I-GON is most effective when used at about 5% solution so the following dosing guide will give an indication of the quantity required for a range of boreholes : -

Rinsing

Primary Rinse : After soaking for 48 hours ( by which time reaction will be complete ) reconfigure the pipework to divert most of the water to the effluent tank and re-start the pump. Run it until all the I-GON solution - by now a green turbid liquid - has been flushed and the water runs clear. During this stage it is advisable to maintain a small flow ( perhaps 5% ) recirculating into the well in order to displace the solution standing above the level of the pump – alternately an equivalent supply of fresh water can be used.

( If the pump is used to continuously recirculate the solution samples should be taken at intervals to determine the progress of the reaction : initial samples will show a progressive change in colour until a steady state is reached. Completion of the reaction can then be checked by testing successive samples with the I-GON Acidity Test Kit until no change is detected. At this stage divert most of the water to the effluent tank as above.)

Secondary Rinse : Once the water runs clear divert the flow to waste ground or other approved clean water disposal facility and continue to run the pump for two hours.

Neutralization & Disposal / Environmental Impact of I-GON

If the correct dosage has been used the I-GON treatment should have resulted in an effluent tank full of near-neutral bio-degradable oxalate solution which can be disposed of within the guidelines of the relevant water service company or Environment Agency, as appropriate. Any residual acidity can be treated with I-GON Neutraliser, in accordance with instructions provided, prior to disposal.

Neither I-GON nor its reaction products will remain within the borehole system in measurable quantities if rinsing instructions are followed correctly.

I-GON Test Kits

I-GON Acidity Test Kit : is used to check the acidity of the I-GON solution during and after cleansing. A water sample should be tested prior to treatment of the borehole and compared with a sample taken on completion : a similar steady state ph figure will indicate exhaustion of the I-GON ( but this could mean that insufficient has been used and the treatment is unfinished ) whereas a slightly lower ph figure will show traces of acid remaining and confirm that all iron oxide contamination has been removed.

I-GON Oxalate Test Kit : is used to test the level of reaction product remaining in the water after treatment – specifically during the rinsing phase.

Problems after Cleaning

Recurrence of Contamination : I-GON is not a ‘Miracle Cure’ and the contamination will reappear in the borehole as it is an entirely natural process. Experience will dictate the frequency of treatment necessary to keep the problem in check with a minimum of down-time.
Riser Porosity : Steel risers ( & other downstream pipework ) will suffer from corrosion over time and may rust through entirely to cause minor leakage holes – removal of the surrounding oxide layers with I-GON will reveal the true severity of the problem and can increase leakage. Unless the bore is sufficiently large for a CCTV survey the only way to check for this problem is to lift the riser for inspection. Care should be taken as severe corrosion could have weakened the steel leading to a danger of losing the pump in the bore.

Cleaning other Systems & Components with I-GON

As above, a 5% solution of I-GON can be used to clean pipework or other items such as pump or valve components.

Each pipework system will, of course, be different but a sequence similar to above – filling, 48 hour soak or recirculation if possible and rinse – should remove Iron Oxide deposits as before.

Contamination of smaller components can be removed by soaking in a bowl or tank of solution of appropriate size. Agitation of the solution and scrubbing with a stiff nylon brush will speed the process – though sensible personal safety precautions must be taken ( as above ).

The I-GON Recirculation Tank comprises a frame-mounted enclosure & pumped recirculation supply – similar to a solvent-cleaning station – and is designed as a work-station for Companies who have regular Iron Oxide component cleaning requirements.

Chlorine & Ozone Facts

Chlorine Loading : The rinsing phases will reduce oxalate levels in the borehole to immeasurable levels ensuring that the process results in no increased Chlorine Loading.
Chlorine & Ozone : Treatment of potable water supplies with chlorine or ozone will neutralise the active ingredient of I-GON. Any equipment which doses the well or pipework to be cleaned must, therefore, be turned off prior to treatment and any treated water should be purged to waste.