Where does lead in groundwater come from?
Lead, extracted from galena, anglesite and cerussite ores, is mainly used in lead acid batteries, copper-alloys and as shielding material for radiation protection equipment. It was also intensively used as antiknock agent in petrol, but many countries have abandoned this usage for over 20 years. Lead exposure results in various health dangers including neurodevelopment and teratogenic effects, fertility decline and renal failure.
Lead concentration in natural water is generally below 5 ppb, however a contaminated area may contain groundwater with concentration exceeding the WHO guideline of 10 µg/l. The Pourbaix or potential/pH diagram in figure 1 of lead shows that the lead speciation is dominated by its cationic elementary Pb²⁺form.
Figure 1 The Pourbaix or potential/pH diagram of lead species:
This is the Pourbaix diagram of lead in water. Note this graph is not from Jacobi. Reproduction is possible but no disclosure as is. The area between red lines represents the stability zone of water.
How is lead (Pb²⁺) removed from groundwater
Resinex™ CH-23 exhibit a very high efficiency chelating resins for lead removal in their cationic elementary form (Pb²⁺). As a magnitude of order, the average removal capacity of Resinex™ CH-23 is respectively 90 g of Pb²⁺ per litre resin*. Resinex™ CH-23 is a chelating resin that also efficiently removes cobalt, cadmium, nickel and copper in their elementary cationic form.
* These figures are indicative only, please contact our technical department for specific study.
Recommended lead (Pb²⁺) removal operating conditions
One AquaFlow™ can be used for the removal of lead (Pb²⁺) at a superficial contact time of a minimum of 6 minutes but usually two AquaFlow™ in series, merry-go-round systems are used with a typical flow rate per vessel: 10- 20 BV/h.
A calculated Lead (Pb²⁺) removal case
Assume a contaminated groundwater with 1 mg/l lead (Pb²⁺) with an average flow of 30m³/h operating 24/24 -7/7 then we have 1 mg/l x 30m³/h x 8600 hpa/(1000 mg/g) /(1000 g/kg) = 258kg. This gives an average loading of 90kg Pb²⁺/m³ Resinex™ CH-23 a consumption of approximately 3m³ Resinex™ CH-23 per annum. An AquaFlow™ can then be selected from our industrial mobile filter range in order to obtain the desired exchange frequency.
It is always recommended that you contact our technical expert for sizing of a heavy metal removal system as other metals can interfere in the estimated consumption.