REMEDIATION TECHNIQUES FOR DRINKING WATER

CONTAMINATION AND FOR ELEVATION OF WATER TABLE,

A CASE STUDY FROM KERALA, INDIA

Dr. V.R.Prakasam

University of kerala

INDIA

Scope of study

• The aim of the present study :

• to investigate the ground water (well wall) quality in one of the selected districts of the state viz. Kollam in India in relation to contamination sources,

• and suggest remedies at household level for decontamination of water

• and for augmentation of water availability.

Open dugwell used by villagers in a Panchayat

Another open dugwell of villagers

Methodology

• The work consisted of a Survey among the households using a questionnaire in two panchayats viz. Mayyanad (Coastal land) and Edamulackkal (midland) in Kollam district and water quality analysis following APHA .

Methodology(contd.)• The survey was to find out :

• The dependence of the households on well water, • The well protection measures adopted by villagers• The sources of contamination of well water.

• FILTRATION AND BOILING• It was also attempted to solve issues such as high coliform

contamination, low pH and high iron (Fe) content of well water using simple techniques such as filtration and boiling.

• CONSTRUCTION OF PITS• Construction of two rain water recharging pits of 2 ft × 2ft × 2ft at a

distance of 7 ft from the well was evaluated for elevation of water level in the wells of Mayyanad Panchayat.

Result• The survey showed that• In Mayyanad and Edamulakkal panchayats 91% and 95% of

households were depending on dug well water.• Almost all the wells were of open type and did not have water tight

casing or lining.• Wells were mostly protected by platform and net covering.• In Mayyanad panchayat majority of people used septic latrines

whereas • In Edamulakkal panchayat majority used pit latrines. • The dugwells were found located at a distance less than 30 ft from

latrines in 80-90% of cases.• Similarly in 75% to 87% of households, the distance between cattle

waste pit and dug well was less than 30 ft. • The percentage of households disposing domestic waste in their

backyard ranged from 45 to 51%.

RESULT(CONTD.)

• Well water was found contaminated with coliforms and fecal coliforms in the range of 200 – 1200 MPN/100 ml and 40 to 150 MPN/100 ml respectively.

• pH of well water was always acidic, below the desirable limit of Bureau of Indian Standards (1991). The annual mean was 5.64 ± 0.69.

• Similarly Fe fluctuated seasonally from 0.19 ± 0.18 mg/l to 0.51 ± 0.34 mg/l.

Water filtration unit

The water filtration unit (as in figure) consists of the following materials from top to bottom1.Crushed rock(gravel)-1.5 inch thick

2.Sand-1.75 inch thick3.Charcoal-1.5 inch thick

4.Crushed rock(gravel)-1.5 inch thickWhen water is filtered through this unit the acidic pH of water turns to permissible limits of drinking water

Conclusions

• Filtration of water using the simple filter unit- consisting of gravel, sand, coconut shell charcoal and gravel- resulted in elevation of low pH.

• Excess iron could be removed through filtration of water through cotton cloth followed by boiling.

• Bacterial contamination could be avoided by heating the water to roll boil.

• Construction of rain pits (21 × 21 × 21) near dug wells increased the well water level during summer, by more than 2 ft.

• The above simple techniques are valuable tools in purification of water as well as in improving water availability.