In the Foster Home that we support in Ghana, the water from 60 m deep bore well can no longer be used for drinking due to a mud contamination. The water quality (specifications) is still good, but the mud colors the water brown and negatively impacts the taste.
The well water is pumped via a PVCpipe to 4 reservoirs (plastic containers), filtered, and then distributed to approx 100 users.
The question is what filtration/purification system can we use to best alleviate these negative effects and where should the filters be installed? Can we add something in bore well itself to get better water?
Please note that we are situated in a rural area, with limited access technical support and spare parts.
We do attach a nano clay candle for filtration, there are larger community level tanks fitted with our clay candles and there is provision for sludge removal using a vent valve. Basically 2 tanks one above the other, forms the filtration system and the clay candles are fitted in-between, at the bottom portion of the top tank. Water gets filtered and percolates through the candle thereby removing pathogens and colloidal materials, heavy metals etc. The pictures shows tanks modified to suit Terafil filtration and the green colour one is the same type of tank designed and moulded in a tender coconut shape! For details visit watsan.in. This is electricity free, maintenance less and does not need membranes or any replacements often!
SaferEx - Water Purifier , a multi-action safe liquid that purifies contaminated borehole/well groundwater, makes it safe for drinking, hygiene and sanitation uses by killing pathogens, sedimenting particles, heavy metal ions and salts, removes odour and colour, "on single application", by simply mixing it with the unsafe water and decanting/filtering after 1-6 hours (depending on contamination type/extent) at less time and cost with efficiency compared with combinations of other treatments without desired results. It brings the pH of highly acidic and alkaline water towards/close pH7. It forms a cloudy solution with certain impure water (sediments impurities)and clear solution with pure water (without sediments), therefore can be used to preliminary detect safe and certain unsafe water instantly. It is formulated from regular and refined water treatment chemicals.
Addition of SaferEx water purifier in the overhead tanks at 5ml/20 litres water, allowing 1-6 hours and wasting the bottom sediment before passing the water through a composite filter bed or 3 micron (5, 1, 0.5 or less micron) filters in series will make the water potable.
Alternatively, the well can be compressed and flushed to reduce the mud content. Then a coagulant/clarifier can be dropped into the well. Then a measured disinfectant dosed into it in mixing before filtering and distribution.
A basic sand filter in the system will go a long way to solving your problems. We would suggest that the addition of our 100% fully organic product to the water before it enters the filters would keep the filters healthy and give you quite clean water. Our product needs about 72 hours residency time in a tank of water to be really effective.
Solutek is extremely low tech.....just tip it in with a cup of put a small pump into the system.
My instinct would be filter the water through sand protected by a porous ceramic, bound sandstone (perhaps held with a bentonite clay) or cementitious layer than can be maintained and cleaned. Water will gradually be absorbed and make its way through the porous ceramic, stone or slab and the sand (the clay will remain on the surface). It can then be run off into suitable storage containers/ ponds. If quality/taste is still an issue then you will need to consider running the water through activated carbon (as already suggested) after it passes through the sand. A simple, low cost and easy technique to try out. Worth a try.
You can use a sand filter or multimedia filter to remove turbidity from the source water. But the filter media will quickly foul if the water is very muddy. The best thing to do is eliminate the problem at the source. You may be able to rehabilitate the well. A good well driller could give you a better idea what you could do. Perhaps pumping the well for a long period woul clear it up. Maybe the well needs to be drilled deeper and then sealed off with bentonite. Maybe a new well is needed. Running a camera down the well may provide more details of the well failure. For the camera to be of any use the well would have to be left idle so the water column could settle and be clear enough to see through.
You have a problem with suspended solids though probably and that silt is colloidal in nature and super small. Some type of coagulant (alum) and flocculant (acrylamide) could be used but I'm sure you don't have access to those on a regular basis for re-supply.
Construct a settling tank where suspended solids will settle down and clear water can be taken from the top. A floculant may be added to speed up the settlement.
