What are some of the feasible methods to treat river water contaminated with industrial effluents?

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I'm would like to gain some knowledge about treatment of contaminated river water with industrial effluents. In our Water and Sanitation Project here in Jamaica, Mukuru Slums, Nairobi, Kenya, we have an operational WASH project.

However, we have been going through a lot of challenges with regard to accessing clean water regularly. I am wondering if there are feasible methods for treatment of Ngong River that flows near our project area.

My idea is to seek ways to transform this River water and make it usable for our WASH Project and for domestic use.

Thank you and looking forward to your insights.

David.

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5 Answers

  1. Dear David,

    First try to identify the source of pollution (i.e., the inlet to river from industry) and its strength; what is the quality of the river water? BOD or COD is more? Based on the quality of the river water, you can select a suitable treatment procedure (lots are available on the internet), so you have to choose the best that suits your requirements.

    Regards,

  2. Hi David,

    Constructed wetland would be a suitable option to reduce the pollution before further treatment of river water for domestic use. There are different types of constructed wetland design. These depend on flow condition and WQ parameters like COD, TS, heavy metals, nutrients etc. Extensive WQ data will be required to plan and design treatments. Monitoring and controling toxic substances & heavy metals are very important as they negatively impact treatment processes. River bank filtration would be good option to extract better quality water before further treatment.

    Regards

    Sam

  3. Thank you very much Tom Mallard,Your insights sounds very insightful.I would like to gain further details about how it can be remodelled to suit diverse contexts.I would like to learn how it can be done in our context.I am willing to sahre more details about ways we can utilize this contaminated waters.As we speak,women washes polythene bags for recycling using this waters.The benefits that can be gained by simple purification of these contaminated waters can be overemphasized.

    Thank you again for your feedback Tom.

    Eros Kaw,Thank you very much too for your input.Kindly expound more on biocleaner units.

  5. To convey a strategy not often mentioned, that is to take on full wastewater effluent recycling, solids removed as a source of drinking water by growing algae for biodiesel.

    In doing that the algae purifies water better than chemicals and particular species of algae do take up metals and pollutants my studies used 11% oil Spirogyra found in any pond for volume estimates.

    This gets the water purity to where a final filtration would produce drinking water, basically too pure so needing minerals for potable, I have a connection to a small wastewater utility wanting to help with the biology they also needing farm spill remediation and these units are semi-portable, we are after a certified drinking water system for home-ranch-farm that scales up.

    In any case, the cost of purification without the biodiesel is about what putting in a system to gain the biodiesel would be, in any city a lot of money goes to transportation fuels is the math.

    Look at the money spent on city vehicle fuel, when the treatment plant becomes the "oil refinery" the costs are trivial compared to fossil fuels, in Phoenix a local biodiesel producer is at $1.99/gallon retail.

    By using biological purification the secondary effluent process to remove dissolved solids doesn't use chemicals so costs are mainly electrical, thus saving a lot over standard methods beyond gaining the biodiesel.

    For a city sewage system doing this it's worth about 7.5L/day per person using Phoenix, AZ, and 38M-liters/day of effluent, that's 21,000 tons of dissolved solids to grow algae from daily, it's enough to power all transportation and a lot of home heating in volume for any city.

    Consider small cubes full of glass plates means the volume grows like the top 6mm of a pond that stack using fiber-optics for lighting as growing units, insulated, they interconnect, takes 5/person capacity at the plant. For a city that's a lot yet can be added incrementally so self-financing that advised.

    It takes about 50w/person to process the ongoing waste for lighting, aeration, fluid pumps & controls. Recent micro-algae harvesting methods use EMF to release the oil using far less energy than centrifuges.

    This sounds high tech, it is, yet the units scale from household-farm-ranch to big city. My work was for the home-farm-ranch system, miniaturizing the larger standard. It's easy to grow algae every lab in the world does. Once the units are refined they can be volume mfg'd locally now using 3D-printing.

    By putting capital into the system it pays back to society so much more beyond drinking water so wanted to post these thoughts for a viable long-term solution freeing towns from cashflow out of the locale that just for transportation & household cooking fuels.

    A related R&D in the switch to biodiesel entails work on soot elimination for anything using it, from cars to porting for home stoves so always considered part of the solution in this strategy.