Stabilization Ponds in The Gambia

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Hello there, I am from Gambia and have been working in the WASH sector.

Most of the population, >90%, use on site sanitation (toilets and some with soakaways and others with holding tanks). The sewerage network is provided for the tourism area (Hotels are connected to a waste stabilization pond).

The pond is the only treatment plant available in the area. Collected sewage from households also ends up at the pond, which initially was designed for only waste from the tourism area. The industries also smuggle and dump at the ponds at times.

The ponds currently produce so much odour that it raises alarms and authorities are watching.

Kindly advice on suitable technology for this community?

What ways can treatment be rehabilitated at the ponds?

Thank you

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16 Answers

  1. The nuisance odors appeared might be due to several reasons

    1. the design of the stabilization ponds ( as the main design is to treat light wastewater generated from hotels, where water consumption is high and consequently low biological load)
    2. high organic/hydraulic load sourced from disposal of wastewater generated from local communities (I assume that water consumption is low and therefore generated high biological load)
    3. considering the stabilization ponds treatment plants are based on biological treatment, the whole treatment system will be affected due to industrial wastewater disposal
    4. the retention time of the wastewater at the ponds are less than the design due to overloaded
    5. proposed suggestions to reduce odors:
    • stop receiving wastewater from industrial source
    • install aeration mixers at the aeration ponds to increase the dissolved oxygen
    • applying additional chemical additives to the system which enhance the biological treatment system

    for further information or consultancy services you can contact me by sending email to zrashdan@yahoo.com or WhatsApp to 00966 55 637 0937

     

    regards

    Zaid

  2. We can work that problem with you. We are currently working with a technology that eliminates bad odor, gets rid of the organic sludge and improves the treatment as well. Contact us at: anoriega@tyesac.com.pe  Please put: Stabilization Ponds in Gambia, so i will know it's not spam

  4. Hi  james,

    Please note that all ponds which are overloaded will be operatiting anaerobically with result that they will be emmiting  offensive

    smell or odour,

    To avoid this scenario you should adopt a chane to shallow ponds which are laid out in series from the primary to the factatitve to the tertially.

    As advised ealier in my e-mail to you do check on work done by D,D. Mara who has done extensive work in this area,

  5. French

    Bonjour 

    On peut opérer un procédé de filtration de l'eau mais ce dispositif va générer des résidus de boues dont on ne sait plus quoi faire à part les stocker en plein air. ils seront soumis à l'assaut des vents et des intempéries pluviales qui disperseront ces boues dans l'environnement voir dans l'étang.

    On peut aussi effectuer une action préventive en opérant un réel traitement dès l'origine de production de ses effluents d'eaux usées.

    A ce stade il en va d'une politique décisionnaire d'état.

    Je propose l'assainissement Biologique avec une biotechnologie qui élimine la totalité des matières organiques en suspension définitivement.

    Chaque habitat doit en être équipé et en avoir la charge  d'entretien et de protection suivant le principe du polleur/payeur.

    Une biotechnologie de revalorisation des eaux usées produisant un liquide de fertilisation des terres d'agriculture biologique.

     

    English 

    Hello we can operate a water filtration process but this device will generate sludge residues which we do not know what to do except the storage in the open air. They will be subjected to storming winds and stormy weather that disperse these sludges into the environment see in the pond.

    Preventive action can also be carried out by real treatment from the origin of its sewage effluents.

    At this stage it is a policy of state decision-making.

    I propose biological sanitation with a biotechnology that eliminates all organic matter suspended permanently.

    Each habitat must be equipped with a maintenance and protection charge according to the principle of the poller/payer.

    A biotechnology to revalorize wastewater producing a fertilizing liquid from organic farming land.

     

     

     

  7. Hi
    as you notice the pond was OK till it was over loaded

    i recommand you to keep it simple by addining a additional volume and considering cleaning the sludge from the current pond.

    solid separation in front, and aerobic pond at the end may help

    Israel has a pond system in many places, that work perfectly

    you are welcome to contact me for ferther information
     

    Ilan - ilan@enviro-eng.co.il 

  8. Hi Musa, stabilisation ponds are common place across Africa, we utilise them in South Africa and I have seen many across Africa. Like any process, they need to be sized according to the load they receive, it seems in your application the load is exceeding the designed capacity, hence the smells - this is usually a first indicator that the process is not aerobic and typically then overloaded.

    Ponds require space, and lining is becoming expensive, you may want to consider some alternate, basic treatment technologies that are established on the African continent as an alternative, you will get a superior effluent quality that can be re-applied, for example.

    You are welcome to make contact with me directly if you require any additional information on ways to extend the existing ponds, or if you want to know more about alternate technologies working across Africa

    Regards

     


  9. We offer the EEC High-Speed Bio Tec and EEC Desal RO plants at competitive price without compromising quality, as a matter of fact, for the EEC Bio Systems, we have incorporated  proprietary technology that handles sludge fully automatic and secures optimal bio-digestions so to minimize the same, this is one of the reason why US Mil and NATO have bought over 40 systems based on 12 repeat contracts over 10 years.

     

    Finally I would like to mention that our EEC MBBR Bio Systems has no filters, use no chemicals, and our proprietary self-cleaning  AMB Bio Media comes with 20 years warranty. EEC MBBR systems does not require any dedicated operator as regular maintenance personnel can operate our systems after reading our manual. The EEC MBBR’s are fully automatic and require only a brief check once or twice a week.  www.eecusa.com

  10. EEC Global Operation LLC offers EEC High-Speed Bio Tec and EEC Desal RO plants at competitive price without compromising quality, as a matter of fact, for the EEC Bio Systems, we have incorporated  proprietary technology that handles sludge fully automatic and secures optimal bio-digestions so to minimize the same, this is one of the reason why US Mil and NATO have bought over 40 systems based on 12 repeat contracts over 10 years.

     

    Finally I would like to mention that our EEC MBBR Bio Systems has no filters, use no chemicals, and our proprietary self-cleaning  AMB Bio Media comes with 20 years warranty. EEC MBBR systems does not require any dedicated operator as regular maintenance personnel can operate our systems after reading our manual. The EEC MBBR’s are fully automatic and require only a brief check once or twice a week. www.eecusa.com 

  11. Sewage is a complex mixture of chemicals, with many distinctive chemical characteristics. These include high concentrations of ammonium, nitrate, nitrogen, phosphorus, high conductivity (due to high dissolved solids), high alkalinity, with pH typically ranging between 7 and 8. The organic matter of sewage is measured by determining its biological oxygen demand (BOD) or the chemical oxygen demand (COD).

    Sewage and many types of industrial wastewaters contain organic matter. If wastewater is discharged untreated into surface water bodies (for instance, rivers and lakes), their organic matter serves as food for microorganisms living in the surface waters. These organisms use the organic matter for energy generation for their growth and reproduction. This is done via their respiration, in which they convert the organic matter into carbon dioxide and water. These stable components do not cause water pollution problems. Therefore, this is frequently called "stabilization" of the organic matter.Sewage treatment is the process of removing the contaminants from sewage to produce liquid and solid (sludge) suitable for discharge to the environment or for reuse. It is a form of waste management. A septic tank or other on-site wastewater treatment system such as biofilters or constructed wetlands can be used to treat sewage close to where it is created.

    Sewage treatment results in sewage sludge which requires sewage sludge treatment before safe disposal or reuse. Under certain circumstances, the treated sewage sludge might be termed "bio solids" and can be used as a fertilizer.

    In developed countries sewage collection and treatment is typically subject to local and national regulations and standards.Oxidation ponds have many advantages. The oxidation pond treatment process is natural, because it uses microorganisms such as bacteria and algae. This makes the method of treatment cost-effective in terms of its construction, maintenance, and energy requirements. Oxidation ponds are also productive, because it generates effluent that can be used for other applications. Finally, oxidation ponds can be considered a sustainable method for treatment of wastewater.

     Anaerobic ponds are usually used for treatment of industrial and agricultural wastes which contain high organic matter and sulphate. Competition for substrate between sulphate reducing bacteria and methane producing archaea, and the inhibitory effects of sulphide produced from microbial sulphate reduction reported in the literature varied considerably.

     laboratory scale column-in-series anaerobic pond reactor, consisting of five cylindrical columns of acrylic tubes, operate to evaluate the effect of COD and sulphate ratio on pond performance treating wastewater containing high organic matter and sulphate from a tapioca starch industry.

     

     

     

  13. Please check organic loading kg/hectare/day). For tropical country with hot climate the value recommended 275 to 350 kg/ha/day. Malfunction is  due to organic overload.

    Following can be done to improve the efficiency of the pond

    A.  Pre & Primary treatment to remove the suspended solids.

    B. It can be converted to aerated lagoon by providing floating aerators

    Rajendrakumar V Saraf

  14. Hi James,

    Stabilization ponds are the most economical  and technologically appropriate means of treating sewage in hot areas and more so in Africa. Thats what we use here in Kenya.

    The ponds mus t meet with good desing criteria if the are to be efficient and oduorless.For reference look for work done by D.D Mara which i believe must be available in the internet or alternatively you revert back to me through  wemcons@gmail.com

    1 Comment

    1. Hi James, I agree with Peter that stabilisation ponds are a good solution. In your case dosing of microbial products and some desludging should help to restore performance. More detailed analysis figures would be required. Some of the industrial wastewater will be causing problems but there are solutions for that also.

      Best regards,

      Ciaran

  15. Suitable technology is the pond system as it require less mechanical equipment and big land area.

    I assume you have a single shallow pond of 1.5 m deep(aaproximately) and overloaded with sludge.

    Dig a pit adjacent to the pond and line it with PVC or Poly. Dredge the sludge stored in the pond and transfer to the lined pit online. Once the all the sludge are dredged and transferred to the pit the ponds will return to normal treatement and odour reduced. Dredged sludge allowed to dry out and disposed.

  16. Dear Musa,

     

    If the pond is over load, you need construcct a bigger pond or help the actual pond to treat the wastewater.

     

    You must describe the system and send the inflow lab analysis and outflow requirement and the flow and size of the system. But, whatever data, if you can't construct new ponds, you must help yout actual system aerating and using the addequate bacterial cultures as in a biocleaner system that even can diggest the sludge.


    With a low energy compsume you can treat the wastewater and eliminates the offensive odors in just one simple step without complex controls or special skills operators.

    Write to me to my contact data on my profile and we can help you designing the appropiate system.

     

    Regards,

     

    Orlando D. Gutiérrez Coronado