Are organic effluent treatment chemicals better for the environment?

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Would you recommend any papers which address the efficacy and environmental impact of organic Vs synthetic chemicals for industrial effluent treatment?

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3 Answers

  1. I am not sure if you mean organic chemicals over biological products. Biological products are good microbes and they are ideal to treat effluent wastewater. The best treatment is a combination of microbes and microalgae. Selection of the microalgal species as well as the microbes is carried out after study the effluent wastewater and its pollutants. There are several papers available on the internet that can be accessed by typing specific search's.

  2. Dear Maeve,

    Organic pollutants originate from domestic sewage (raw or treated), urban run-off, industrial (trade) effluents and farm wastes. Sewage effluents are the greatest source of organic materials discharged to freshwaters.

    The effects of organic effluents on receiving waters


    when an organic polluting load id discharged into a river it is gradually eliminated by the activities of micro organisms in a way very similar to the processes in the sewage treatment works. This self-purification requires sufficient concentrations of oxygen, and involves the breakdown of complex organic molecules into simple in organic molecules. Dilution, sedimentation and sunlight also play a part in the process. Attached micro organisms in streams play a greater role than suspended organisms in self-purification. Their importance increases as the quality of the effluent increases since attached microorganisms are already present in the stream, whereas suspended ones are mainly supplied with the discharge.

    Effects on the biota

    Organic pollution affects the organisms living in a stream by lowering the available oxygen in the water. This causes reduced fitness, or, when severe, asphyxiation. The increased turbidity of the water reduces the light available to photosynthetic organisms. Toxic pollution occurs when synthetic chemicals are discharged or natural chemicals accumulate to toxic levels in the environment, causing reductions in wildlife numbers, degrading ecosystem functions and threatening human health.

    Among the many naturally-occurring substances involved are certain metals (such as mercury, lead, chromium) and petroleum. Synthetic, or human-made, chemicals include, among others, pesticides, PCBs and dioxins. A large group of these, known collectively as persistent organic pollutants, or POPs, are complex compound-all containing hydrogen and carbon and many containing chlorine-that persist unchanged in the environment for long periods. Human activities are also responsible for environmental contamination by radioactive substances, some of which are natural and some synthetic.

    Toxic pollution occurs as a result of a variety of human activities. Industries and sewage treatment plants discharge wastes which contain toxic substances directly into waterways, These direct pipeline discharges are called point sources. Separate treatment – for the purpose of separating materials that require special treatment. This is important when the wastewater contains high concentrations of BOD, COD, H2S, NH4 or poisonous materials. It may be more costly to dispose of the water than to treat it in certain ways;

    Preliminary treatment – useful for all industries and important for food and agricultural industries. It includes (1) grit removal in some cases (iron and steel foundries, rainwater and sandpits), (2) oil removal for hydrocarbons and oils, and (3) equalization of liquid flow and pollutant load.

    Physical-chemical treatment -- this treatment can be an intermediate or final stage, based on the type of treatment. It is conducted for (1) settling of poisonous minerals or salts, (2) removal of oils in emulsions, and other suspended substances, (3) clarification and dilution of colloidal BOD and COD concentrations (the pH has to be maintained in a realtively narrow range depending on the nature of the used process, either settling, crystallization or absorption), and (4) floatation units for oil and fibber removal. The physical-chemical treatment is preceded, or followed, by other methods such as (1) electric neutralization, (2) oxidation or reduction, and (3) degassing or stripping.

    Biological treatment -- the use of this treatment depends on the biodegradable contents of the wastewater.

    Removal of non-biodegradable material -- the biological purification process is considered on of the best methods for reducing the BOD concentration and the COD resulting from decayed organic compounds of different types (solvents, aromatic materials, hydrocarbons).

    Industrial sludge – although organic sludge exists in some cases, the sludge is primarily inorganic in nature. Industrial wastewater contains large quantities of sludge, resulting particularly from physical-chemical treatment methods.

    Please find attached herewith related articles.

    Regards,

    Prem Baboo

  3. Dear Maeve,

    I have no papers to recommend on this topic but just my own recommendation based on 38 years international expertise in R&D, design and operation of mainly industrial effluent treatment plants (new and retrofit upgrades). The source of a chemical (natural resp. scientific) makes little difference as opposed to the kind of chemicals (class and chemical formula) and the quantities being dosed. We learned that the use of chemicals (different kinds and amounts) can be minimized by replacing physical-chemical treatment by advanced biological treatment starting with anaerobic methanisation where feasible. Most acid organic industrial effluents can be neutralized without chemicals (lye) by biologically converting the organic acids to methane, carbon dioxide and water. In addition, biological adsorption and flocculation can replace conventional (electro-)chemical coagulation and flocculation. Finally heavy metals can be removed by anaerobic biological treatment without any chemicals other than a bit of (waste) organics if not already present in the effluent.