 In this module as we have discussed in our previous module the significance of the effluent treatment, but in this module we will talk about that what are the indicators that guide us for the treatment of the effluent. As we know that since the oxygen is essential for the survival of the most of the organisms, so it is important to ensure that there are the adequate level of the dissolved oxygen in river, lakes, reservoirs, etc. So if there is to be managed satisfactory just by controlling the oxygen concentration in the aquatic environment. So it is therefore important to know that how the effulents contain soluble and particulates which we called as organic matter can influence the dissolved oxygen concentration. So one widely used method for the assessment of the pollution level that is the term that is used as the BOD which we called as biochemical oxygen demand which is the measure of the quantity of oxygen required for the oxidation of the organic matter in the water by the microorganisms present in a given time interval at a given temperature. So that is the BOD, so the level of the BOD in our effluent that actually give this standard of the effluent treatment. So the complete survey of the industrial operation is essential for an individual site before an economical waste treatment program that can be planned. So the factors to investigate in a site survey that is the daily flow rate you can see here these are the different factors, daily flow rate, fluctuations in daily, weekly and seasonal flow. So what are the changes, BOD and COD ratio suspended solids, turbidity, pH range, temperature of the effluent, order and the taste, color, hardness, detergents, radioactivity, presence of specific toxins and the inhibitors and some heavy metals and the phenolic compounds. So while processing the effluent, while selecting the effluent treatment as an economical waste treatment program, these are the different which we have to first survey of the effluent produced through the fermentation process. So if the survey is comprehensive it should be possible to plan an overall treatment program for the site to the establish. So the first one the water source which can be combined or reused, the strategy to reuse the water. The second is the concentrated waste, concentrated waste stream which contain the valuable waste to be recovered as food, animal feed, fertilizers or the fuel. So if there is any possibility to recover such by products that can be used. So the toxic effluents needing special treatment or the acids or the electrineed neutralization. And before throw into the water course we have to neutralize such things. The effluent loading expected under maximum production conditions because the fermentation is a batch process mostly used. So during the batch harvesting then there is a more discharge air compared to the normal days. So the effluents which might be discharged onto the municipal sewer. The effluent which might be discharged directly without any treatment or to the land or to the water course if there is no risk of the pollution. So mostly there is the two choice either you directly discharge the fermented effluent into the open land where the water will evaporate and the remaining residual material will be just to deposit on that soil either that you throw into the water channels. So these are the two basic techniques which is possible for that.