What is the composition of pharmaceutical wastewater?
In general, these wastewaters contain the following: Organic constituents in abundance, with a major portion of it easily biodegradable (alcohol, acetone, etc), organic molecules that degrade slowly, refractory chemicals (aromatic compounds, chlorinated hydrocarbons), and compounds that inhibit and are harmful (antibiotics).
Pharmaceutical compounds in drinking water sources
Pharmaceutical compounds are found in drinking water from two sources: pharmaceutical industry production processes and general use of pharmaceutical compounds, which results in their presence in wastewaters.
Composition and characteristics of pharmaceutical wastewater
High-concentrated antibiotic wastewater is the main source of biopharmaceutical wastewater, which has a low C/N, high SS concentration, high sulphate concentration, complicated composition, biological toxicity, and high chroma. Chemical pharmacies have a single composition, resulting in a lack of nutrients. It also contains a lot of salt and has excess concentration. It's very difficult to biodegrade, and it's hazardous to microbes.Furthermore, most pharmaceutical manufacturers operate on a batch basis, with diverse raw ingredients and manufacturing processes, resulting in a wide range of effluent, as,
-COD (mg/L) = 1000-10,000;
-BOD-5 (mg/L)=500-2500;
-TN (mg/L) = 500-1500;
-TP (mg/L) = 50-250;
-SS (mg/L) = 200-500;
-Temp. (?) = 25-80
-pH = 1-8
How is pharmaceutical wastewater produced?
Antibiotic production wastewater, synthetic drug production wastewater, washing water and washing wastewater from the production process of diverse preparations are the primary categories of pharmaceutical industry wastewater.
But the question arises, how to deal with the wastewater from synthetic drugs?
Advanced treatment of wastewater including physico-chemical and tertiary treatment can be utilized not only as a pre-treatment for biological treatment, but also as a separate treatment or post-treatment process for pharmaceutical wastewater in some cases.
Advanced wastewater treatment methods for pharmaceuticals
The focus of scientific study and engineering application has turned in recent years to enhanced treatment of pharmaceutical wastewater, with physicochemical technology as the primary method. Coagulation and sedimentation, flotation, activated carbon adsorption, advanced oxidation processes, and membrane separation are examples of physical or chemical procedures used to treat pharmaceutical wastewater.
1: Sedimentation and coagulation
Coagulation is the process of adding chemical agents to wastewater, rapidly mixing them to disperse, and then converting stable contaminants into unstable and precipitable stuff.
The ability to compress and extract bound water around a hydrophilic colloid is crucial for enhanced treatment of pharmaceutical wastewater. As a result, the flocculant’s nature is crucial in determining the coagulation effect. As flocculants, inorganic metal salts and polymers are often utilized. SS, chromaticity, and harmful organic particles can all be removed with this method. Meanwhile, it can help pharmaceutical wastewater biodegrade more quickly.After coagulation, the most frequent procedure is sedimentation. Pollutants, which have a higher density than wastewater, can be separated using gravity.
Coagulation and sedimentation have several advantages, such as ease of use and proven technology, but removing dissolved organic debris is difficult.
2: Flotation
Flotation can remove suspended particles from secondary effluent in addition to sedimentation. By injecting air into wastewater, the method produces a high number of tiny bubbles, forming floating floc with a lower density than the wastewater. It can also separate wastewater by floating to the surface.
3: Adsorption of activated carbon
As an adsorbent, activated carbon provides a number of advantages. It features a large specific surface area, a multilayer pore structure, a high adsorption capacity, and chemical properties that are consistent. As a result, it is frequently utilized as an adsorbent or catalyst carrier for the removal of contaminants. Physical adsorption and chemical adsorption are two types of activated carbon adsorption. The former is reversible and has no adsorbate selectivity. It is simple to desorb activated carbon that has been saturated with adsorbates. Chemical adsorption, on the other hand, adsorbs only one or a few distinct adsorbates and is irreversible and difficult to desorb.
Saturation of activated carbon recovers its adsorption property by regeneration for cyclic use.
Because of its capacity to be recycled, higher treatment effect, and wide applicability, this technology is extensively employed for advanced therapy.
4: Processes of advanced oxidation
Advanced oxidation processes (AOPs), use free radicals to oxidize contaminants. These contaminants are incapable of being decomposed by a standard oxidising agent. Wet air oxidation, supercritical water oxidation, Fenton reagent, photocatalytic oxidation, ultrasonic oxidation, electrochemical oxidation, and ozonation are only a few examples of AOPs.
5: Separation by membranes
Membrane separation occurs when a component in water selectively permeates the membrane by applying permselective membrane separating media under a given driving force across the membrane. As a result, the target substance can be separated, purified, and concentrated from the mixture. In wastewater treatment, there are numerous membrane separation approaches. Microfiltration, ultrafiltration, reverse osmosis, and electrodialysis are among examples.
6: Electrodialysis (ED)
The electrolytic and dialysis diffusion processes are combined in the ED process. The anions and cations of the dissolved salts in the wastewater are transported to the anode and cathode, respectively, by the DC electric field. The concentration of anions and cations in the intermediate compartment is steadily lowered in this manner, resulting in separation and recovery.
This approach offers numerous advantages, including reduced energy and pharmaceutical usage, less pollution, and ease of operation and automation. However, it can only extract salt from water and has a lesser desalination effectiveness than RO.
7: Ozonation
Ozone has long been thought to be a highly powerful oxidant and disinfectant. It is predominantly an oxidant in acidic environments. However, it mostly relies on free radical reactions in neutral and alkaline environments. It has the ability to swiftly oxidize and breakdown most organic substances in water, effectively removing contaminants. It may also successfully remove turbidity and germs from wastewater at the same time.
Ozone advanced oxidation technology is formed when ozone is mixed with other wastewater treatment technologies. This approach has a higher oxidation ability but a worse reactant selectivity.
Conclusion
Pharmaceutical wastewater has some characteristics, such as poor biodegradability and high concentration, due to the complexity of pharmaceutical processes. Advanced treatment of pharmaceutical wastewater is critical due to these properties. There are many different types of advanced treatment, each with its unique set of characteristics. The quality of pharmaceutical wastewater effluent can be effectively improved via the logical application of diverse technologies.
Taking these considerations into account, Netsol Water can customize WWTPs and STPs, ETPs as per clients’ requirement. These treatment facilities require less maintenance and is known for producing water that is safe to re-use or discharge after treatment. We can offer these structures in a variety of sizes to meet the needs of our clients. We provide design and consulting services for various types of industries including pharmaceuticals.
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