Aastha Maingi ,Sacred Heart School, Sector 26, Chandigarh,4 Nov : Objective: Anaerobic treatment of biodegradable industrial effluent and bio remediation of heavy metal laden chemical effluent
Related Principle: Anaerobic fermentation and adsorption technique (solid materials will absorb toxic substances from industrial effluent)
Industrial Effluent: Industrial effluents when discharged into the surface water or land without adequate treatment effects the multi segments of environment leading to irreversible persistent change. The biodegradable industrial effluent is treated using anaerobic fermentation and chemical waste is filtered using a packed bed reactor.
Anaerobic treatment is considered as the core technology for mineralizing organic compounds in waste water.
Procedure: The anaerobic treatment is carried out using batch reactor. The effluent and biogas slurry is mixed in the ratio 3:2. The acclimatization of slurry is carried out in reactor for about 45 days. The biogas produced can be quantified in gas collecting bottle containing some indicator solution.
Nitrogen and phosphorous are provided in the form of urea and ammonium dihydrogen orthophosphate at the rate of 200 mg/l. Glucose can be added to develop faster anaerobic conditions.
Anaerobic digestion: process of conversion of organic matter in waste to biogas and manure by microbial action in the absence of air. It occurs by a series of three steps:
1. Hydrolysis: Initial stage when cattle dung and other organic polymers are dissolved in water to make slurry. Anaerobic bacteria hydrolyze polysaccharides and proteins into organic acids and alcohols.
2. Acidoyenesis: Facultative anaerobic bacteria convert simple organic material into acetate, hydrogen and carbon dioxide by oxidation/reduction.
3. Methanogenesis: Acetate, hydrogen and carbon dioxide are converted to methane, carbon dioxide and water by methanogens.
Packed Bed Reactor: Filter in the packed bed reactor contains crushed groundnut powder treated with formaldehyde and sulphuric acid. Groundnut powder acts as an adsorbent that will absorb elements like chromium present in the chemical effluent. Now, water being filtered will be free of this element.
Cost: Its approximate cost is Rs 250.
Utility: Biogas produced using anaerobic treatment can be used for cooking, electricity generation, and energy resource and as manure in agricultural fields whereas water treated from packed bed reactor can be used for irrigation purposes.
Further Scope: For distillery water treatment, high strength molasses wastewater treatment, food processing, extended to continuous anaerobic fermentation.