Industrial Waste: Hazards, Types, and Treatment Technology

Industries produce various types of waste which includes biodegradable, non-biodegradable, toxic, and radioactive, out of which 10 to 15 % are non-biodegradable and hazardous waste. Examples are plastic, glass objects, silver foil, gypsum etc. The increase Industrial wastes are categorized into two types:

1. Process waste is waste generated during processing of raw materials. The inorganic process wastes may come from chemical industries like, caustic soda industry (Mercury), pesticide industry. It includes solid waste such as Fly ash which is a byproduct of combustion of coal. It contains trace levels of heavy metals and elements like Arsenic, Beryllium, Mercury, Chromium etc. which causes pollution in air as well as groundwater contamination. Metallic industries also produce solid metallic waste and slag.
2. Chemical waste is the byproduct of harmful chemicals. It includes heavy metals, detergents, acids, and other toxic substances. They are usually produced from industries like Fertilizer industries (Ammonia, Cyanide), paper and pulp industries etc. The wastes are liberated into water bodies or land. It alters the pH, COD and BOD of these bodies. The aquatic animals and plants absorb, accumulate and bio-concentrate the chemical wastes leading to bio magnifications and finally destroying the tropic levels and food chains of the eco-system. Wastewater containing nitrates and phosphates causes Eutrophication(over enrichment of water bodies with minerals and nutrients).
3. Electronic-Waste refers to the waste produced from electrical/electronic devices. This waste is increasing largely due to rapid expansion in technology, as newer tech emerges, older tech becomes e waste.

It is estimated that 50 million tons of E-waste are discarded every year. And only 15-20% of this waste is recycled. E waste includes: Cathode Ray tubes, Printed circuit boards, Computer wires, Plastics from body of the devices etc. E wastes are non-biodegradable and toxic. E waste contains hazardous components like:

1. Epoxy Resins are used as electrical insulators inside electrical components. They contain amines which are carcinogenic and mutagenic.
2. Lead used for soldering the electrical components, found in lead acid batteries, CRT monitor glass is a heavy metal which is highly toxic.
3. Mercury is found in fluorescent tubes, thermometers, batteries are extremely toxic.
4. Beryllium Oxides used in high-performance semiconductor parts, fillers in thermal paste causes lung cancer and other adverse health effects.
5. Polyvinyl Chloride is used for the insulation of electrical cables. It causes bioaccumulation of chlorine in water bodies. As they contain many heavy metals and carcinogenic compounds we must handle e waste carefully and give them to dealers for recycling. One of the major challenges faced in recycling of E-waste is recycling of PCBs. They contain precious metals like gold, platinum, tantalum and base metals like copper, aluminum etc. The base and precious metals can to be separated by grinding the boards into powder, but recycling efficiency is less. Better methods are still being discovered.

Treatment technology

At present, contaminated industrial waste is contaminated, and the uncontrolled discharge has become a major issue. Heavy metals are non-biodegradable, persistent and continue to exceed the permissible concentration of very large compounds in cells and cause cellular toxicity. The only way to think of them is to eliminate them is immobilizing. For this purpose, there are predefined traditional methods of chemistry, oxidation, reduction, filtration, electrochemical, evaporation, concentration and exchange of ion exchange resins. These techniques require more energy consumption, especially reducing solutions.

Treatment by Biosorption

Here, microbial biomass provides a financial opportunity to eliminate heavy metals through the biosorption phenomenon. Some reactive groups, such as carbohydrates, congenital, imidazole, phosphate, sulfhydryl, sulfate and hydroxyl groups are metal sequestrants on their cell surface due to lack of biomass or death. This process can be achieved economically by using biomass from biomass from industry. Using a batch or direct drive without biomass is a constant process for removing heavy metals that can develop into a fixed bed reactor. The additional biosorption probability of biomass is improved by various physical and chemical treatments. The diversity of microbial biomass and its potential availability of metal bonding make it an economical and sustainable choice for developing a waste water treatment process for removing and recovering heavy metals.

Solidification

Solidification is the physical stabilization process aimed to improve the engineering parameters of the materials, such as compressive strength, bearing capacity, wear resistance and erosion prevention strength, and permeability so that the happen of release of contaminants from solidified blocks in a disposal site can be decreased. Binders such as cement, pozzlonas, and thermoplastics are used to immobilize contaminants in sludge. The extent of stabilization is tested using leachability analysis.