Waste Management and Sewage Treatment - Class VIII

• An electrostatic precipitator($ESP _s$) is a device that removes suspended dust particles from a gas or exhaust by applying a high-voltage electrostatic charge and collecting the particles on charged plates. It can remove 99% of particulate matter from thermal power plant exhaust.
• e-waste is discarded electronic appliances such as mobile phones, computers, and televisions. Over half of the e-waste generated in developed countries are exported to developing countries, mainly to China, India, and Pakistan, where metals like Cu, Fe, Si, Ni, etc., are recovered during the recycling process.
• Nuclear waste is the radioactive waste material, for example from the use or reprocessing of nuclear fuel. Hence Use of nuclear energy has two very serious inherent problems first is accidental leakage and the second is the safe disposal of radioactive wastes. Hence It has been recommended that storage of nuclear waste after sufficient pretreatment should be done in suitably shielded containers buried within rocks about 500m deep to prevent its harmful effects.
• So, the correct answer is 'All the above',

The material by and large utilized for sound sealing of rooms like chronicle studio, film lobby, assembly hall which assimilate sound and encourage in sealing is styrofoam. Earplugs are comprised of fine glass wool or cottonwood impregnated with wax while ear covers contain liquid seals or plastic froth for engrossing sound.

Water resources are limited in an ecosystem. There is an urgent need to minimize the waste of water. It can be done by either reuse or recycle of water. Recycling of water can be done by purifying waste water and reusing again for another purpose. The various ways to reuse water is using treated water for toilet flushing, in agriculture, for industrial processes, etc.

The term waste is often subjective (because waste to one person is not necessarily waste to another) and sometimes objectively inaccurate (for example, to send scrap metals to a landfill is to inaccurately classify them as waste, because they are recyclable). 

Waste is defined as any material that is no longer required, wanted, or usable by the person or entity that generated it.

According to natural disposal, the pollutants may be biodegradable or nonbiodegradable.

1. Biodegradable Pollutants: These are quickly degraded by natural means. Sewage and heat are pollutants of this category. These pollutants are disposed of by microbial action and radiation respectively.

2. Nondegradable Pollutants: These are not degraded or are degraded slowly in nature. DDT, arsenic salts of heavy metals, glass or tin containers, radioactive materials, and plastics are the pollutants of this category. These pollutants accumulate and may get biologically magnified as they pass through the food chains.

So, the correct answer is 'True'.

Settleable solids are the portion of suspended solids in sewage that will settle out of the liquid phase under the influence of gravity if left undisturbed for a period of time.

Explanation: Organisms which breakdown dead or waste matter in to simpler substances is termed as Decomposer

Solid waste that are generated must be segregated as dry waste and wet waste. This would help in better treatment and disposal of waste.

The nutrients present in domestic sewage added in a lake will cause the dense growth of microbes, The microbes use oxygen and may deoxygenate the water which may lead to the death of the fish.

Biochemical oxygen demand is the measure of oxygen required by aerobic decomposers for biochemical degradation of the organic materials. BOD indicates the degree of organic pollutants present in water.

The sources of phosphate pollution are sewage treatment plants, phosphate fertilisers used in agricultural fields, etc.

Water hyacinth (Eichhornia crassipes) also called as "terror of Bengal" is the plant that sometimes chokes ponds, lakes, and rivers resulting in an imbalance of ecosystem dynamics of water bodies. It is the world's most problematic aquatic weed. It accelerates eutrophication.

Sewage is a water-carried waste, in solution or suspension, that is intended to be removed from a community. Also known as domestic or municipal wastewater, it is more than 99% water and is characterized by volume or rate of flow, physical condition, chemical and toxic constituents and its bacteriologic status (which organisms it contains and in what quantities). It consists mostly of grey water (from sinks, tubs, showers, dishwashers, and clothes washers), black water (the water used to flush toilets, combined with the human waste that it flushes away); soaps and detergents; and toilet paper (less so in regions where bidets are widely used instead of paper). Whether it also contains surface runoff depends on the design of sewer system.

Organic matter in sewage consists of biological materials like food waste and human waste, which can be broken down by microorganisms, making it biodegradable.

Point sources of pollution are identifiable, localized sources such as pipes or specific treatment plant outlets. In contrast, diffused or non-point sources are spread out over a large area.

A low pH in sewage indicates acidic conditions, which are often the result of the fermentation of organic matter, commonly referred to as septic conditions.

Anaerobic bacteria are organisms that thrive in environments lacking free dissolved oxygen, utilizing other compounds for respiration.

Suspended solids are particles that remain floating or suspended in the water column because they are not heavy enough to settle out quickly.

Turbidity is the cloudiness of a fluid caused by large numbers of individual particles, specifically suspended and colloidal solids that scatter light.

Strong sewage contains a higher concentration of organic and inorganic matter, which increases the number of suspended and colloidal particles, thereby increasing turbidity.

Sewage water is defined as wastewater that contains various dissolved and suspended impurities originating from domestic or industrial sources.

Sewage treatment is necessary to prevent the pollution of water bodies and to protect aquatic life from the harmful effects of untreated waste.

The wastewater mixture will contain large numbers of microscopic organisms, mostly bacteria that are capable of consuming the organic component (fats, proteins, and carbohydrates) of the mixture and bringing about rapid changes in the wastewater. The solid components of wastewaters actually represent a very small part of most discharges, usually less than 0.1% by weight. However, it is this small component of the wastewater that presents the major challenges in wastewater treatment, operation, and disposal.

Residential and commercial waste streams are heavily composed of packaging materials, such as cardboard, plastics, and containers, alongside food waste.

Dissolved solids refer to the inorganic salts and small organic molecules that are completely dissolved in water and cannot be removed by simple filtration.

Contamination of water reservoir with sewage water leads to increased level of phosphate in water. Due to increased level of phosphate algae starts growing on it. This decreases the dissolved oxygen level in water thus all the aquatic lives can't survive and leads to mortality. This is called eutrophication.

Water gets contaminated due to industrial effluents, sewage water, radio biological pollutants etc. These can be purified by several techniques like electodialysis, Ion exchange chromatography, Reverse osmosis etc.

Sewage treatment constitutes of 3 stages primary, secondary and tertiary. BOD i.e biological oxygen demand decreases during secondary stage. This makes water permissible to let into natural water resources.

Radioactive substances resulting from explosions of nuclear testing laboratories and industries giving rise to nuclear dust radioactive wastes, penetrate the soil and accumulate giving rise to land/soil pollution.

Sewage is the term used for wastewater that is contaminated with waste matter from domestic, industrial, or commercial sources.