Robert A. Gearheart, Paul V. Roberts and  Abel Wolman are the names of distinguished Environmental Engineers.

Use of pesticides and  biocides can be controlled by using better technology that does not pollute the soil. Use of genetically modified crops can reduce the use of fertilisers and pesticides, but it has serious impact on food chain and food web.

Reduction and prohibition of CFC and greenhouse gases is one of the strategies to deal with Global warming. Due to increase of emission of greenhouse gases like carbon dioxide, nitrous oxide, ethane, methane, sulphur dioxide, CFC11(chlorofluoro carbon), CFC12, CFC113, and CFC114,  the amount of heat that could be radiated back into space at night is reduced considerably and as a result the temperature of earth is increased.

Actual reason is the emission of sulphur dioxide (SO₂) and nitrogen oxide (NO₂) from incomplete combustion of fossil fuel. When these polluted gases are released, they start to chemically react with water, oxygen and some other gases, which normally found in the atmosphere to produce sulphuric acid, ammonium nitrate and nitric acid. These acids then start to spread over large areas due to wind direction and  later fall back to earth’s surface as acid rain or any different form of precipitation.

Noise pollution is unwanted noise that may interrupt the balance in our daily activities and affect animal life. It causes number of adverse effects on both human and animal life. Noise above 80 db is considered as hazardous noise pollution.

Thermal pollution refers to the change in normal temperature of water that degrades the quality of water. This change in temperature may be in upward or downward directions. The main reason behind this is our industry/power plant where water is used as cooling agent. After the water is used as cooling agent, it returned back to the environment at a higher temperature that has an adverse affects on ecosystem of water bodies.

This is a grassland food chain. In this food chain, grass represents 1^st trophic level, insects represent 2^nd trophic level, and frog represents 3^rd trophic level whereas birds represents 4^th trophic level.

Steady state community refers to a community that is more concerned about quality than quantity. We will try to have that kind of growth of our environment, which is more qualitative in terms of sustainable. Example of steady state community is a standard wetland where it continuously changing, developing or sometimes shrinking but alive never changes its overall aspect.

Water cycle is the constant movement of water on, above and below the surface of the earth. In the different places of water cycle, water can alter its states among liquid, vapours and ice. Here the water is moved from one reservoir to other like from river to ocean, or it may be from ocean to the atmosphere by some physical processes such as evaporation, condensation, precipitation, infiltration and subsurface flow. It exchanges heat energy resulting in alteration of temperature

Greenhouse gases constitute CO₂, CH₄, N₂O, C₂H₆, SO₂, CFC₁₁, CFC₁₂ andCFC₁₁₃.  It is a major air pollutant  and the actual reason of global warming. Due to increase of emission of greenhouse gases, the amount of heat that could be radiated back into space at night is reduced considerably  and  as a result the temperature of the earth is increased.

In primary treatment, different suspended and floating pollutants of water like plastic, paper, solid substances, etc. are passed through a system of screening and degrading, grease and scum removal, sedimentation, sludge thickening. The waste water passed through a series of wire-meshes of decreasing size where suspended and floating solid are maintained in a large water body in stagnant condition where sedimentation and precipitation occur.

Basin biome have different parts like continental depth of shelf & slope, ocean floor & trench so it constitutes different types of microscopic & macroscopic plants, varieties of invertebrates, & vertebrates. Taiga biome have number of lakes, annual precipitation below 25 cm, avg temperature 60⁰C (winter) & 20⁰C (summer) & constitutes . Few shrub, pines, mosses, ferns, maples, elk, deer, grouse, squirrel, pumas, lynx, etc. Vertical biome light can extend up to 200 mt. so it constitutes phytoplankton in photosynthetic form of microbes, algae, zooplanktons, tubiculous annelids, deep marine and bio- luminescent fishes. Chaparral biome covers Pacific coast of North America, Chilie, S. Africa & S. Australia with moderate temperature & humid air which constitutes evergreen vegetations, resinous plants, eucalyptus, insects, reptiles, rats, rabbits, deer, chipmunks etc. Tundra biome covers Asia, Europe, North America, during winter avg temperature is -570C or even below constitutes treeless, lichens, mosses, foxes, polar bear, shrew aves, snow owls, migratory birds, horse flies, etc.

Trickling of water does the process of passing waste water over stones or racks of plastic surface by gravity that creates an aerated surface resemble the rapid in the natural stream. In presence of oxygen, bacteria degrade organic matter and role of detritus feeding invertebrates in such microbial digestive system is a great importance.

Because detritus means debris or disintegrated substances, so here detritus matches with parts of dead animals and plants. Edaphic defines physical and chemical conditions of soil,  so here edaphic matches with pertaining to soil, ecotone is the transition region between two biome so here ecotone matches with transformation territory between two communities, Chresard defines water is available to the plants that is actually absorbed from soil, keystone is a species that constitutes a small proportion of total biomass within a community though they has great impact on the organization and survival of the community.

This method involves the preparation of wastes and decomposing the organic solid wastes by aerobic microorganisms. Waste is prearranged in order to isolate the materials, which can ot be composted so that the degradation process can be done more efficiently. Then these wastes are deposited in machinery in order to produce humus by biological degradation, which contains nitrogen, phosphorus, and potassium. After 3 weeks, the end products are treated mixed with additives and then it is ready for marketing.

Landfill is the cheapest method of disposing waste, which requires a particular amount of land. It needs 75% of total estimation of waste management. In this method, the disposal is distributed over the selected land in a thin layer and then bulldozer is used to make it compact. When 3m of waste has been spread out, then a clean layer of land is covered which then also compacted.

In Ex-situ conservation, threatened species are actually move on to special preservation from their natural habitat. Gene bank is an institute that keep group of feasible seeds, live developing plants, tissue cultivation and chilled germplasm having maximum genetic variability. Hot spot is a region with high endemism and  rich in level of species. In-situ conservation threatened species are conserved in their natural habitat in order to conserve the entire ecosystem. Offsite collection is the collection of known wild and domestic species from zoological park, safari, wild life and  botanical garden.

Carbon cycle was invented by Joseph Priestley and Antoine Lavoisier, and later popularised by Humphry Davy. It is the most essential cycle where carbon is recycled and reused throughout the biosphere. Basically carbon is exchanged between hydrosphere and atmosphere.

Volcanic eruption, dead and decay in organic matter causes changes of pH in water and may be acidic. Presence of dissolved gasses beyond their normal concentration affect physical characteristics of water and is harmful for aquatic life.

Domestic sewage and animal waste are the sources (anthropogenic source) of pathogen class of water pollutants, which cause different water borne diseases like cholera, typhoid, hepatitis, etc.