Is Water Pollution A Bad Thing?

The briefing of a large subject is an enviable task when the subject is as large as the present one. Everyone knows that pollution is “bad thing” or Pollution is the introduction by man into the environment of substances or energy liable to cause hazards to human health, harm to living resources and ecological systems damage to structure or amenity or interference with legitimate uses of the environment. Pollution is divided into three main categories i.e., air pollution, water pollution and land pollution. Although there is only ‘one pollution' that is water pollution because every type of pollutant, whether it belong to the air, or land tends to end up in the ocean and marine pollution is a major threat to the health of millions of people,

Degradable wastes are organic materials are subject to bacterial attack which is an oxidative process. Since bacteria play an important role in food chain. Therefore the additions of organic material in to the sea represent an enrichment of the ecosystem. Inorganic compounds like carbon dioxide water and ammonia are produce as a result of breakdown of organic material. If the input of wastes increases then organic material accumulate and bacteria activity increase until the oxidative processes of degradation outrun the supply of oxygen dissolved in water. The excess use of oxygen leading to deoxygenation and hydrogen sulfide and methane gases become produce that have a great impact on both plants and animals, sometime die. In degradable wastes urban sewage, agricultural wastes, oil spillages, food and brewing processing wastes, textile mills and chemical industries wastes are included.

2. Dissipating wastes are those industrial discharges into the sea that very quickly diluted to harmless levels after they enter the water.

3. Conservative wastes are heavy metals, halogenated hydrocarbons and radioactive isotopes. This type of wastes is not subject to bacterial attack and therefore they are essentially permanent addition in to the sea, regarded as serious

None has a pretreatment facility except Steel mill and effluents from all these areas drain their untreated effluents into the municipal sewers. Thus, untreated sewage from the industries flows into the municipal sewer system, from where the combined effluents, through the Lyari and Malir Rivers, outfall into the sea. The Lyari River brings 120 mgd of municipal and industrial waste waters with an organic load of 2,000 tons of BOD/day. About 1,200 tons, i.e., 60% is contributed by the industries, with textiles producing the major share (90%) followed by the chemical industries (8%). The Malir River discharges 42 mgd into Gizri Creek bringing 1,500 tons of BOD/day. All these industries contributes approximately 99% of the total industrial