Addressing thermal water pollution

To handle large quantities of heated effluents, large tanks or reservoirs should be constructed to retain the water

Water can be heated through various ways – thermal or nuclear power plants, industrial effluents, sewage effluents and bio-chemical activity. Heated or thermal water is ecologically harmful for water ecosystem. In an aquatic system, temperature is an important factor which affects physic-chemical parameters of water quality as well as plants, animals and microbial life considerably.

Aquatic life is usually well adjusted to diurnal and seasonal changes in temperatures which occur naturally. Man-made changes in temperature of water often cause adverse changes which damage its utility and productivity.

In Bangladesh, water bodies – river, wetland, lake, beel, and canal are guiltless sufferer of industrial effluents and thermal water. Approximately 250 industries are discharging chemical effluents into water bodies. Each day 4000 tons solid waste & 22,000 tons tannery waste mixes with water in 4 rivers of Dhaka city. Canals in Dhaka city are losing its ecological stability. Rivers across the sundarban has also fallen into the same condition by unplanned industries.

Heated water normally escalates the existing temperature of water bodies. Living organisms within the water bodies are unfavorably affected by the additional heat. Most of the biota in aquatic system consists of poikilotherms whose body temperature is regulated by the temperature of the outside environment. Metabolic reactions in a biological system are speeded up higher temperatures which cause an increased demand of oxygen. As a result, increased irritability and swimming speed are observed among fishes and micro-organisms.

Heated waters are less dense. Lower amount of oxygen escalates the water temperature. Also, rise in water temperature causes the excess oxygen to form bubbles. Gas bubbles may be formed within the bodies of aquatic organisms. For most of the fishes, these bubbles are injurious as they adhere to the gills and block oxygen intake. This has virtually the effect of forcing the fishes to breathe in air which they cannot. This phenomenon is known as gas-bubbles disease which chokes the fishes to death. In addition, at higher temperatures – pathogenic forms become more vigorous while plants and animals become simple prey to various types of infections.

If the heated waters contain some organic matter, microbial activity is stepped up for its degradation. Assorted toxic chemicals – organic acids, hydrocarbon sulphide, ammonia etc. accumulate and smash up the plant and animal life in water bodies.

The elimination of aquatic species or their migration to the other places leaves the tolerant forms.  As a result, the diversity in species composition is lost. Number of species – snakes, frogs, cyanobacteria, phytoplankton, and zooplankton present in aquatic system are mislaid their life.

There is a little one can do about thermal pollution except to wait and allow the waters to cool down to biologically harmless temperatures before being discharged into aquatic ecosystem. For liquid wastes and effluents disposal, industries have to erect waste and effluent treatment plant.  It is now urgent for every red and orange colored factory to follow the rules and regulations provided by department of environment through environmental laws and policies in order to save water bodies and aquatic ecosystem.

Apart from that, to handle large quantities of heated effluents, large tanks or reservoirs should be constructed to retain the water for a short time. After the water have cooled down a tolerate temperature, then may be released into natural water bodies. It is advisable to discharge the heated waters into some lotic system, wherein active churning occurs due to flow of water which causes rapid cooling, instead of a lentic system.

The writer is environment analyst and Associate Member of Bangladesh Economic Association

 

Addressing thermal water pollution

To handle large quantities of heated effluents, large tanks or reservoirs should be constructed to retain the water

Water can be heated through various ways thermal or nuclear power plants, industrial effluents, sewage effluents and bio-chemical activity. Heated or thermal water is ecologically harmful for water ecosystem. In an aquatic system, temperature is an important factor which affects physic-chemical parameters of water quality as well as plants, animals and microbial life considerably. Aquatic life is usually well adjusted to diurnal and seasonal changes in temperatures which occur naturally. Man-made changes in temperature of water often cause adverse changes which damage its utility and productivity. In Bangladesh, water bodies river, wetland, lake, beel, and canal are guiltless sufferer of industrial effluents and thermal water. Approximately 250 industries are discharging chemical effluents into water bodies. Each day 4000 tons solid waste 22,000 tons tannery waste mixes with water in 4 rivers of Dhaka city. Canals in Dhaka city are losing its ecological stability. Rivers across the sundarban has also fallen into the same condition by unplanned industries. Heated water normally escalates the existing temperature of water bodies. Living organisms within the water bodies are unfavorably affected by the additional heat. Most of the biota in aquatic system consists of poikilotherms whose body temperature is regulated by the temperature of the outside environment. Metabolic reactions in a biological system are speeded up higher temperatures which cause an increased demand of oxygen. As a result, increased irritability and swimming speed are observed among fishes and micro-organisms. Heated waters are less dense. Lower amount of oxygen escalates the water temperature. Also, rise in water temperature causes the excess oxygen to form bubbles. Gas bubbles may be formed within the bodies of aquatic organisms. For most of the fishes, these bubbles are injurious as they adhere to the gills and block oxygen intake. This has virtually the effect of forcing the fishes to breathe in air which they cannot. This phenomenon is known as gas-bubbles disease which chokes the fishes to death. In addition, at higher temperatures pathogenic forms become more vigorous while plants and animals become simple prey to various types of infections. If the heated waters contain some organic matter, microbial activity is stepped up for its degradation. Assorted toxic chemicals organic acids, hydrocarbon sulphide, ammonia etc. accumulate and smash up the plant and animal life in water bodies. The elimination of aquatic species or their migration to the other places leaves the tolerant forms. As a result, the diversity in species composition is lost. Number of species snakes, frogs, cyanobacteria, phytoplankton, and zooplankton present in aquatic system are mislaid their life. There is a little one can do about thermal pollution except to wait and allow the waters to cool down to biologically harmless temperatures before being discharged into aquatic ecosystem. For liquid wastes and effluents disposal, industries have to erect waste and effluent treatment plant. It is now urgent for every red and orange colored factory to follow the rules and regulations provided by department of environment through environmental laws and policies in order to save water bodies and aquatic ecosystem. Apart from that, to handle large quantities of heated effluents, large tanks or reservoirs should be constructed to retain the water for a short time. After the water have cooled down a tolerate temperature, then may be released into natural water bodies. It is advisable to discharge the heated waters into some lotic system, wherein active churning occurs due to flow of water which causes rapid cooling, instead of a lentic system. The writer is environment analyst and Associate Member of Bangladesh Economic Association