Environmental Science

LESSON 28. Agricultural Wastes

Effects: If more C: N ratio, wastes like paddy husk or straw may cause immobilization of nutrients if applied on the fields. It occupies to large land areas if not properly disposed.

MANAGEMENT

WASTE TO ENERGY

i) Gasification: It is the process in which chemical decomposition of biomass takes place in the presence of controlled amounts of oxygen, producing a gas. This gas is cleaned and used in an internal combustion engine to produce electric power. Without clean up also, the gas can be used in boilers to produce electric power. This technology is highly suited to generate electric power from agrl wastes like rice husks, groundnut shells etc.

ii) Pyroalysis: It is similar to gasification except that the chemical decomposition of biomass wastes take place in the absence or reduced presence of O2 at high temp. Mixtures of gases result from decomposition including H2, NH4 Co, CO2 depending on the organic nature of waste matter. This gas used for power generation.

2. Biogas production: Animal wastes, food processing wastes and other organic matter are decomposed anaerobically to produce a gas called biogas. It contains methane and CO2. The methane can provide gas for domestic use. The byproduct of this technology is slurry, settled out at the bottom of the digester. This can be used as manure.

3. Agricultural waste like corn cobs, paddy husk, bagasse of sugarcane, waste of

wheat, rice and other cereals, cotton stalks, coconut wastes, jute waste etc can be used in making of paper and hard board.

Waste production can be minimized by adopting the 3 R’s principle: Reduce, Reuse and Recycle

• Reduce the amount and toxicity of garbage and trash that you discard.

• Reuse containers and try to repair things that are broken.

• Recycle products wherever possible, which includes buying recycled products i.e. recycled paper books, paper bags etc.

These are processes that involve integrated waste management practices (IWM).

They can reduce the wastes generated by approximately 50 %.

Reduce (Waste prevention): Waste prevention, or “source reduction,” means

consuming and discarding less, is a successful method of reducing waste generation.

Backyard composting, double sided copying of papers, purchasing durable, long- lasting environmentally friendly goods; products and packaging that are free of toxics, redesigning products to use less raw material production and transport packaging reduction by industries are the normal practices used and have yielded substantial environmental benefits. Source reduction prevents emissions of many greenhouse gases, reduces pollutants thereby saves energy, conserves resources, and reduces wastes for new landfills and combustors. It reduces the generation of waste and is generally preferred method of waste management that goes a long way toward saving the environment.

Re-use: Re-use is the process, which involves reusing items by repairing them, donating them to charity and community groups, or selling them. Reusing products is an alternative to recycling because the item does not need to be reprocessed for its use again. Using durable glassware, steel using cloth napkins or towels, reusing bottles, reusing boxes, purchasing refillable pens and pencils are suggested.

Recycling: The process of recycling, including composting, has diverted several million tons of material away from disposal. Recycled materials include batteries, recycled at a rate of 93%, paper and paperboard at 48%, and yard trimmings at 56%. These materials and others may be recycled through drop off centers, buy-back programs, and deposit systems. Recycling prevents the emission of many greenhouse gases that affect global climate, water pollutants, saves energy, supplies valuable raw materials to industry, creates jobs, stimulates the development of greener technologies, conserves resources for our children’s future, and reduces the need for new landfills and combustors. For example, by recycling of solid waste in 1996, the United States prevented the release of 33 million tons of carbon into the air roughly the amount emitted annually by 25 million cars. Recycling can create valuable resources and it generates a host of environmental, financial, and social benefits. Materials like glass, metal, plastics, and paper are collected, separated and sent to processing centers where they are processed into new products. The advantages of recycling are: it conserves resources for future generation, prevents emissions of greenhouse gases and pollutants, saves energy, supplies valuable raw materials to industries, stimulates the development of greener technologies, reduces the need for new landfills and incinerators.

6.9 DISASTER MANAGEMENT

Natural calamities of different types and intensities affect nations all over the world. The Indian subcontinent is very vulnerable to droughts, floods, cyclones,

earthquakes, landslides, and forest fires. While not all natural calamities can be predicted and prevented, a state of preparedness and ability to respond quickly to natural calamity can considerably mitigate loss of life and property and human suffering, and restore normalcy at the earliest.

‘Post Disaster Management’ and ‘Disaster Mitigation’ :

The post disaster approach towards dealing with natural disasters, involving problems such as evacuation, warnings, communications, search and rescue, fire- fighting, medical and psychiatric assistance, provision of relief, shelter, etc, is generally referred to as ‘Post Disaster Management’ . It is a primarily a ‘Reactive Mechanism’ to the natural disasters.

‘Mitigation’ means lessening the negative impact of the natural hazards. It is defined as sustained action taken to reduce long term vulnerability of human life and the recovery property to natural hazards. While the preparatory response and the recovery phases of emergency management relate to specific events mitigation activities have the potential to produce repetitive benefits over time. It is a ‘Proactive approach’ to natural disasters.

Multidisciplinary and Multi- sectoral nature of Disaster Management:

Disaster management is a multidisciplinary area in which a wide range of issues

that range from forecasting, warning, evacuation, search and rescue, relief, reconstruction and rehabilitation are included. It is also mult-sectoral as it involves administrators, scientists, planners, volunteers and communities.

Guidelines for effective management of mitigation program.

1. Pre- disaster mitigation can help in ensuring faster recovery from the impacts of disasters.

2. Mitigation measures must ensure protection of the natural and cultural assets of the community.

3. Hazard reduction methods must take into account the various hazards faced by the affected community & their desires and priorities

4. Any mitigation programme must also ensure an effective partnership between the Govt, Scientific, private sector, NGOs and the community

The main elements of a mitigation strategy

1. Risk assessment and Vulnerability analysis: This involves the identification of hotspot areas of prime concern, collection of information on past natural hazards, information on the population and infrastructure.

2. Applied research and technology transfer: There is a need to establish or upgrade observation equipment and networks, monitor the hazardous properly, improve the quality of forecasting and warning.

3. Public awareness and training: Training to be given to officials & staff of various Departments involved in state & district level of the Government and NGOs.

4. Institutional mechanisms: There is need to emphasize on proactive and predisaster measures rather than post-disaster response. It is thus essential to have a permanent administrative structure which can monitor the developmental activities across departments and provides suggestions for necessary mitigation measures. The national disaster management centre (NDMC) can perform such task. Professional like architects, structural engineers, doctors and chemical engineers who are involved with management of hazardous chemicals, can be asked to form groups that can design specific mitigation measures.

5. Incentives and resources for mitigation: Provide stable source of funding for all mitigation programs.

6. Land use planning and regulations .

7. Hazard resistant design and construction.

8. Structural and Constructional reinforcement of existing buildings: This can be done by the insertion of walls, specially on chored frames, construction of new frame systems, designing residential electrical equipment above flood level, designing water storage tanks to be able to withstand cyclonic winds, earthquakes & floods.

Some of the causes, effects and mitigation measures of the disasters commonly occurring in India are detailed below:

Floods : Floods can be caused by natural, ecological or anthropogenic factors either individually or as a combined result. Human activities such as deforestation and shifting cultivation can also contribute to floods. Heavy rainfall is the main cause of floods in the rivers. The breaches to tanks and reservoirs due to inflow of large quantities of water from excessive rainfall also result in floods. Floods occur sometimes in a flash due to intensive rains at the time of cyclones. Next to Bangladesh, India is the most flood – affected country in the world. The west coast of India has an advantage of having it has western ghats with thick forests which act as natural buffer to floods.

Effects: floods cause heavy suffering to people living in low lying areas because the houses and the properties are inundated or washed away. Most of the victims are rural folks who are economically poor. Floods also damage standing crops and livestock.

The mitigation measures for floods include both structural and non structural measures.

The structural measures include

1. Reservoirs for impounding monsoon flows to be released in a regular manner after the peak flood flow passes.

2. Prevention of over –bank spilling by the construction of embarkments and flood walls

3. Improvement of flow conditions in the channel and anti erosion measures.

4. Improved drainage

The non structural measures include

1. Flood-plain management such as Flood Plain zoning and flood proofing including disaster preparedness

2. Maintaining wet lands

3. Flood forecasting and warning services

4. Disaster relief and public health measures.

5. Flood insurance

Case study

Since 2006, Mumbai faces flooding in most of the Suburban Locations Like

Andheri, Dahisar, Goregaon, Malad Subway, Milan Subway, Santacruz, Chembur,Dombivali, Worli etc which are low line areas and also highly affected during Monsoon and Heavy rainfall. Because of Unstable weather, Mismanagement of Natural Resources by People, Old or No proper drainage systems and Real Estate development, Mumbai is underwater Mostly every year even if Bombay Municipal Corporation tries it level best to help the disaster.

Flood 2006 will never be forgotten by any person who was in Mumbai during that day, Everything was like stand Still, the Transportation, Private Vehicles, Mobile Services and all major communication and transport channels stopped. Still salute to mumbaikers for the Humanity shown that day by helping each others at there level best. Someone helped giving Biscuits and Few by preparing whatever fast food like Vada pav, samosas etc. Lots of NGO’s and Private organizations came up for the help. All this happened within couple of hours of very heavy rain in Mumbai. Many lost there lifes and many saved it loosing just there belongings like Mobiles and bags etc. Every person stayed where they were for next 24 hours.

Flood 2007 of Mumbai was not as hard as 2006, few of the slums and people stying in low line ground floor locations faced terrible problems. People of Mumbai are now tough enough to face such flooding disaster’s and bomb blasts and Epidemics and Diseases because of flood. Mumbai In 2008 and 2009 Flooding in Mumbai is comparatively low because of not so heavy rainfall. Almost opposite situation like cloud seeding experiments are undertaken to save mumbai from low rainfall.

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Earth quakes: An abrupt and tremendous release of energy stored in the rocks and the earth’s crust through the action of tectonic process is described as an earth quake. Some areas on the planet earth are so located that more than one tectonic plate constantly change against one another and an earthquake can result when one or more of these plates move against the others at high speed. In certain regions of earth, earth quakes occur with regularity. In India,Assam and the Himalayan regions are more infested with earthquakes. Earthquake that occurred in 2001 in Gujarat taking a toll of 30,000 people was major one. The intensity of earth quake is measured on Richter scale. As of now there is no way of predicting an earth quake. Earthquake by themselves do not cause casualties but the houses collapse due to poor construction. The construction of quake-proof houses may reduce human loss but it may be economically difficult for poor countries. The Government of countries which are quake prone should ensure that the infrastructure could withstand earth quakes.

On 26 January 2001 an earthquake registering 7.9 on the Richter scale

devastated the Indian state of Gujurat. It was the second largest recorded earthquake in India, the largest being in 1737, and was the worst natural disaster in India in more than 50 years. The earthquake struck at approximately 8.46am local time, its epicentre located 80 kilometres north-east of the city of Bhuj .The place in the earth's crust where an earthquake occurs is known as the focus. The epicentre of an earthquake is the place directly above the focus. The shock waves or tremors from the Gujurat earthquake lasted about two minutes, followed by aftershocks for more than a month. The scale of the impact of the earthquake is almost impossible to comprehend. The shock or seismic waves spread out in a 700 kilometre circumference from the epicentre, and within this

area the devastation was immense. There were more than 20,000 deaths and 167,000 people injured. Four districts of Gujurat lay in ruin and altogether, 21 districts were affected. Around 300,000 families and at least 3 million children aged 14 and under were affected. Around 600,000 people were left homeless. In the city of Bhuj, more than 3,000 inhabitants of the city lost their lives, the main hospital was crushed and close to 90% of the buildings was destroyed. Nothing was left of the town of Bhachau. The town resembled a quarry. Few structures remained standing.

Cyclones: Cyclone is a meteorological phenomena of intense depressions forming over the open oceans and moving towards the land on the shore. In reaching the shores, it moves into the interior of the land or along the shorelines. The cyclone once formed may be active from days to weeks and affects many areas Globally North Westt pacific regions are more prone to cyclones. The Indian Ocean is one of the six major cyclone prone regions of the world. India has a long coastline of 5700 kms, which is exposed to tropical cyclones arising in the Bay of Bengal and the Arabian Sea. The eastern coastline is more prone to cyclones as it is hit by about 80 percent of the total cyclones generated in the region. In India, cyclones originating from Bay of Bengal are more in number and intensity. In India, cyclones occur usually between April and May and also between October and December. The damage depends on the intensity of cyclone, the damage to human life, crops, settlements, roads, communications, tanks, canals, and livestock; sometimes, their occurrence slow down the developmental activities of the areas.

Mitigation measures are:

• Installation of early warning systems

• Developing communication infrastructure

• Developing shelter belts

• Construction of permanent houses

• Training and education on land use control and settlement planning.

LAND SLIDES: are recurring phenomena in Himalayan region. and western ghats It is a geological process which includes a wide range of mass movements, such as rock falls, deep failure of slopes and shallow debris flows. Although gravity action on an over steepened slope is the primary reason for a landslide, there are other contributing factors affecting the original slope stability erosion by rivers, glaciers, or ocean waves create over steepened slopes. In recent years, however, intensive construction activity and the destabilizing forces of nature have aggravated the problem. Landslides occur as a result of changes on the slope, sudden or gradual either in its composition, structure, hydrology or vegetation. The changes can be due to geology, climate, weathering, changing land use and earth quakes.

• Rock and soil slopes are weakened through saturation by snowmelt or heavy rains, earthquakes create stresses that make weak slopes fail.

• Volcanic eruptions produce loose ash deposits,

• Vibrations from traffic, machinery, thunder and blasting can trigger weak slopes

• Groundwater pressure acting to destabilize the slope

• Excess weight from accumulation of rain or snow, stockpiling of rock or ore

from waste piles, or from man- made structures may stress weak slopes to failure and other structures.

Measures to prevent land slides are drainage measures, erosion control measures such as bamboo check dams, terracing, jute and coir netting and rock fall control measures such as grass plantation, vegetated dry masonry walls, preventing deforestation and improving forestation. A significant reduction in the hazards caused by land slides can be achieved by preventing the exposure of population and by physically controlling the land slides.

TSUNAMI The term Tsunami comes from the Japanese language, meaning harbor (tsu) and wave (nami). A Tsunami is generated when the sea floor abruptly deforms and vertically displaces the overlying water. It is the wave disturbance that rapidly displaces a large mass of water like an under sea earth quake, volcanic eruption or submarine land slide. Tectonic earthquakes are a particular kind of earthquakes that are associated with earth’s crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position. Waves are formed as the displaced water mass, which acts under the influence of gravity attempts to regain its equilibrium. When large areas of the sea floor elevate or subside, a tsunami can be created. Tsunami wave can travel at the speed of a commercial jet plane, over 800 km/h. they can move from one side of the pacific ocean to the other in less than a day. The waves can be extremely dangerous and damaging when they reach the shore. The wave travels across the ocean at speed of 500-1000 km/ha. As the wave approaches the land, it compresses some times upto a highest of 30mts and the sheer weight of water is enough the crush the objects in its path, often reducing the building to their foundations and scouring exposed ground to the bed rock. When there is a tsunami warning:

1. If you are at home and there is a tsunami warning, you should make sure your entire family is aware of the tsunami. Your family should evacuate your house if you live in a tsunami evacuation zone.

2. If you are at the beach or near the ocean and you feel the earth shake, move immediately to higher ground. Do not wait for a tsunami warning to be announced.

3. If you are on a ship or boat, do not return to port if you are at sea and a tsunami warning has been issued for your area. Tsunami can cause rapid changes in water level and unpredictable dangerous current in harbours and ports.

On the morning of Sunday, 26 December 2004, there was a severe earthquake in the Indian Ocean off the coast of northern Sumatra, Indonesia. The earthquake measured 9.0 on the Richter scale and was followed by aftershocks ranging from 6.3 to 7.0 in severity in a zone 1,000 kilometres north to the Andaman Islands. The underwater earthquake also resulted in a powerful tsunami ('soo-na-mi', from the Japanese words meaning 'harbour wave'). The wave travelled quickly under the ocean, building to a wall of water up to 10 metres high when it reached the shallow coastal waters and causing massive destruction when it hit land. Without an effective warning system and disaster plan, many people did not know to move quickly to higher ground to escape the wave and its load of debris. In some places the sea receded for hundreds of metres before the wave rushed in. Curious people looking at this strange occurrence from the beaches did not recognise this as a sign of danger, and as a result were killed by the tsunami. The tsunami caused extraordinary damage. The death toll was put at roughly 187,000, with nearly 43,000 missing and many hundreds of thousands injured and suffering trauma and the grief of losing family members, their homes and their livelihoods. Countries lost people

with the knowledge and skills that were needed for their ongoing development. Roads, bridges, water and electricity supplies, health centres and schools were destroyed. The landscape was altered unrecognisably, with some areas lifted high out of the water while others were washed entirely away. Debris and waste were scattered widely and salt inundated farmland and underground water supplies.

One of the most severely affected areas was that closest to the epicentre, the province of Aceh on Sumatra,Indonesia. More than 130,000 people died and 36,786 were missing. The highest tolls were among the women and children who were in the low lying coastal areas while their husbands were at sea fishing. Over 800 kilometres of coast was severely affected, often up to five kilometres inland. At least 654 villages were damaged or destroyed, more than 500,000 people lost their homes, and more than 150,000 children were left without schools. To add to the devastation an earthquake measuring 8.7 on the Richter scale struck the west coast of Sumatra near the island of Nias on 28 March 2005.

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