Projects World

Although Britain is relatively rich in natural aggregate reserves, planning approvals to develop new quarries are running at about half the rate of aggregate extraction. The use of secondary materials, such as recycled aggregate, might not create a major course of aggregate but if secondary material were used in less demanding situations, the quantity of natural aggregate required by the construction industry would be reduced.

This dissertation reports mainly on laboratory tests conducted on crushed concrete and demolition debris to examine the potential use of these materials in new construction. Standard aggregate tests were conducted on the materials to check their compliance with the Specification for Highway Works (1986), particularly for use as aggregate in road sub-base layers.

A more detailed examination of the aggregates was conducted with regard to CBR, shear strength and frost susceptibility where the influences of moisture content, density and particle packing on these properties were investigated. One part of the study involved examining the use of recycled aggregate as the coarse aggregate fraction in new concrete.

An analysis of the shear strength data was conducted using the dilatancy index defined by Bolton (1986). From the frost susceptibility results, it was concluded that further work would be required in this area to determine the main factors which influence the frost heave of recycled aggregates. The recycled aggregate concrete compared well with the natural aggregate concrete and appeared to be of superior quality than that produced in other research.

During the study, it became evident that the recycled aggregates could perform as well as limestone in most cases and therefore could be considered for many potential uses. Some recommendations are presented at the end of this dissertation for the development of a standard on recycled materials which would help to promote the use of recycled aggregates in the construction industry in Britain.

This study examines the dynamic instability known as flutter using a two-degree-of-freedom airfoil section model in both quasi-steady and unsteady flow. It explains the fundamental forces and moments involved in the bending-torsion flutter of an airfoil section, and demonstrates a solution method for determining the critical flutter frequency and speed for both flow cases.

Additionally, through the use of a programmed Mathcad 11 worksheet, it evaluates the flutter characteristics of six example sections, illustrating the effects of the elastic, inertial and aerodynamic properties of an airfoil section.

For each section, a parametric study of the effect of the section Center of Gravity position along the section chord is performed. The flutter frequency and speed are calculated using both quasi-steady and unsteady aerodynamic forces and moments, and the results compared. Software used was MathSoft Mathcad 11, Microsoft Word and Intergraph Smart Sketch LE.

This thesis is carried out with the aim of identifying if, and how, low-cost airline services have their effects on planning issues. Low-cost airlines have set new trends in the travel market and induced air travel demands without competition with established airlines: creating new travel networks with new entry points in countries in Europe.

The development of this network is apparently grounded in the expansion of the European Union and its policies. This was also obviously present in the development of the case studies. These case studies illustrated that low-cost airlines have created a complementary system in the region which enhances theoretical network ideas.

Furthermore, it becomes more than clear that low-cost services attract passengers from larger distances and therewith have a more spread out effect to the greater region instead of what is often expected to be to the benefit for the locality. That is also why the perceptions between the adjacent town and the region differ, as respectively opportunity and support.

The conclusion of the thesis is in the end that low-cost airlines do have an effect on planning issues, though it is indirectly with more reaction from the locality but rather more meaning to the region. The implications for planning are presented and a few directions are discussed on how to handle the phenomenon and what the future might hold for this concept.

The aim of this thesis was to study the load bearing capacity of anchor plates, used for anchorage to concrete located at nuclear facilities. Two different type of anchor plates were examined, which together constitute the majority of the anchor plates used at Forsmark nuclear facility in Sweden.The first is a cast-in-place anchor plate with headed studs and the second is a post-installed anchor plate which uses sleevetype expansion anchors. Hence, anchors with both a mechanical or a frictional interlock to the concrete were examined.

The main analysis tool was the finite element method, through the use of the two commercially available software packages ABAQUS and ADINA and their non-linear material models for concrete and steel.As a first step, the numerical methods were verified against experimental results from the literature. However, these only concern single anchors. The results from the verifications were then used to build the finite element models of the anchor plates. These were then subjected to different load combinations with the purpose to find the ultimate load capacity. Failure loads from the finite element analyses were then compared to the corresponding loads calculated according to the new European technical specification SIS-CEN/TS.

Most of the failure loads from the numerical analyses were higher than the loads obtained from the technical specification, although in some cases the numerical results were lower than the technical specification value. However, many conservative assumptions regarding the finite element models were made, hence there might still be an overcapacity present.All analyses that underestimate the failure load were limited to large and slender anchor plates, which exhibit an extensive bending of the steel plate. The bending of the steel plate induce shear forces on the anchors, which leads to a lower tensile capacity.

In design codes, which assume rigid steel plates, this phenomenon is neglected. The failure loads from all different load combinations analysed were then used to develop failure envelopes as a demonstration of a useful technique, which can be utilised in the design process of complex load cases.

Shallow offshore foundations, which achieve their stability through the foundation bearing on the seabed, can in most applications be idealised as large rigid circular footings subjected to vertical, horizontal and moment loading.A small strain linear-elastic perfectly-plastic three- dimensional finite element program was developed to analyse this combined loading problem.

The selection of a suitable three-dimensional finite element for accurate and computationally efficient analysis was based on the element’s ability to model incompressible soil conditions, using exact numerical integration. A new approach for evaluating element suitability is developed and is quantified in terms of the parameter free degrees-of-freedom (equal to the degrees-of-freedom minus the incompressibility constraints).

The tetrahedron family of three- dimensional elements is found to be in general more suitable and computationally efficient than the Serendipity and Lagrangian cube families. The 20-node quadratic strain tetrahedron is adopted for all analyses presented in this thesis.

For combined loading, most of the available elastic numerical analyses also examine the effect of footings embedment from three cases of embedment geometry. This demonstrates that the increase in footing stiffness (reduction in displacement) due to embedment for horizontal and moment loading is developed at shallower depths, and has a greater magnitude, than for vertical loading.

The stability of a rough rigid circular footing placed on the surface of an undrained clay is examined. Zero thickness interface elements, despite experiencing some numerical instability problems, were found to model the footing-soil interaction better than conventional continuum elements. However, application of interface elements to footings which can lose contact with the soil, under moment loading conditions, resulted in numerical instability of the solution. A simpler model was therefore used to define the shape of the three-dimensional failure envelope at high vertical load. Comparisons with the semi-empirical inclination factors of bearing capacity solutions are included.

Prestressing and the advent of high strength materials enable the construction of more slender floor slabs with lower values of natural frequency and damping. Under certain circumstances, the vibrations due to forcing frequencies of normal human activities can be annoying to the occupants.Since the occupants are both the source and the sensor, the vibration cannot be isolated and must be controlled by the structural system. At present, there is a limited knowledge about the overall dynamic characteristics of such concrete slabs, including contributions from individual structural and non-structural components.

An extensive programme of modal testing on a slender one-way spanning 50% scaled post-tensioned concrete slab is described. Testing was performed using electromagnetic shaker, instrumented hammer, heeldrop, and walking excitations, to determine full floor dynamic characteristics. The tests investigated the effect on vibration performance of the level of prestress, and of various non-structural additions, including vibration absorbers and effect of occupants.

It was found that an increase in prestressing force increases natural frequency and decreases damping due to closing up of microcracks. A model is presented to reflect these changes in terms of effective second moment of area. Cantilever partition tests showed energy to dissipate by swaying, and full-height partitions were seen to act as line supports leading to a significant stiffening of the slab.

Analytical models are derived for both forms of partitions. Tests with false floors showed a significantly higher increase in slab damping when the floor panels rested on the pedestals, as opposed to being rigidly fixed to them. Although the addition of viscoelastic screed layers were not seen to have great effect in damping, an analytical model is derived which shows the advantages of using such layers. A TMD system was designed and installed on the floor, using plywood sheets, which led to a reduction in vibration response by as much as 80%. A theoretical model is derived to represent the TMD results and a design criterion is suggested.

Finally, the effect of human-structure interaction is investigated. An analytical model shows the natural frequency of the body to be 10.43Hz with a damping of 50%. Results are also reported of tests on a full-scale field slab, confirming some of the findings of the model slab experiments. Broadly, the results show that contrary to popular belief, merely the presence of non-structural components does not necessarily enhance the dynamic behaviour of the system. The design of these components and nature of their installation are important factors affecting their contribution to the overall floor vibrational behaviour.

The seasonal snowpack dynamics of the Siberian mountains and plains play a critical role in the freshwater fluxes of northern rivers into the Arctic Ocean. This study is part of a larger project seeking to quantify the freshwater discharge of the Ob River (Russia) to the Arctic, using satellite remote sensing and hydrologic modeling.

Subareas of the Tom River watershed (a tributary to the Ob) are delineated using digital elevation and land cover data within a Geographical Information System (GIS). Daily satellite snow images for 1981 to 1985 are analyzed with the GIS to give time series of percent snow cover for each subarea.

These time series are compared with model-generated snow cover visually and statistically, allowing spatially distributed evaluation of the model’s snow sub-routines. This study will contribute to improved models and better understanding of important and climate-sensitive snow processes and freshwater supply in Arctic river basins.

This thesis uses the Minimum Norm Quadratic Unbiased Estimation (MINQUE) to estimate standard deviation of observations of a total station. Different setups are created by altering the number of stations and targets and their relative position in the network to study the effect that different setups have to the estimation and define what are important to minimize the effect of the setup to the estimation.

A lot of research has been done around methods for estimation of variance and covariance components, since it is useful in many fields. Various approaches exists to solve the problem of variance components estimation. Geodesy is a special case, were their often is a a prior knowledge of how well an instrument is able to record measurements. There is an ISO-standard for testing and verification of geodetic instrument but also an alternative approach the KTH-Total Station Check.

For the estimation three main types of setups were defined and used in the simulation. These main types were then altered to see how different changes to the setup effect the overall estimation. The alterations were changes in distance between station and targets, changes in vertical distance between stations and targets and the amount of observations carried out by adding more stations and targets to the setups.

The result of the simulations shows that the tested changes in the setups do effect the estimation. It was not possible to determine by how much for each change, because a change in vertical displacement also meant a change in angles and distance between the station and the target. Increasing the amount of stations and targets or one of them shows that standard deviation of the estimation becomes smaller. The effect can be seen independent of which type of setup that is used. The most important factor to how good the estimation will be is the amount of observations.

This master thesis is a study of test methods for determination of uplift resistance of fixed roof tiles, which currently are under preparation to become a European standard. This work also includes a study of wind load mechanisms for roof tiles.This is an important character sincce the existing wind loading codes in Scandinavia, Finland and Estonia does not consider these mechanisms and the draft prestandard does not give any guidance in how to calculate the wind load.

A study of the British wind loading code shows that the uplift loads that acts on roof tiles calculated with this method are about one third to half of the loads if calculated with normal wind loading code.

This research has been emphasized on integration of plants in skyscraper design which play a vital role for the energy conservation by the building as well as improving the living quality into these vertical cities. Throughout the work it has been studied to establish the necessity of planting to incorporate into skyscrapers, for the well being of our economy, society and the environment.

The rules and regulations in various countries have been studied. The provisions of integrate plants into skyscraper includes the four possible options like, Green roof, Green wall, Biofilter and Indoor potting plants which can be incorporate into the  design. Benefits and impacts have been studied in terms of energy savings and  indoor environmental qualities. For example green roof can reduce 50% of cooling  load; green wall can reduce 10 degree centigrade indoor temperature, where as biofilter and indoor plants purifies indoor air by 50% to 60%.

Available technologies for green installments, like complete, modular and vegetated blanket system for green roof; modular, freestanding and cable-rope system for green wall; active and passive system for biofilter and different types of indoor plants have been addressed here along with their examples and case studies.

At the end the recommendation shows that integration of plants into skyscrapers can change the micro and macro environment, climate, can restore the ecology and benefited to the economy. Results are the noticeable decrease in urban heat island, rapid reduction of energy consumption and cost, refreshing air for a healthy environment.

The 1994 Northridge and 1995 Kobe earthquakes, which were moderate in seismological terms, showed that many buildings were subjected to demolition or very expensive repairs because if severe damage in principle members, mainly in the column-beam connections. As a result, the development of dissipative systems was encouraged, which limit the damage parts to easily replaceable elements, in case of moderate earthquakes.

One such system is the knee braced frame. Knee braced frames are a modified form of cross bracing in which the brace is cut short and connected to the mid point of a knee element spanning between the adjacent beam and column. The key component is the knee element, which controls both the initial elastic stiffness of the frame, and the onset of yield and subsequent energy dissipation.

The knee elements are required to ensure energy absorption through repeated large deformations without suffering collapse or instability. This thesis describes the development of different knee element designs and their performance assessments. It is shown that the dissipative mechanism of the web yielding in shear is advantageous because it is independent of the moment distribution and it does not affect the connections and extends the dissipative zones to all its lengths. Extensive finite element modelling and experimental testing have been undertaken.

In the shear yielding mode excellent performance was achieved using standard hot rolled sections, modified by the addition of web stiffeners to prevent localised buckling failure. Weakening of the knee element’s webs so that it yields very early in an earthquake has potential benefit, but is shown to be unsafe as it promotes premature failure of the element.

A knee element model for non-linear dynamic analysis of an entire building has been developed. Time history analyses showed that knee braced frames with the developed knee element have a large global ductility and an outstanding performance.

Results obtained with different pushover analysis methods (Eurocode 8, FEMA-356 and ATC-40) have been compared to those obtained wit the time history analyses. Moreover FEMA-356 method, which includes a more accurate representation of the structure’s significant post-yield stiffness, gave the closest agreement with the time history analyses and is recommended for the design of knee braced frames.

This thesis describes in detail how a mobile Geographical Information System (GIS) was designed, implemented and evaluated for the prevailing circumstances of a land regularisation project in Lesotho in Southern Africa. The GIS was developed as an application for the Android platform, primarily with the tablet-computer format in mind, to be used for land registration field work.

The main purpose of the paper is to determine whether an adhoc mobile GIS solution can improve the efficiency of the field work as well as the integrity of the data collected in the field work of the land regularisation project in Lesotho. The aim is also to evaluate the performance and usefulness of modern tablet computers in this context.

The application was developed and tested on site in Lesotho on two tablet computers borrowed from Samsung Electronics AB in Sweden. After the development phase, the solution was later implemented on tablet computers of a different model for the remainder of the land regularisation project in Lesotho.

The design process started with a field visit where the work-flow of the project was analysed. From this a needs analysis were formed together with the management staff on site that served as a base for the development process. The development and implementation was then performed with continuous communication and evaluation with the personnel of the project. As the development progressed, the solution was also tested and evaluated continuously in the field work.

Not only did the solution perform well both software- and hardware-wise, despite strong sun from high altitudes and lack of internet connection in Lesotho, it also exceeded the expectations of the staff. The solution significantly improved the work environment for the field workers of the project and the efficiency was raised, according to the evaluation. A unified management staff concludes in the evaluation of this paper that they will consider using tablet computers together with an ad hoc application for the field work of their next project.

This study examines an innovative strategic operation for next day air package delivery. The proposed system, in which some packages are sorted twice at two distinct hubs before arriving at their destinations, is investigated for its potential savings.

A two-stage sorting operation is proposed and compared to the currently operated single-stage sorting operation. By considering the endogenous optimization of hub sorting and storage capacities, cost minimization models are developed for both operations and used for performance comparison. Two solution approaches are presented in this study, namely the Column Generation (CG) approach and the Genetic Algorithm (GA) approach.

The first method is implemented to optimize the problem by means of linear programming (LP) relaxation, in which the resulting model is then embedded into a branch-and-bound approach to generate an integer solution. However, for solving realistic problem sizes, the model is intractable with the conventional time-space formulation. Therefore, a Genetic Algorithm is developed for solving a large-scale problem. The GA solution representation is classified into two parts, a grouping representation for hub assignment and an aircraft route representation for aircraft route cycles. Several genetic operators are specifically developed based on the problem characteristics to facilitate the search. After optimizing the solution, we compare not only the potential cost saving from the proposed system, but also the system’s reliability based on its slack.

To provide some insights on the effects of two-stage operation, several factors are explored such as the location of regional hubs, single and multiple two-stage routings and aircraft mix. Sensitivity analyses are conducted under different inputs, including different demand levels, aircraft operating costs and hub operating costs. Additional statistics on aircraft utilization, hub capacity utilization, circuity factor, average transfers per package, and system slack gain/loss by commodity, are analyzed to elucidate the changes in system characteristics.

Concentrations of microorganisms and chemical components in groundwater are serious threats for groundwater resources sustainability and contribute to technical and health problems. Recent studies and reports in Gotland revealed huge concerns about water quality in the area.

In this study a range of methods such as GIS and statistical analysis including multivariate analysis and non-parametric analysis, have been used in order to identify natural and human factors which affect groundwater contamination. Main focus of the study was on using existing data and available databases in analyses. Consequently, several important factors such as land use, overlaying soil cover, soil thickness, bedrock, elevation, distance to deformation and fracture zones and slope were evaluated considering 8 variables including micro-organisms and chemical components.

The results clarified several significant factors which statistically affected the micro-biological and chemical components of groundwater. These relations can be used for development of risk maps which can be used in spatial planning.

This work deals with the bearing capacity of wood based I-joists Finite element models were analyzed to determine the bearing capacity of I-joists, using the finite element software Abaqus CAE.The purpose of this study is to compare the results from the developed FE-models with experimental results, and with a previously proposed design formula.To perform the analyses finite element models were created. The model consists of three parts:, the web (made of shell element), the flanges and steel plates used at the supports and loading points (made of solid elements).

To determine the bearing capacity of the I-joist two types of analyses were performed, a linear buckling analysis to check the risk of web buckling and a static (stress) analysis to check the risk of splitting of the flanges.

This study shows that the steel plate length, in some cases, has little or no impact on primarily the splitting load. Furthermore, the buckling load decreases as the depth of the beam increases, the influence of the depth being proportional to 1/h2. The depth of the beam has no impact on the risk of splitting of the flange.

By producing vegetables year-round, small-scale growers can increase their incomes and enhance the diets of their families and communities. Vegetable crops respond well to irrigation, which helps to improve yield and quality, and increases the efficiency of other inputs.

Simple, low-cost drip irrigation systems can ensure small-scale producers benefit from water resources. This 10-chapter manual provides basic, step-by-step procedures for installing simple drip irrigation systems for different crops, climates, and soils. It addresses common problems, provides troubleshooting and maintenance tips, and offers irrigation scheduling guidelines to avoid under- or over-irrigation.

Methods to determine soil types, water quality, water-holding capacity, crop coefficient, and crop water demand are illustrated. The information presented in this guide has been compiled from relevant literature, research and development projects, and is based on practical field experience.

This manual is intended as a guide for small-scale vegetable producers, and as a reference for extension agents to use in training and demonstrations. Agricultural input suppliers in rural and peri-urban areas may also find it a useful resource to support and promote drip irrigation.

/This study is intended as a contribution to the understanding of the influence structural changes has on urban transformation in housing domain, by focusing on mechanisms behind the upgrading as accidental model for regeneration of the collective housing. In particular, the aim is to do so in relation to a comparison between different operational scales on which process is carried out. The process is investigated at the city,neighborhood and street/square scale.

With the use of qualitative methods, such as interviews, in depth analysis of policies and regulations and observations, differences in manifestation of the regeneration on different scales are discovered. It is suggested that undefined strategy, indifferent attitude of local authorities, inconsistent legislative environment, disconnection between the operational scales and presence of the market as essential driving force of the process, results in asymmetric outcomes of upgrading, both in physical and social terms.

But on the other hand, in respect to wider political and economical environment in which regeneration happened, it is acknowledged that considerable housing stock is renovated and living standards are improved. The most critical issue in the process is proved to be the uneven awareness of the importance of the regeneration among the actors at different scales and consequently their performance in respect to it. Furthermore,influence of upgrading on the community life and social relation in the regenerated neighborhoods are totally neglected, which has for its consequences decreased use of common space between the buildings and erosion of existed communities.

It is proved also that fully market driven regeneration has rather regressive consequences on urban transformation in context of N is but in same time gives valuable lessons for improvement of the future upgrading as regeneration model for collective housing. Based on these lessons,adaptive policy changes are suggested and platform for further studies in system or process oriented urban regeneration and design is established. Thesis is organized as follows: first methodological approach is explained, second it situate problem in wider regional and local context in respect to urban transformation and housing trends, third thesis discuss analysis of operational scales and conclude with final cross-scale discussion and potentials for further research.

Shotcrete is the sprayed concrete, which was first used in Pennsylvania, USA in 1907 by Dr.Aneley. The technology is improving giving us enhanced comforts and the task is completed with a greater economy in terms of both time and investment. This innovative technology of shotcrete was introduced to make the work easier and immediate where any alterations are to be made or any architectural effects are to be enhanced.

Shortcreting has proved to be the best method for construction of curved surfaces. Domes are now much easier to construct with the advent of shotcrete technology. Tunnel linings are also becoming easy with this technology. Not only are these but there a wide range of applications where this technology has been a leading one. This technical paper includes the concept of shotcrete and how it differs from conventional concrete. It also enumerates the different types of process involved in shotcreting i.e. dry mix process and wet mix process. Advantages of shotcrete and its applications in various fields like tunneling, canals, buildings etc. are specified in detail. This paper presents an overview of shotcreteing technology along with its applications.

Unlike conventional concrete, which is first placed and then compacted in the second operation, shotcrete undergoes placement and compaction at the same time due to the force with which it is projected from the nozzle. Shotcrete is more dense, homogeneous, strong, and waterproof than is possible to obtain by any other process. For most bridges original concrete will require additional repair long before shotcrete needs repair and it suffers little detoriations. Shotcrete is not placed or contained by forms. It can be impacted onto any type or shape of surface, including vertical or overhead areas. It forms an excellent bond with the substrate and can be given a variety of surface finishes.

There are two classifications of shotcrete namely- 1. Dry process 2. Wet process They are discussed below.

Working of dry process proceeds as per the following steps:

Step1: Pre blended, dry or semi-dampened materials are placed into shotcrete equipment and metered into a hose.

Step2: Compressed air conveys materials at high velocity to the nozzle where the water is added.

Step3: Then the material is consolidated on receiving surface by high impact velocity.

The dry process can be used for any shotcreting applications from the smallest patching and sealing works to largest projects like tunnel linings, pools, canal linings or reservoirs. The maximum production achievable with dry process equipment ranges from 10-12 yards per hour of dry mix depending on the conditions. To achieve ultimate capacity it is necessary to use 2”-2.5” hose and larger compressors. Most applications have production rates of 2-6 cubic yards per hour of mix. Patching and sealing are done at even low rates by employing 1”-1.5” hoses. In dry process rebound and over spray should be considered.

 Easy start up, shutdown and clean up.

 Control of materials is on site.

 Nozzle man can be up to 1000ft horizontally or 500ft vertically from the gun.

Working of wet process proceeds as per the following steps:

Step1: All ingredients, including water, are thoroughly mixed and introduced into the shotcrete equipment.

Step 2: Wet material is pumped to the nozzle where compressed air is introduced to provide high velocity for placement and consolidation of the material onto the receiving surface.

Step 3: Mostly wet-process shotcreting is done with premixed mortar or small aggregate concrete.

The mix design and consistency of supply are very important in order to provide a mix with the workability or plasticity to be pumped through a small-diameter hose. Sand gradation is the same as for the dry process and for coarse aggregate mixes; 20-30 percent of 3/8" aggregate is added. Cement content will vary according to the aggregate gradation and surface area. However, most mixes contain approximately 700 pounds or more of cement.

 Little or no formwork is required.

 Cost effective method for placing concrete.

 Ideal for irregular surface applications

 Allows for easier material handling in areas with difficult access

The use of Shotcrete to build new concrete structures as well as to restore and repair existing structures is well known and documented and it is perhaps the most diverse method available for concrete construction. The use of this innovative technology is increasing day by day and procedures for its proper performance are well developed and high quality work is regularly obtained.

Rainwater Harvesting is the accumulating and storing, of rainwater for reuse, before it reaches the aquifer . It has been used to provide drinking water , water for livestock , water for irrigation , as well as other typical uses given to water. Rainwater collected from the roofs of houses, tents and local institutions, can make an important contribution to the availability of drinking water.Water collected from the ground, sometimes from areas which are especially prepared for this purpose, is called Stormwater harvesting . In some cases, rainwater may be the only available, or economical, water source. Rainwater harvesting systems can be simple to construct from inexpensive local materials, and are potentially successful in most habitable locations.

Roof rainwater can be of good quality and may not require treatment before consumption. Although some rooftop materials may produce rainwater that is harmful to human health, it can be useful in flushing toilets, washing clothes, watering the garden and washing cars; these uses alone halve the amount of water used by a typical home. Household rainfall catchment systems are appropriate in areas with an average rainfall greater than 200 mm (7.9 in) per year, and no other accessible water sources (Skinner and Cotton, 1992). Overflow from rainwater harvesting tank systems can be used to refill aquifers in a process called groundwater recharge , though this is a related process, it must not be confused with Rainwater harvesting.

Rainwater harvesting systems channel rainwater that falls on to a roof into storage via a system of gutters and pipes. The first flush of rainwater after a dry season should be allowed to run to waste as it will be contaminated with dust, bird droppings etc. Roof gutters should have sufficient incline to avoid standing water. They must be strong enough, and large enough to carry peak flows. Storage tanks should be covered to prevent mosquito breeding and to reduce evaporation losses, contamination and algal growth. Rainwater harvesting systems require regular maintenance and cleaning to keep the system hygienic.

Currently in China and Brazil, rooftop rainwater harvesting is being practiced for providing drinking water, domestic water, water for livestock, water for small irrigation and a way to replenish ground water levels. Gansu province in China and semi-arid north east Brazil have the largest rooftop rainwater harvesting projects ongoing.

In Rajasthan , India rainwater harvesting has traditionally been practiced by the people of the Thar Desert .

In Bermuda , the law requires all new construction to include rainwater harvesting adequate for the residents.

The U.S. Virgin Islands have a similar law.

In the Indus Valley Civilization , Elephanta Caves and Kanheri Caves in Mumbai rainwater harvesting alone has been used to supply in their water requirements.

In Senegal and Guinea-Bissau , the houses of the Diola -people are frequently equipped with homebrew rainwater harvesters made from local, organic materials.

In the United Kingdom water butts are often found in domestic gardens to collect rainwater which is then used to water the garden. However, the British government's Code For Sustainable Homes encourages fitting large underground tanks to new-build homes to collect rainwater for flushing toilets, washing clothes, watering the garden and washing cars. This reduces by 50% the amount of mains water used by the home.

In the of Myanmar , the groundwater is saline and communities rely on mud-lined rainwater ponds to meet their drinking water needs throughout the dry season. Some of these ponds are centuries old and are treated with great reverence and respect.

Until 2009 in Colorado , water rights laws almost completely restricted rainwater harvesting; a property owner who captured rainwater was deemed to be stealing it from those who have rights to take water from the watershed. Now, residential well owners that meet certain criteria may obtain a permit to install a rooftop precipitation collection system. Up to 10 large scale pilot studies may also be permitted).The main factor in persuading the Colorado Legislature to change the law was a 2007 study that found that in an average year, 97% of the precipitation that fell in Douglas County , in the southern suburbs of Denver , never reached a stream-it was used by plants or evaporated on the ground. In colorado you cannot even drill a water well unless you have at least 35 acres. In New Mexico, rainwater catchment is mandatory for new dwellings in Santa Fe .

In Australia rainwater harvesting is typically used to supplement the reticulated mains supply. In south east Queensland, households that harvested rainwater doubled each year from 2005 to 2008, reaching 40% penetration at that time (White, 2009 (PhD).

The scarcity of water is a well-known fact. In spite of higher average annual rainfall in India (1,170 mm, 46 inches) as compared to the global average (800 mm, 32 inches) it does not have sufficient water. Most of the rain falling on the surface tends to flow away rapidly, leaving very little for the recharge of groundwater. As a result, most parts of India experience lack of water even for domestic uses. Surface water sources fail to meet the rising demands of water supply in urban areas, groundwater reserves are being tapped and over-exploited resulting into decline in groundwater levels and deterioration of groundwater quality. This precarious situation needs to be rectified by immediately recharging the depleted aquifers. Hence, the need for implementation of measures to ensure that rain falling over a region is tapped as fully as possible through water harvesting, either by recharging it into the groundwater aquifers or storing it for direct use.

In scientific terms, water harvesting refers to collection and storage of rainwater and also other activities aimed at harvesting surface and groundwater, prevention of losses through evaporation and seepage and all other hydrological studies and engineering inventions, aimed at conservation and efficient utilization of the limited water endowment of physiographic unit such as a watershed. Rain is a primary source of water for all of us.

There are two main techniques of rainwater harvesting:

Storage of rainwater on surface for future use.

 Recharge to groundwater.

 Directly collected rainwater can be stored for direct use or can be recharged into the groundwater.

All the secondary sources of water like rivers, lakes and groundwater are entirely dependent on rain as a primary source.

The term water harvesting is understood to encompass a wide range of concerns, including rainwater collection with both rooftop and surface runoff catchment, rainwater storage in small tanks and large-scale artificial reservoirs, groundwater recharge, and also protection of water sources against pollution. The objective of water harvesting in India differs between urban and rural areas. In urban areas, emphasis is put on increasing groundwater recharge and managing storm water. On the other hand, in rural areas securing water is more crucial. There the aim is to provide water for drinking and farming, especially for life-saving irrigation, and to increase groundwater recharge.

Water harvesting is the deliberate collection and storage of rainwater that runs off on natural or manmade catchment areas. Catchment includes rooftops, compounds, rocky surface or hill slopes or artificially prepared impervious/ semi-pervious land surface. The amount of water harvested depends on the frequency and intensity of rainfall, catchment characteristics, water demands and how much runoff occurs and how quickly or how easy it is for the water to infiltrate through the subsoil and percolate down to recharge the aquifers. Moreover, in urban areas, adequate space for surface storage is not available, water levels are deep enough to accommodate additional rainwater to recharge the aquifers, rooftop and runoff rainwater harvesting is ideal solution to solve the water supply problems.

1. To meet the ever increasing demand for water. Water harvesting to recharge the groundwater enhances the availability of groundwater at specific place and time and thus assures a continuous and reliable access to groundwater.

2. To reduce the runoff which chokes storm drains and to avoid flooding of roads.

3. To reduce groundwater pollution and to improve the quality of groundwater through dilution when recharged to groundwater thereby providing high quality water, soft and low in minerals.

4. Provides self-sufficiency to your water supply and to supplement domestic water requirement during summer and drought conditions.

5. It reduces the rate of power consumption for pumping of groundwater. For every 1 m rise in water level, there is a saving of 0.4 KWH of electricity.

6. Reduces soil erosion in urban areas

7. The rooftop rainwater harvesting is less expensive, easy to construct, operate and maintain.

8. In saline or coastal areas, rainwater provides good quality water and when recharged to ground water, it reduces salinity and helps in maintaining balance between the fresh-saline water interfaces

9. In Islands, due to limited extent of fresh water aquifers, rainwater harvesting is the most preferred source of water for domestic use.

10. In desert, where rainfall is low, rainwater harvesting has been providing relief to people.

A hazardous waste is any waste or combination of wastes that poses a substantial danger, now or in the future, to human, plant or animal life and which therefore cannot be handled or disposed of without special precautions. The Hazards and Disasters can be classified into four categories viz., Natural events, Technological events, Man-made events and Region-wise events.The adverse impacts caused due to the indiscriminate disposal of Hazardous Wastes (HWs) come under the category of Environmental Disasters. For example, in 1982, 2242 residents are evacuated after dioxin is found in soil in Missouri, U.S.A. In 1996-97, 265354 tonnes of soil and other dioxin-contaminated material from Times Beach (Missouri, U.S.A) and 26 other sites in eastern Missouri had been incinerated. Release of Methyl Isocyanate (MIC) gas in Bhopal (1984) caused a severe disaster in India. So there is a growing concern all over the world for the safe disposal of hazardous waste generated from anthropogenic sources.

Identification of Hazardous Waste Generation: Identifying the HW generating industries is the first step. The HWs are classified under 18 categories and this information may be used to screen the wastes generated and classifying them as HWs. However there are few observations that- there is a probability of occurrence of wastes in more than one category; and this classification system does not give any information to understand the toxic characteristics of HW. Few suggestions are also given to improve the classification system. The data available with the State Industrial Development Corporation (IDC), District Industries Centre (DIC), State Pollution Control Boards etc. may be utilized to identify the industries with a potential for HW generation.

Data Collection: After identifying the HW generating sources, the inventory of the data pertaining to HW generation can be developed by conducting surveys through specially prepared questionnaires to each of the identified sources. This should be followed by field visits for data verification. It is essential that, the data that is obtained from the above options is verified from secondary data (either published data or available for another industry producing similar products).

The HW that is generated from the study region should be characterized. For this purpose, it is advisable that the samples may be collected from the waste generation source and analyzed in the laboratory. Literature data may be used in the absence of primary data.

The HWs ar · e quantified based on their individual characteristics. The several options of compatibility of wastes with different characteristics should be studied and segregated. The quantity of HWs will be expressed in terms of each category for disposal (e.g. Recyclable, Incinerable, or Disposable etc). The wastes that are recyclable are used/waste oil, lead wastes, zinc wastes.

After quantifying the HW, and assessing the probable area requirements for its treatment, storage and disposal, the sites are to be identified. For this purpose, toposheets and/or remote sensing images of the study region may be used. The sites are to be physically verified in the field and to draw observations pertaining to the four different types of attributes available for ranking the sites. The site with a minimum score out of the available sites for ranking should be chosen as the site for establishing TSDF.

Identifying the HW generating industries is the first step. The HWs are classified under 18 categories and this information (Refer Table-1) may be used to screen the wastes generated and classifying them as HWs. However there are few observations that- there is a probability of occurrence of wastes in more than one category; and this classification system does not give any information to understand the toxic characteristics of HW. Few suggestions are also given to improve the classification system. The data available with the State Industrial Development Corporation (IDC), District Industries Centre (DIC), State Pollution Control Boards etc. may be utilized to identify the industries with a potential for HW generation.

After identifying the HW generating sources, the inventory of the data pertaining to HW generation can be developed by conducting surveys through specially prepared questionnaires to each of the identified sources. This should be followed by field visits for data verification. It is essential that, the data that is obtained from the above options is verified from secondary data (either published data or available for another industry producing similar products).

The HW that is generated from the study region should be characterized. For this purpose, it is advisable that the samples may be collected from the waste generation source and analyzed in the laboratory. Literature data may be used in the absence of primary data.

The HWs ar•e quantified based on their individual characteristics. The several options of compatibility of wastes with different characteristics should be studied and segregated. The quantity of HWs will be expressed in terms of each category for disposal (e.g. Recyclable, Incinerable, or Disposable etc). The wastes that are recyclable are used/waste oil, lead wastes, zinc wastes.

After quantifying the HW, and assessing the probable area requirements for its treatment, storage and disposal, the sites are to be identified. For this purpose, toposheets and/or remote sensing images of the study region may be used. The sites are to be physically verified in the field and to draw observations pertaining to the four different types of attributes (viz., Receptor related-, Pathway related-, Waste characteristics related-, and Waste management practices related-) available for ranking the sites. The site with a minimum score out of the available sites for ranking should be chosen as the site for establishing TSDF.

The Environmental Impact Assessment (EIA) should be conducted in the site identified in the above step. The impacts from the project should be identified and public acceptance should be obtained for clearing the site for TSDF.

The TSDF programme should be implemented at the final designated site. The site should contain adequate provisions for storage, treatment (Stabilization, Incineration etc.) and final disposal. Layouts for collecting the HW from the waste generation sources should be planned. The site should have the laboratory facilities to monitor the function of TSDF from time to time. Landfill is the final disposal option in TSDF. The leachate that has percolated should be treated in Effluent Treatment Plant (ETP) before disposal. Monitoring of ambient environmental qualities and TSDF performance should be done regularly during the postclosure period of landfill (30 years).

Treatment when used in connection with an operation involved in hazardous waste management, means any method, technique, or process, including neutralization or incineration, designed to change the physical, chemical, or biological character or composition of a hazardous waste, so as to neutralize such waste or to render such waste less hazardous, safer for transport, amenable for recovery or reuse, amenable for storage, or reduced in volume.

Wastes remain after the implementation of waste minimisation must be treated to detoxify and neutralise them. There are large number of treatment technologies available.

Examples:

• Biological oxidation

• Chemical precipitation, oxidation-reduction

• Ion exchange

• Carbon adsorption

• Membrane separation

• Other/new technologies

The principal use of vapour phase activated carbon in the environmental field is for the removal of volatile organic compounds such as hydrocarbons, solvents, toxic gases and organic based odours. In addition, chemically impregnated activated carbons can be used to control certain inorganic pollutants such as hydrogen sulphide, mercury, or radon.

When properly applied, the adsorption process will remove pollutants for which it is designed, to virtually non detectable levels. In fact one of the first large- scale uses of activated carbon was in military gas masks where complete contaminant removal is essential. Carbon adsorption is equally effective on single component emissions as well as complex mixtures of pollutants.

In the industrial area, the most common applications of activated carbon are for process off-gases, tank vent emissions, work area air purification, and odour control, either within the plant or related to plant exhausts. Additionally, activated carbon is used in the hazardous waste remediation area to treat off-gases from air strippers and from soil vapour extraction remediation projects.