Showing posts with label Hydrology. Show all posts
Showing posts with label Hydrology. Show all posts

AXIOMS OF ECOLOGICAL ENGINEERING


The notion that human beings can design incredible processes such as ecosystems has been described as the height of hubris by some; ecosystems are too complex, the argument goes, and our knowledge too incomplete. In reality, we design ecosystems every time we start a bulldozer or tractor, every time we change land use or reroute stream flow.

We just do not design explicitly, and the consequences are apparent. Designing ecosystem services should be approached with a deep sense of humility and respect for what we do not know.

In order to ensure that this philosophy is embodied in the practice of ecological design, we propose the following three axioms of ecological engineering:

1. Everything is connected
2. Everything is changing
3. We are all in this together

The first two axioms are fundamental principles of systems ecology described by H. T. Odum (1988) and are the foundation of ecological design. They are critical for understanding and conceptualizing solutions to the challenges of developing sustainable design strategies.

The interconnectedness of all biotic and abiotic processes throughout the biosphere is demonstrated by the effects of urban land use on almost every aspect of ecosystem function, from climate to hydrology to biodiversity. Everything is changing, and the rate of change is increasing.

Changes in the biosphere are being driven by changes in global climate, land use, and human population, among other factors.

The third axiom, embodied by the Cherokee cultural ideal gadugi, roughly translated as “we are all in this together,” is a normative claim that connects ecosystem theory with sustainability. This is the essence of the ecological engineering ethics.

DRINKING WATER PLANT PROCESS SELECTION


Fundamental Precepts

Experience has taught us the following fundamental precepts in process selection (MWH, 2005):

1. The raw water quality of every source is different.

2. Raw water quality is variable.

3. There is no standard water treatment plant design that is applicable to all sources.

4. For every source, a number of treatment process alternatives are available.

5. Site conditions often limit the types of treatment process that can be used.

6. Retrofitting and upgrading of existing plants requires creative solutions that are not presented in standard textbooks such as this one.

7. Pilot plant testing is highly recommended in the selection of retrofit and upgrade alternatives.

8. Pilot plant testing requires careful planning and execution to obtain useful design and operating criteria.

9. It is essential that the multibarrier concept be a feature of all designs.

10. Operator experience is invaluable in developing a design.

WELL CONSTRUCTION AND WELL DRILLING BASICS AND TUTORIALS

WELL CONSTRUCTION AND WELL DRILLING BASIC INFORMATION
How To Construct and Drill Wells? The Different Well Drilling Methods


Well Construction
Geologic conditions dictate two general types of well construction. A well that taps an aquifer of water-bearing sand is cased through the overburden and screened in the water-bearing sand as shown in Figure 4-1 a (Johnson, 1975).

A well that taps an aquifer of consolidated rock consists

Well Drilling.
There are numerous methods for drilling the well. A few of these are highlighted
here.

• Cable-tool percussion:
The drilling operation is carried out by lifting and dropping a heavy string of drilling tools. The reciprocating action of the drilling tools mixes the crushed or loosened particles with water to form a slurry that is removed by a sand pump or bailer.

• Jet drilling:
The drill tools for the jet-percussion method consist of a chisel-shaped bit attached to the lower end of a string of pipe. Water is pumped through the drill bit and flows upward in the annular space around the drill bit carrying the cuttings to the surface.

• Hollow-rod or hydraulic percussion:
This method is similar to jet drilling except the water is pumped down through the annular space, and the cuttings are carried up through the pipe by the reciprocating motion and a set of valves that keeps the water from flowing downward.

• Rotary drilling:
The borehole is cut by a rotating bit. The cuttings are removed by drilling fluid that passes down the drill pipe system and out through the nozzles of the bit.

When the fluid reaches the surface, it is pumped to a pit where the bulk of the cuttings settle out. The drilling fluid is then reused.

• Reverse circulation rotary drilling (RCR): The flow of drilling fluid is reversed from that used in conventional drilling. This is a common method for drilling community wells. This method is favored when completion of the well is to be by artificial gravel packing.

CIVIL ENGINEERING HYDRAULICS FREE EBOOK DOWNLOAD LINKS

CIVIL ENGINEERING HYDRAULICS FREE E-BOOK LINK
Free E-Book Download Link of the Book: Civil Engineering Hydraulics


This well established text provides a succinct introduction to the theory of civil engineering hydraulics, together with a large number of worked examples and exercise problems with answers, to help readers assess their understanding of the theory and methods of analysis and design.

The Fourth Edition features a new chapter on hydraulic structures and an expanded section on the gradient method for pipe networks design. Additional problems and worked examples have been added.

Civil Engineering Hydraulics will be invaluable throughout a student's entire course, and will also be welcomed by practicing engineers as a concise reference.

A Solutions Manual is also available online exclusively to lecturers. Log on at: http://www.blackwellpublishing.com/nalluri/ to find out more.

This first/second year textbook provides a succinct introduction to the theory of civil engineering hydraulics, together with a large number of worked examples and exercise problems with answers.

The revised edition features a new chapter on some basic hydraulic structures and an expanded section on pipe networks design, with some more worked examples.

DOWNLOAD LINK!!!

WATER SOURCE QUALITY SELECTION BASICS AND TUTORIALS

QUALITY OF WATER SOURCE
Hydrology Tutorials


The quality will be determined by the planned use. Physical, chemical, and bacteriological testing of source waters is required to determine the level of treatment to supply the necessary water quality.

When the quantity withdrawn exceeds the recharge rate, quality inherently decreases; therefore, this must be considered during design.

a. Physical characteristics. The physical characteristics of the raw water source that must be evaluated are total suspended solids (TSS) and temperature. Turbidity and silt density index (SDI).

(1) Total suspended solids. The total suspended solids level of raw water sources must be evaluated to determine the level of pretreatment processes required. Raw water having low total suspended solids levels generally requires less pretreatment. The source with the lowest total suspended solids is preferred.

(2) Temperature. The temperature of the raw water source must be matched to the specific desalination process. In extreme cases, the water temperature may control the desalination process selection. A climatological survey must be made prior to finalization of process selection to determine the seasonal maximum and minimum water temperatures of the proposed water sources.

(3) Turbidity and silt density index. These two characteristics provide two different measures of the amount of fine particulate matter in the water.

Turbidity is measured in nephelometric turbidity units (a measure of the amount of light scattered by a known water sample thickness). Silt density index is a measure of the amount of 0.45-micron filter plugging caused by passing a sample of water through the filter for 15 minutes.

Turbidity must be determined for all desalination processes. Also, the silt density index must be determined for water being considered for reverse osmosis treatment.

b. Chemical constituents. The chemical constituents of the raw water must be determined to provide information for treatment selection.

c. Bacteriological quality. The bacteriological testing of the raw water must include a type of a coliform indicator organism count.

Procedures for filter membrane, most probable number fermentation tube, and standard plate count, coliform organism bacteriological testing techniques can be found in Standard Methods for the Examination of Water and Wastewater and TB Med 576.

Manufacturers' recommendations as to the media and procedures used to identify microbiological activity detrimental to the operation of a particular desalination system shall be followed.
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