literature

i- Engineering services is one of the most important force, which classified under ministry of defense. MODES Cooperated with SAF (Sultan Qaboos armed forces). They are support service directorate of civilian, as well as army, Navy and RAFO due to its several different of engineering sections (example, mechanical, electrical, public health and projects). They are associate of water, electricity, vehicles transport, mechanical and electrical related assistance (example, gas, water, electricity as well as transport). Thus, MODES has established at 1979 as small organization then it starts to develop to become as one of lead organization in the engineering sector, at the beginning the services were provided by contractors but nowadays MODES has its own equipment’s and human resources.

They do have drilling for water and distributed water to the camp. It is as service and support. Also analyzing water quality, to use in standard classification to make sure that all the parapets meets the water regulatory. In addition to that they do maintenance and repair unit for all kind of pumps. According to civilian requirement they do maintain the annual plant maintenance record (example either water production and sewage treatment and electricity). MODES Serving Sultan Qaboos Armed Forces as well as the main responsibility of its customer. Also, whenever the service civilian request for the help and in case of emergency situation such as cyclones.

There is no annual production, but the water treatment plant producing the water as per Oman standard volume of water approx. 3000 M3 per day. Also drilling of new borehole to get water according to the civilian requirement for example, MAM camp B/H NO1 produce 10000 Gallon per hour. in addition to the side of electricity there are gas turbines 46 mw capacity per day.

The Major business on MODES is providing the major living services such as (Electricity, water) for the sultana Qaboos armed forces. Those forces can be provided by neither contracted company or it on human resources and equipment’s.

ii- 1. The first process that I will explain more in detail is Sewage treatment water process which is the process of removing contaminants from wastewater, primarily from household sewage. Sewage treatment water is used for irrigation purpose. This process includes:

· Preliminary process: this process consists of two steps:

1. Screening which is removing the large objects and the suspended matters for example: papers and small pieces of wood that may block and damage the equipment.

2. Grit Chamber is a conically constructed pit in the steam of the sewage input to the sewage plant. The sewage is forced to whirl through two paddles fixed on a shaft that is driven by motor, by the help of both the paddle and the conical shape of the grit chamber when the sewage is whirling the solid materials gather at the bottom center and then the lift pump lifts them along with water and then go to classifier where the separation happens by means of screw shaft mechanism. Sewage water thus separated will be transported for the treatment process.

· Secondary treatment: Sewage composed of 99% water and 1% impurities. However, it contains many types of bacteria. These indigenous water-born micro-organisms are useful for sewage treatment whereas some are harmful to individual general health. The sewage is purified by the beneficial bacteria which digest the pollutant. The sewage become septic once no oxygen left in it. the bacteria then convert the complex organic compound present in the sewage to simpler and more stable compounds resulting in clarifying the water.

Bacteria exists in the sewage can be divided into two categories:

1. Anaerobic bacteria: These bacteria do not need the oxygen to function. These organisms can decompose the sewage in closed air-free tank. These will treat the sewage and remove part of the pollutants and some of the contaminated substances. The effluent from this process still contain significant amount of pollutants and smells badly because of the existence of hydrogen sulphide thus further treatment is required.

2. Aerobic bacteria: In contrast to anaerobic, aerobic bacteria need oxygen (from aeration process) and food which is available in the sewage to live and continue their role removing the contaminated substances from the sewage hence purifying it. this type removes organic matter and convert it to Carbon Dioxide, water and nitrogen and help eliminates the odor. Aerobic bacteria integrate the process of the anaerobic bacteria in clarifying the sewage.

· Final treatment: the water at this step is almost free from harmful substance and chemicals. Then, it will pass through a chlorination step to kill any kind of bacteria where the range of chlorine must be from 3 to 5 ppm. After that, it goes to contact tank where bacteria cells are destruction in 30 minutes. Finally, the filter water is stored in a final tank.

2. The second process is Drilling of borehole which is normally carried out in order to find suitable steady flow of water resource, the procedure for drilling new borehole consist of:

· Site selection: the most important step to ensure uninterrupted production of the borehole drilled. In this step the site selected must not lie near any infrastructure or buried services for example: Electric, Water and Telephone lines.

· Equipment and tools: in this step select the suitable drill bit in relation to the soil formation at that site. We have three types of bits: Teeth, Tricon and Hammering. Usually the Tricon bit is used in the mountainous areas because the formation there is hard, but for soft to medium formation teeth bit is used. Also, the hammering bit is used for the beach formation.

· Method of drilling: there are two methods used for rig(rotary and hammer method), the classification of methods depend on formation example all kind of formation can be drilled by rotary method except beach formation which can be drilled by hammering method.

· Drilling fluids: fluids used while drilling to lubricate the drilling bit , to increase rate of penetration and to prevent borehole from collapse. But selecting the proper fluids for suitable formation is the goal. There are so many types of chemicals to add, but MODES uses three types of chemicals which the formation can control by these chemicals. Foam is the first chemical and fit for soft to medium formation, bentionute is the second chemical and fit for soft- medium and hard formation, final chemical is Easy mud and it is as a treatment for the drilling issue.

· Final process content on drilling activities is casing installation. This process protects the borehole from collapse and maintain the borehole from pollution.

3. The third process I will discuss about is Bacteriological water analysis which is a method of analyzing water to estimate the number of bacteria present. This stage represents one important aspect of water quality. As we know that the presence of bacteria is a concern when considering the safety of drinking water because it can cause intestinal infections, dysentery, typhoid fever and other illnesses. In the laboratory we used IDEXX method because it provides easy, rapid and a very accurate bacterial count. This method is used for the detection of coliforms and E. coil.

So, in order to obtain the right results using this method we have to:

1. First, open snap pack and add reagent to 100 mL of water sample in a sterile vessel.

2. Then, carefully squeeze the upper part of the Quanti-Tray and pull the foil tab away from the well side to open it.

3. Pour the sample into the Quanti-Tray and put it inside the machine.

4. Place the Quanti-Tray in an incubator for 24 hours at 35 ºC.

Then, analyzing the results that has been obtained as follows:

· If no yellow color is observed, the sample is negative for total coliforms and E. coil.

· If the sample has a yellow color, the presence of total coliforms is confirmed.

· If yellow is observed, check vessel for fluorescence by placing the sample in a UV light. If the fluorescence is observed, the presence of E. coil is confirmed.

iii- Water treatment technical issue because of booster pump not working, otherwise membrane shock and blocks. To overcome the issue the membrane shock needs to follow up necessary periodic preventive maintenance record (example 6 month use to replace the membrane, sensor and filters).

Second technical issue is related to water well drilling, as I said that while drilling there are some fluids to be added as a chemical to prevent the borehole from collapses and to increase the rate of penetration, but the formation of ground earth is different and each formation has got special fluid to treat. So, because of the formation changing while drilling the fluid added will not be able to do its function therefore drilling stuck will occur. To overcome that issue MODES employed geologist to study the formation of earth before starting the drilling operation to classify the proper fluid for the suitable formation.

iv- During my training at MODES and as per the schedule program for various section , I have learned that the method of maintenance which MODES follow it is breakdown maintenance and preventive maintenance.