Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : lime


Color Removal from Industrial Textile Wastewater Using Chemical Adsorption

Najah M. Al-Shuwaiki; Balasim A. Abid; Mahmood M. Brbooti

Engineering and Technology Journal, 2013, Volume 31, Issue 4, Pages 471-489

Industrial wastewaters from local state textile industry (Al-Khadimia Textile Co.) as well as aqueous prepared solutions of color dyes were subjected to simple physico-chemical treatment. The effect of pollutants concentrations, magnesia and other coagulants doses, filtration rate and the overall run time on the water quality were studied in detail.
The treatment involves the addition of either magnesia or lime-water suspensions (combined with CPE) in various doses, 0.1-1.0 g/l to the wastewater and colored samples, to study the effect of varying doses on the treatment efficiency. The optimum values of MgO doses were found to be 0.2-0.4 g/l for synthetic colored. Doses of 0.05-0.2 g/l were the best for industrial wastewater. The removal efficiency of all the pollutants in the different samples increases to more than 95% by increasing the pH values to the range of 9.5 to 10 with MgO coagulant and pH of 11.5 to 12 with CaO coagulant.
In the jar experiments the rotation speed, N, of 120-140 rpm, for two minutes was the most favorable speed of coagulation mixing for industrial waters. For flocculation, the mixing speed of 35-40 rpm, (G of 40-45 s-1) gave the best removal efficiencies with 20-30 min detention time.
At the best operating conditions of the pilot plant, the removal efficiencies of Turbidity, TSS, and color were 97-99%, 94-96%, 94-95%. The TDS removal efficiency was of 39% for Al-Khadimia wastewater.

Pretreatment of Sawdust for Producing Sawdust Concrete

Haitham H. Saeed

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 541-549

Sawdust concrete has some shortcomings due to the harmful effects of some organic soluble components existing in the sawdust which affects setting and strength of sawdust concrete. Also, volume changes of sawdust as an aggregate due to variation of moisture content, cause large volume changes in the sawdust concrete. In this work, sawdust was treated before using as an aggregate for making sawdust concrete. The treatment included boiling the sawdust in water containing hydrated lime in order to dissolve all soluble organic components. To reduce water absorption of sawdust, it was dried and treated with waterproofing material. Two types of waterproofing materials were used (cutback asphalt and classic varnish). The properties of sawdust concrete were highly improved using pretreated sawdust. The increase of compressive strength was up to 50% for moderate sawdust ratios. Flexural strength is also increased, water absorption and thermal conductivity were highly reduced, while the basic advantages of sawdust concrete such as lightness of weight, sawability and nailability were not affected.

Effect of Fibers on Some Engineering Properties of Cement and Lime Stabilized Soils

Suhail A. Khattab; Ibrahim M. Al-Kiki; Abderrahmane H. Al-Zubaydi

Engineering and Technology Journal, 2011, Volume 29, Issue 5, Pages 886-905

Recently, many attempts were made to use metal fiber reinforcements to
improve some soil properties. In this research, the effects of fibers on the
compaction and mechanical properties of cement and lime stabilized soils (silty
and clayey soils respectively) were studied. Variables such as stabilizer (cement
and lime) content, amount and type of metal fibers were studied. Results indicated
that the addition of fibers lead to increase in the maximum dry unit weight. On the
other hand, a maximum values of unconfined and tensile strength were obtained
with the addition of 0.5 % short fiber (FS) and 1.5 % long fiber (FL) respectively.
During the flexural test a brittle manner failure was observed for the unreinforced
samples and samples prepared with little amount of fibers 0.5%. Finally, the
addition of fibers increases the fracture energy of cement stabilized silty soil and
lime stabilized clayey soil.