Cairo University

Current study was aimed to propose a novel design for compact sewage water treatment plant with a capacity of 100 m 3 /day (2x50 m 3 /day). The major pollutants are SS, BOD5, COD and organic pollutants. The recommended treatment process is an aerobic activated sludge. The analysis results of the sewage water are: pH average values 6-8, turbidity 12 UNT, daily suspended solid 850 mg/L, BOD is760 mg/L. The proposed design for the treatment plant consists mainly of: a bar screen, aerated gas trap, aeration tank and a collection pit. The main components of the extended aeration unit are: clarifier, sludge holding tank and diffused air system. The general objective of this investigation is to treat sewage wastewater and produce treated water which coincides with environmental regulations. While the specific objective is to get odourless, colourless treated water free of pathogens and toxic materials so it can be used for irrigation of non-edible trees.

Water shortage is an important issue facing the world today. Due to the increasing demands of fresh water in deserted and remote areas, the development of non-conventional water resources in Egypt is essential. A case study for a 3000 m 3 permeates/day RO desalination plant in Ain El Sokhna-Suez, Egypt is reviewed and analyzed. According to the plant location and site characteristics, several considerations have been evaluated in the design of the RO desalination plant. The Design of the plant has been adopted using ROSA software as well as basic design equations for RO system design. Detailed economic study has been adopted to evaluate the feasibility of the plant. The cost calculations of the RO plant indicated that the main factors which affect the cost of the produced water are membrane cost and the power consumption cost, whereas the chemical treatment represents almost 10% of the total cost. Introduction Fresh water shortage nowadays becomes a major problem in many coastal areas. Seawater desalination is used for providing fresh water aimed at both domestic and industrial usage. There are two main methods dominating the desalination process technologies, thermal and membrane-based process. The thermal desalination process has the advantage of using without complicated pre-treatment, nonetheless. It has a disadvantage of high energy consumption. Currently, there is a growing demand on using membrane based seawater desalination technology [1]. Choosing an appropriate seawater pretreatment system is mandatory for providing feed water with low turbidity for the reverse osmosis desalination process. Ultrafiltration membranes used to remove particles, virus, bacteria, moreover eliminating colloidal substance and they are more reliable in producing RO feed water with low fouling potential than using the conventional pre-treatment techniques even through destructive algal blooms event [2]. The process of water recovery of seawater using reverse osmosis (SWRO) desalination process ranged between 30% and 40% [3], and there is an important design parameter which determine the size and cost of SWRO desalination system. Nevertheless, the increase of water recovery possibly causes scaling inorganic substances on membrane surface and therefore SWRO systems will require abundant regular membrane cleaning and this may lead to short membrane life and membrane replacement [4-5]. Hence, increasing the water recovery of SWRO process while evading membrane scaling has become a significant goal. Shammiri and Dawas [6] found that when reducing the feed water pH from 7.2 to 7.0, even if no scale inhibitor has been added, the water recovery of SWRO plant has been improved from 22.5% to 34.2%, without any damage to the membrane surface due to scaling. Kurihara and coworkers [7-9] designed a brine conversion system (BCS) consists of two stages for SWRO desalination process where an 60% overall water recovery has been attained. Kim et al. [10] designed a multistage RO system for the desalination of seawater on 5 m 3 /h pilot plant using micro-filtration as a pre-treatment technique, the results showed that the water recovery successfully increased from 30% up to 50%. The main issue in desalination technologies, either membrane or thermal, is the energy cost as these processes are energy intensive. In the attempt to reduce operating cost, RO systems with large scale are nowadays equipped to improve the mechanical compression energy from the discharged concentrated brine stream [11].

The aim of this paper is to design a water desalination plant using Reverse Osmosis membrane to treat salt water to be usable for drinkable, domestic, industrial or agricultural uses. RO unit is designed to conservative standards for versatility in the event of feed water quality variations. The design includes a feed water flush cycle to minimize membrane fouling and piping corrosion during shutdown. The system will be all appropriate controls and instrumentation for automatic operation. All system components are available and of heavy duty industrial design and fabricated with the highest quality workmanship. Quality control will be maintained throughout all manufacturing processes. The system will produce permeate water minimum of 3600 m 3 /day with a quality of approximately 100 ppm total dissolved solids (TDS) when operating on well feed water with a 10,000 ppm TDS and a temperature of 25-30 degrees C. The design permeate recovery is 50%; and energy recovery device which saves $30,556.28/year.

Dye-house industrial processing includes pretreatment, dyeing, printing and finishing. These production processes are not only energy and water intensive but also a major source of heavy chemical pollution. Of all dyed textile fibers, cotton occupies a dominated loading position. As cotton is dyed with reactive dyes in Al-alamia Company for Dyeing and
Weaving, the effluent wastewater is heavily polluted with cotton fibers (unfixed dyes >50% of the used dyeing material) owing to their technical properties. These ecologically harmful effluents are relatively heavily colored; contain high concentrations of salt, exhibiting high COD/BOD and TDS values. Dyeing 1 kg of cotton with reactive dyes requires an average of 70-150 L water, 600 g NaCl and 40 g reactive dye. The composition of the usually practiced dye bath contains solid particles, dyeing auxiliaries, hydrolyzed reactive dyes,
substantial quantities of alkalis and very high concentration of sodium chloride or sodium sulfate. Convential separation methods failed to achieve satisfactory results for dye removal. Fortunately the application of membrane separation processes proved its technical reliability and feasibility. The main objective of this work is to investigate the performance
of low pressure driven membrane separation of nanofiltration as an advanced separation technology for treating effluent dye-house stream in order to recover dyes and recycle treated water. For this purpose removal of C.I. Reactive Black B (RB5) from dye-house effluents was investigated on a bench scale. In these experiments the performance of a Desal HL2521TF nanofiltration membrane element under various operating conditions of pressure, flow rate, and temperature was investigated. Permeate and salt fluxes, system recovery and salt rejections under variable operating conditions were discussed. In fact, experimental test results in terms of color, COD, and TDS were measured routinely. It is noteworthy that in course of the experimental work complete chemical analysis for feed, permeate, and concentrate were conducted. Direct analysis of membrane fouling has been performed using scanning electron microscopy (SEM) on the standard NF membrane element. An IR-technique was used to determine the actual chemical composition of the reactive dye being used.

Recently, Nanofiltration plays an important role in dye wastewater treatment. The efficiency of membrane separation system for wastewater treatment plant is complicated due to different operating conditions involved in the separation process. Estimation of the Nanofiltration membrane performance is essential to evaluate the final water quality for further reuse. This work focus on the development of a simplified predictive model for membrane performance estimation under a set of parameters. A linear multiple regression model with coefficient of determination (R 2) of 1 has been developed for COD values in the permeate stream, while (R 2) of 0.85 for membrane rejection estimation. Seven investigated parameters have been related to formulate the model. The model has been applied for dye wastewater scheme comprising Nanofiltration with proper pretreatment. The model has been validated with an average deviation of 15% for membrane rejection and almost no deviation for COD level estimation in the permeate stream.

A nanofiltration based separation process is used to treat the
7 effluent from a textile plant to allow for water reuse and fulfill
8 environmental standards. The wastewater effluent contains reactive black
9 (RB5)- and disperse(DR60) dyes. A NF-unit model E2 series with HL 2521 TF
10 spiral wound module was used to carry out experiments. Color removal and
11 COD reduction up to 90,93% for RB5 and 98,95% for DR60 were achieved
12 respectively. A parametric study of the separation process is undertaken to
13 characterize the effects of the operating variables, e.g., trans-membrane
14 pressure, dye/salt concentration in the feed, temperature, and cross flow
15 velocity. The solution diffusion model was used to develop power
16 correlations to calculate the permeate side solute mass transfer coefficient
17 as a function of effective cross-flow Reynolds number. In contrast to the
18 commonly assumed constant hydraulic solvent permeability, a non-linear
19 relationship was developed over the applied trans-membrane net driving
20 pressure. The latter correlates exponentially with salt permeability for both
21 dyes. The effect of feed salt-content on solute mass transfer coefficient,
22 water and salt permeability, concentration polarization, dye hydrophobicity
23 and ionic strength were studied. Results were used to assess engineering
specifications of a commercial size NF-plant (500m324 /d capacity).