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Industerial waste water treatment and reuse in delta sugar company

El_Shanshoury, A.R. (1); Hashim, E.Y. (2); Zohri, A.A.(2); El_Tabake, M.M. (3) and Hamad, A.M.S. (3)

(1)Faculty of science, Tanta University, Tanta, Egypt(2)Faculty of science, Assiut University, Assiut, Egypt

(3)Delta Sugar Company, Egypt

Abstract:Great difficulties face Egypt in the modified convention of the Nile Basin

countries to reduce their share of water. So, this study conducted on reuse of treated waste water in Delta sugar factory - as non-conventional water resources- after adding a new tertiary treatment to use the whole water safety and economically without causing any problems in industrial processes. That could be done by: disinfection of treated waste water by CaO for use as flume water, use of treated waste water as a juice extract water after disinfecting it by Na2S2O5 ,and chlorination of condensate water by NaOCl.

Introduction:All sugar factories require water and consequently discharge waste water.

Beet, cane factories and factories refineries produce waste water with different organic strengths, with beet being by far the most aggressive influents. Waste water treatment plants are designed to comply with local environment regulations and vary from country to country(1).

While sugar, the main contaminant of sugar factory effluent, is not toxic, it readily provides a source of soluble food which is an ideal substrate for microbial growth. The exponential growth of microbes causes the depletion of oxygen in natural streams. Aquatic organisms that require oxygen will suffer and may die as a result (2). Waste water treatment systems utilize the very same process, but under controlled conditions. The quest for zero effluent is a desirable journey and has economic and environmental benefits.

Egypt is an arid country, which covers an area of about 1,000,000 km2 of which only 4% is occupied by its population. According to the 2010 census, the population has reached 85x106. The United Nations reports pointed that per capita in Egypt of water per year is less than 1000 cubic meters, but it is close to many of the line of water scarcity by 2025, bringing per capita to 337 cubic meters per year; also pointed out that per capita is declining continuously after

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the share was 3000 cubic meters in 1960, and decreased to 1200 cubic meters in 2000(3).

Water resources in Egypt are restricted to the following resources:1. Nile River2. Rainfall and flash floods3. Groundwater in the deserts and Sinai4. Possible desalination of sea water

Each resource has its limitation on use, whether these limitations are related to quantity, quality, space, time, or use cost.

The Nile River is the major supplier of water to the 85 million Egyptians based on the 1929 treaty with the Nile River basin countries. Which gives Egypt the right to use 55.5 billion cubic meters of Nile water, as well as the right to veto any projects detrimental to such a quota there are great difficulties faced Egypt in the modified convention of the Nile Basin countries to reduce their share of water(4).

The Nile River sources are beyond Egyptian national boundaries. In previous posts, references were made that Egyptian government officials have been meeting with their counterparts from the Nile River basin countries to re-examine and re-evaluated the 1929 Nile River water sharing with Egypt. As of January 2011, no agreement has been reached. Recently, the Ministry of Housing and Urban Development and the U.N. and UNICEF sponsored an awareness campaign about the fact that Egypt is facing a critical state of water shortages (5).

This problem and continue to be under continuous solution does not appear in the near future and far wishes to remain Egypt's water quota fixed, It is not suitable at all with the constant increase in population as well as large-scale projects to reclaim desert land in Egypt. Delta Sugar Company should think of a solution to this problem so this study give water supply in an unconventional way, a process of re-use of 400m3 / h industrial treated wastewater resulting from the treatment plant of Delta sugar company and re-use it fully back into the Industrial operations.

Beet sugar factories produce more waste products than cane factories or raw sugar refineries. Beet plants generate two types of waste waters, flume wastes and factory wastes. The flume waste water system is used for transporting and preliminary cleaning of beets. The sugar that is leached into this water contributes a high organic load in the flume system and can vary form a few hundred mg/L BOD to more than 20,000 mg/L. BOD (6).

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Water is used for six principal purposes: a) Transporting (fluming) and washing of beets. b) Processing, i.e., extraction of sugar from beets.c) Transporting solid wastes - lime cake.d) Condensing vapors from evaporators and pans and cooling.e) Dilution of molasses. f) Cleaning of equipment and plant.

Biological waste water plants are designed and operated on the basis of oxygen demand (BOD or COD) received and removed. For this reason, a quick and easy measurement needs to be made and COD due to its raid determination is almost universally used. The BOD test takes five days to completion and is not practical for process control (7).

The waste water treatment process can be broken down into two treatment systems:

a) Primary. b) Secondary

Primary Systems

This consists of unit operations to remove suspended solids, oils and major debris. This is accomplished by screening, grit removal and oil skimming, air flotation unit to remove large particles of suspended solids which may interfere with the secondary treatment systems(8).

Secondary Systems

There are basically two types of secondary treatment, i.e. anaerobic and aerobic. The goal of all biological wastewater treatment systems is to coagulate and remove or reduce the no settling organic solids and the dissolved organic load from the effluents by using microbial communities to degrade the organic load through biochemical reactions(9).

Materials and Methods:

Experimental Procedures

The experimental procedures was carried out at laboratories of Delta sugar company, Kafr El-Sheikh Governorate, Egypt, during (2008, 2009, 2010 and 2011) seasons. Heavy metals (Cu, Fe, Pb, and Cd.) and toxicity test were carried out in National research center (NRC) and the identification of bacterial isolates

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was achieved in the city for scientific research and technology applications, Borg El-Arab, Egypt.

Preparation of Samples

For greatest accuracy, thoroughly clean sampling devices and containers to prevent carryover from previous samples. Normally, analyze the samples as soon as possible after collection. Preservation methods include pH control, chemical addition, refrigeration and freezing. Obtain the best sample by careful collection. In general, collect samples near the center of vessel or duct and below the surface. Fill sample containers slowly with a gentle stream to avoid turbulence and air bubbles. Filtering separates particles from the aqueous sample. Two general methods of filtration are gravity and vacuum (Laboratory Waste Management 1993).

Treated Waste Water Analysis

Physical parameters:

Unless otherwise stated that all water quality analysis was don according to the standards methods for examination of water and waste water, American Public Health Association (APHA, 1999). The temperature was determined using an ordinary mercuric thermometer. pH was measured by using digital bench pH –meter, model pH-S26/Sentix-20/As-DIN/SIN/STH/650 according to the procedure of Delta Sugar Company. Conductivity was determined by using conductivity meter, model LF538, (WTW) according to ICUMSA method (GS1/3/4/7/8-13) 1994. Wissenschaftlich -Technische Werkstätten, 82362 Weilheim, Germany.

A suspended solid (SS) was determined using a paper filtration method. The strength of waste water was judged by BOD. This is defined as theamount of oxygen required by microbes while stabilizing theorganics in waste water under aerobic conditions which accountsfor 70% of the total BOD. The measurement of BOD is based on theprinciple: determination of dissolved oxygen content of water/waste water on the first day and dissolved oxygen content onthe fifth day ('5' in BOD5 indicates this). The difference indissolved oxygen concentrations between first day and fifth day isexpressed as BOD of waste water. Biochemical oxygen demand is an empirical measurement of the oxygen consumed during five days incubation at 20°C, in the dark and under aerobic conditions. Results are expressed as milligrams of oxygen per liter of sample. The BOD determination predominantly represents the microbial oxidation of organic matter. Prior to incubation appropriate dilution of

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the samples is required to optimize accuracy while avoiding oxygen depletion. The dilution water is prepared by addition of ml per liter distilled water of each to the following: 0.0125%w/v magnesium sulfate solution and phosphate buffer solution (pH7.2). The concentration of the diluted samples was determined in 250 ml stoppered glass bottles using the oxygen probe. A blank was determined by treating the dilution water as a sample. The stoppers were inserted in the bottles in a way that excluded all air bubbles and the diluted samples were incubated for 5 days at 20°C.After this period the dissolved oxygen was determined and BOD calculated.

Chemical oxygen demand was measured determined by using digital spectrophotometer, model (HACH DR 5000). Measuring the absorbance at the appropriate wavelength (420nm). The mg/L COD results are defined as the mg of O2 consumed per liter of sample under conditions of this procedure. In this procedure, the sample is heated for two hours with a strong oxidizing agent, potassium dichromate. Oxidizable organic compounds react, reducing the dichromate ion (Cr2O7

2-) to green chromic ion (Cr3+). When the 0-150 mg/L colorimetric method is used, the amount of Cr6+ remaining is determined. When the 0-1500 mg/L or o-15000 mg/L colorimetric method is used, the amount of Cr3+ produced is determined. The COD reagent also contains silver and mercury ions. Silver is a catalyst, and mercury is used to complex the chloride interference.

Chemical parameters

Heavy metals (Cu, Fe, Pb, and Cd.) were determined using spectrometer model. Analyst 400, S/N 20/85, 071505, Autosapler. Ammonia, sulfate, nitrate and phosphate were determined using digital spectrophotometer; model (HACH DR 5000), according to the procedure of Delta Sugar Company. Ammonia compounds with salicylate to form 5-aminosalicylate. The 5-aminosalicylate is oxidized in the presence of a sodium nitroprusside catalyst to form a blue-colored compound. The blue color is masked by the yellow color from the excess reagent present to give a final green color solution.

Sulfate ions in the sample react with barium in the sulfate reagent to form insoluble barium sulfate. The amount of turbidity formed is proportional to the sulfate concentration. Cadmium metal reduces nitrates present in the sample to nitrite. The nitrite ion reacts in an acidic medium with sulfanilic acid to form an intermediate diazonium salt which couples to gentisic acid to form an amber-colored product. Phosphate was determined using the molybdovanadate method. In this method, the orthophosphate reacts with molybdate in an acid medium to produce a phosphomolybdate complex. In the presence of vanadium, yellow

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vanadomolybdophosphoric acid is formed. The intensity of the yellow color is proportional to the phosphate concentration.

Biological assay

Nutrient agar medium was used for isolation and preservation of different bacterial cultures as well as enumeration of total bacterial count of water. Czapeks medium was used for counted the fungi. Emmons’ culture medium was used for counted the yeast present in waste water. Lauryl tryptose broth was used for the determination of total coliform count by most probable number (MPN) technique. Brilliant green bile lactose (2%) (BGB) broth was used for the determination as of total coliform confirmed test by MPN technique.

In determining the number of organisms present in water, the standard plate count (SPC) is universally used. It is relatively easy to perform and give excellent results. This basic technique could be used to calculate the number of organisms in a water sample. The procedure consists of a series diluting the tested water samples. From the suitable dilution, measured amounts of the water samples were transferred into empty Petri plates. Selected agar medium for bacteria, yeast or fungi cooled to 50°C and then poured into each plate. After the agar media had solidified, the plates are incubated for the suitable incubation periods. Incubation periods are 24 hr, 48 hr and 7-10 days for bacteria, yeast and fungi, respectively. Suitable dilution rate must be formed 30-300 colonies for bacteria, 30-100 colonies for yeast and 15-30 colonies for fungi. From the count, it is a simple matter to calculate the number of organisms per milliliter of the original water samples. It should be pointed out that greater accuracy can be achieved by pouring 3-5 plates for each dilution and averaging the counts.

Identification of some selected bacterial isolates

Identification of selected five bacterial isolates was achieved at sequencer unit and biotechnology research institute, in City for scientific research and technology applications, Borg El-Arab, Egypt. PCR (polymerase chain reaction)- sequencing based technique was used for identification of these bacterial isolates at their molecular level. This method is mainly based on the conservation of ITS rRNA(Internal Transcribed Spacer of rRNA) or rDNA gene among bacterial species.

The DNA of the selected bacteria were extracted using GenElute™Bacterial Genomic DNA Kit, sigma Aldrich. PCR product of 16 S rDNA using set of forward and reverse universal primers. Purification process occur at sequencer lab of city of scientific research and technology application, using 3130xl genetic analysis (applied Bio system).

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Treated waste water to be used as flume waterWaste water after primary and secondary treatments was treated with

different concentration of CaO (0.0, 0.4, 0.6, 0.8, 1.0, 2.0, 3.0, 4.0, 5.0 and 9.0 gm/l). These treated samples were inoculated on nutrient agar and Czapekes media for detecting the total bacterial and fungal counts, respectively.

Treated waste water to be used in diffusera) Using H2SO4

Different doses of H2SO4 98% (0.0, 0.4, 0.9, 1.2, 5.0, 15.0, 20.0, 25.0 ml/l) were added to secondary the treated waste water. These treated samples were planted on nutrient agar medium for bacterial count estimating.

b) Using TemperatureWaste water after secondary treatment was exposed to different degree of

temp. (30, 45, 60, 65, 70, 75, 80, 85 and 90 °C) and estimating the total bacterial count on nutrient agar medium.

c) Using Formalin 37%Different doses of formalin 37% (5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55,

60, 65, and 70 ppm) were added to the secondary treated waste water and determine the total bacterial count on agar media.

d) Using Na2S2O5

Treated waste water after secondary treatment was treated with different doses of Na2S2O5 (5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85,90, 95, 100, 105 ppm) and the total bacterial and fungal counts were detected.

Condensate was chlorinated by NaOClCondensate water was chlorinated by different dose of NaOCl.(0.00, 0.01,

0.015, 0.02, 0.03 gm/l) Each treated sample was inoculated on a nutrient agar and Czapek´s media for total bacterial and fungal counts estimating, respectively. HCl (1ml/ l) was added for decrease the pH value from 8.7 to 7.0

Results and Discussion:

A- Physical and chemical properties of beet waste water:

After and before conventional waste water treatment process, the influent and effluent waste water from Delta sugar waste water plant were analyzed and the results recorded in Tables (1 & 2).

Table (1) Physical properties of the treated waste water

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Parameters Temp° C pH TDS ppm

B.O.D ppm

C.O.D ppm

S.S ppm

EC µs /cm

Toxicity test

Influent 35-40 6-8 2880 1596 2968 214 1728 Toxic

Effluent 35 7-8 1675 35 50 9 921 nontoxic

Low 48/1982 Art 66 35 6-9 2000 60 100 60 - nontoxic

Table (2) Chemical properties of the treated waste water

Parameters NO3 ppm PO4

ppmCU ppm

Fe ppm

Pb ppm

Cd ppm

SO4

ppm NH3ppm

Influent 14.7 9.95 o.370 0.05 0.29 0.340 0.89 1.9

Effluent 5.4 3.10 0.230 0.00 0.15 0.01 0.64 0.50

Low 48/1982 Art 66 40 10 1 1 0.50 0.05 1 3

From Table (1), (2) the physical and chemical characters of treated beet waste water in Delta beet sugar factory suitable to use safety in beet sugar processing.

B- Biological Assay of Treated Waste Water

The samples were inoculated on bacterial, yeast, and fungal media and incubated for 24 hr, 48 hr & 7 – 10 days, respectively. Results clearly show that the total microbial counts by colony forming unit per ml (cfu/ml) were:

1. 37.5×102/ 100 cm3 coliform colonies (on lauryl tryptose broth media and brilliant green lactose bile broth, BGB).

2. 9 ×103 (cfu/ml) bacterial colonies (on nutrient agar medium) 160×102 (cfu/ml) Fungal colonies and 7×102 Yeast colonies (on Czapeks and Emmons media, respectively).

Identification and Characterization of Selected Bacterial Isolates

With screening the treated waste water samples on nutrient agar culture medium, the dominant bacterial growth culture was restricted in different five groups. Five isolates (one isolate represented each of the different five groups of

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the growing colonies) were isolated, purified and identified at sequencer unit and biotechnology research institute, in City for scientific research and technology applications, Borg El-Arab, Egypt. By comparison of the sequences of tested isolate no 1 with sequences

obtained from the GenBank database, isolate no 1 scored 81% similarity percentage with(AM410705.1) Acinetobacter junii (strain AC1289), and 79% with (FJ976573.1) Acinetobacter calcoaceticus.

By comparison of the tested sequence of isolate no 2 shown that 90% similarity is gaind with (HQ127622.1) Bacillus subtilis (strain CF92 ), (AM882686.1) Bacillus amyloliquefaciens (strain Ks3-17),( HQ238544.1) Bacillus methylotrophicus (strain S652Ba-149), (JF912890.1) Bacillus vallismortis (strain SCSAAB 0015) & ( HQ857764.1) Bacillus tequilensis (strain GZAL15) and give 89% similarity with ( HQ238652.1) Bacillus megaterium (strain S32Ba-203)& (HQ650594.1) Bacillus licheniformis (strain MMSTP-fxj).

Similarity at 99 % with (CP003488.1) Providencia stuartii strain (MRSN 2154) for sequence of tested isolate no 3 comparing with sequences obtained from the GenBank database, that means isolate no 3 is related to Providencia sp. and close to Providencia stuartii with 99% similarity.

There are a relative similarity at 95% with (HM588156.1) Bacillus licheniformis (strain RSNPB16) and (JN409451.1) Bacillus subtilis ( strain SP2 ) by comparison of the sequences of tested isolate no 4 with sequences obtained from the GenBank database.

From the GenBank database with comparison of the sequences obtained from isolate no 5 , 93% similarity with (FJ407187.1 ) Aeromonas punctate (strain D7022) and (JN019024.1 ) Aeromonas hydrophila (strain PIA31).

These results appeared that the treated waste water had a high load of microorganisms. The industrial problem is that this water is containing microorganisms specialized in breaking hydrogen bond, leading to hydrolyzing of sucrose in the factory. So, searching for suitable disinfectant to this treated waste water to kill microorganisms and safety reuse this water in sugar beet processing in the form of adding new treatment process (tertiary treatment) is the main goal of this research.

Tertiary SystemsThe key to the success of any waste water reuse program is to employ

technology capable of producing advanced waste water treatment plant effluent that is safe and cost effective. Tertiary filtration and disinfection of secondary

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effluents are the acceptable and prevailing technologies for meeting this challenge.

The most important results can be summarized in this study as follows:

A- Use calcium oxide as disinfection for flume water

This experiment was designed to determine the sufficient amount of CaO to be added to treated waste water to be used as flume water, to kill all micro-organisms.Table (3) Effect of different concentration of CaO on the total bacterial and fungal

counts in effluent treated waste water.

CaOmg/L 0.0 0.4 0.6 0.8 1.0 2.0 3.0

pH 8.3 10.4 10.7 11.1 11.4 11.9 12.0

Total bacterial

count(cfu/ml)6×104 1.3×102 59 8 0 0 0

Total fungal count(cfu/ml) 3.3×103 1.7×102 22 3 0 0 0

As shown in Table (3), both total bacterial and fungal counts reached zero in the effluent treated waste water when used 1.0 gm / l of CaO. This dose of CaO increase the pH value into 11.4. So, this is ideal dose of CaO for completely sterilizing the effluent treated waste water and reuse it in washing and transporting the beet in the factory.

The quantity of CaO which will be add to 250 m3/h of treated waste water for using it in washing and transporting the beet in the factory can be calculated as follow:

250 m3/h require 250 kg CaO So, 6 ton CaO / day at optimum dose 1.0 gm /LIn beet sugar factory we already use calcium oxide in beet washing to raise

pH at 11.5 to disinfect the bacterial growth in water and prevent the hydrolyzing of sucrose in the beet washing process and at this pH it is very suitable medium to forth settling mud from water to be recycled and reuse after released from mud in washing beet again.

So there is no economic cost when using the treated waste water instead of the row water in beet washing and transporting.

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B- Uses the treated waste water in diffuser for juice extraction

The biggest challenge is how to use the treated waste water in juice extraction in diffuser because the pH in diffuser ranges between 5.8 to 6.2. At this pH, best juice extraction from beet slice happened and it is not possible to use Cao which raise pH to 11.4. In the factory, 100 m3/h as fresh water must be added to the condensed water from evaporating system to decrease its temperature to 70°C to be forced in the diffuser.

b1) Use sulfuric acid as a biocide for treated waste water

By using sulfuric acid which we already use to decrease pH of fresh water and press water in diffuser, the following experiment was to determine the optimum pH to kill all microorganisms in treated waste water by using H2SO4.Table (4) Effect of different concentrations of H2SO4 98% on total bacterial count

in effluent treated waste water.

Effluent pH 6.5 5.1 4.6 4.0 3.3 2.8 2.4

Total bacterial count(cfu/ml) 4×104 32×103 15×103 1.1×103 8×102 4.4×102 1.5×102

From Table (4) it was found that there is no complete disinfection to the bacterial growth with all the levels of H2SO4 under examination. Thus, sulfuric acid cannot be used as a biocide for the treated waste water.

b2) Effect of increasing temperature for disinfection the treated waste water.

In this experiment the temperature of treated waste water was increased until 90°C for examining their ability to kill bacteria as an economical method (Table, 5).Table (5) Effect of increasing temperature on bacterial total count in the effluent

treated waste water.

Temp°C 45 60 70 75 80 90

Total bacterial count(cfu/ml) 3.4×105 4.1×103 3.7×102 1.2×102 90 16

From data recorded in Table (5) it can be concluded that raising temperature up to 90°C caused a decrease in the number of bacterial count to certain extend. Thus no complete disinfection was observed until 90°C. So, this method is not effective in disinfection of effluent treated waste water.

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b3) Use formalin 37% as biocide for treated waste water

The biocide which already use in beet sugar factory for disinfection the treated waste water is formalin at 37 %. The following experiment was designed to determine the optimum dose of formalin to kill all bacterial isolates in effluent treated waste water. The results are recorded in Table (6).Table (6) Effect of formalin at 37% on bacterial total count in the effluent treated

waste water.

HCHO

Ppm5 10 15 20 25 30 35 40 45 50

Bacterial count(cfu/ml) 2.2×104 5.0×103 2.9×103 1.4×103 6.0×102 140 80 25 7 0

From Table (6) the suitable concentration of 37% HCHO is 50 ppm which the first concentration at which there is no living bacteria found. The maximum dose for injection formalin in beet sugar industry is 90 ppm, and the already dose which use in Delta sugar factory is 45 ppm. So from economic view formalin is very good to be used.

But the application of formaldehyde has been discontinued in some countries and is expected to be discontinued in the remaining countries soon.) The discontinuation of formaldehyde is for one or more of the following reasons: Harmful to human health Affects natural environment Contributes to high lime salts Contributes to high ash in sugar Damages the respiratory and nervous systems Creates safety risks during handling and application

So the use of formalin has a lot of healthy issues.

b4) Use sulfur dioxide as biocide for the treated waste water

Several attempts are being made by sugar technologists to find a suitable substitute for formaldehyde, including sulfur dioxide (SO2). Today, sulfitation is used in many factories because sulfur dioxide is a good biocide, which improves sugar beet processing in the following ways: Disinfects the diffusion juice

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Lowers the pH of the diffuser Improves the pressing qualities of the pulp because of the lower pH of the

diffuser Reduces the color of the juice and also prevents color-formation in the next

processing stations, where the temperature is too high (during evaporation)Sodium metabisulfite can be used as biocide. It is a white to slightly

yellowish crystalline powder with sulfur dioxide odor and readily soluble in water. Sodium metabisulfite containing more than 66 % SO2 w/w releases sulfur dioxide gas when mixed with water.

The following experiment was designed to determine the optimum dose of Na2S2O5 to kill all bacteria and fungi in the effluent treated waste water (Table, 7).Table (7) Effect of different concentrations of sodium metabisulfite on the total

bacterial and fungal counts in effluent treated waste water.

Na2S2O5

ppm10 20 30 40 50 60 70 80 90 100

Bacterial count(cfu/ml) 4.6×104 1.2×104 3.9×103 2.9×103 1.8×103 1.1×103 330 70 13 0

Total fungal count(cfu/ml) 3.1×103 9.0×102 6.0×102 2.5×102 1.6×102 90 27 3 0 0

As shown in Table (7) the total bacterial and fungal counts reached to zero in the effluent treated waste water at 100 and 90 ppm of Na2S2O5, respectively. So,100 ppm ideal dose of Na2S2O5 for complete disinfection of the effluent treated waste water from both bacteria and fungi.

10 Kg 100 m3/h 240 Kg/dNet weight of package 25 Kg and it is price 82.5 £ = 792 £ / d

This calculation for disinfection of the treated waste water which will be used for 100 m3/h as fresh water in diffuser, while 0.3 Kg/t of SO2 is needed as a diffuser biocide which equates 370 ppm Na2S2O5 as illustrated below:

Na2S2O5 2 SO2

190 1280.445 0.30

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When 16000 ton of beet are processed per day, 7120 Kg of Na2S2O5 will be needed, that will cost 23496 £

Also the treated waste water can be used after secondary treatment without any additions in: Condensing vapors from evaporators and pans and cooling. Cleaning of equipment and plant. Transporting solid wastes - lime cake.

Because, there is no contact between juice or beet and the treated waste water in these processes.

C- Water management in Delta sugar plant

Delta beet-sugar plant is capable of processing approximately 16000 t of beet in 24 hours. There are several water and waste water streams used or generated in various operations of a sugar plant. The streams have specific characteristics and require different handling or treatment. In the sugar plant studied, there are three qualitatively dissimilar water streams and circuits, respectively Fresh water (river-water) Treated waste water, used for beet unload, transport and washing (circuit I) Treated waste water, used for juice extraction in diffuser (circuit II) Condensate, warm water, cooling water and evaporated water from the

crystallization stage (circuit ш).The circuit (I) water is used for unloading beets, transporting them through

the flume and washing. 250 m3/h of treated waste water is discharged from polishing basin, to reusing as flume water in steed of the fresh water which using in this process after adding dose of CaO 1.0 gm/L to raise the pH of treated waste water to 11.4, which suitable to disinfection the microorganism growth in water and prevent the denaturation of sucrose in the beet washing process and at this pH it is very suitable medium to forth settling mud from water to be recycled and reuse after released from mud in washing beet again, and the suitable place for CaO addition is the flume-water clarifier, which allows several returns (recycles) of the water to the flume.

The circuit (II) using 100 m3/h of treated waste water in juice extraction in diffuser in steed of the fresh water which using in this process after adding dose 100 ppm of sodium meta bisulfite which suitable to disinfection the microorganism growth in water and prevent the denaturation of sucrose in diffuser .

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The circuit (ш) using 50 m3/h of a “dirty” stream of evaporation condensate and evaporated water from a crystallization stage is used in the cossettes extraction unit (diffuser); this water connection is not active because of its high microorganism's content and large distances between the water source and potential consumers. Microorganisms would cause pipeline fouling, diminishing water flow rate. Chlorination with sodium hypochlorite, containing 15 % to 16 % of active chlorine, is an economical and effective procedure for this water chemical disinfecting. Amount of chlorine that would destroy microorganisms was estimated to approximately 0.02 g/L of technical NaOCl. The water pH value must be maintained at 7.0 to increase the efficiency of sodium hypochlorite by using technical hydrochloric acid, HCl 33 % (10). The required volume fraction of technical HCl that would decrease the pH value of water from an average value 8.7 to7.0 was determined experimentally to 0.1 mL/L.Table (8): Effect of different doses of NaOCl on the total bacterial and fungal

counts in condensate water

NaOCl doseGm/l 0.0 0.01 0.015 0.02 0.03

Total bacterial count(cfu/ml) 4 ×102 60 7 0 0

Total fungal count(cfu/ml) 1.1×102 40 3 0 0

As shown in Table (8), both total bacterial and fungal counts reached to zero in the condensate water when used 0.02 g/L of technical NaOCl (mass fraction of active chlorine being 15–16 %). So, this is ideal dose of NaOCl for completely sterilize the condensate water this is equal to approximately considering the water flow rate, 1.00 kg/h of NaOCl would be required.

RecommendationsTo achieve zero effluent of the treated waste water from the Delta sugar

company by reusing the whole amount it in three circuits: 250 m3/h used for beet unload, transport and washing(treated with 1 gm

CaO / L) 100 m3/h used for juice extraction in diffuser ( treated with 100 ppm of

Na2S2O5 ) 50 m3/h without any additions to industrial process which there are no

contact between juice or beet and the treated waste water.

10-13 November 2012, Aswan, Egypt Ahmed M. S. Hamad et al 15

TL3.1/

International Conference on: “New Role for the World Sugar Economy in a Changed Political and

Economic Environment ”

On the basis of results, and after recycling 400 m3/h which discharged from Delta Sugar Waste water Plant and achieved zero effluent, we suggest taking into consideration the following simple, but effective rules: good housekeeping and regular maintenance (diminished costs on one side

and prevention of unnecessary water losses on the other). 50 m3/h with condensate, warm water, cooling water and evaporated water

from the crystallization stage ( treated with 0.02 gm/L of technical NaOCl + 0.1 mL/L HCl 33 % ).

division of waste water streams with different quality in order to enable more possibilities for water reuse, regeneration reuse or recycling reuse.

mixing of waste water with fresh water in order to equilibrate contaminant concentration and temperature.

References1. Asadi, M., 2007. Beet-sugar handbook. John Wiley and Sons, Inc., Hoboken,

New Jersey2. Krajnc, D; Mele, M and Glavic, P. (2007): Improving the economic and

environmental performances of the beet sugar industry in Slovenia: increasing fuel efficiency and using by-products for ethanol. J. Clean. Prod., 15, 1240–1252.

3. MPWWR (2009): Ministry of Public Works and Water Resources, Integrated Water Resources Management Plan . The Ministry of Water Resources and Irrigation; Arab Republic of Egypt, Retrieved on November 7.

4. Abu-Zeid. (1992): Water resources assessment for Egypt, paper from Roundtable on Egyptian Water Policy, Alexandria, Egypt, 11-13 April 1992.

5. El-Sadek, A. (2010a): Serious threat to Egypt's water quota needs to be addressed. National Water Research Center, Delta Barrage.

6. Löf ,G. 0. G , Kneese, A. V. (1968): The economics of water utilization in the beet sugar industry. Pub. Resources for the future Inc., Washington D.C.

7. Prashanth, S; Kumar, P. and Mehrotra. (2006): Anaerobic degradability: Effect of particulate COD. J. Environ. Eng. 132(4), 488–496.

8. Weber, J.W, Jr. (1972): Physicochemical processes for water quality control. 640pp. New York: John Wiley & Sons.

9. Bitton. (2005): Waste water microbiology. Third Edition John Wiley & Sons, Inc., Hoboken, New Jersey.

10. Tchobanaglous, G and Burton, FL. (1991): Waste water Engineering: treatment, disposal and reuse. 3rd ed. New York: Metcalf& Eddy Inc. McGraw Hill.

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