بسم الله الرحمن الرحيم

Industrial Waste Water Treatment And Reuse In Delta

Sugar Company

معالجة مياه الصرف الصناعى وإعادة

استخدامها بمصانع شركة الدلتا للسكر

ChemistAhmed M. S. Hamad

B.Sc. Microbiology , Faculty of Science, Tanta University(1997)

and Diploma of Science and Technology

of sugar industry (Chemistry section), Sugar Technology Research Institute

Assiut University(2007)and

Master in Science and Technology of sugar industry

Sugar Technology Research Institute, Assiut University (2012)

PREFACEOver a period of 30 years, the Egyptian citizen's

share of Nile water will drop from 2000 cubic meters to only 600 cubic meters per capita.

While the international water poverty line is set at 1000 cubic meters per year .

Now with Egypt's water quota is remaining as it is and the population is growing year after year, the water share of every citizen will continue to drop further.

So we look for non-conventional water sources like reusing of treated waste water.

North Delta especially Delta Sugar Company suffers from water shortage at the campaign (during the season of rice cultivation).

High lights the importance of research in complete recycling and reuse of 400 m3/h treated waste water, by adding a new tertiary treatment under very economic conditions.

Introduction Beet factories produce more waste products than

cane factories or raw sugar refineries. Beet factory generate two types of waste waters,

flume wastes and factory wastes. The flume waste water system is used for

transporting and cleaning of beets. The sugar that is leached into this water contributes a high organic load in the flume system (few hundred mg/L to more than 20,000 mg/L BOD).

Due to the high strength of beet factory wastes (flume wastes and factory wastes), anaerobic digesters are almost universal.

While sugar (the main contaminant of sugar factory effluent) is not toxic, it readily the ideal substrate for microorganisms growth .

The exponential growth of microorganisms causes the depletion of oxygen in natural streams.

Aquatic organisms that require oxygen will suffer and may die as a result.

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.

• The United Nations reports pointed that per capita is declining continuously after the share was 3000 cubic meters in 1960, and decreased to 1200 cubic meters in 2000.

• Also pointed out that at 2025 bringing per capita to 337 cubic meters per year.

Status of Water SupplyWater resources in Egypt are restricted to

the following resources:

· Nile River· Rainfall and flash floods,· Groundwater in the deserts and Sinai· Possible desalination of sea water

Each resource has its limitation on use; the following is a description of each of

these resources.

1. Nile River Water• Main and almost exclusive resource of fresh

water is the Nile River.

• The Convention on the Nile Basin countries, concluded in 1929, gives Egypt the right to use 55.5 billion cubic meters of Nile water.

• There are great difficulties faced Egypt in the modified convention of the Nile Basin countries to reduce their share of water.

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. No agreement has been reached.

Without the Nile River flowing through, there will be no more Egypt as we know.

2 . RainfallRainfall happened only in the winter season in the form of scattered showers. Therefore, it cannot be considered a dependable source of water.

3. Flash Floods Flash floods due to short-period heavy storms are considered a source of environmental damage especially in the Red Sea area and southern Sinai.

This water could be directly used to meet part of the water requirements or it could be used to recharge the shallow ground water .

4 .Groundwater in the Western Desert and Sinai

Groundwater found in the western desert ,the New Valley governorate and the region east of Owaynat. It has been estimated that about 2000,000 BCM of fresh water are stored in this aquifer. However, groundwater found at great depths and the aquifer is generally non-renewable. Therefore, the utilization of such water depends on pumping costs and its depletion rate versus the potential economic return on the long run.

5 .Desalination of Sea Water

Desalination of seawater in Egypt has

been given low priority as a source of

water.

That is because the cost of treating

seawater is high compared with other

sources, even the unconventional sources.

Non-conventional Water Resources

There are other sources of water can be used to meet part of the water requirements.

These sources are called non-conventional sources, which include :-

· The reuse of agricultural drainage water

· The reuse of treated sewage water

Reuse of Treated Waste WaterWaste water treatment could become an

important source of water and should be considered in any new water resource development policy.

Proper attention must be paid to the associated issues with such reuse.

The major issues include public health and environmental hazards as well as technical, institutional, and socio-cultural.

Objectives of this studyPhysical, chemical and biological analysis of

the influent and effluent water after factory treatments

Different treatments of the effluent water after factory treatments by using:

1- CaO for fluming water 2- H2SO4 for juice extraction 3- Temperature for juice extraction 4- Formalin for juice extraction 5- SO

2 for juice extraction

6- Chlorination for condensate water A.

RESULTS

After this conventional waste water treatment process the treated waste water from Delta Sugar waste water plant is 400 cubic meters per hour. I. Physical analysisII. Chemical analysisIII. Biological analysis

Table (1) : Physical properties of the treated waste water

Law 48/1982 Effluent Influent Parameters

35 35 35-40 Temp° C

2000 1675 2880 TDS ppm

6-9 7-8 6-8 pH

60 35 1596 B.O.D ppm

100 50 2968 C.O.D ppm

60 9 214 S.S ppm

-  921 1728 EC µs /cm

- Nontoxic Toxic Toxicity test

Table (2) Chemical properties of the treated waste water

Parameters Influent effluent Law

48/1982NO3 ppm 14.7 5.4 40

PO4 ppm 9.95 3.l 10

Cu ppm 0.370 0. 230 1

Fe ppm 0.05 0.00 1

Pb ppm 0.29 0.15 0.5

Cd ppm 0.340 0.01 0.05

SO4 ppm 0.89 0.64 1

NH3 ppm 1.9 0.5 3

From Tables (1,2) the physical and chemical characteristics are suitable and safe to be used in beet sugar processes

Biological assay of treated waste water• The samples were inoculated in bacterial and

fungal media and incubated for 24 hr. and 7 days, respectively. The results were:

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

2. 9 ×104 (cfu/ml) Bacterial specices. (on nutrient agar media)

3. 160×102(cfu/ml) Fungi organisms and 7×102 Yeast sp. on Czapeks̓’ Culture and Emmons media, respectively.

oThe industrial problem is that this water is containing microorganisms specialized in breaking hydrogen bond, leading to hydrolyzing of sucrose in the factory.

oSo, searching for suitable disinfectant to kill microorganisms and safety reuse in sugar beet processing in the form of new treatment process (tertiary treatment) is the main goal of this research.

Identification of bacterial samplesWith screening the treated waste water sample

on nutrient agar culture medium the dominant

bacterial growth was restricted in five colonies.

These five 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.

• The isolate no. 1 is related to be Acinetobacter sp., Acinetobacter junii with 80 % similarity , and Acinetobacter calcoaceticus with 79%. It may be new isolates or mutated bacteria.

Acinetobacter species

• The isolate no. 2 is related to Bacillus subtilis, Bacillus amyloliquefaciens and Bacillus methylotrophicus. with 90% similarity

A BA: Bacillus subtilis and B: Bacillus amyloliquefaciens.

• The isolate no. 3 is related to be Providencia sp. and close to Providencia stuartii with 99% similarity

Providencia species

• The isolate no. 4 is related to be Bacillus sp.

With 95% similarity to Bacillus licheniformis

and Bacillus subtilis

Bacillus licheniformis

• The isolate no. 5 is related to Aeromonas sp and

give 93% similarity with Aeromonas punctata

and Aeromonas hydrophila .

A BA: Aeromonas hydrophila sp, and B: Wound infections caused by Aeromonas hydrophila, in a fish

Tertiary TreatmentThe residual carbonated mud was the first think for disinfecting the treated waste water for using as flume water due to:No economical costHigh concentration of CaCO3

Unfortunately, this residual mud elevated the pH 8.7 only. Moreover the COD was increased due to the organic component adsorbed on the mud. Also the springily soluble of the carbonated mud another disadvantage. calcium oxide was the second choice.

1. Use calcium oxide as disinfection for flume water

Raw water which used in washing beet, is 250 cubic meters per hour.

The following experiment was designed to determine the sufficient amount of CaO to be added for killing all micro-organisms in the treated waste water to be used as flume water.

Table (3) Effect of different concentration of CaO on the total bacterial and fungal counts in effluent treated waste water.

CaO dose g/L

pH Total bacterial

count(cfu/ml)

Total fungal count(cfu/ml)

0.0 8.3 6×104 3.3×103

0.4 10.4 1.3×102 1.7×102

0.6 10.7 59 22

0.8 11.1 8 3

1.0 11.4 0 0

2.0 11.9 0 0

3.0 12.0 0 0

0.4 12.1 0 0

5.0 12.2 0 0

9.0 12.3 0 0

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

So, the quantity of CaO which will be add to 250 m3/h is 250 Kg CaO / h (i.e 6 ton Cao / day )

In beet sugar factory calcium oxide already be used in beet washing to disinfect the bacterial growth in flume water, prevent the destruction of sucrose in the beet washing process and improve settling mud from water to be recycled

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

Calcium oxide is an alkaline compound that can create pH levels as high as 12, the cell membranes of microorganisms are destroyed.

When quicklime (CaO) is used, an exothermic

reaction with water occurs. This heat release can increase the temperature of the biological waste to 70ºC, which provides effective pasteurization.

The solubility of calcium hydroxide also provides free calcium ions, which react and form complexes with odorous sulfur species.

How Lime Treatment Works

2. Uses the treated waste water in juice extraction

• The biggest challenge is how to use the treated waste water in juice extraction(100 m3/h) in diffuser because the pH in diffuser is (5.8 to 6.2) needed for best juice extraction from beet slice.

• It is not suitable for using CaO at pH 11.4.

A. Use sulfuric acid as a biocide for treated waste water

H2SO4

ml/l

pH of Effluent Total bacterial

count(cfu/ml)

0.0 8.2 6×104

0.4 6.5 4×104

0.9 5.1 32×103

1.2 4.6 15×103

5.0 4.0 1.1×103

15.0 3.3 800

20.0 2.8 440

25.0 2.4 150

There is no complete disinfection to the bacterial growth. Thus, sulfuric acid cannot be used as a biocide for the treated waste water.

B. Effect of increasing temperature for disinfection the treated waste water.

Temp. °C Total bacterial

count(cfu/ml)30 6×104

45 3.4×105

60 4.1×103

65 3.2×103

70 3.7×102

75 1.2×102

80 90

85 40

90 16

Raising temp 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.

C. Effect formalin 37% as biocide for the effluentDose of HCHO ppm Total bacterial

count(cfu/ml)

5 2.2×104

10 5×103

15 2.9×103

20 1.4×103

25 6×102

30 140

35 80

40 25

45 7

50 0

55 0

60 0

The effective dose of 37% HCHO is 50 ppm

Formalin is traditionally being used as biocide in beet sugar diffuser with maximum dose 90 ppm.

The application of formalin has been discontinued in some countries and is expected to be discontinued in the remaining countries soon.

D. Use sulfur dioxide as biocide for effluentSeveral 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 juiceLowers the pH of the diffuserImproves the pressing qualities of the pulp 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, containing more than 66.0% SO2 w/w releases sulfur dioxide gas when mixed with water.

• The following experiment was to determine the

optimum dose to kill all microorganisms in treated waste water by using Na2S2O5.

• The suitable concentration of Na2S2O5 is 100 ppm at which there is no living microorganism is found.

• The proposal daily amount of sodium metabisulfite for disinfecting 2400 m3 treated waste water is 240 Kg costs 792 £ per day.

Effect of different concentrations of sodium metabisulfite on the total bacterial and fungal counts in effluent treated waste water.

Dose of Na2S2O5 ppm Total bacterial count(cfu/ml) Total fungal count(cfu/ml)

5 5.2×104 3.1×103

10 4.6×104 2.9×103

15 2.9×104 1.4×103

20 1.2×104 9×102

25 8×103 7×102

30 3.9×103 6×102

35 3.1×103 4×102

40 2.9×103 2.5×102

45 2.4×103 2.2×102

50 1.8×103 1.6×102

55 1.5×103 1.2×102

60 1.1×103 90

65 8×102 60

70 3.3×102 27

75 1.2×102 9

80 70 3

85 32 1

90 13 0

95 4 0

100 0 0

105 0 0

This calculation for disinfection of the treated waste water which will be used for 100 m3/h as fresh water in diffuser but if we want to use Na2S2O5 as a biocide for juice in diffuser. Where the rate of using SO2as biocide in sugar beet processing is 0.3 Kg/t the calculation will be as the following. Na2S2O5 2 SO2

190 128 0.445 0.30the rate of beet processing in our factory 16000 ton of beet in day. 16000 ton/d × 0.445 = 7120 Kg/d = 23496 £

how sulfur dioxide acts as biocide Sulfur dioxide is most effective as an antimicrobial

agent in acidic media.

This effect may result from conditions that permit dissociated compounds to penetrate the cell wall.

The reduction of essential disulfide linkages in enzymes, and the formation of bisulfide addition compounds that interfere with respiratory reactions.

3. Disinfection of the condensate watero 50 m3/h of a “dirty” stream of evaporation

condensate and evaporated water from a crystallization stage is used in diffuser.

o This water connection is not active because of its high microorganism's content.

o Chlorination with sodium hypochlorite, containing 15 % to 16 % of active chlorine, is an economical and effective procedure for this water disinfecting.

Effect of different doses of NaOCl on the total bacterial and fungal counts in condensate water

NaOCl dosegm/l

Total bacterial count(cfu/ml)

Total fungal count(cfu/ml)

0.0 4×102 1.1×102

0.01 60 40

0.015 7 3

0.02 0 0

0.03 0 0

Amount of chlorine that would destroy microorganisms approximately 0.02 gm/L of technical NaOCl.

The water pH value must be maintained at 7.0 to increase the efficiency of sodium hypochlorite by using technical, HCl 33 %.

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.

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 after secondary treatment used without any additions to industrial process which there are no contact between juice or beet and the treated waste water ( cleaning, transporting, cooling,…).

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 (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.