Characterization of Metal Exchanged Zeolite-A using Quantasorb and Mercury Porosimeter


ISSN-1996-918X 

 

Pak. J. Anal. Environ. Chem. Vol. 13, No. 2 (2012) 103 – 106  

 

 

Utilization of Paper Sludge Wastes for Treatment of 

Wastewater from Food Processing Industries 
 

Ahmed H.A. Dabwan1*, Kiyoyuki Egusa2, Daizo Imai2, Hideyuki Katsumata2, 

Tohru Suzuki3 and Satoshi Kaneco2 
1Faculty of Chemical Engineering Technology, Tati University College, Jalan Panchor, Teluk Kalong, 24000 Kemaman, 

Terengganu, Malaysia 
2Department of Chemistry for Materials, Graduate School of Engineering, Mie University, Tsu, Mie 514-8507, Japan 

3Environmental Preservation Center, Mie University, Tsu, Mie 514-8507, Japan 

 

Received 18 July 2012, Revised 05 October 2012, Accepted 11 October 2012
 

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Abstract 

The food processing industries usually produced large amount of wastewater containing fine and 

small particles. It takes long time for complete settlement of the fine and small particles in the 

wastewater. The coagulation method appears to become one of the useful treatments. New 

inorganic coagulant named “Agoclean‒P” has been developed from paper sludge ash. The 

treatment by coagulation and flocculation were carried out for the wastewater from three different 

food processing industries namely soup, tofu, and natto. “Hi‒Biah‒System”, which is an in‒situ 

solidification system, was used for the continuous treatment of wastewater. The parameters for the 

water quality were pH, five‒day biochemical oxygen demand (BOD5), chemical oxygen demand 

(COD), total suspended solids (TSS), total nitrogen (TN) and total phosphorus (TP). These 

parameters after the treatment became much lower values relative to those obtained before the 

treatment. 

 

Keywords: Food processing industries; Paper sludge ash; Coagulant; Wastewater treatment; 

Chemical oxygen demand. 

----------------------------------------------------------------------------------------------------------------------------- --------------- 

Introduction 

 

Wastewater treatment from the food processing 

industries needs special treatment method owing to 

high chemical oxygen demand (COD), high 

concentration of fats, oils, greases, ammonia, and 

minerals, and high levels of suspended solids with 

low settling property. Generally, the food treatment 

processing uses large amount of water at different 

stages. Because large amount of wastewater 

contains fine and small particles, it takes long time 

for complete settling. Different approaches for 

wastewater treatment have been investigated in 

order to develop effective methods for the 

treatment of wastewaters from food processing 

before releasing the wastewater into the open 

environment. Therefore, the coagulation method 

seems to be one of the promising treatments, 

because it is simple, easy to operate and low cost.  

 
Paper sludge is generally dried in air, and 

subjected to incineration. The resulting ash is then 

disposed by landfilling or is used by mixing in 

cement. The quantity of paper sludge produced is 

approximately 1.5 million tons per year in Japan, 

and about 0.6 million tons of incinerated ash is 

formed thereby [1]. Paper sludge ash has been used 

in many applications such as cement replacement 

materials [2], raw material for constructional brick 

[3], and effective adsorbent for arsenic, cadmium 

*Corresponding Author Email: ahmedmie2000@gmail.com  

 



Pak. J. Anal. Environ. Chem. Vol. 13, No. 2 (2012) 

 

104 

and lead ions in the wastewater [4]. 
In the present work, new inorganic 

coagulant named “Agoclean‒P” has been 

developed from paper sludge ash. Furthermore, the 

inorganic coagulant has been applied to the 

treatment of wastewater from food processing 

industries. 

 

Materials and Methods 

Preparation of inorganic coagulant named 

“Agoclean‒P” 

 

Waste paper sludge was provided from 

the paper mill wastewater treatment plant. The 

paper sludge was dewatered and given to the 

incinerator for the generation of heat energy. Paper 

sludge ashes were collected from fluidized 

bed‒reactor in the incinerator. The temperature in 

the incinerator was 800 oC or higher in order to 

operate the system without the formation of 

dioxins. Since the paper sludge ashes alone could 

not become a coagulant, the addition of other 

inorganic materials was necessary. 

 

Wastewater from food processing industries 

 

The slurry wastewaters were collected 

from three food processing industries (soup, tofu 

and natto factories). Approximately 5 m3 of each 

wastewater was applied into the continuous flow 

wastewater treatment process. 

 

Jar tester experiment (Coagulation and 

flocculation) 

 

The Jar‒tester was used to evaluate the 

optimum time for coagulation and flocculation 

with inorganic coagulant (Agoclean‒P). The tests 

were performed in one liter plastic jar (rectangular 

shape) at ambient temperature (about 25oC). 

 

Continuous wastewater treatment with Hi‒Biah‒ 

System (HBS) 

 

The in‒situ solidification system named 

“Hi‒Biah‒System” was used for the continuous 

wastewater treatment. The detailed information has 

been described previously [5,6]. The HBS consists 

of a main stock tank of sediments, a coagulant 

chamber, reactors (coagulation and flocculation) 

and a dewatering section. The treatment capacity 

was approximately 1~2 m3/hour. The 

agglomeration of small particles into big flocks, 

the separation, handling and disposal for the sludge 

were performed during the continuous treatment. 

 

Analytical methods 

 

Chemical oxygen demand (COD), 

five‒day biochemical oxygen demand (BOD5), 

total nitrogen (TN) and total phosphorus (TP) were 

measured by Japanese Industrial Standard 

(JIS)‒standard analytical methods. The 

concentrations of total suspended solid (TSS) was 

determined by a spectrophotometer with a 

resonance line of 660 nm, based on the Japanese 

Industrial Standard (JIS)‒standard analytical 

methods (K0101). 

 

Results and Discussion 

 

The developed inorganic coagulant was 

applied into the treatment of wastewater from 

Japanese food processing industries such as soup, 

tofu and natto factories. Soup is used in the instant 

noodle making. Tofu is very popular in Japan and 

Japanese people have had the tofu in daily life. 

Tofu is prepared from grained soybeans. Natto is 

produced from the ferment of soybeans. 

 

The chemical compositions of paper 

sludge ash are shown in (Table 1). Since the paper 

sludge ashes alone cannot be applied as the 

coagulant, the inorganic coagulant Agoclean‒P 

was prepared by the addition of other inorganic 

materials. The chemical compositions for 

Agoclean‒P are shown in (Table 2). 

 
Table 1. Chemical compositions for paper sludge ash 

 

Components Content (%) 

CaO 10~35 

SiO2 25~35 

Al2O3 23~40 

SO3 3~8 

Fe2O3 1.5~5 

MgO 1.5~5 

TiO2 0.5~1.5 



Pak. J. Anal. Environ. Chem. Vol. 13, No. 2 (2012) 

 

105 

K2O 0.3~1 

 

Table 2. Chemical compositions for Agoclean-P coagulant 

 

Components (%) 

CaO 44.2 

SiO2 26.9 

Al2O3 12.7 

SO3 12.2 

Fe2O3 1.2 

MgO 1.2 

TiO2 0.8 

K2O 0.4 

Others 0.4 

 

Although the traditional coagulants such 

as polyaluminium chloride (PAC) and polymer 

coagulant were tested for the treatment of 

wastewater from Japanese food processing 

industries, the coagulation could not occur for the 

wastewater. The reason is not clear. May be, high 

concentration of fats, oils and greases in the 

wastewater hinder the coagulation and flocculation 

processes. 

 

First, the Jar‒tester was applied to 

evaluate the optimum time for coagulation and 

flocculation with Agoclean‒P. Rapid mixings at 

200 rpm for 4 minutes after the addition of 

Agoclean‒P, followed by slow mixing 20 rpm for 

1 minute, were selected as the optimum conditions. 

 

The purification parameters before and 

after the treatment are pH, 5‒day biochemical 

oxygen demand, chemical oxygen demand, total 

suspended solids, total nitrogen and total 

phosphorus. The continuous HBS treatment with 

inorganic coagulant Agoclean‒P was applied into 

the treatment of wastewater from Japanese food 

processing industries. The results are summarized 

in (Table 3). Although the initial pH for the three 

wastewaters was in the acidic range from 5 to 6, 

pH values were neutral between 8‒8.5 after the 

treatment.  

 

The values for chemical oxygen demand 

and five‒day biochemical oxygen demand 

drastically decreased after the treatment, and the 

removal efficiencies for COD and BOD5 were 

88‒92 and 85‒97%, respectively. Although the 

total suspended solid before the treatment was very 

high (>8000 ppm), all of the values became less 

than 100 ppm after the continuous HBS treatment 

with inorganic coagulant Agoclean‒P. Also, the 

values of total nitrogen and phosphorus after the 

treatment were much lower compared with those 

obtained before the treatment. 

 
Table 3. Continuous wastewater treatment with HBS with 

inorganic coagulant Agoclean‒P 

 

Food factory pH 
BOD5 

(ppm) 

COD 

(ppm) 

TSS 

(ppm) 

TN 

(ppm) 

TP 

(ppm) 

Soup 
before 4.5 600 1100 >8000 80 39 

after 8.2 16 120 <100 18 <1 

Tofu 
before 4.5 1100 2100 8000 100 52 

after 8.0 92 170 <100 5 <1 

Natto 
before 5.5 660 1500 >8000 30 27 

after 8.5 100 180 100 19 2.6 

 
Flow rate; 1.5 ton/hour. 

Dose of Agoclean‒P; 2000 ppm for soup, 1000 ppm for tofu, 2500 

ppm for natto. 

 

In order to explain possible basic 

fundamental coagulation mechanisms for the 

wastewater treatment with Agoclean‒P, the micro 

structure of the surface of the dried products after 

the coagulation was evaluated by scanning electron 

microscopy (SEM). The needle‒shaped ettringite 

was observed in the coagulated products (Fig. 1). 

We can conclude that the ettringite formed a 

three‒dimensional network structure in the 

coagulated products for the wastewater treatment 

[7]. Therefore, the coagulation owing to the 

formation of ettringite may play the significant role 

on the purification of wastewater. 

 



Pak. J. Anal. Environ. Chem. Vol. 13, No. 2 (2012) 

 

106 

 

 
 

Figure 1. Ettringite observed in the dried products after the 

coagulation. 

Conclusion 

 

The wastewater treatment by the 

coagulation with Agoclean‒P inorganic coagulant, 
which consisted of paper sludge ash wastes, 

appears to become one of very effective methods 

for the wastewater from food processing industries. 

The continuous HBS treatment system with 

inorganic coagulant Agoclean‒P can be applied 
into 5m3/h of wastewater. The quality of aqueous 

solution released from different food processing 

industries after the treatment could be drastically 

improved by the present methods 

 

Acknowledgments 

 

The main research was partly supported 

by the Ministry of Education, Culture, Sports, 

Science, and Technology of Japan. All experiments 

were conducted at Mie University, Japan and Tati 

University College, Malaysia. Support was 

provided to A. H. A. Dabwan as the researcher for 

an Invitation Fellowship Program for Research in 

Japan (Long‒term) from the Japan Society for the 

Promotion of Science. Any opinions, findings, 

conclusions, or recommendations expressed in this 

paper are those of the authors and do not 

necessarily reflect the view of the supporting 

organizations. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Ettringite