Study on Application of Multifunctional Compound Microorganism

Product in the Sewage Plant Treatment for Sludge Reduction

Can Wang

, Xin Jin, Jilin Teng and Ruozheng Li

Beijing GuoDian FuTong Science & Technology Development Co. Ltd., NARI Group Corporation ,Fengtai Disteict,

Beijing 100070, China.

Email: wangcan0305@aliyun.com

Keywords: Sludge reduction, A

/O, sewage plant treatment, microorganism

Abstract: Reducing the quantity of excess sludge has become a popular research subject in wastewater treatment.

Therefore, based on the current sludge reduction theory, some special microbial strains were selected, and

through certain cultivation process, a multiifunctional compound microorganism product was developed to

reduce the sludge quantity. The microorganism product was used in sewage wastewater treatment plant for

pilot test. Five sets of identical equipment with the A

/O process and the same operating method were

adopted, and the effect of SV and MLSS were analysed. The effects on sludge reduction were

compared.The results show that the sludge reduction reaches 57.3%. The multifunctional compound

microorganism product improved the effluent quality and the COD, NH

-N and TN in the effluent are

37.85mg/L, 0.30mg/L and 12.37mg/L respectively. The microorganism does not require any special

treatment unit, and does not change the original treatment process also. Therefore, the microorganism

product will effectively improve the sludge reduction effect, and reduce the pressure of the sludge disposal

for the wastewater treatment plants.

1 INTRODUCTION

Sludge reduction refers to the physical, chemical

and biochemica l means to minimize the amount of

biosolids discharged from the entire wastewater

treatment system. At present, more attention has

been paid to sludge reduction technology. At the

same time, the research of sludge reduction

technology is also the necessary way to make sludge

harmless and resourceful (Li et al., 2007; He and

Zhou, 2004). In the past ten years, sludge reduction

technology has been focused on improving sludge

containing organic degradation methods such as: 1)

sewage treatment process variant; 2) the

biodegradation of sludge was enhanced by

mechanical, biological, thermal or en zy matic

treatment; 3) sludge stabilizat ion process

modification (Zhang and Hong, 2005; Lin and Guan,

2005). At present, sludge reduction technology

based on uncoupling metabolis m, maintaining

metabolism, bioaugmentation and biological

predation are gradually being applied for the

biological treat ment of wastewater (Wang and Song,

2003; Rensink and Ruckens, 1998). However, there

are still many researchers have done much work on

sludge reduction technology.So far, a feasible

treatment method towards sludge reduction , which

can integrate validuty and environmental security

perfectly, has not been developed yet.

In the process of sludge reduction,

bioaugmentation is the means of reducing sludge by

adding microorganisms with specific functions in

the biological treatment system of sludge (Liang et

al., 2004; Li, 2008). Bioaugmentation technology

has been widely used in many aspects of

environmental protection, such as livestock and

poultry manure deodorizat ion, sewage treat ment,

water eutrophication treatment, domestic waste

treatment and so on, with good results achieved

(Zhang et al., 2008; Yuan et al.. 2007; Neyens et al.,

2004). In this study, a sewage treatment plant with a

treatment capacity of 30000 m

/d was used for the

sludge reduction by adding a compound microb ial

preparation. The objective are to investigate the

effect of biological agents on improving effluent

quality of existing treatment systems, and the effect

of sludge reduction.

Wang, C., Jin, X., Teng, J. and Li, R.

Study on Application of Multifunctional Compound Microorganism Product in the Sewage Plant Treatment for Sludge Reduction.

In Proceedings of the International Workshop on Environment and Geoscience (IWEG 2018), pages 44-49

ISBN: 978-989-758-342-1

2 EXPERIMENTAL AND

METHODS

2.1 Raw Water and the Quality

The water quality is shown in Table 1 and 2 as

follows:

Table 1: The quality of Influent.

COD

BOD

mg/L

Index

500

170

160

6.0

Table 2: The quality of effluent.

COD

BOD

mg/L

Index

≤50

≤10

0.5

2.2 The Technological Progress

The municipal wastewater treat ment plant adopts

the A

/O ordinary activated sludge process which

has biological function of biological phosphorus and

nitrogen removal with pre anaerobic and ano xic

stages. Sludge treatment was carried out by gravity

concentration and dewatering with belt dewatering

machine.The process flow is shown in Figure 1.

2.3 Experimental Device and Method

2.3.1 Experimental Equipment

Each point dosing equipment adopts the mixing

barrel and metering pump integrated dosing device,

as shown in Figure 2. The agitator is used when

dispensing, and the dosing solution is added to the

target pool at a certain flow rate by a metering pump.

The total amount of aeration was controlled, and the

amount of aeration grit chamber accounted for 50%,

in addition the other four points accounted for 50%.

2.3.2 Experimental Method

Through the actual influent flow (36000 m

/d) and

the target concentration (2 ppm) of the sewage

treatment plant, the total dosage of mu ltifunctional

compound microorganism product was determined.

The mu ltifunctional co mpound microorganism

product were a mixture of Bacillus,Pediococcus,

Lactobacillus plantarum and some nutrient.

The total amount to be treated is controlled

during the dosing process, the distribution of each

point is added to ensure the total dosage unchanged.

At the same time, according to the operation and

processing of the reasonable adjustment, the dose

distribution at the beginning of the start-up is shown

in Table 3 as follows:

Figure 1: The technological process route.

Figure 2: The picture of the dosing equipment.

Table 3: The dosage of product at the beginning.

Grit

Removel

Anaerobi c

tank-

South

Anaerobi c

tank-

North

Anoxic

tank-

South

Anoxic

tank-North

Dosage

proportion

50%

15%

10%

Study on Application of Multifunctional Compound Microorganism Product in the Sewage Plant Treatment for Sludge Reduction

The test started on the eighth day, the target

concentration was adjusted to 1ppm, the total

dosage of the reagent was determined, and the

dosage was reduced at the same point with each

other in the dosing process. Dosing at this stage was

shown in Table 4 as follows:

Table 4: The dosage of product at the stable period.

Grit

Removel

Anaerobic

tank-

South

Anaerobic

tank-

North

Anoxic

tank-

South

Anoxic

tank-

North

Dosage

proportion

50%

15%

10%

Continuously adding the compound

microorganis m agent, the change of effluent water

quality in each section of sewage treat ment process

were analyzed, and the quality of raw water,

primary sedimentation tank effluent, the two series

of anaerobic tank effluent, biochemical pool water,

the final effluent were detected.

2.4 Test Method

Routine test data for water and various units COD,

-N, TN, MLSS, SV30, nitrification liquid reflu x

ratio, sludge reflu x rat io and regular bio logical

microscopy etc..

The common indexes such as COD, NH

-N, TN

were detected by the national methods. The sludge

concentration (MLSS) were monitored by

gravimetric method. The by national standard

method. Microscopic examination were measured

by optical microscope (XSZ-G, Chongqing optical

instrument factory).

3 RESULTS AND DISCUSSION

3.1 The Effect about COD

The difference between two series biochemical

process unit is not much, the quality indices are

shown in Figure 3.

Figure 3 indicates that in despite of the raw

water quality fluctuate, the effluent COD can be

kept below 50 mg/ L, which can fully meet the

demand of first-degree A standards of GB18918-

2002. The research that using MEMA(multi-

environmental microbial agent) in Carrousel

oxidation ditch have the consistent conclusion

(Yang et al., 2016).As the influent contains a large

number of organic suspended substances, the COD

concentration of influent is very high, and generally

fluctuates between 800~2000 mg/L. A fter the

treatment of aerated grit tank, large particles

suspended solids were removed, the COD of the

effluent decreased significantly, could generally

reach as low as 200~250 mg/L. The effluent COD of

primary sedimentation tank was relatively stable,

which reduces the load impact on the subsequent

biochemical treat ment. The COD was reduced

gradually after biochemical treatment, the effluent

was below 50 mg/ L.The average concentrations of

COD in effluent were 37.85 mg/L. The two series of

North and South were stable. In addition, the COD

of effluent was stable within two weeks after adding

compound microbial preparation, and all of them

could reach the first level A emission standard.

Figure 3: The removal of the COD.

3.2 The Effect about TN

Generally, the influent TN is between 60~90 mg/ L,

and the removal rate of TN is about 50% by the

removal of suspended particulate matter in the

aeration grit chamber. As shown in Figure 4, the

effluent TN of primary sedimentation tank is

between 30~45mg/ L, and it is relatively stable

before entering biochemical pool, the TN in

biochemical react ion area is greatly reduced, and

nitrificat ion denitrification occurs at this stage, it

can be concerned that there exists SND in A

system (Fang-Ying et al., 2006). At the same time,

the compound microbial preparation products were

added in the anaerobic zone and ano xic zone, and

the TN of the South and North aerobic section had

litt le difference, all of wh ich were between 11-

15mg/L. After second sedimentation tank treatment,

TN removal little. Within 8 days of treat ment, the

IWEG 2018 - International Workshop on Environment and Geoscience

effluent fluctuated but remained stable.After 13 days

(about a sludge age cycle), the concentration of TN

was reduced to 9~10 mg/L when adding the target

concentration of 1 ppm. The average concentrations

of TN in effluent were 12.37 mg/ L and which could

reach the first class A standard (<15mg/ L). However,

dosing the compound microorganism product 13

days later (about a sludge age period), the TN

decreased to 9~10 mg/L.

Figure 4: The removal of the TN.

3.3 The Effect about NH

-N

After adding multifunctional co mpound

microorganis m product, sludge age is prolonged,

which is conducive to the growth of nitrifying

bacteria, and increased nitrification in the same

conditions. It is conducive to nitrification of

ammon ia nitrogen. As shown in Figure 5, the NH

N remova l efficiency is stable after adding the

compound microbial agent, and kept the good

treatment effect.The average concentrations of NH

N in effluent was 0.3 mg/ L, the removal rate was

more than 99%.

Figure 5: The removal of the NH

-N.

3.4 Sludge Sedimentation Performance

Change Analysis

The structure of microbial floc also direct ly affected

the proportion of aerobic zone and anoxic zone in

sludge floc and mass transfer effect in the floc, it

also affects the degree of difficu lty in microbial

acquisition of DO and substrate. The larger sludge

particles increased the proportion of anoxic

microenvironment, and the mass transfer resistance

of sludge particles with compact structure was large

(Guo et al., 2007). The organic carbon source in

water is difficult to penetrate into the sludge floc,

and the results is that it is difficu lt for the internal

microorganis m to contact with carbon source, which

affects the removal efficiency of carbon and

nitrogen.

The changes of SV30 and M LSS were observed

after adding co mpound microbial preparat ion, as

shown in the Figure 6. During the whole experiment,

the MLSS in the biochemical pool of the North

Series decreased from 5300 mg/ L to 4700 mg/ L

after the addition of microorganis m, and the MLSS

in the South series also decreased. Fro m the change

curve of SV30, the SV30 g radually decreased, and

the sludge settling performance was in good

condition.SV30 has a gradual downward trend, and

the observation of settlement process shows that

sludge settling speed is significantly accelerated,

sludge settlement performance becomes better.After

adding microbial preparation, the sludge settlement

performance was imp roved, the sludge volume was

reduced by 57.3%, the mic robial preparation could

improve the effluent quality.

3.5 Microscopic Examination of

Microbial Biochemical Pool

Routine microscopic examination of activated

sludge in the biochemical tank, microscopically

observed case worms, roaming insect, vorticella,

epistylis, rotifers, dun pellionella, a little

whipworms, as shown in the Figure 7. The dominant

species are Vorticella and rotifer. After adding

mu ltifunctional compound microorganis m product,

the microbial phase changed a little, and the

microbial species were abundant. The growth

condition is stable, the floc structure was fluffy, the

color was yello w brown, and the sludge activity

strong.

Study on Application of Multifunctional Compound Microorganism Product in the Sewage Plant Treatment for Sludge Reduction

Figure 6: The sludge performance.

a. Epistylis

b. Rotifers

c. Vorticella

Figure 7: The microscopic examination.

4 CONCLUSIONS

The study highlights the effectiveness of

mu ltifunctional compound mic roorganism p roduct

in increasing efficiency and reducing consumption

of infrastructure. There is no effect on the stability

of existing system in WWTP. Moreover, the

removal rate of COD, NH

-N and TN can be

improved by the biochemical system when the

influent water quality fluctuates greatly. The results

suggest that adding compound microorganism

product target concentration was 2 ppm, the A

system was very stable. After adding

mu ltifunctional compound microorganis m product,

the sludge settlement performance was improved,

the sludge volume was reduced by 57.3%, the

average concentrations of COD, NH

-N and TN in

effluent were 37.85 mg/ L, 0.3 mg/L, 12.37 mg/ L,

respectively.The compound microbial preparation

has good sludge reduction effect. At the same time,

reduce the burden of sludge treatment and disposal

of sewage treat ment plant, reduce the degree of

organic sludge. It does not change the original

treatment facilities and operation mode, and the

power consumption of the whole system will not

increase.

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Study on Application of Multifunctional Compound Microorganism Product in the Sewage Plant Treatment for Sludge Reduction