EVALUATION OF INDUSTRIAL WASTEWATER TREATMENT PLANT

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A CASE STUDY OF NBC

*Check the Final Water Analysis and Compare with WHO & FAO

CHAPTER ONE

INTRODUCTION

1.1 Background of study                                                                         1

1.2 Statement of the problem                                                                  3

1.3 Objectives of the study                                                                      3

1.4 Limitations of the Project                                                                  3

1.5 Scope of the Project                                                                           4

1.6 Justification of the Study                                                                  4

 

 

 

CHAPTER TWO

LITERATURE REVIEW

2.1 Wastes from Water Treatment Plant                                       5

2.2 Waste Characteristics                                                                         8

2.3 Management of Sludge                                                                      13

2.4 Minimizing Sludge Production                                                        13

CHAPTER THREE

METHODOLOGY

3.1 Effluent Treatment Plant at Nigerian Bottling Company               15

CHAPTER FOUR

RESULT AND DISCUSSIONS

4.1 Anaerobic                                                                                           28

4.2 Treatment of Brewery Waste Water for Re-use                     29

4.3 Membrane Filtration                                                                          31

4.4 Non-Thermal Quenched Plasma                                                       33

4.5 Electrochemical Methods                                                                  37

4.6 Microbial Fuel Cells                                                                          38

4.7 Carbon                                                                                                          38

4.8 Discussion and Synthesis of Findings                                             40

4.9 Comparison of Technologies                                                            40

CHAPTER FIVE

CONCLUSION AND RECOMMENDATIONS

5.1 Conclusion                                                                                         44

5.2 Recommendation and Suggestion                                                    45

REFERENCES                                                                                       47

 

 

 

 

ABSTRACT

The study was carried out to evaluate the performance of wastewater treatment plant [WTP] consisting of membrane Bio-reactor [MBR], Nano-filtration [NF] and Reverse osmosis [Ro] processes for wastewater treatment to determine its reuse characteristics. Water samples were collected from raw sewage effluent, Membrane Bio-reactor [MBR], reverse osmosis [RO] and Nano-filtration [NF] water treatment processes. Experiment results showed that some water quality parameters reduction [%] was 96.5, 95.17, 80.1, 98.29 and 94.37 for Ca, Mg, Na, SO and Cl, respectively in the new RO membrane-product water. Whereas in the case of new NF membrane, the reduction [%] in some water quality parameters was 75.56, 75.34, 32.85, 97.22 and 11.59 for Ca, Mg, Na, Cl and SO, respectively.

The removal efficiency [%] of RO-membrane for some ions was 61.2, 70.4, 58.8, 33.33 and 57.93 for Ca, Mg, Na, Cl and SO respectively. The significant in the ion removal efficiency might be subjected to fouling and bio-fouling of the membrane bio-reactor [MBR], RO and NF membranes due to the presence of organic pollutants coupled with wear and tear of membranes after 9years of installation. Waste water which causes disease called water borne disease which may be treated with the application of primary, secondary or tertiary methods. The study findings provided concrete clue for the existing wastewater treatment methods with more advanced methods using ceramic membranes. The research further highlighted the necessary to replace the NF and RO membrane used in these two water treatment techniques.

 

 

CHAPTER ONE

INTRODUCTION

  • background of Study

EVALUATION OF INDUSTRIAL WASTEWATER TREATMENT PLANT

Most water treatment plants [especially large plants] employ coagulation, sedimentation, and filtration processes for water purification. The major sources of waste are the sedimentation basins and filter backwashers. Alum coagulation sludge, which are high in gelatinous metal hydroxides, compromise large quantities of small particles. These are among the most difficult sludge to handle because of their low settling rate, low permeability to water, and thyrotrophic characteristics.

Generally, about 5% of the treated water is used foe washing filters. Volume reduction of backwashes and recycling of wash water to the plant influent can reduce waste production and cut costs. In the case of treatment plants that remove iron and manganese through Aeration or potassium permanganate oxidation, disposal of sludge to receive water may cause problems such as water discoloration and destruction of aquatic life. Treatment plants that use an ion exchange softening process have brine waste [high salts] which become critical disposal problems, especially when the sludge has a high manganese content. The salts cannot readily be recovered or removed from the wastes.

Brine wastes are almost impossible to treat.

Formerly, wastes from water treatment plants were returned to their original source or discharged to nearby receiving water. Illinois laws and regulations now consider waste discharge directly from water treatment plants to receive water as pollution. All wastes have to be treated to an acceptable level prior to their release into the environment and water treatment plant wastes are no exception. Site-specific variance for direct discharge may be granted by the pollution control authorities. In these cases, treatment of water plant wastes is not necessary before final disposal.

Many water treatment plants do not have facilities to investigate the quality of waste production have not been well defined, and the composition of wastes has scarcely been reported in the literature.

According to the UNEP/UNHABITAT document, wastewater is referred to as “sick water”. Thus, waste water is defined by Corcoran et al….. [2010] as a combination of one or more of;

  1. Domestic effluent, consisting of black water [excreta, urine and fiscal sludge] and grey water [kitchen and bathing wastewater].
  2. Water from commercial establishments and institution including hospitals.
  3. Industrial effluent, storm water and other urban run-off.
  4. Agricultural, horticultural and aquaculture effluent, either dissolved or as suspended matter.

Very little research has been conducted on the effects of coagulation and lime sludge applied to farmlands. Thus, cheremissi, 1981investigation that the quality as well as the quantity of clean water supply is of importance for the welfare of mankind.

 

  • Statement of Problem

According to Parawira Gains D, 2005, oxygen demanding waste causes depletion of dissolved oxygen from the water and this is harmful to aquatic organisms. Diseases causing waste such as pathogenic micro organism causes dangerous water borne disease like Cholera, typhoid, dysentery and Polio. Synthetic organic compounds such as pesticides, insecticides and other chemicals are very toxic to plants and animals and humans. Some of them cause offensive, odors and taste in water. Inorganic waste stimulates algal growths in water and metal toxicity in aquatic ecosystem. It causes chromosome damage and interferes with the process of heredity in man.

 

  • Objectives of the Study

The main objectives of his project work was to describe the treatment method and processes used for treating wastewater from chemical, agricultural and petroleum industries in order to reduce their effect on the environment and public health while the broad objectives include;

  1. To know the amount of solid matter generated and their site specific condition in organic and inorganic substances.
  2. To improve the quality of wastewater
  3. To protect the aquatic life from the toxicity wastes.
  4. To make wastewater usable for aquaculture, agriculture e.t.c.

 

1.4 Limitations of the Project

These generally relates to the cost of construction and ease of operation. Mechanical systems can be costly to build and operate as they require specialized personnel. Nevertheless, they do offer a more controlled environment which produces a more consistent quality of effluent.

Generally, the complexity and cost of wastewater treatment technologies increase with quality of the effluent produced.

 

  • scope of the project

The scope of this study was to:

  1. Define the characteristics of waste.
  2. Assessing the environmental impacts of current waste disposal practices
  3. Obtaining information regarding the impact of water plant waste on the land and vegetation, if available.

 

  • Justification of Project

Wastewater treatment plants do just as they say. They treat the water that goes down the drain before releasing it back into the environment. Wastewater treatment plants have evolved considerably over time. Their first and most important purpose is to clear the water we use in our homes/industries of solid materials. This process of screening and settlement is known as primary treatment. In many cases the water is then discharged, often after sterilization with ultra violet light which kills potentially disease causing bacteria and viruses. This was the case in Rhode Island until about 2005. However, recent advancements in technology and awareness have brought about new technologies which can treat wastewater to remove these nutrients in the tertiary treatment.

CHAPTER TWO

LITERATURE REVIEW

2.1 Wastes from Water Treatment Plants

This literature review on wastes from water treatment plants discusses previous literature reviews on the subject, sources and types of waste, characteristics of each type of waste, and waste management. The discussion of management of sludge [waste] covers minimizing sludge treatment, and ultimate sludge disposal.

 

2.1.1 Previous reports

During the period 1969 to 1981 the American water Association [AWWA] research foundation and the AWWA sludge disposal committee prepared a series of reports with a comprehensive literature review on the nature and solution of water treatment plant waste disposal problems. The first report, prepared by the AWWA research foundation, was divided into four parts [AWWA research foundation, 1969a, 1969b, 1969c, 1970] and was entitled “disposal of waste from water treatment plants”. The first part of this report, [AWWA, 1969a] covered the status of research and engineering practices for treating various waste from water treatment plants. The second part [AWWA 1969b] review plant operations for the disposal of various types of waste, and the regulatory aspect of disposal. The third part AWWA [1969c] described various treatment processed employed and their efficient and degree of success, and presented cost analysis the last part [AWWA 1970] summarized research needs, plant operation need, and regulatory needs.

Concurrently with the initial preparation of the report by the AWWA research foundation, the water resources quality control committee of the Illinois sections of the conducted a survey of the handling of wastes from water treatment plants in Illinois [Evans et al., 1970]. This effort was made to determine the type and quantities of waste produced, characteristics of waste, and the exciting methods of waste disposal in Illinois.

In 1972, the AWWA disposal of water treatment plant waste committee published on updated report [AWW 1972]. It dealt with processing and re-processing in sludge production, i.e. selection and modification of treatment processes, reclamation of lime and alum, recovery of filter backwash water, processing of waste to recover useful by-products, processing of waste for disposal, and future research needs.

In 1978, the AWWA sludge disposal committee prepared a 2-part article [AWWA sludge disposal committee, 1978a, 1978b] entitled water treatment plant sludge an updated of the state of the art. Part 1 dealt regulatory requirements, sludge production and characteristics, minimizing waste production, and European and Japanese practices. Part 2 detailed non-mechanical and mechanical methods of dewatering water plant sludge, ultimate solids disposal and research and development needs. These reports focused mainly on coagulation sludge.

In 1981, the AWWA sludge disposal committee provided an overview of the production, processing and disposal of lime-softening sludge; and research needs [AWWA 1981].

 

 

2.2 Waste Characteristics

The amount and composition of waste produced through each treatment process are unpredictable. Because of the wide variation in raw quality and treatment operations, sludge is different in their characteristics and quantities from time to time within the same treatment plant, and from plant tom plant.

Russian [2005] discussed general characteristics of water plant waste. In addition he addressed special characteristics of coagulation wastes, filter backwashes, ion-exchanged brines, and screenings from a few water suppliers. He concluded it is impossible to make generalization concerning sludge production in terms of millions of gallons of water treated because sludge pro9duction is entirely dependent on raw water quality, the method of treatment, and efficiencies of the treatment processes.

Sludge from water treatment plant may be divided into eight major categories [westerhoff, 2010] pre-sedimentation sludge; coagulation sludge, lime sludge, iron manganese removal sludge, ion exchange sludge [brine waste], activated carbon wastes spent diatomaceous earth, and sludge from saline water conversion. These categories, as well as filter backwash wastewater are discussed below.

 

2.2.1 Pre-sedimentation Sludge

Some water plants treating high-turbidity surface waters employ pre-sedimentation prior to coagulation to reduce the solids loading on the downstream treatment process. The residues generate consists of clay, silts, sands, and other heavy settle able materials present in the raw water.

Treatment and disposal of pre-sedimentation residues in and itself, it is not a major problem. They can be treated and disposal of with other sludge. The cleaning cycle of a pre-sedimentation basin is usually very long, 10 years or more [westerhoff, 1978].

 

2.2.2 Coagulation Sludge

Is generated by water treatment plants using metal salts such as aluminum sulfate [alum] or ferric chloride as a coagulation to turbidity. The dewatering characteristics of alum sludge, in terms of specific resistance, was measured by Gates and McDermott [2007] as 1*10 to 4.4* 10 secvg. Which is about one order of magnitude greater than the dewatering properties of alum sludge were comparable to those of sewage sludge? Apparently the properties of alum sludge are highly variable from one plant to another, and even within the same treatment plant.

Fourteen chemicals, physical and biological parameters were measured in the alum sludge from the clarifier below-downs at Centralia, from the clarifier blow downs at Centralia Illinois [Lin and Green, 2011]. The raw water source for this community is a 286-ha [700-acre] lake. The annual values of the blow-downs.

 

Table 2.1

Parameter                      Geometric mean           Parameter            Average

Tss,rag/L                       2800                              Vss,mg/L                 750

Turbidity,NTU             2800                              set.solids,mg/L        380

T.iron,mg/L                  58                                 temperature,e           15.7

T.aluminium,mg/L         240                          PH[median]                  6.6

Fecal coliform/100L          5                           T.alkalinitymg/L           95

Dissolved solids mg/L        215                        BODs,mg/L                  29

 

Settling basin alum sludge contains extremely high concentrations of aluminum and iron. The observed values at three water treatment plants in Illinois, which derive their raw water supplies from streams and rivers, are as follows, [Evans et al.2000, 2003, Lin et al., 2005].

Aluminum, mg/kg

Pontiac                          1000-134,000

Alton                             39,300-55,000

East St. Louis               13,900-61,200

 

 

2.2.3 Iron and manganese sludge

These types         of sludge are produced by the precipitation process for removal of iron and manganese from water. This sludge is red or black in color. The sludge solids consist of ferric oxide, manganese oxide, and other iron and manganese compounds.

 

2.2.4 Brine Wastes

Spent brine waste comes mainly from the rinse water for the regeneration of ion-exchange softening units using zeolite as the resin. These wastes are in aqueous solution. The volume of brine waste generated is about 2 to 10% of the water treated, depending on the raw water hardness and the operation of the ion-exchange unit [AWWA, 1969a, 1969b; O Connor and Novak, 1975]. These wastes contain extremely high concentration of chlorides of calcium, magnesium, and manganese. Brine waste is characterized by very high chlorides, total solids, and total dissolved solids [TDS]. Very few suspended solids are present in brine wastes.

The high chloride content derived from the salts used for regeneration causes problems in the disposal of brine wastes. Chlorides cannot be removed from waste water through my inexpensive method. These wastes can generally be discharged to deep underground strata or oceans with a permit.

 

2.2.5 Filter Backwash Wastewater

Is produced during the filter washing operation. Filters are washed daily, once every two days, or less frequently. There is usually a large volume of wash water with low solids content. The volume of wash water is large because the backwash may be 10 to 20 times the filtration rate. For alum coagulation plants, the volume of wastewater ranges from 2 to 5% of the water filtered.

The average solids concentration in wash wastewater is generally low. However the maximum Tss concentration was found to be about 1800mg/L in the wastewater treatment plant at East St. Louis, Illinois [Lin et al., 2005]. Average Tss values vary widely from plant to plant and from time to time within the same plant. A high average value was cited as 15000 mg/L of Tss for a plant with iron and manganese removal [AWWA, 1969a]. About one-fourth to one-third of the total solids is volatile in most cases [AWWA, 1969a; Lin et al., 2005; Lin and Green, 2008]. Detailed solids and chemical analysis for filter backwash wastewater of alum coagulation plants can be found elsewhere [Lin et al., 2005; Lin and Green, 2008; O’Connor, 2003; O’Connor and Novak, 2006].

 

2.2.6 Diatomic Filter Sludge

Because of the nature of diatomite filters, the spent diatomaceous earth has characteristics similar to the DE itself. DE is composed almost entirely of pure silica. It has a dry weight of about 10ib/cu ft and a specific gravity of approximately 2.0 [AWWA, 1969a]. Since the waste consists of chiefly of silica it is easily dewatered. The amount of spent DE is small, because the volume of water treated in a diatomic filter is generally small.

2.2.7 Sludge from Saline Water Conversion

There are few existing saline water conversion plants which treat highly saline waters to produce drinking water. Virtually no chemicals are added in the saline water conversion process.

From raw brackish waters in the range of 1000 to 3000mg/L of TDS, the waste stream from saline water conversion plant constitutes from 10 to 30 of the water treated and contains 5000 to 10000mg/L of TDS. For sea water conversion plants the wastewater usually consists of TDS ranging from a little above sea water concentration [35000mg/L] tom as much as 70000mg/L TDS [katz and Eliassen 2000].

 

2.3 Management of Sludge

Traditionally the waste residues from a water plant have been discharged to a nearby waterway and forgotten. Currently it is required that these wastes [sludge] be well managed. The direct discharge of waste can be continuous, intermittent, sludge treatment, and land applications. Chemical recovery can be used as a way of both minimizing sludge production and treating sludge.

 

2.4 Minimizing Sludge Production

The methods and cost for handling, treatment and disposal of sludge are influenced by the raw water quality and the treatment chemicals used during the water treatment processes. Sludge generation can be minimized by the removal of water to reduce the sludge volume, the reduction of the solids content present in the sludge, or some combination of the two. The methods for minimizing sludge production are reduction of chemical dosage [alum or lime], direct filtration of the water, recycling of filter wash water, substitution of coagulation and softening material and chemical recovery [waterhoff, 2006; AWWA, 1981].

CHAPTER THREE

METHODOLOGY

3.1 Effluent Treatment Plant at Nigeria Bottling Company (NBC)

The effluent treatment plant (ETP) is made up of different stages that ensure that the effluent from the company is well treated before sending out to the environment.

 

The stages are listed below

3.1.1 The stages are:

Static Point, Self Clearing Device, Oil Separation Tank, Equalization Tank

Biological Tank [A], Sedimentation Tank, Biological Tank [B] Final clarification

Firstly, the Nigerian Bottling Company has a well organized, functional plant that is used to treat the effluent from the company and safety procedure are followed from the entrance of the gate to the plant location which is done by yellow marked laired that allows for walkway to the plant.

The various components of effluent treatment plant have been derived from unit operations, every unit operation aid at the removal or reduction of special objectionable substances to the desire degree. Depending upon the kinds are magnitude of the treatment order for the purpose of modifying the quality of water to meet desired standards.

The company flout rates of effluent into the plant is 200m3/hr and the discharged rate of influent to the environment is 65 to 70m3/hr and the rest 130m3/hr in recycled and surface aerators is used in the tank to remove the odours and colours from the tank.

 

3.1.2 The Two Process Used in this Plant is:

The constant Flow, Valve

The constant flow/buffer tank: Hereby, checkmates the rate of flow of the effluent in the tank while the valve act as an aid for serving by passing a less concentrated effluent flow directly to the biological tank B, serving and maintenance are needed. The effluent from the Nigerian Bottling company contains pieces of broken bottles, oil, chemical and pipes which are screen at the unit operation section known as the static point.

While the screenings of the floating matters are holdback, the rest flows down to the self clearing device where plain sedimentation takes place.

 

3.1.3 Plain Sedimentation

Simply means that the sedimentation is not affected of chemical or other processed in a relatively quiescent state, solids, having specific gravity greater than that of the liquid containing them settle while solid with specific gravity lower that the liquid tends to rise. Through the debris are removed but the effluent still contains sand and oil. But on reaching the strain device some of the debris that escape are been trapped by the screen at the strainer device which is 3mm apart each other. It is normally taken as a bath separation process where some of the sand which were unable to pass the hole are retain but the rest are sent to the separation unit but due to the fact the pressure of effluent entering into the separation tank is on high pressure tends to push and missed with the oil that is meant to settle after the first processing but on the third process tank the separation takes place settling the sand and floating the oil at the surface of the third process tank of the oil separation tank which is scooped out with net, the water in-between the oil and sand flow into the fourth stage know as equalization tanks. After the separation of sand and oil, the treatment of the effluent starts properly at these stage, the water that flows into the equalizer tank so contain chemical known as sodium hydroxide which is transformed into the tank. The moment you start agitation of the equalization tank, it helps to reduce th4e concentration of sodium hydroxide [NaOH] which is base in nature then manually hand hydroxide acid is coagulated allowing it to doze into the equalization tank. To determine or know the quantity Hcl (hydrochloric acid) to be applied the equalization tanks is by simply dipping it in a meter reader in the tank at the rate of 1000m3 water you apply 600litre hydrochloric acid which is a standard but, can be changed depending the amount of sodium hydroxide present in the equalization tank. Micro-organisms that are present in the effluent are enriched in the biological process with urea at decomposition process take place producing water, biomass and carbon dioxide (carbon (iv) oxide) easily escape the atmosphere and leaving behind biomass and water which either sent to sedimentation tank for separation or to the belt press room where sludge is abstracted from biomass and it is pressed to a sludge cake which is used as a manure in agriculture. Before the sludge cake is produced it pass through the polymaker unit where polyellctrolyte coagulate with biomass before sending it to the sludge belt press at the sedimentation tank which is the south stage, normally defined as a separation to wanted from unwanted.

Sedimentation tank may be considered which consist of four parts.

  1. Inlet zone where influent flow suspended solids dispense over.
  2. Settling zone where settled particles accumulate and are withdrawn
  3. An outlet zone through which effluent flow out.

In the sedimentation tank there is cylindrical scalper bridge machine. They rotate and collect the scum to pit then to sludge (BIOMASS) to sludge tank and take minimum of 6months/one year for sludge to be matured before sending it to belt press room for sludge cake.

The effluent is then sent to the biological tank which is the seventh stage and surface aerator is turned on to stirs, removing the odors, the final stage which is the final classification tank where chlorine is added before sending it to pond or to the lake/river around the company known as Otamiri River.

The following are the challenges and precaution taken in the effluent treatment plant.

At the static point the effluent discharge was overflowing it with a reason being that the pipe was not enough to accommodate the flow.

At the time of inspection the hydrochloric acid needed to prevent odor from the effluent was not available whereby causing un-conditional environment.

 

Table 3.1: Characteristics of Brewery Waste Water

Parameter Value
Ph 3-12
Temperature (oC) 18-40
COD [mgl-1] 200-6000
BOD [mgl-1] 1200-3600
COD: BOD ration 1.667
VfA [mgl-1] 1000-2500
Phosphates as pO4 [mgl-1] 10-50
TKN [mgl-1] 25-80
TS [mgl-1] 5100-8750
TSS [mgl-1] 2901-3000
TOS [mgl-1] 2020-5940

 

In fact, the brewery wastewater is characterized by large variation in the parameter mentioned in Table 1. As a result, most large breweries require some degree of wastewater pretreatment. In cases where the brewery does not discharge to the municipal sewer, then primary and secondary treatment of the effluent is required.

However, if the brewery is permitted to discharge into a municipal sewer, pretreatment may be required to meet municipal bylaws and/or to lessen the load on the municipal treatment plant. In some cases, sewer discharge fees imposed on effluent volume and the suspended and organic loads, by the municipality may encourage the brewery to install its own treatment facility. Pretreatment is meant to alter the physical chemical and/or biological properties of feed water, thus improving the performance of upstream process. Therefore, pretreatment is done by physical, chemical or biological methods, or by combination of all these methods. Table 2 lists the unit operations included within each category, and detailed schematic representation of a conventional wastewater treatment processes can be found in Spellman’s standard handbook for wastewater of operators. Table 3 is a summary of the generic advantages and disadvantages of various wastewater treatment processes as shown in literature. These characteristics generally relate to the cost of construction and ease of operation. Generally, the complexity and cost of wastewater treatment technologies increase with the quality of the effluent produced. In fact, the water management and waste disposal in the brewery industry are considered as significant cost factors and important aspects in the operations of brewery plant.

 

Physical Methods

Among the first treatment methods used are physical unit operation, in w3hich physical forces are applied to remove contaminants physical.

Table 3.2 Wastewater Treatment Unit Operations and Processes

Physical Unit Operation -Screening

-Communication

-Flow Equalization

-Sedimentation

Floatation

-Granular medium filtration

 

 

Table 3.3 Wastewater Treatment Unit Operations and Processes

Physical Unit Operation -Screening

-Communication

-Flow Equalization

-Sedimentation

-Floatation

-Granular medium filtration

Chemical Unit Operation -Chemical Precipitation

-Absorption

-Disinfection

-Chlorination

-Other Chemical Application

Biological Unit Operation -Activated Sludge processes

-Aerated Lagoons

-Trickling filters

-Rotating Biological contactors

-Pond Stabilization

-Anaerobic Digestion

-Biological nutrient removal

 

G.S simate et al/ Desalination (2011)

A wire gaze was constructed to reach the flow race coming into the pipes.

 

 

 

3.1: primary Treatment plant

Place other of the replacement of hydrochloric acid which was not enough to neutralize the base [NaOh]

 

 

 

 

 

 

 

 

 

 

 

CHAPTER FOUR

CONVENTIONAL METHOD OF PRE-TREATMENT BREWERY WASTE WATER

Table 4.1: Generic Advantage and Disadvantage of Conventional and Non-conventional wastewater

Treatment Technologies

 

Treatment type   Advantages Disadvantages
Aquatic system Stabilization lagoon Low capital cost

Low operation & maintenance cost

Requires a large area of land

May produce undesirable odours

Aerated Lagoons Low technical manpower      requirements requires relatively little land area

-Produces few undesirable odours

Requires mechanical devices to aerate basis.

Produces effluent with a high suspends solids concentration.

Terrestrial systems Septic tanks -Can be used by individual households

-Easy to operate and maintain

-Can be built in rural areas

Provide a low treatment efficiency

Must be pumped occasionally

 

  Constructed wetland Removes up to 70% of solids and bacteria

Minimal capital cost

Low operation and maintenance requirement costs

Requires a landfill for periodic disposal of sludge and septage

Remains largely experimental

Mechanical system Filtration system Relatively low cost

Can be used for household scale treatment

Easy to operate

Requires periodic removal of excess plant material

Best used in area where suitable native plants are available

Vertical biology reactors Highly efficient treatment method

Requires little land area

Applicable to small communicates for local scale treatment and to big cities for regional scale treatment

Requires mechanical devices
Activated sludge Highly efficient treatment method

Requires little land area

Applicable to small communicates for local scale treatment and to big cities for regional scale treatment

High cost

Complex technology

Requires technically skilled manpower for operation and maintenance

Needs spare parts availability

Has a high energy requirement

High cost

Requires sludge disposal area (sludge usually land spread)

Requires technically skilled manpower.

 

 

Micro –organisms and inorganic end- product (principal Co2, NH3 and H2O),

Aerobic treatment utilizes biological treatment processes, in which microorganisms

Convert non-settle-able solids to settle –able solids. Sedimentation typically

Follows; allowing the settle-able solids and separate out. There options include:

 

Activated Sludge Process: In the activated sludge process, wastewater flows into

An aerated and agitated tank that is primed with activated sludge. This complex

Mixture containing bacteria, fungi, protozoan and other micro-organisms is

Collectively referred to as the biomass. In this process, the suspension of aerobic

Micro-organisms in the aeration tank is mi9xed vigorously by aeration device,

Which also supply oxygen to the biological suspenssion.

Attached Growth [Biofilm] Process: The second type of aerobic biological

Treatment system is called “attached growth (bio-film) process” and deals with

Micro-organisms that are fixed in place on a solid surface. This “attached growth

Type” aerobic biological treatment process create an environment that support the

Growth of micro-organisms that prefer to remain attached to a solid material

 

 

 

 

 

 

Table 4.1: Anaerobic Treatment as compared to Aerobic Treatment

Aerobic Systems Anaerobic
Energy consumption –          High –         Low
Energy production –         No –         Yes
Bio-solids production –         High –         Low
COD removal (%) –         90 – 98 –         70-85
Nutrients (N/P) removal –         High –         Low
Space requirement –         High –         Low
Discontinuous operation –         Difficult –         Easy

 

Tricking Filter Process: In the tricking filter process, the wastewater is sprayed

Over the surface of a bed of rough solids (such as gravel, rock or plastic) and is allowed to “trickle down” through the micro-organism covered media.

Bio-filtration Towers: A variation of a tricking filtration process is the bio-

filtration tower or otherwise known as the bio-tower. The bio-tower is packed with plastic or redwood media containing the attached microbial growth.

Rotating Biological Contractor Process: The rotating biological contactor

Process consists of a series of plastic disks attached to a common shaft.

Lagoons: These are slow, cheap and relatively inefficient, but can be used for Various type of wastewater. They rely on the interaction of sunlight, algae, micro-

Organisms and oxygen [sometimes aerated].

Sludge Treatment and Disposal: In general, aerobic treatment systems like the

Activated sludge system produce relatively large quantities of sludge, which requires disposal. The sludge can undergo a dewatering treatment either by reconsolidated centrifugation, vacuum filtration, or in a pressure filter.

 

4.1    Anaerobic

Anaerobic wastewater treatment is the biological treatment of wastewater without the use of air or elemental oxygen. Anaerobic treatment is characterized by biological conversion of organic compounds by anaerobic micro-organisms into biogas, which can be used as a fuel; mainly methane 55 ___ 75 vol% and carbon dioxide 25 __  40vol% with traces of hydrogen sulfide. In breweries, direct utilization of biogas in a boiler is usually the preferred solution. The reason for this is that investment cost for a combined heat and power unit (CHp) are higher and more extensive biogas treatment is required. In the context of decreasing fossils fuel reserves, anaerobic wastewater treatment makes a brewery more independent from external fuel supply; it contributes to a more sustainable brewing process.

 

Up-flow Anaerobic Sludge Blanket: one of the most popular anaerobic processes

In the Up- flow Anaerobic Sludge Blanket (UASB).In the USAB reactor; the wastewater enters a vertical tank at the bottom. The waste water passes upwards through a dense bed of anaerobic sludge where the micro-organisms in the sludge come into contact with wastewater substrates. This sludge is mostly of a granular

Natures [1 __ 4mm] have superior settling characteristics (i.e at a rate of more than 50mh-1). At the top of the USAB reactor, a so called three __phase separator

Separates the biomass from the biogas rises, it carries some three-phase separator is also known as the gas-liquid-solid –separator.

Fluidized Red Reactor: In a Fluidized Red Reactor [FBR], wastewater flow in

Through the bottom of the reactor, and up through a media (usually sand or activated carbon) that is colonized by an active bacterial bio-film. The media is

“Fluidized” by the upward flow of wastewater into the vessel, with the lower density particles (those with highest biomass ) moving to the tap.

4.2Treatment of Brewery Wastewater for Re-use

The discharged wastewater from the biological pretreatment processes can be further treated. In this section various methods that may be used.

 

 

 

Figure 4.2: Quality Standards for Rinse and Cooling Water, and Aimed                  

Value for Drinking Water

Table 6: Typically Characteristics of Membrane Processes

Process Operating Pressure

(Bor)

Pore – size

(nm)

Molecular

Weight cut­- off

Size –cut of range (nm)
Microfiltration <4 100-

3000

>500,000 50 – 3000
Ultra- filtration 2 – 10 10  – 200 1000-

1000000

15 – 200

 

Nano – filtration 5 -40 1- 10 100 -20,000 1 -100
Reverse Osmosis 15 -150 <2 <2 <1

 

Quality

Standard      rinsing water

Quality

Standard

Cooling water

Quality

Standard

drinking

water

COD (mgO2L-1) 0 -2 0 – 2 0 __ 2
Na+ (mgL-1) 0 – 200 / 20
CI–  (mgL-1) 50 250 / 25
pH 6.5 _ 9.5 6.5 __ 9.5 6.5 _ 9.5
Conductivity (Us Cm-1 )

 

To treat brewery wastewater for reuse are explored, it must be noted,

However, that recycling of regenerated water as brewing water is considered

Inappropriate and would require that drinking water, stands for rinsing, cooling and drinking water. Among the parameter in the table 5, the important parameter for recycling water or required to be measured is the COD. COD is a measure of the oxygen equivalent of the organic matter content of a sample that is susceptible to oxidation by a strong oxidant. The COD is considered an appropriate index for showing the amount of organics in water. The COD value of a wastewater mainly represents the biodegradable and non – biodegradable organic components, although inorganic compounds may be significant in certain cases. BOD/COD ratio in the range 0.6 _ 0.7 the organic components in the brewery effluent (expressed as COD) consists of sugars, soluble, starch, ethanol, volatile fatty acids e.t.c.

 

4.3 Membrane Filtration

The separation by porous membranes is of great interest in environmental and chemical engineering processes. In fact, filtration technology is considered as an integral component of drinking water and wastewater treatment application. Membrane filtration can be divided into four categories, depending on the effective pore size of the membrane, and hence the size of the impurities removed. In order of the decreasing pore size the impurities removed. In order of the decreasing pore size, they are as follows: microfiltration, ultra filtration, nanofiltration and hyper filtration. Table 6 summarizes the essential features of these processes, such as pore size and operating pressure. However, the characteristic listed in table 6

Are not exhaustive, thus different range may be quoted elsewhere.

Fig 4 shows two ways of operating a membrane filter, i.e dead- end

Filtration, all of the feed water flows through the membrane (as permeate) so that all impurities that are too large to pass through the pores accumulate in the filter

Module .Some means of removing these is necessary. Cross- flow filtration involves flowing the feed water parallel to the membrane surface, with only a proportion passing through the membrane. The retained impurities remain in the retentate which is normally recirculated.

Membrane can be classified according to their material of construction. There is a variety of materials that are used for the manufacture of membrane filters.

 

Figure 4.3 :    Membrane Filters Membrane Filters

 

 

 

 

 

 

4.4 Non – Thermal Quenched Plasma

     Plasma is a highly ionized gas that occurs at high temperatures. The intermolecular forces created by ionic attractions and repulsions give these compositions distinct properties; for this reason, plasma is described as fourth state of matter. In summary, plasma usually result from the increase of the energy of a gas provided by various sources, such as electric, magnetic, mechanical [shock waves ultrasound], thermal or even optical (cases) sources.

 

 

 

4.4.1 Membrane Bioreactor

Depletion of water resources, increasing water price, and stringent regulation that has caused the development of various combinations of membranes with other conventional treatment components, membrane bioreactor (MBR) is becoming one of such flourishing technology in water and wastewater treatment fields.

The MBR combines two proven technologies; i.e enhanced biological treatment and is applied municipal water treatment at full scale. Li and Chu found that nearly 60% of influent total organic carbon (TOC) was removed by MBR, accompanied by more than 75% reduction in trihalomethanes formation potential (THMEP). The MBR technology is also applied to the brewery wastewater for reuse.

 

 

 

 

 

Figure 4.5 : Slide – stream MBR

The organic fouling of the membrane is mainly dependent on several factors including the following;

  1. The components of organic matter such as colloidal fraction and dissolved fraction.
  2. Organic characteristics such as hydrophobicity and molecular size and configuration.
  3. Solution chemistry such as pH, divalent ions concentration and ionic strong then, and
  4. Membrane properties such as pore size surface roughness, practice , membrane fouling can be controlled by two types of approaches, i.e (1) Periodical air scouring, back washing and chemical cleaning, and (2) The addition of adsorbents and pretreatment by coagulation.

 

 

 

  • Combined Anaerobic and Treatment

Anaerobic and aerobic treatment are often combined in brewery wastewater treatment as shown in figure 7, there are essentially four types of integrated anaerobic-aerobic bioreactors are as follows;

Firstly, in the anaerobic reactor the bulk of the COD, 70 – 85%, is converted into biogas on a small surface are. Secondly, in an aerobic or anoxic post – treatment step, up to 98% of the COD and nutrients are removed. Since the “rediscovery” of carbon nanotubes (CNTS) in 1991 by Iijima, several researcher worldwide cutting across all discipline have embarked non stimulating research to utilize the mgriad unique properties of these nanomaterials. The CNTs consist of honeycomb structures of grapheme sheets rolled up into cylinders with a diameter of a few nanometers.

 

 

 

  • Nanosorbents

Carbon nanotubes have shows exceptionally good adsorption capability and high adsorption efficiency for various organic pollutants and inorganic pollutants such as fluoride . The CNTs have also been found to be superior sorbents for heavy metals. The CNTs are particularly attractive as sorbents because, on the basis of mass, they have large surface areas than bulk particles, and can be functionalized with various chemical groups to increase their affinity towards target compounds.

Secondly, the CNTs are very expensive.

 

  • Nanofilters

The successful fabrications of carbon nanotube filter have been reported. These filtration membranes consist of hallow cylinders with radically aligned carbon nanotubes. Efficiently carried out filtration of heavier hydrocarbon species, CmHn and in the removal of Escherichia coli from drinking water and filtration of the nanometer – sized poliovirus. The high organic content of a brewery effluent is classified as high strength waste in terms of COD, from 1000mgl-1 to 4000mg-1

and BOD of up to 1500mgl-1. This makes brewery wastewater good candidate for the treatment with these CNT filters.

Membranes that have CNTs as pores could be used in desalination and demineralization. The nanotube filter could separate diesel and water layers, and even surfactant – stabilized emulsions. The successful phase separation of the high viscosity lubricating oil and water emulsions was also carried out.

 

4.5 Electrochemical Methods

Electrochemical method of wastewater treatment came into existence when it was first used to treat sewage ge3nerated onboard by ships. Thereafter, the application of electrochemical treatment was widely received in treating industrial wastewaters that are rich in refractory organics and chloride content. The electrochemical organic pollutants, because they are neither subject to failure due to variation in wastewater strength nor due to the presence of the toxic substances and require less hydraulic retention time.

 

  • Microbial Fuel Cells

Recently, brewery wastewater has been simultaneously treated while generating electricity from organic matter in wastewater. This device that treats wastewater and generates electricity the same time is termed microbial fuel cell (MFC). The MFC is a combined system with anaerobic and aerobic characteristics. They are designed for anaerobic treatment by bacteria in the solution near the anode, since high COD removal efficiencies were achieved in these studies. It can be concluded that MFCs, particularly, sequential, anode cathode type, can provide a new approach for brewery wastewater treatment while offering a valuable alternative by energy generation.

 

 

4.7 Carbon  

The characteristics of a water treatment plant have a great influence on the characteristics properties of the end product. Even when the incoming process water is from a municipal drinking water source, the water may contain residual tastes, odors, disinfection by-product, and free and combined chlorine.

Molecules with carbon sulfur bonds often smell and taste bad, but these are often preferentially adsorbed on carbon.

The treatment of tannic acid for flavor and odor removal is a process application in brewery where carbon absorption is used. Carbon is also used to removed color from malts for use in the clear beers and flavored malt beverages, several granular and powdered products can be used for this type of application. Activated carbons are an effective treatment to assure water that is contaminant, taste and odor free.

 

 

Figure 4.6; Complete Water Treatment Processes in a plant 

4.8 Discussion and Synthesis of Findings

This section provides a discussion and synthesis of the review findings of this paper. This discussion includes a comparison and possible integration of the processes and technologies. In an nutshell the discussion primarily addresses the following two fundamental questions:

  1. How do the process and technologies compare with each other?
  2. Can they be integrated with each other, and if so , what are the potential challenges and benefits?

 

 

 

4.9 Comparison of Technology

This review highlighted the need for treatment of brewery wastewater, and looked at various methods that may be used to safely and cost – effectively treat brewery wastewater for reuse. In addition, some challenges associated with these methods were discussed. It should be noted and emphasized herein that the treatment of brewery wastewater effluents is a costly and relatively complex activity, particularly with the need to meet governmental regulations and environmental friendliness.

Conventional Separation Methods such as coagulation/ flocculation, centrifugation and gravity separation exhibit shortcomings including incomplete COD removal. These methods are generally associated with low separation efficiency, high operation cost, large setup size, and the generation of secondary pollutants. It was also noticed that biological treatment is widely applied as a pretreatment method.

Generally, aerobic treatment has been applied for the treatment of brewery wastewater and recently, anaerobic system has become an attractive option, among other advantages, because of their high COD content removal. Through these biological methods have found widespread application for the treatment of the characteristically high organic content of the brewery wastewater, further treatment is required for water reuse.

Table 8 shows a summary of some of the studies conducted on brewery wastewater, showing the COD reductions, and whether the effluent is suitable as primary or secondary water based on a criteria listed in table 5. It must be noted however, that this studies had different experimental designs applications with good economics and high degree of energy efficiency. Coupling these processes together as two or three stage process combinations are proposed and discussed.

Electrochemical methods can be well suited to be coupled in the latter stages of the integrated process. Sanitizing agents (often called disinfection) which are present in brewery wastewater contain chloride compounds.

Plasma methods through very effective, the process is expensive because of the high energy requirements by the gas, and the cost of energy sources such as caser, therefore, if coupled with other methods, the process can be very expensive.

CNTs have shown remarkable adsorption power, combining CNTs with UF will result in substantial removal of organics; however, the addition of CNTs would rapidly increase the trans-membrane surface. In this case, CNTs may need to be of large enough diameters to reduce the trans-membrane pressure effect. As for the MBR or filtration in general fouling mitigation can potentially be done by coupling coagulation and flocculation to the process.

Water is a common element in the lives of all people and societies.

Water has been the foundation sometimes, the undoing of many great civilizations.

Today, water continues to be essential for the life sustenance (both human and animals), agricultural, economic and industrial, activities that help society to develop less than a century ago, it was widely assumed that there enough freshwater supplies in the world for everyone.

Yet today, increase use of freshwater for industrial, agricultural, and domestic use has created acute water shortage in some areas of the world particularly the developing countries. These shortages are stimulating or worsening international conflicts over water, which has joined oil as a major commodity triggering wars. The pr4esence of the pollutants in raw water due to human activities has also exacerbated the situation. On the other hand, wastewater reclamation and reuse has become an important option, since industrialization and urbanization have accelerated environmental water pollution, making it a limited resource for the water supply.

When properly treatment and recycled, wastewater can be an alternative water source that can beneficially and cost-effectively reduce the demands for freshwater. It can be concluded that, along with the growing world population and industrial activities coupled with stringent environmental requirements, the cost of the water is increasing as a result; the demand for water reuse in the brewery industry is expected to increase at an unprecedented rate.

Consequently, an increasing need of processes capable of achieving an efficient treatment under extreme operational conditions that simultaneously optimize operational cost can be expected in the future. Information obtained from this review show that in order to remove impurities efficiently, integration of different processes is recommended.

 

 

 

 

 

 

 

CONCLUSION AND RECOMMEDATION

5.1 CONCLUSION

The reduction in some water quality parameter was 96.5% [Ca], 95.17% [Mg],

80.1% [Na], 98.29% [SO] and 94.37%[C] in the new RO membrane – product water. Whereas in the case of new NF membrane, the reduction in some water

Quality parameter was 75.56% [Ca]. After 9- years of installation, the removal efficiency [%] of RO- Membrane for different selective icons was 61.2, 70.4,58.8,33.3 and 57.26,47.81,22.89 and 51% for Ca, Mg,  Na, Cl and So, respectively. The removal of divalent icons was considerably higher than the monovalent caions / anions from the composition of the product water from RO and NF treatment process. There is a significant reduction in the ion removal efficiency after 9- years of installation of RO and NF membranes. This might be attributed to membrane fouling and bio-fouling due to the presence of some organic pollutants in the product water of membrane Bio-reactor [MBR] process and due to wear and tear of the membrane over a long period of time. The study findings provided concrete clue for the replacement of the existing wastewater. The research further highlighted the necessary to replace the NF and RO membranes used in these two water techniques.

 

5.2. Recommendation and Suggestion

Based on the study findings, the following recommendations are made for considerations are made for consideration while using RO and NF membrane

Processes for water for water and wastewater purification.

  1. Replace the RO and NF membranes when the water purification and the ion removal efficiency of membrane is less than 50 percent to avoid economical losses.
  2. Observe the performance of the new membrane after installation and make backwash when the ion removal efficiency of membrane is less than 10%.
  3. Conduct training program of technicians working in RP and NF systems maintenance including the backwash and fouling problem.
  4. Scheduling the membrane cleaning on regular basis to achieve high performance efficiency.
  5. Autopsy of the old membrane to determine the possible reasons for reduction in ion removal efficiency of RO and membranes.
  6. Substitute the RO and NF membranes with the improved ceramic membranes.

 

Table 5.1 summary of Brewery Wastewater Treatment Processes

Process Initial COD (mg/L) Final COD

(mg/L)

COD Reduction (%) Potential Use Primary (Process water) Second (Non-Process water)
Quenched Plasma 1018a 18a 98 No No
UASB (*1) 1947-3079 Not given 73-79 No No
Aerobic reactor Not given Not given 90-98 No No
Combined bioreactor (*1) Not given Not given 98 No No
Membrane bioreactor 500-1000 40 96 No No
Electrochemical method 2470 64 97 No No
Microbial Fuel Cell (*2) 1710 105 94 No No
Nanifiltration 3692 143 96 No No
Reverse Osmosis 850 0 100 Yes Yes

 

 

 

 

 

 

 

 

 

 

 

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Enlighten your day with some of our articles : read ( Achilles Greek Methology)

 

 

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