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The Most Heterogeneous Industries Environmental Sciences

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more and more firms trying to enter the market each year. The brewing sector holds a strategic economic position in the food industry, with the annual global beer production amounting to 185.62 million kilolitres in 2010(Kirin Institute of Food and Lifestyle Report Vol. 30; August 2011). The process of making beer is known as brewing.. Brewing is the production of alcoholic beverages from barley, yeast, hops, water, and grains and its alcoholic content comes during production, beer alternately goes through three chemical and biochemical reactions (mashing, boiling, fermentation and maturation) and three solid, liquid separations (wort separation, wort clarification and rough beer clarification).

Beer is the fifth most consumed beverage in the world behind tea, carbonates, milk and coffee and it continues to be a popular drink with an average consumption of 23 liters/person per year (ABIWSI ,2010), with the world consuming over 100 billion liters of beer and the world with for example Americans consuming 23billion liters whilst Zimbabweans currently consume an average of 14 liters of beer per person a year and this is more than the Sub-Saharan Africa average of 10 liters per person (Claude Harding, 2011).,. Beer has been brewed for thousands of years. The most primitive beers were brewed in Ancient Egypt, Greece, and China. Now, in the United States, the most common beers are lager beers, which are characterized by their balanced flavors and bubbly texture while other countries that consume a great deal of beer usually consume large quantities of beers made in their native country (Johnny alicea,2001)

The brewing industry has an ancient tradition and is still a dynamic sector open to new developments in technology and scientific progress. Brewers are very concerned that the techniques they use are the best in terms of product quality and cost effectiveness. Consequently water consumption, wastewater and solid, liquid separation constitute real economic opportunities for improvements in brewing.

Breweries are a widespread industry in Africa with the majority of them being profitable businesses, making them significant contributors to national economies, through the employment that they create whether directly or indirectly. In Zimbabwe Delta is largest brewer and manufacturer of soft drinks. The company's brands include Castle Lager, Eagle .its soft drinks portfolio includes a range of Coca-Cola brands and it also manufactures Chibuku, the market leader in the traditional sorghum beer category. SABMiller, the world's second-largest brewer by volume, holds a 36% stake in the company.

Delta Lagers Southerton Plant has a monthly production output of 745,000 hl, the main part of production is focused on 750 ml product units (ABISWI 2010). The daily production output is 4000hl,3500hl, 1700hl and 10780hl per day for quarts, Pints, canned beer and carbonated soft drinks respectively. The brewery has 7 working days comprising of 3 shifts of 8 working hours each. (ABISWI 2010). There are two packaging lines which are bottling and canning with a third one already under installation and will thus mean in increase in the volume of effluent to be generated and thus more water to be treated.

.1.2 BACKGROUND

Water management and waste disposal have become a significant cost factor and an important aspect in the running of a brewery operation. Brewery industry consumes large volumes of water and discharge large volumes of effluent throughout the year, with the flow of waste water from a brewery varying greatly with the time of day, often with the day of the week and with the time of year, worse, the water will vary widely in its temperature pH, load of suspended solids and the amounts of organic and inorganic materials in solution. In general brewing industries generate waste with 95% being wastewater and the remainder being solid waste.(Goldammer 2008). Brewery waste water is chiefly contaminated with putrescible organic matter.. If the waste is being discharged to a public sewer the operating authority will usually set limits on the composition, volume, rate of flow, temperature and pH of the effluent, with penalties if the limits are exceeded.

Globally brewery wastewater management is a serious problem that is not only confined to developing countries but also to developed countries. The food and beverage processes including brewing are water consuming with specific consumptions of water ranging from the average water consumption of around 5-6 hl/hl beer is correlated to beer production for industrial breweries (Fillaudeau et al 2004). Water consumption is divided into 2/3 used in the process and 1/3 in the cleaning operations, in the same way, effluent to beer ratio is correlated to beer production and has been shown that the effluent load is very similar to the water load since none of this water is used to brew beer and most of it ends up as effluent (Fillaudeau et al, 2004).

In the same way some European countries have tightened legislation that deals with waste water to ensure that breweries also play their part in managing their brewery water and examples include the severity of waste management requirements in beverage industry (including brewing) have been increased in Europe in recent years (Scheer, 2010). In brewing, diatomaceous earth (Kieselguhr) is increasingly scrutinized because legislation about dumping has been in effect since 2002 for example in Germany; legislation was reinforced in 2005 by a technical regulation related to domestic waste and material recycling law (Scheer, 2010). In terms of water management, strict legislation favors a reduction of water consumption and wastewater production in order to reduce the volume to treat. Brewery effluent contains organic material such as spent grains, waste yeast, spent hops and grit and effluent pH averages about 7 for combined effluent but can fluctuate from 3-12 depending on the use of acid or alkaline cleaning agent (Salamu, 2012).

Most of the effluent discharged by the breweries in some countries does not meet the national discharge standards as many of them release their effluent with little or no prior treatment. The practice of discharging effluent of low quality into the environment causes numerous problems, in Ghana, the effluent discharged to the Sisa Stream (a tributary of the Subin River) and the Odaw River impacts on the downstream water users that rely on this water for irrigation and domestic purposes (ABREW 2005). In Uganda, untreated effluent from the Nile Breweries is discharged into the Nile River and contributes to nutrient enrichment of downstream water bodies and bacteriological contamination and in turn affects the communities that rely on the Nile for food (fish), drinking and personal hygiene (ABREW, 2005).

In Zimbabwe Delta Lagers is a high quality local brewery has for many years experienced problems related to High pV values and TDS within their effluent treatment system (Operational report, 2011). This has increased their operational costs with excessive amounts being paid to the City of Harare due to the non compliance of the plants' wastewater with the Municipal by-laws on effluent disposal.

Research Problem

Delta Lagers a business unit of Delta Beverages involved in the Brewing, Packaging and distribution of clear beer, located in the Southerton industrial area has been of late been paying fines to the Harare City Council for discharging effluent into the sewer pipes that is not compliant with the Municipal By-Laws on effluent disposal. This was noted for the period under review, from January to June 2011 the Company paid fines ranging from US$40 000-115 000 because of the high values of Pv and TDS.

Fines represent an expense that is unnecessary and unbudgeted for being paid to the Harare Municipality. The publication of this in the local dailies is not good for the corporate image of the company. The effluent does not only violate Municipal by laws on effluent disposal but also in terms of Environmental Occupational Safety and Health (EOSH) module on Wastewater and also ISO 14001.

1.4OBJECTIVESGeneral Objective

to improve wastewater quality inorder to meet the demands of discharging standard.

Specific Objectives

To determine the waste water stream (pV, TDS and pH)

To establish the effectiveness of the existing effluent plant in reducing pV, TDS and Ph from the plant effluent.

To determine ways of reducing pV, TDS and pH at minimal cost

RATIONALE

Many countries have invested billions of money in research and development of efficient wastewater treatment methods and some of the efforts have been successful and numerous technologies for treating industrial wastewater. Beer breweries generate a sizeable amount of wastewater, especially the firms that produce on a national level and is estimated that the water wasted is about five times the amount of beer produced (Ganai 2011). Studies will provide local breweries with ideas on how to deal with their wastewater, as well as give them an idea of how to effectively manage their wastewater. The installation of new beer bottling lines at Delta Lagers Belmont and Harare breweries are a clear sign of the growing business of beer brewing in Zimbabwe but also a sign of an increase in the amount of wastewater generated. The research is not only important in managing waste water quality but to also aid Delta Lagers in meeting Sustainable Development targets set by the major shareholder, SABMiller. The project can help in ensuring compliance with EOSH requirements, ensuring compliance with ISO 14001 standard.

LITERATURE REVIEWBREWERY EFFLUENT

The quantity and quality of brewery effluent can fluctuate significantly as it depends on the various processes taking place in the brewery which includes processes such as raw materials handling, wort preparation, fermentation, filtration, CIP, packaging and so on (Huei, 2005). Meanwhile the amount of water being used differs between the processes.

Brewery effluent is categorized as medium to high strength organic wastewater. However organic components in the brewery effluent are generally easily biodegradable as these consists mainly of sugars, soluble starch, ethanol, volatile fatty acids and so on. The BOD/COD ratio for raw brewery effluent is relatively high which is in the range from 0.6-0.7 and therefore implies a high pV (Huei, 2005). Thus the brewery effluent is considered to be treated also by biological processes (Metcalf and Eddy, 2003)

On the other hand the brewery solids mainly consists of grains, waste and yeast trub and effluent pH levels are generally determined by the amount and type of chemicals being used at the CIP unit ( Anna-Rodriguez etal.,2005). Basically the chemicals being used are caustic soda, phosphoric acid, nitric acid and so on. The levels of nitrogen and phosphorus in the brewery effluent are mainly dependent on the handling of raw material and the amount of spent yeast present in the effluent from the plant.

Wastewater treatment methods

Many countries have invested billions of money in research and developing efficient wastewater treatment methods. These technologies range from simple clarification in a settling pond to a complex system in advanced treatment requiring ample equipment in highly skilled operators. Basically wastewater treatment methods can be divided into 3 categories which are physical treatment process, chemical treatment process and biological treatment process.

Biological treatment process

Biological treatment is the most appropriate industrial treatment technology. The objective of biological treatment processes is to remove or reduce the concentration of organic and inorganic compounds this because some of the constituents and compounds found in industrial waste water are toxic to microorganism( Huei, 2005). The principal process used for the biological treatment of wastewater can be classified with respect to their metabolic function as aerobic processes, anaerobic processes, anoxic processes, facultative processes and combined processes.

Aerobic treatment is characterized by biological conversion of organic compounds (usually expressed in COD) into biogas (mainly Methane 70%-85% and CO2 15%-30% with traces of hydrogen sulphide) (Metcalf and Eddy, 2004). The aerobic treatment, Oxygen is supplied to oxidize COD into CO2 and H2O and this also has a direct link of reducing pV (Huei, 2005). Wastewater generated by breweries are highly polluting with COD in the range of 2000-6000mg/l with a BOD/COD ratio of 0.6-0.7 (Metcalf and Eddy, 2004).

Basically aerobic sludge treatment is the most frequently used and widely applied treatment technology (Huei, 2005). The technology is based on an aerated reactor with suspended flocculant aerobic sludge, mixed by aerators supplying the necessary O2.however it is important to note that the quality of the effluent depends very much on the hydrodynamic conditions in the clarifier tank and the settling characteristics of sludge. Besides aerobic activated sludge aerobic fixed bed moving systems are also applicable on brewery effluent. The Brewers of Europe, 2002 in their report stated that Aerobic Fluid Bed reactors are susceptible for clogging due to solids in the wastewater or grow or grow of the biomass, furthermore if no aeration is applied these systems will be subjected to odour emission due to sufficient oxidation. Mekete, 2008 stated that Moving Bed Reactors often have a relatively high energy consumption and sludge production.

The increasing productions, expansion of treatment plants capacity are necessary as aerobic plants may not be able to cope with the increasing pollution loads and as such anaerobic treatments have been developed and applied to reduce the loading to the aerobic treatments. Anaerobic treatments are more efficient and better in terms of economics. The nature and strengths of brewery effluent provide ideal conditions for the anaerobic digester operations. The advantages of anaerobic treatment have led to an increasing interest in the application of anaerobic treatment to the brewery effluent. The most widely used anaerobic treatment is the Upflow Anaerobic Sludge Blanket (UASB) reactor.

Comparison of aerobic and anaerobic treatment systems

Aerobic systems

Anaerobic systems

Energy consumption

high

low

Energy production

No

yes

Biosolids Production

High

low

COD,BOD,(pV) removal

90-100%

70-85%

Nutrient N/P removal

high

low

Discontinuous operation

difficult

easy

Source: Metcalf and Eddy, 2004

1.1Physiochemical treatment process

Operations used for the treatment of wastewater in which change is brought about through applications of physical forces known as physical treatment process (Huei, 2005). The physical method is commonly used in wastewater treatment include screening, grit removal, mixing and flocculation, sedimentation, clarification, aeration and volatilization and stripping of volatile compounds

The process is used for the treatment of wastewater through which change is brought about by means of chemical reactions. The principal chemical processes used for wastewater treatment include chemical coagulants, chemical precipitation, chemical disinfection, chemical oxidation and ion exchange. A significant disadvantage of chemical treatment process is additive processes involved this meaning that something is added to into the wastewater to achieve the removal of something else. Besides that another disadvantage of chemical treatment is that the cost of most chemicals is related to the relative cost energy and the end user has little control over the cost of chemicals (White and Verdone, 2000). . In this study, flocculation and coagulation in the physiochemical process is being used as pre treatment.

1.11Coagulation, flocculation and precipitation

Coagulation and flocculation are important treatment processes that are used for rapid and economical removal of suspended, inert and undesirable colloidal materials in brewery effluent (Tatsi et al., 2003). Coagulation and flocculation are generally combined in a two staged transformation process (Nazariff and Alvarez-Cohen, 2001). Specifically, coag-flocculation is a chemical process used to destabilize the colloidal particles. The addition of a chemical agent generates positively charged ions in water, which conventionally contains negatively charged colloids and as a result, there is a suppression of the repulsion between the particles (Menkiti et al., 2011). Flocculation is the aggregation of particles in suspension into visible flocs that sediment under gravity. Flocculants carry active groups with a charge which will counterbalance the charge of particles and the process works by reversing electrostatic changes on small colloidal particles which are allowed to aggregate or floc together and are then removed via sedimentation or filtration (Tatsi et al.,2003).. Chemical precipitation can also been employed to remove undesirable dissolved ions which are converted to solids and then removed by sedimentation (Veeken et al., 2003; Dabrowski et al., 2004). The process also comprises of natural and man- made chemicals to act as flocculant and coagulants

Natural Flocculants/Coagulants

Natural flocculants are those that are derived from nature and examples include Moringa olifera seeds, Papain and a species of afzelia bella seeds which was used in an experiment in a Nigerian brewery and recorded efficiencies of up to 60-70% when compared with Alum in treating brewery effluent (Menkiti, 2011) .The option was also seen as eco-friendly compared to alum.

Aluminium Chlorohydrate(K300)

http://www.chemicalbook.com/CAS%5CGIF%5C12042-91-0.gif

Aluminium chlorohydrate is a group of salts having the general formula AlnCl (3n-m)(OH)m. It is used in deodorants and antiperspirants and as a flocculant in water and wastewater purification. Aluminium chlorohydrate is best described as an inorganic polymer and as such is difficult to structurally characterize

POLYELECTROLYTES

The polyelectrolytes used in water treatment are high molecular weight, synthetic organic polymers, produced by the polymerization of one (homopolymer) or more (copolymer) types of monomer units. Since the type and number of monomer units can be varied during the manufacture of polyelectrolytes, a wide variety of polymers can be produced. In addition to this the polymer chains can be linear, branched or cross-linked, adding to their complexity (Letterman and Pero, 1990). The molecular weight, solubility and electronic charge can provide useful information regarding the efficacy and the toxicity of a particular polymer (Nabholz et al, 1993). Polymers can contain both negatively and positively charged sites and are usually classified according to this, cationic having an overall positive charge, anionic an overall negative charge, non-ionic being neutral and amphoteric having both positive and negative sites (Letterman and Pero, 1990; Hamilton et al, 1994). The more highly charged a polymer, the more soluble it is likely to be Cationic polyelectrolytes are usually referred to as primary coagulants, while non-ionic and anionic are referred to

as coagulant aids or flocculants and these have relatively high molecular weights, often in the region of ten times or more that of the typical primary coagulant (Letterman and Pero, 1990).

Anionic Polymer

Anionic polymers are those flocculants that will usually react against a positively charged suspension (positive zeta potential) and in the case suits metallic hydroxides. In anionic flocculants, 1-100% of the monomer units contribute to the charge. Molecular weights tend to be in the high or very high range. Although several types of anionic sites in a polymer are possible, the major type in commercial flocculants is the polymers having carboxylate ions

Cationic Polymer

A cationic flocculant will react against a negatively charged suspension (negative zeta potential) like silica and other organic substances. Water-soluble cationic polymers are a class of polyelectrolytes that derive their unique properties from the density and distribution of positive charges along the macromolecular backbone. Chain conformation and solubility of such flocculants depend on the extent of ionization and interaction with water. Cationic functional groups can strongly interact with suspended, negatively charged particles or oil droplets and hence are useful in many applications, including waste treatment and paper making process.

CHAPTER 3MATERIALS AND METHODS

The research project was conducted in Harare at Delta Lagers Brewery located in Southerton industrial area just opposite the Southerton residential area. Delta Lagers brewery factory produces bottled, canned and draught beer and in the process produces substantial volume of wastewater. Partially treated wastewater is currently discharged from the Effluent plant to local wastewater treatment plant through a sewage line. The brewery receives approximately 1296 m3 of water per day (Delta Lagers January 2012 month end report).

Design

The project will make use of three flocculants namely Suid AP161 (Anionic Polymer), Suid3870(Cationic Polymer) and Suid K300(Aluminium Chlorohydrate). The experiment will consist of all the three flocculants plus a control that would measure the success of the three chemicals.

Sampling Points

The selection of sampling points was done based on the movement of the effluent including the main production sections up to the point of discharge. Five sampling points were located along the plant up to point of discharge into the municipal sewage drain and the points were as follows:

(1) One from Packaging Hall

(2) One sampling point was taken from Brewing

3) One was taken from the Engineering

4) Effluent Plant

5) Discharge into Municipal drain

A point to note is that in the first phase all the five sampling points were considered but in the second phase only one point was considered, the effluent plant. Sample collection was carried out in November 2011 and July 2012. The samples were collected directly from the factory's different sampling locations. Prior to sampling the2-Lpolyethylene bottles were cleaned by a cleaning detergent, washed and rinsed with distilled. They were thoroughly rinsed with the wastewater from the sampling sites before sampling.

Sampling Methods

Wastewater samples were collected using grab sampling from all sampling points and they consisted of a single sample taken at a specific time. Each sampling point was sampled twice on the sampling date with the samples combined to give a composite sample for the day.

.Statistical Analysis of Data

As the study is aimed at assessing suitable methods that can be used to reduce pV, TDS and pH

physicochemical parameters, data obtained were analyzed by means of appropriate statistical tools. The analysis of variance that is used to compare three or more means is

called a one way analysis of variance since it contains one variable. Analysis of variance

Commonly abbreviated as ANOVA. Excel spreadsheet and statistical software like SPSS version 15 were used for the statistical analysis.

.PARAMETERS TO BE ANALYSEDPermanganate value (pV)

This is a measure of the total oxidisable material in a given sample which is likely to be composed of organic compounds is found by using method No 725 by titration, based on SCA "The Permanganate Index and Permanganate Value Tests for Waters and Effluents" This Permanganate Value (PV) method determines the amount of oxygen used up by a sample in 4 h from a solution of potassium permanganate in dilute H2SO4 in a stoppered bottle at 27°C. It gives an idea of the oxi-dizable materials present in water, although the actual oxidation is only 30-50% of the theoretical value

Total dissolved solids (TDS):

Total dissolved solids (TDS) are the measure of total inorganic salts and other substances that are dissolved in water. TDS was determined following the procedure of using Electrical Conductivity (EC) meter. Measuring electrical conductance with a meter is a quick way to get a measurement of the total dissolved solids. TDS meter is actually an electrical conductivity meter (EC meter) that calculates TDS concentration in mg/L.

pH

pH of samples was noted using potentiometric method using pH meter already standardized by using buffer solutions of known value before analyses.

CHAPTER 4RESULTS AND DISCUSSION

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