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Liquid Waste Management in Kenya

liquid waste management in Kenya

The need for liquid waste management in Kenya is a point of discussion quickly gaining momentum throughout the country. That is because of the ballooning population coupled with rapid industrial development in the country.

In the past, the emphasis was on solid waste management, with liquid waste considered unimportant. The practice was to have a trench from the home, school, factory, hospital, etc., that empties any available liquid waste to the nearby open area. While one or two such disposal methods may appear harmless, hundreds of them will indeed harm the environment, hence the need for an effective liquid waste management plan.

Today’s discussion will be about the different types of liquid waste produced in Kenya, the management and disposal methods available, the need for managing liquid waste properly, and the advantages gained from the practice. Join us through the article and be informed.

Table of Contents

A Wastewater Treatment Facility

Liquid waste is any non-solid material you have no further use for and needs proper disposal. It includes domestic sewage, wastewater, oil, grease, hazardous house discharges, and industrial chemical discharge.

Liquid waste management is the safe discharge of liquid waste to the environment after all the harmful agents have been eliminated, treated, or processed into non-harmful forms.

Types/Sources of Liquid Waste

Liquid waste is classified according to the source. The source or the waste generator will also determine the appropriate treatment plan. The following are the primary sources of liquid waste:

1. Domestic/residential liquid waste

The liquid waste comes from households, schools, hotels, health centres, etc., and other establishments with people. It is mainly generated from the daily living activities of the people. Kitchen sink activities, washing, bathing, and toilet sewage are significant sources of residential waste.

In urban areas, all this waste is collected through underground sewerage systems and delivered to a central treatment facility. The liquid waste is treated through different processes at the treatment facility before it can be safely released into the environment.

Many establishments like schools and hotels have independent septic or holding tanks that temporarily store liquid waste before it is treated or transported to a treatment plant. These tanks are recommended in places with no standard sewer system, especially in rural Kenya. Biozone Kenya is the country’s leading design and construction agent for domestic and industrial septic tanks. Contact the company for more details on constructing a new septic tank or managing an existing one.

2. Commercial liquid waste

It is the liquid waste that comes from establishments with human activities like shops, markets, cafes, and restaurants. It is similar to domestic/residential liquid waste since they are both generated by human activities as opposed to industrial activities. Portable toilets and commercial holding tanks also form part of this waste.

Commercial liquid waste may contain flammable material, or it may have a lot of solid particles. The disposal process of this waste will be more detailed and advanced than domestic/residential liquid waste. Mostly, the waste will need to be filtered before it can be transported to the treatment facility.

3. Industrial liquid waste

Industrial liquid waste comes from industrial activities that produce byproducts. The waste comes from the processing and manufacturing activities of these industries. Industrial liquid waste is potentially harmful and hazardous to the presence of chemical substances used in the industrial process. Some processing factories, like those dealing with human food production, may release less harmful liquid waste than others, like those producing chemicals, metals, fertilizers, etc.

Industrial liquid waste should follow the same sewer system as domestic and commercial liquid waste because the treatment and disposal procedures are different. Industrial liquid waste must be tested and analyzed to establish available chemical agents before adopting any means of treatment and disposal.

4. Storm/runoff water waste

The wastewater results from excess rains washing away debris from the land surface. Although not considered waste like domestic, commercial, and industrial liquid waste, stormwater washes away any loose material on its way, which is deposited to the local water bodies like rivers.

Runoff water will cause flooding and spillage when it mixes with the sewer system. In towns and cities where runoff water may pose the most significant challenge and risk, the authorities should ensure proper drainage and that runoff water does not get into the sewerage systems.

Characteristics of Liquid Waste

Before adopting any liquid waste management, treatment, and disposal plan, you should know about the notable characteristics of liquid waste. The following are the attributes of liquid waste:

  • Solids. Liquid waste may or may not contain solid material. These solid materials are divided into settleable and suspended solids. Settleable solids are the ones that sink (settle out) to the bottom when the liquid waste is not moving, like when the liquid is held in a septic tank. Suspended solids are the ones that float in the liquid and do not dissolve. Whether the liquid waste is moving or stagnant, suspended solids will stay on top of the water.
  • Higher temperatures. Due to the way it is generated, liquid waste is warmer than usual. That is because most of the water included comes from bathrooms and industrial processes.
  • Odour. Due to the biodegradation of organic matter found in liquid waste, it tends to have a foul smell. Human, animal, food, and other types of waste will produce a foul odour when they start decomposing.
  • Gases. Apart from a strong odour, the decomposition of organic matter also produces gases. The Biozone biogas production process uses this principle to produce methane and carbon dioxide gases. The methane gas is harnessed for domestic energy purposes like cooking and lighting while the less harmful carbon dioxide is released to the environment.
  • Organic matter. Any part of liquid waste that comes from animals or plants is called organic matter. It is the part that will decompose and is the primary pollutant in all surface waters.
  • Inorganic matter. It is made up of all other materials besides animal and plant remains. It is the part of liquid waste that does not decompose. It is made of chemicals and other solids like salts that will not dissolve or break down. When inorganic matter ends up in water bodies, it will negatively affect marine life.
  • Microorganisms. Tiny organisms and bacteria are to be expected in liquid waste. These organisms are essential for the decomposition process of the organic matter in liquid waste. These organisms are necessary but will become dangerous if they contaminate clean water and food. They are likely to cause diseases and infections in people and animals.

The Process of Liquid Waste Management in Kenya

The process of liquid waste management in Kenya follows the same stages as wastewater treatment. The process goes through a series of steps which are outlined below:

Step I. Collection

The first step in liquid and wastewater treatment is the collection of waste. Home and business owners are responsible for directing their liquid waste to the municipal sewer systems. If your home is not near a shared sewer system, you should use septic or holding tanks to collect liquid waste and transport it to the treatment plant using exhausted lorries.

Step II. Odor Control

Odour control is the next step in liquid waste management. It can also be said to be the first step in the treatment process. The many organic materials in the liquid waste will begin the decomposition process before the actual treatment occurs. It is, therefore, essential to neutralize the odour-causing materials using special chemicals and enzymes. All Biozone wastewater treatment enzymes and microbes (discussed later) are designed to deal with any odour produced by the liquid waste.

Step III. Screening

Screening of the liquid waste is the next step. It is necessary to remove any solid material from the wastewater. Screening is done in two mini-steps:

  • Initial/bar screening. It is the removal of any large materials or objects that are in the system. Diapers, cotton buds, nappies, sanitary towels, face wipes, bottle caps, etc., are some common materials screened out at this stage. They should be removed because they may damage the pipes and other machines in the treatment process. They can also prevent the wastewater from flowing correctly.
  • Secondary/fine screening. It removes the smaller and finer material, grit, from the wastewater. Grit may cause damage to the pumps and other machines later in the treatment process. Secondary screening is done by passing the liquid waste through a grit chamber. The grit settles down at the bottom of the chamber while the wastewater flows to the next stage. The grit will be physically scrapped from the bottom of the chamber and discarded after it has accumulated to sufficient levels.

Step IV. Primary Treatment

The next stage in wastewater treatment is the primary treatment stage. The wastewater is pumped through big holding tanks that allow for the organic matter, known as sludge or slurry, to settle at the bottom. Here, between 25% and 50% of any solid organic matter will be separated from the wastewater. The sludge at the bottom of the clarifiers is later pumped out for further treatment or to be used in agricultural activities as organic fertilizer. The wastewater, or effluent, is pumped further for secondary treatment.

Step V. Secondary Treatment

The next step in wastewater treatment is secondary treatment. It is done to further break down the organic matter in the effluent. It is a two-step process:

Aeration. The effluent goes through large aeration tanks for oxygen to be introduced into the process. The aeration process encourages the growth and development of bacteria that are useful in the digestion of organic matter. The larger the amount of oxygen introduced at this stage, the better the organic matter will be broken down, and the better the treatment process.

Secondary clarifier. After the effluent is pumped from the aeration tanks, it is moved to the secondary clarifiers. Here, just like in the primary treatment tanks, the organic matter is allowed to settle at the bottom of the tanks. Up to 85% of organic matter available in wastewater is removed at this stage. The sludge after this stage can either be removed and used as fertilizer in agricultural activities or it can be re-introduced at the primary treatment tanks for further processing.

Step VI. Bio-solids handling and Disinfection

The solids in the primary and secondary wastewater treatment stages are sometimes directed to biodigesters for further treatment through anaerobic treatment. The treatment produces methane gas and nutrient-rich sludge. The methane gas is used in the treatment plant for heating while the nutrient-rich sludge is sold as organic fertilizer.

The water produced after the primary and secondary wastewater treatment is still not pure and needs to be further treated and disinfected to kill any disease-causing bacteria still in the system. Chlorine is the most common disinfection agent at this stage because it is cheap and readily available.

Step VII. Water Analysis and Testing

The final water produced after a wastewater treatment process still needs to be tested and analyzed to ensure that it meets the specified and acceptable chemical components. The main objective of wastewater treatment is to ensure that the final water released is safe for the environment, people, and animals. It is, therefore, necessary to test to ensure that this primary objective is met.

Proper pH levels, chlorine, ammonia, phosphates, oxygen, etc., are tests required to be carried out. Increased levels of these constituent water components may render the water to be deemed as not fit to be released, where the treatment process will be required to be carried out again.

Step VIII. Water Disposal

Since the objective of wastewater treatment is to have safe water in the environment, once the effluent has been certified as fit to be released, it is re-introduced to the environment. Although this water may not be fit for drinking or cooking, it can be used for a number of other activities like washing, and flushing toilets, and for agricultural activities like irrigation.

Biozone Wastewater Treatment Plant

For better liquid waste management, you will need to know about the various wastewater treatment options available to you. At Biozone Kenya, we offer consultancy based on the kind of liquid waste you generate so that you may be better placed to have the best Liquid waste treatment plant for your establishment. Biozone offers three alternatives for liquid/water treatment, as explained below:

1. Primary Liquid Waste Treatment plant

Biological treatment is not always the best, or at least not the complete solution to all industrial wastewater applications. The wide range of possible impurities in industrial wastewater streams sometimes requires the employment of several physical-chemical treatment steps to remove the contaminants to a level that will allow for the discharge or reuse of the wastewater.

Dissolved contaminants, suspended matter, fats, oils, and grease (FOG) can require other technologies and solutions for effective treatment. For a low-cost industrial liquid waste treatment plant, consult Biozone Kenya today.

2. Anaerobic Liquid Waste Treatment Plant

In the absence of oxygen, many groups of anaerobic microorganisms work together to decompose organic matter. The microbiology behind the process is more complex and delicate than that of aerobic processes, where most bacteria work individually. It is the main reason why anaerobic systems require greater control and monitoring in order to perform efficiently.

This type of treatment is very effective in the removal of biodegradable organic compounds. It is especially suitable for organic wastes and wastewater streams highly loaded with organic contaminants. It effectively converts them to mostly methane gas and carbon dioxide, with very little excess sludge generation. 

Wastewater streams from food and beverage production, biofuels production, pulp, and paper mills, and the chemical industry, are highly-loaded with organic pollutants and can be treated advantageously by the means of various anaerobic processes. For further inquiries or a quotation on an anaerobic wastewater treatment plant, contact Biozone.

3. Aerobic Liquid Waste Treatment Plant

Highly effective and able to generate very high-quality effluents, aerobic biological wastewater treatment processes were once the solution applied to treat most types of industrial wastewater. Nowadays, with far greater emphasis on energy efficiency and the minimization of residuals (i.e. waste sludge), they are mostly limited to diluted industrial wastewater and municipal applications, and as a polishing step after anaerobic treatment.

However, when strict discharge requirements are present, it is still impossible to design a full biological treatment for any type of wastewater without applying at least one aerobic step. Therefore, our portfolio of technologies also includes a variety of different aerobic treatment systems. This way we are able to offer you a complete range of wastewater treatment solutions able to meet any discharge requirements. For further inquiries on aerobic wastewater treatment, contact Biozone Kenya.

Liquid Waste Treatment Enzymes and Microbes

Biozone Environzyme BFB

The Environzyme BFB is a microbiological combination of aerobic and anaerobic bacteria and multi enzymes that break down wastewater to clean effluent. It is a dry free flowing powder that contains a concentrated source of free-flowing hydrolytic enzymes and ten strains of natural bacteria that are capable of producing enzymes in wastewater treatment systems under aerobic and anaerobic conditions.

Whether it is in the Biozone Wastewater Treatment Plants or an existing wastewater treatment plant already in your establishment, the Environzyme BFB is the enzyme and microbial formula you will need to effectively break down and digest organic matter.

The notable advantages of Environzyme BFB are:

  • More volumes will be digested and hence the sludge volume will be reduced.
  • Eradicates bad odour.
  • To pump and dewater the sludge will be easier.
  • The capacity of your treatment will be increased since more organic matter will be digested.
  • The time taken to digest organic matter is less.
  • The treatment system is easily balanced.
  • The aeration stage in the treatment will be faster and more effective.
  • The digesters will perform evenly and uniformly since the organic matter is properly digested.

Liquid Waste Disposal Methods in Kenya

Not all types of liquid waste can undergo the wastewater treatment process to be cleaned for safe reuse or release to the environment. Still, not every organization or establishment can afford a wastewater treatment plant. The following are other alternative liquid waste disposal methods:

1. Dewatering

For non-hazardous waste material, dewatering is a process that can be applied. Just like in the primary wastewater treatment stage, dewatering involves separating the solids from the liquid. The liquid waste is pumped into filtration bags that will allow the water to pass while retaining the solids. The wastewater will still need to be treated before it can be safely released into the environment while the solids are disposed in a landfill.

2. Sedimentation

Sedimentation is similar to dewatering in that the aim is to separate the solids from the liquid. While dewatering uses filter bags, in sedimentation, a sedimentation basin is used. The purpose of this basin is to slow down the flow of liquid waste to allow the solid materials to sink to the bottom. The remaining wastewater still needs treatment before it is safe while the solids can be taken to a landfill.

3. Compositing

Composting is another method establishments can use to dispose liquid waste. The liquid waste is first separated into water and organic material. These organic materials are then processed to become organic fertilizers that are rich in nutrients like nitrogen, sodium, potassium, etc. These nutrients are very beneficial in crop farming. Compared to the other methods of liquid waste disposal, composting is the easiest and most advantageous.

4. Incineration

Incineration is also a method that can be adopted for disposing liquid waste. The liquid waste is pumped into special furnaces and then extreme temperatures are introduced. Chemicals, oils, acids, and other kinds of waste will be burned leaving only water. Incineration is not an advisable method of liquid waste management since it is expensive and the process emits harmful gases into the atmosphere which contribute to global warming and extreme weather like acid rain.

5. Solidification

Solidification is the addition of binding agents into the liquid waste to make it sturdy and solid. The process is concerned with altering the physical nature of the liquid waste so that it can be easily handled or transported. Binding agents include lime ash, sawdust, cement kiln dust, lime kiln dust, gypsum, phosphate, and fly dust. Once the liquid waste has solidified and stabilized, it is then moved to landfills or taken to incinerators to be burned.

Industries That Need the Biozone Wastewater Treatment Plant in Kenya

1. Beer and beverage industry

Beer and beverage industries are significant consumers of water in their production processes. A substantial portion of their overall energy consumption is a result of water and wastewater treatment. In many parts of the world, the availability of sufficient amounts of water is under severe stress, and costs continue to rise as a result. The Biozone Wastewater Treatment Plant will help in treating the water so that it can be reused in the process as well as produce biogas that can be used as energy in the production process.

2. Food industry

The food industry is among the leading generators of wastewater. The industry would greatly benefit from the technology employed in the Biozone Wastewater Treatment Plants to recycle the water for further use as well as produce energy (biogas) which will be beneficial o the industry.

Depending on the nature of production and products generated, food processing wastewater can contain a wide range of concentrations of impurities, from low to high levels of organic pollutants, suspended solids, fats, oil and grease (FOG), proteins, and even ammonia.

With a portfolio of advanced anaerobic, aerobic, and physical-chemical processes, Biozone Kenya can offer you a complete tailor-made solution that will efficiently handle your waste, and when possible, generate renewable energy and useful end products, for further profit and value.

3. Pulp and paper industry

Recycled paper, bleached paper, cardboard production, and other paper mills will all generate wastewater with different compositions. They require proven and efficient technologies to effectively treat the high-strength wastewater generated, in order to prevent environmental pollution and restrict the production plant operations.

Paper and paper products are something that all of us utilize each day. While a wide variety of useful products can be made from paper, the transformation of wood, straw, bagasse, and other materials into paper is a very complicated process that requires significant amounts of water and energy.

The anaerobic Wastewater Treatment Plant form Biozone will treat any wastewater from the process into reusable water while producing enough biogas to supplement the energy needs of the process.

4. Distillery and winery industry

Distilleries and wineries generate both solid and liquid waste, which are, in most cases, high in organic content and difficult to treat. The complexity and variable nature of wastewater from such installations make them applications that often require complex treatment. Depending on the local nature of production, the molasses, wine, agave plants, grains, vegetables, and fruits also have to be cleaned and adequately handled before they can be used in the production process, generating wastewater that needs to be treated.

The large amount of water and energy needed in this industry makes recycling and reusing water a cost-cutting initiative. Generating biogas that will supplement the energy needs of the process will also offset major costs. The Biozone Wastewater Treatment Plant will be a necessary inclusion in the operations of these industries.

5. Tannery industry

The tannery industry is among the rapidly rising industries in Kenya, especially within the pastoralist communities. Tanning is the process of converting animal hides into leather. Animal skin from cows, goats, sheep, camels, and other animals needs to be processed before it can be used to make leather products.

Tannery wastewater contains chromium, sulphides, acids, organic matter, and other solid materials. It is recognized as among the worst water catchment pollutants since chromium is a heavy metal that is toxic and should not be released into the environment. Tanneries, therefore, require wastewater treatment to get rid of these heavy metals and organic matter from the effluent. The Biozone physical-chemical (primary) Wastewater Treatment Plant is among the best suited for this process. It will clean the effluent and make the water reusable again within the process.

6. Textile Industry

Textile industries in Kenya should also consider adopting a Biozone Wastewater Treatment Plant to aid in their operations. The main materials in this industry are cotton, wool, and other synthetic fibres. Before these materials can be used to make garments, they need to be processed and water is used in different stages of the process.

The effluent from that process contains chemicals, organic matter, and also dye which can all pollute the environment. The Biozone treatment plant will treat the effluent and remove all harmful material and chemicals and make it reusable in the production process.

7. Carwash industry

The carwash industry in Kenya is another industry on an upward growth. That is because many young people have taken on the exercise due to the unemployment levels. The main contaminants of carwash wastewater are mainly soap and salt. In small quantities, they may not have a large impact but continued discharge to the environment will affect the surrounding area eventually.

For such smaller effluent, you will need a tailor-made wastewater treatment plant that will help you treat the water and make it reusable again. Contact Biozone for inquiries about such a plant and start saving on the water cost.

8. City, town, and county authorities

Every city, town, or county authority handles a lot of liquid waste generated by its inhabitants and industrial processes. It also needs a lot of water and energy to be used in residential areas and industries. That is why the adoption of a Biozone Wastewater Treatment Plant should be among the priorities of these authorities. BioZone Kenya will design, develop, and implement a tailor-made treatment that will be suitable to your needs and according to your capacity.

9. Healthcare industry

All healthcare facilities generate sensitive wastewater which should be handled with care. Hospitals, clinics, and also pharmacies produce wastewater highly concentrated with medical waste and pharmaceutical chemicals that if not properly contained and treated, will be a major pollutant to the environment.

The treatment and handling of such kind of wastewater need great expertise, with normal treatment not sufficient. At Biozone Kenya, not only will we design and deliver a treatment plant good enough to handle this sensitive wastewater, but we will also recycle the water to make it reusable in the facility again.

Importance of Liquid Waste Management in Kenya

Unlike solid waste which is easy to collect, move, and dispose, liquid waste poses a challenge when it comes to its handling and treatment. It is very easy for liquid waste to pollute the environment and endanger people, animals, and plants. Since most liquid waste is not recyclable, it needs careful disposal methods due to the sanitation issues it brings.

The following are the reasons why it is important to properly manage liquid waste:

1. Protects the environment

An important point for proper liquid waste management is to protect the environment. Liquid waste can be more devastating than solid waste in the environment. It is easy for liquid to contaminate surface water and groundwater. The chemicals contained in the liquid waste can leak into the water bodies without anyone being the wiser. These chemicals and other inorganic materials in liquid waste will also easily pollute the soil by significantly altering its pH.

2. Maintains hygiene

Improper liquid waste management leads to diseases for both people and animals. That is because liquid waste will pollute the water, air, and land that people and animals depend on for survival. Proper liquid waste management is, therefore, necessary to prevent these diseases.

3. Requirement by law

The environmental protection laws in Kenya require every establishment producing liquid waste to have proper management practices in place. This law applies more to industries than residential places since a majority of the residences, especially in urban areas, are connected to a sewer system. That is why many industries have liquid waste septic tanks and holding tanks to keep the waste before it can be safely treated and disposed. For the best septic tank design and construction, consult Biozone Kenya today.

4. Reduces greenhouse emissions

Burning or incineration of waste, especially solid waste, causes the release of harmful gases into the atmosphere, which will lead to global warming. Proper treatment and disposal methods of liquid waste do not release these gases which makes it necessary to have the process done right. Methane gas that is released in liquid waste management can be utilized for energy purposes, while the carbon dioxide released is in minimal quantities that have no adverse effect ot the atmosphere.

5. Aesthetic value

The majority of the liquid waste generated contains a foul odour. That is mainly attributed to the decomposition process of the organic matter found in the waste. Properly managing liquid waste will therefore eliminate that foul smell which will make the lives and activities of the neighbouring community unbearable. It should be part of the social responsibility of any establishment generating liquid waste to ensure that it does not become a nuisance to the community.

FAQs About Liquid Waste Management in Kenya

What is liquid waste?

There are many people who ask what is liquid waste. Liquid waste can be defined as such liquids as wastewater, fats, oils or grease (FOG), used oil, liquids, solids, gases, or sludges and hazardous household liquids. These liquids are hazardous or potentially harmful to human health or the environment. They are usually generated from residential places, industries, and any place that hosts people.

Can liquid waste be positively utilized?

Still, there are some who ask whether there are any uses for liquid waste. Some liquid waste can be recycled or reconstituted to form new products, or useful material can be extracted from it. Biogas, organic fertilizer, and clean water are all useful byproducts of an effective liquid waste management system.

Why is liquid waste a problem?

Some ask what liquid waste is problematic and needs careful handling. Improper treatment, disposal, or discharge of liquid waste into the environment is harmful to people, animals, and plants. People and animals can acquire diseases and infections from liquid waste while plants will be affected once the pH levels of the soil change due to chemicals contained in liquid waste.

In Summary

The need to protect the environment should be the driving force for everyone, individuals or organizations, to properly manage, treat, and dispose any liquid they generate. It is the collective responsibility of everyone to ensure that no harmful and hazardous liquid is released into the environment without proper treatment.

Biozone Kenya is the leading designer and construction specialist for all liquid waste treatment facilities in the country. Contact them today for inquiries and consultations on all matters relating to waste management.

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