Kenya's Water Crisis...

There are about 40 million people living in Kenya today and within that number about 17 million (43 PERCENT!!!) do not have access to clean water. For decades, water scarcity has been a major issue in Kenya, caused mainly by years of persistent droughts, poor management of its water supply, contamination of the available water, and a sharp increase in water demand resulting from the moderately high population growth.

 The lack of rainfall affects also the ability to acquire food and has led to eruptions of violence within the African Nation. In many areas, the shortage of water in Kenya has been amplified by the government’s lack of investment in water, especially in rural areas. Kenya is a relatively dry country with about 80 percent of the country being arid and semi-arid.

The high potential/fertile agricultural land only amounts to a mere 17 percent, which sustains 75 percent of the population. 

The average annual rainfall in Kenya is about 630 millimeters (mm) with a variation from less than 200 mm in Northern Kenya to over 1,800 mm on the mountain slopes of Mt. Kenya. Over the past decade Kenya and most of East Africa has experienced a severe drought leaving many dead. 

Global warming is one of the critical factors that has prolonged the drought killing millions as a result and of the Kenyans that have survived are unable to grow their crops and keep their livestock alive. Because most Kenyans rely directly or indirectly on agriculture, when severe droughts occur, many Kenyans are left to starve unless food aid prevents a famine.

Another main reason why droughts have prolonged as a long as they have is due to deforestation. The largest forest in Kenya is Mau,  which distributes water to six lakes plus eight wildlife reserves, and some 10 million people depend on its rivers for a living. However, loggers and farmers have destroyed a quarter of Mau’s 400,000 hectares. The problem with deforestation is that it almost always leads to increased surface water runoff, which has negative implications in both the rainy season as well as the following dry season.

The inability to maintain clean water in Kenya is another main reason for the constant worsening of the water crisis in Kenya and the rest of East Africa. 

Most Kenyans use wells to obtain domestic groundwater and also use pit latrines that are often close in distance to the wells. This causes contamination of the wells because the microorganisms travel from the pit latrines to the wells. The wells should be placed in elevated areas (at least 2 meters above the water table) and at least 15 meters from pit latrines, which however is not the case in most overcrowded urban slums.

At the global level about 1 billion people are sealed out of having access to safe water due to poverty, inequality and government failure. It is also clear that not having access to clean water is a main driver and cause of poverty and inequality. In Kenya, largely due to recurrent droughts, millions of families that rely on crops and livestock are threatened and thousands of people die each year as a result of thirst and hunger. According to the World Bank (2010), the mortality rates of adult males, adult females, children under five, and infants has increased from 1990 to 2008.

Rainwater Harvesting....

Rainwater harvesting is the capture, storage and utilization of rainwater for a meaningful purpose. There has been a huge spike in rainwater harvesting systems across the United States as a result of drought, increasing population and aging infrastructure. Rainwater harvesting offers many benefits, which include conservation of groundwater, low on salts, gravity systems help to conserve energy and can reduce flooding and erosion. 

Commonly, rainwater harvesting methods are isolated into two categories, passive and active systems. Passive systems utilize no moving parts and generally use the landscape for rainwater diversion to a desired locality. The water is stored in the soil rather than a containment object for a Passive System. Passive systems include rain gardens and permeable pavements.

The design of rainwater harvesting systems will vary for each building type. A usual system will consist of three components, which include the catchment, the detention basin, and the conveyance system, but the most important element is the catchment, which is used to collect the rainfall. The catchment can be on the roof depending if it is flat. 

If the roof were sloped then there would be some form of collection area or gutter on the overhangs that will lead to the detention basin. Since, rainwater is considered, in terms of it being potable, in between groundwater and surface water then passing it through a sand filter will sufficient and adding baking soda to increase its pH to the desired level will work as well.

An example of a complex rainwater harvesting system that is used is the HighDRO system. This system consists of a flush filter, rainwater collection tank and an advanced water filtration/disinfection system. This system can help a building achieve Net-Zero Water, but it could cost the building in becoming a Net-Zero Energy building if the energy requirement is high.

Rainwater harvesting shows great potential to reduce municipal water supply costs and protect adjacent ecosystems. The U.S. EPA reports that “reducing [municipal] potable water demand by 10 percent could save approximately 300 billion kilowatt-hours of energy each year” in the U.S. alone.

Best practices for designing rainwater-harvesting systems use relatively simple, little technological methods for collection and the storage. Water should enter the cistern near the bottom of the tank where it is subsided by means of a diffuser to avoid disturbing sediment in the tank.

Rainwater harvesting systems have the potential for incorporation into a wide number of other building systems. “They are ideally suited for incorporation into on-site stormwater management strategies, allowing temporary storage after storm events and helping to reduce runoff.” They are also ideal for use in landscape irrigation, counteracting the need for potable water.

 Further occasions may exist to integrate rainwater cisterns into both active and passive solar systems by providing a potential location for storage of thermal energy. Large storage tanks may both provide or require additional structural support so careful attention is needed when designing them either on or near other structures. Finally, catchment and conveyance systems may be integrated into both interior and exterior spaces of a building in such a way that they provide a valuable connection between occupants and the natural water cycles outside the building.

Eutrophication in Aquatic Ecosystems....

Eutrophication is the over-enrichment of aquatic ecosystems with nutrients leading to too many nutrients stimulating the rapid growth of plants and algae, clogging waterways and sometimes creating blooms of toxic blue-green algae.  The result of this is that when the plants and algae die and decompose, they use up large amounts of oxygen (O₂). 

So the amount of oxygen that is available for fish and other aquatic species will be reduced. In extreme cases, it can lead to a completely oxygen-less aquatic environment that can support nothing except a few species of anaerobic bacteria. It also can kill fish and other aquatic life and reduce the aesthetic and recreational value or aspect of the lake.

The nutrients include nitrates found in sewage and fertilizers, and phosphates found in detergents and fertilizers. Human inputs of nutrients from the atmosphere and from nearby urban and agricultural areas can accelerate the natural eutrophication of lakes, a process called cultural eutrophication. Eutrophication is a persistent condition of surface waters and a widespread environmental problem. Some lakes have recovered after sources of nutrients were eventually reduced. 

In others, recycling of phosphorus from sediments enriched by years of high nutrient inputs causes lakes to remain eutrophic even after external inputs of phosphorus are decreased. Slow changes of phosphorus from over-fertilized soils may be even more important for maintaining eutrophication of lakes in agricultural regions. This type of eutrophication is not reversible unless there are substantial changes in soil management. 

Technologies for rapidly reducing phosphorus content of overly enriched soils, or reducing erosion rates, are needed to improve water quality. Excess phosphorus inputs to lakes usually come from sewage, industrial discharges, and runoff from agriculture, construction sites, and urban areas. Over time, many countries have regulated point sources of nutrients, such as municipal and industrial discharges. Nonpoint sources of nutrients, such as runoff from agricultural or urban lands, have replaced point sources as the driver of eutrophication in many regions.

Lake eutrophication has proven to be a stubborn environmental problem. Instead of alternating rules, many lakes remain eutrophic for extended periods of time. Causes of slow recovery, or non-recovery, from eutrophication are multiple and not really understood. Persistent eutrophication could be due to internal recycling from a large pool of phosphorus in sediments, which leads to alternative stable states. Prolonged release of phosphorus from enriched soils may also explain the persistent eutrophication.

Eutrophication can be avoided by using minimal required amounts of chemical fertilizers or still do away with them and use natural ones instead. Be sure not to have the fields close to the water bodies. Take extra care while using fertilizers during monsoons as due to run-off, they get transmitted to the water bodies. Then they can cause blockage of waterways, death of marine life and breakage of food chain.

Maintaining flat plains adjacent to rivers can also help to reduce nutrient-load in mouth water bodies; as when the river breaks its banks and floods, sediments and nutrients are deposited on the plains either side of the river is another innovative way that Eutrophication can be avoided.

Arsenic Poisoning in Water...

Arsenic is a naturally occurring mineral that can be found in soil, bedrock, and, ground water. It is a highly poisonous metallic element that has three allotropic forms, which are yellow, black and gray, it also occurs in the three states of matter which are liquid, solid and gas. Sometimes found in its pure form as a metal, it is usually a part of chemical compounds such as inorganic and organic. 

Inorganic compounds mean it combines with oxygen, iron, chlorine or sulfur.  Organic compounds mean it combines with carbon and other atoms.  It is often found in drinking water at levels from several hundred to several thousand parts per billion (ppb) and can be in high concentrations in industrial areas and near agricultural activity and cannot be detected by smell or taste.  

The naturally occurring inorganic arsenic is formed from the weathering and decomposition of soil and minerals as well as from volcanic activity.   Inorganic arsenic can also be produced through anthropogenic means such as: ore smelting, burning of coal, pesticide use and combustion of fossil fuel.  

Research of arsenic in water dates back to 1975 and has been noted as an issue for quite some time.  Arsenic contamination of ground water can be found in many countries throughout the world as well as the USA and is known to cause health issues in individuals that ingest it.  

As stated, the USA has had its issues with arsenic in its drinking water in many of its states. “Water in some areas of the United States, especially in the West, contain high levels range from 50 to 100 ppb.”   Based on research by the United States Geological Survey (USGS) such states as California, Oregon, Nevada, Texas, Montana and Minnesota has reported  high levels of arsenic in their drinking water.  

The Figure  below shows the levels of contamination by state as reported by USGS.

Besides the United States of America, it has been found that arsenic poisoning from groundwater has also been reported in recent years in countries such as China, Argentina, Chile and Bangladesh.  In Bangladesh alone, over a million Bangladeshi villagers have been poisoned by groundwater that contains naturally occurring arsenic. 

In an attempt to provide clean drinking water to this poor country, tube wells (steel pipes fitted with simple hand pumps) were sunk to aid the villagers in acquiring water naturally by the United Nations Children’s Fund (UNICEF) as well as various world organizations with no knowledge of the fact that the groundwater would contain arsenic.

Today over a billion Bangladeshis are drinking arsenic contaminated water knowingly because they have no other source of clean drinking water as their government try to come up with a cost-effective measure that would remove/filter the arsenic to acceptable levels. And in the long run find effective ways to deal with the effects of drinking arsenic for an extended amount of time.

Other health effects such as hypertension, diabetes, adverse reproductive effects, respiratory effects, skin lesions, and cognitive effects may be present but further studies will need to be performed to be conclusive. Concern over the potential effects of long-term, chronic exposure to arsenic in drinking water the U.S. Environmental Protection Agency (EPA)was prompted to reduce the drinking water standard for arsenic which has lead to many processes for the filtering of arsenic.  

Currently, there are many processes that allow engineers to reduce the level of arsenic in water, which includes but are not limited to: ion exchange, filtration, reverse osmosis and an innovative way called point of use, point of source/entry.