Examination of The Consequences of Desalination to The Environs

Introduction

As global warming grips the planet and prolonged drought strikes in many areas, citizens and their governments are looking for ways to provide populations with secure freshwater sources. Although desalination has been available for decades it is fairly recently that communities have the resources to embrace its implementation. I want to examine the environmental impacts of desalination because the consequences of the fresh water extraction processes have not yet been fully acknowledged. What would international and national regulations on desalination look like as more countries enter drought and gain the technology to desalinate (Schriber 23-28)? Arid areas that rely on desalinated water have been shown to burden poorer communities, specifically in the case of Israel and Palestine (Elmusa 12). I intend to use these countries as a case study to exemplify how governments and private companies can complicate the process of distributing clean water to a population. Negative effects also are present in marine biota and greenhouse gas emissions. Before treating desalination as a viable and sustainable source of fresh drinking water it is extremely necessary to consider its multi-faceted lasting effects on the environment (The Impacts of Relying on Desalination for Water).

This paper is intended to reach the Joint High-Level Panel on Water consisting of members from the World Bank and United Nations. They work on policy, effective action, and implementation of responsible treatment of the world’s water resources. The first portion of the paper will serve to provide a strong scientific background detailing the desalination process, a concept that is important to have a basic understanding of before judging its usefulness. That will be followed by a scientific analysis of desalination’s effects on both marine life and energy usage. Following that will be the policy section of the paper including recommendations regarding regulations to limit this environmental health problem and those regulations that are already in place. This will include the Israel-Palestine case study which will serve to show how critical of a public health issue desalination can be.

The Desalination Process

Reverse osmosis is a desalination process used at 80 percent of the world’s desalination plants and projected to be the leading process going forward (Greenlee). The most common alternative is using a distillation process (Greenlee). Not all reverse osmosis plants work exactly the same way; however the basic functions and steps are usually similar. They have available for over 40 years so with technological improvements the materials and design varies slightly from plant to plant (Contruvo).

Water is drawn in through intake pipes that reach out into the ocean along the seafloor. It then goes through a pretreatment process that involves the additions of acid and coagulants/flocculants. The acid (usually sulfuric acid) serves to increase the solubility of common precipitates found in feed water. The coagulants/flocculants help to neutralize the charge of the water and drawn suspended particles together so the are more easily filtered out (Greenlee).

After this pretreatment the water either seeps down a filter using gravity or it is pressured. The media filter consists of layers of materials like sand, gravel, and charcoal layered from the finest material to the coarsest for drainage purposes. Then the water flows through cartridge filtration which removes the few remaining large particles missed by the media filter. Oxidizing agents are then added to disinfect the water as the last step of the desalination pretreatment process (Greenlee, Darwish).

Following pretreatment, the most energy intensive part of the reverse osmosis occurs. Water is pressured through a semipermeable membrane made of cellulose acetate, polysulfonate, and polyamide. Primarily water is let through because the hydrostatic pressure of the membrane is higher than the osmotic pressure of the water solution which means the water can diffuse through the membrane while much of the salt is not able to. In some plants this process is repeated because it can be particularly difficult to remove some contaminants such as boron which is only rejected by the membrane at a rate of 75-80 percent whereas salt is rejected at a rate of 99.7 percent. Water temperature and therefore season can also have an effect on the effectiveness of the reverse osmosis membrane (Greenlee).

The membrane is subject to problems because of the strenuous use it gets. The membrane can become less effect because it is essentially clogged by organic matter, particulate matter, dissolved inorganic salts, as well as other contaminants. When these precipitates build up in the layers of the membrane it must be cleaned with chemicals to restore it back to its full operational status (Cotruvo).

The water then continues past the reverse osmosis stage for post treatment. There it is remineralized. Often the alkalinity and pH are modified to increase the hardness of the water, both for taste and to prevent corrosion of water infrastructure. Fluoride is usually added and the water is disinfected again. These components vary depending on the drinking water standards for the location and distribution area of the desalination plant (Greenlee).

The now freshwater goes into holding tanks and reservoirs and is eventually distributed as clean drinking water. Brine water is discharged back into the ocean far away from the site where it is drawn into the plant. This discharge is the main source of concern about desalination plant’s impact on ocean flora and fauna (Danoun).

Negative Effects on Marine Biota

In the process of desalination freshwater is derived from salt water by separating the salt from the water (Cotruvo). The concentrated salt mixture left after the process is called brine which is often discharged back into the ocean. Marine life has been shown to be negatively affected by elevated levels of salinity. Wind speed and direction, wave height and speed, and tidal levels all affect the speed at which the brine is diluted lowering zone that is dangerous for aquatic life (Danoun, 20). High salinity, alkalinity, and temperature in the brine change those components of the ocean water they enter (Danoun, 21). The negative and positive results of these few factors are necessary to consider when planning the brine discharge system for a desalination plant.

Many studies have been done to determine the effect of brine discharge on marine life. Studies are often site specific and thus vary in their findings. A common conclusion of all the studies looked at for this paper is that the brine discharge definitely has an effect on ocean species (Robert, 3). About 50 percent of the water drawn into the plant is recovered as potable water this means that half of the original intake is sent back to the sea (Latterman, 3). The brine water coming out from the desalination plant rejection stream often contains residual chemicals from the desalination process, byproducts, and heavy metals. These contaminants can affect marine ecosystems near the outlet (Latterman, 5). “Negative effects on the marine environment can occur especially when high waste water discharges coincide with sensitive ecosystems (Latterman, 5).” Marine life in shallow outlets without a lot of ocean movement tend to be more affected because the brine water does not disperse as quickly as it does in a high energy part of the ocean (Latterman, 6).

The impact of increased salinity varies from species to species. Research has been done on many types however more case control experiments are necessary to totally determine the effects. Shellfish tend to flourish in environments with higher levels of salt whereas juvenile fish populations shy away from these elevated levels (Danoun 27). High salinity in many cases kills young plankton (Danoun, 27). It has been shown that brine discharge can alter the diversity and species richness in areas near the discharge site (Roberts). This result can be tied back to the conclusion that raised salinity levels can benefit some species while disadvantaging others.

In addition, to monitoring marine biota near actual dispersion sites, studies have been done in laboratories with regards to individual species. For example, seagrass exposed to high levels of salinity over the course of 24 hours had reduced levels of photosynthesis of up to 50 percent (Roberts). Experiments have also shown that the brine can be toxic to certain types of fish embryos if exposed at an early age due to the contaminants left in the solution after reverse osmosis (Latterman, 11).

In summary the combination of high salinity, contaminants, and temperature of brine water affects marine ecosystems in ways that are not fully realized yet. Studies and experiments done at specific sites address the impacts of certain desalination plants, the policy section of the paper will emphasize the importance of this information with regards to what steps should be >taken to reduce these disturbances.

Energy Efficiency Concerns

A common concern about desalination is its energy efficiency and tied to that is financial sustainability. Almost yearly the amount of energy it takes to desalinate water is decreasing due to technological advancements and research (Elimelech). However, desalinating water still consumes large amounts of energy which come from unsustainable resources like fossil fuels.

Nuclear-energy powered water desalination has been implemented in some facilities around the world, but although the technology has been thoroughly tested it is still widely untrusted (Nuclear Energy Institute). Even with extensive work to improve reverse osmosis, the current method used to desalinate water, the process still takes much more energy than it should theoretically to separate salt from water. Alternative methods like staged membrane operation, cyclic desalination, and ion concentration polarization are being pursued (Elimelech).

A current issue that is not specific to desalination is the fact that for the most part renewable energies still cost more than fossil fuels. The plants that currently use alternative energy sources are smaller scale and often do not operate full time (Greenlee). Lauren Greenlee writes on today’s issues in implementing desalination:

Communities that would typically benefit from coupled renewable energy–RO [reverse osmosis] systems are located in rural areas, where financial resources and system maintenance personnel are limited. Factors including capital cost, sustainable technology, technical operation, social acceptance, and energy resource availability, have contributed to the slow growth of the renewable energy–RO market (Greenlee).

In isolated impoverished areas experiencing drought, renewable energy paired with desalination would be a great step towards providing all populations with clean drinking water. Alternative energy sources include solar, wind, and geothermal (Greenlee).

Desalination is still developing and becoming more energy efficient. The process involves tradeoffs. By investing in better infrastructure and membranes energy is saved, however the initial investment is higher (Greenlee). Creating better membranes would allow for a more lax pretreatment and post treatment which would reduce cost, energy, and the environmental impacts of desalination substantially (Elimelech). These membranes are hard to develop because they must be highly selective while not getting clogged in order to only let water through (Elimelech). Financial schemes to encourage the building of renewable energy and more efficient desalination plants have been offered such as subsidies to build that could be paid back eventually with the money saved on fuel (Guidelines for regulation of desalination).

Current Management Strategies

Currently the state of California is actually the leading and best model for desalination management on as far as governmental action goes. The state has a Water Resources Control Board who controls plans for protecting water sources. Specifically, the board has created policy with regards to new desalination plants on the California coast after it was identified as an issue back in 2011. In 2015 a desalination amendment was added to allow for ocean water to be a resource for fresh drinking water while still making sure that oceanic health is maintained. This amendment includes a consistent permitting process so that local municipalities would be able to evaluate and assess the environmental health impacts of a desalination plant (Oceanic Standards).

The board has emphasized its goal to provide reliable freshwater for the entire state of California. This goal is one that many states, countries, and citizens also hold as utmost important. Solutions to meet this goal are there and the Water Resources Control Board articulates how they must be implemented with regards to desalination specifically. “To be sustainable, solutions must strike a balance between the need to provide for public health and safety, protect the environment and support a stable economy. Desalination is no exception” (Oceanic Standards). In addition to the uniform permitting process the desalination amendment also includes mandates for consistently monitoring the impacts of the plant and maximum salinity levels for brine discharge from the plants (Oceanic Standards).

The success of California’s policy surrounding desalination plants has yet to be completely realized because this amendment was adopted just over a year ago. The critical part is that the negative impacts of desalination are being weighed against the positive ones to create effective regulations. With drought and desalination on the rise the Water Resources Control Board will surely continue to adapt and draft policy surrounding new water resources.

The reason this policy paper is aimed at the Joint High-Level Panel on Water is because a permitting process similar to the one in California has merit on an international level as well. The ocean is a shared entity among all nations so it is feasible that it could be regulated as such by the United Nations and World Bank.

In 2010 the United Nations declared that access to clean water is a human right because clean water is necessary for the realization of all greater human rights. This resolution was passed to support the United Nations Millennium Development Goals; eight goals intended to improve the quality of life internationally and ensure human rights (Water and Sanitation). If desalination is to become a larger part of this plan then the environment, social, and political effects of it must be fully considered and analyzed.

This paper intended to bring some of those issues to light in earlier sections and highlight the necessity of creating a proposal for policy surrounding the implementation of desalination plants. By drawing from previous studies on the environmental impacts of these plants and looking at the political implications of them; this paper emphasizes the importance of considering alternatives to desalination as well as recommending serious studies before a desalination plant is constructed on any given site. In securing safe drinking water supplies for all the world must also consider the lasting environmental impacts potentially created by relying on these plants.

Israel-Palestine Case Study

Conflict between Israel and Palestine is decades old and no final resolution has been reached. The conflict over water is one issue that makes the peace agreements between Israel and Palestine so difficult to achieve. Water, a resource necessary for life, makes tensions between these two states even more tumultuous than they would be otherwise(Finklestein).

Desalination has been in place in Israel for decades, however recently has it grown to have a larger impact due to a growing population and less rainfall. In the past ten years four major plants have gone into operation and it is projected that by 2020 seventy percent of Israel’s drinking water will come from them (Lev). The government still closely controls the water in the areas Israel is occupying and the Palestinians are unable to benefit directly from desalination and conservation efforts because of this. This is a circumstance in which desalination does not totally improve the situation for all those affected by a lack of drinkable water (Francisco).

This infographic from the Institute for Middle Eastern Understanding is meant to exemplify the disparity of water access in a geographically close area due to governmental policies. It is not meant to target Israel in, but rather meant to serve as an example for how politics can determine access to freshwater. That is to say that there are ways in water is allocated on a governmental level that have nothing to do with lack of the resource, but instead control of the resource.

Due to Israel and Palestine’s arid climate water has always been a hot topic. Since 1939 Israel’s water has been controlled by a governmental organization called Mekorot. After the United Nations tried to split up land to end conflict in 1947 and after the Six-Day War in 1968 the contested land in the area was relegated the West Bank, Gaza Strip, and East Jerusalem. These areas are all currently occupied by Israel (Global Policy Forum).

With this territory in Israeli control the government also controlled the water in these areas. Surface water is pretty scarce so they accessed water from two aquifers under Palestinian territory. In the 1980s Israel and Palestine experienced a drought, which meant that Israel put extreme water sanctions on the occupied territory. The territory probably had enough water to sustain itself but not Israel as well. This was controversial because Israel was controlling an area that relied on these water resources as well (Francisco).

These water tensions continued as the population of the area grew rapidly but the water supply did not. Palestinians had high water taxes levied on them as well as tough restrictions. Prices rose for Israelis as well though. To combat this the Israeli government turned to conservation and desalination. Israel is a country leading in desalination. Using both the private sector and the public sector they have worked towards making desalination more sustainable through improved infrastructure. The hope of both governments is that conservation efforts and an increase of desalination plants will supply the region with enough water to make it cheaper for the Israelis and that the savings will trickle down to the Palestinians as well (Climate Change and Security in the Israeli–Palestinian Context 2012). The United Nations, who has been a mediator in this conflict, already backs this plan of increasing supply. Water security could definitely be a stabilizer as far as Israel-Palestine relations go and could pave the way for continued resolutions (Climate Change and Security in the Israeli–Palestinian Context 2012).

Earlier this paper mentioned California’s progress towards regulating desalination so that both public health and environmental health are top priorities. The United Nations should follow suit with a similar plan. Countries that intend to engage in building desalination plants should form committees like the Water Resources Control Board in California. Those boards should follow a permitting process that that the Joint High-Level Panel on Water comes up with and that is discussed at the Climate Change Conference with world leaders as well. The permitting process should include mandatory studies of how the plant would effect the ecosystem surrounding it as well as how emissions will be minimized. The plant also must show how it will be a sustainable freshwater resource for its constituency and why it is needed as a new source of freshwater.

After the board reviews this research and the plans they will issue a permit with contingencies along with more mandates for continued observation of the ecosystem and emissions. The desalination plants will be treated as inferior sources to other sustainable sources like lakes, reservoirs, rivers, etc. They will be treated as a good supplement in times of drought and when current water supplies cannot sustain a population. This is because slowing climate change should be a goal not just something countries adapt to through extra sources of water.

Conclusion

The impacts of desalination on the environment are undeniable, but desalination as a source of freshwater may be unavoidable. The critical steps to take are to keep analyzing the impacts on marine ecosystems and looking for ways to modify or improve energy usage. Through more research and innovation, the impact of brine water on ocean species could be avoided and new plants could be build more efficiently and sustainably. As the Israel-Palestine conflict shows, freshwater can be a huge problem for nations a societies. Accepting desalination as a viable way to alleviate the pressures of population and drought could be an important step to achieving water security for all. Policy mechanisms like boards, permits, and regulations would help to make sure that this shift remained eco-conscious and sustainable.