There are some details of an interesting project here Asad Ali Khan

https://oldmooresalmanac.com/reclaiming-the-deserts/

There is however, no mention of the waste product management as yet.

Here is another useful future technology link that involves the oceans

https://futurism.com/images/shimizus-dream-a-vision-of-the-future-infographic

Évaporation and preciptations , oxygen cycle , proteines , ...

The ocean plays a role in the social, economic and environmental balance of

all the countries of the world. Thanks to the presence of marine plants, the ocean releases more

oxygen in the atmosphere than any forest in the world.

• The ocean plays a fundamental role in regulating the global climate: it exchanges

heat and gases with the atmosphere thanks to the currents and winds that sweep the surface

of the sea.

• The ocean is a vital source of animal protein for billions of people across

the world.

• More than 50% of the world population lives on the coasts; that figure will rise to 75% by then

2025.

• 90% of international trade goods circulate by sea.

• The ocean holds considerable amounts of precious minerals and resources

energy, such as oil, gas, salt, precious metals ...

• The ocean provides work for 140 million people in the fields of fishing and

aquaculture, and even more indirect jobs in sea-related sectors (trade

seafood, navigation, tourism, offshore mining, military activities

and scientists, nautical leisure, etc.).

• The ocean is of paramount importance in political and military strategy.

Thanks John Machell for providing valuable information about the question.

Thanks Faiza Alliouche for your worthwhile views about the vital role of ocean water salinity in many environmental systems.

Ocean water is of immense importance to maintaining global ecosystem. Biogeochemical cycle, climate change and harbour unique ecosystem . first Life originated in Ocean water. Tides , waves and currents plays significant role. Role of microorganisms, and food web and chain is proved that immense indefinite importance to run or keep alive our the only living mother earth.

Thanks Faiza Alliouche for your response.

Definitely ocean water is of immense worth but the question is about the salinity of ocean water.

So, with all of the water available on Earth and all that saline water sitting offshore of our coasts, how come we are worried about water shortages? You can think of it as a water-quality situation rather than water-quantity situation. In its raw state, saline water cannot be used for many of the purposes we need water for, such as drinking, irrigation, and many industrial uses. Slightly saline water is sometimes used for similar purposes as freshwater. For example, in Colorado, water having up to 2,500 ppm of salt is used for irrigating crops. Normally, though, moderate to high saline water has limited uses. After all, you don't drink salt water at home; you don't use it to water your tomatoes or brush your teeth; farmers don't usually irrigate with it; some industries can't use it without damaging their equipment; and, farmer Joe's cows won't drink it.

If nothing else, saline water can be just plain fun. If you happen to be one who has been to the Dead Sea in the Middle East, you could have experienced the unique sensation of floating in the extremely dense (and salty) water that apparently holds you up like a mattress. The water is so dense that you truly do not sink, as you do in normal, even ocean, water. Closer to home, many homeowners who have backyard pools fill them with saline water, rather than have to use freshwater and added chlorine.

The main use is for thermoelectric power-plant cooling. About 5 percent of water used for industrial purposes is saline, and about 53 percent of all water used for mining purposes is saline. Saline water can be desalinated for use as drinking water by putting it through a process to remove the salt. Hyper saline systems are harsh environments that have salt concentrations much greater than that of seawater, often close to or exceeding salt saturation. There are many kinds of hyper saline lakes, including alkaline hyper saline lakes, acidic hyper saline lakes, and deep ocean brine pools. Salts affect plant growth due to increasing soil osmotic pressure and to interference with plant nutrition. A high salt concentration in soil solution reduces the ability of plants to acquire water, which is referred to as the osmotic or water-deficit effect of salinity. Under exposure to salinity, the plant adjusts its water potential by losing water, which causes a decrease in osmotic potential and turgor. This induces a signal that triggers adaptive responses. Saltwater also affects plants by inhibiting their growth and photosynthetic capabilities. All living organisms need salt, and plants absorb theirs through their root system along with their water. However, in salinated soil, plants absorb too much salt. Despite being produced for drinking water, it is also used for a variety of purposes such as for food products, cosmetics, aquaculture, and agriculture. Thus, due to the availability of numerous minerals in order to discover its benefits to health. Oceans cover about 70 percent of the Earth's surface and about 97 percent of all water on and in the Earth is saline there's a lot of salty water on our planet. Evaporation of ocean water and formation of sea ice both increase the salinity of the ocean. However these "salinity raising" factors are continually counterbalanced by processes that decrease salinity such as the continuous input of fresh water from rivers, precipitation of rain and snow, and melting of ice. Salinity affects production in crops, pastures and trees by interfering with nitrogen uptake, reducing growth and stopping plant reproduction. Some ions are toxic to plants and as the concentration of these ions increases, the plant is poisoned and dies. The study suggests that even a small increase in water salinity can cause a significant loss of biodiversity, and alter the ways that the ecosystem functions. Increasing ocean salinity results in warming, particularly at high latitudes and reduced sea ice. Decreasing ocean salinity has the opposite effect, decreasing surface temperature on global average and increasing the extent of sea ice.