Aqua sea

SEAiniation not Desalination

PRODUCING DRINKING WATER FROM NON-POTABLE WATER, SALINE WATER (OCEAN, SEA, BRACKISH), RIVER WATER, etc.

Introduction and Background

Types of Water

Seawater is a complex mixture of 96.5 percent water, 2.5 percent salts, and smaller amounts of other substances, including dissolved inorganic and organic materials, particulates, and a few atmospheric gases.

Brackish water is water with salinity levels between seawater and freshwater. It occurs where surface or groundwater mixes with seawater, in deep “fossil aquifers,” and where salt dissolves from mineral deposits over time as precipitation percolates down into aquifers.

Non-potable water is water which has not been treated to standards safe for human consumption but is useful for specific end uses such as irrigation, dust suppression, toilet and urinal flushing, or make-up water for mechanical equipment. Non-potable water contains the same substances that are found in local creeks and the local environment. Like water in creeks, lakes, and reservoirs used for recreation, lake water for irrigation is non-potable, meaning it is not suitable for drinking. Lake water quality is also similar to rain water that puddles on the ground, and includes minerals from soils and naturally occurring bacteria commonly present in soils and the environment.

Water Standards

Drinking water quality standards describes the quality parameters set for drinking water. Despite the truth that every human on this planet needs drinking water to survive and that water may contain many harmful constituents, there are no universally recognized and accepted international standards for drinking water.^[1] Even where standards do exist, and are applied, the permitted concentration of individual constituents may vary by as much as ten times from one set of standards to another.

Many developed countries specify standards to be applied in their own country. In Europe, this includes the European Drinking Water Directive (https://ec.europa.eu/environment/water/water- drink/index_en.html) and in the United States the United States Environmental Protection Agency (EPA) establishes standards as required by the Safe Drinking Water Act (https://en.wikipedia.org/wiki/Safe_Drinking_Water_Act). For countries without a legislative or administrative framework for such standards, the World Health Organization publishes guidelines on the standards that should be achieved (Guidelines for Drinking-water Quality, Fourth Edition; World Health Organization; 2011). China adopted its own drinking water standard GB3838-2002 (Type II) enacted by Ministry of Environmental Protection in 2002. (https://en.wikipedia.org/wiki/Ministry_of_Ecology_and_Environment).

In the United States, the federal legislation controlling drinking water quality is the Safe Drinking Water Act (SDWA) which is implemented by the U.S. Environmental Protection Agency (EPA), mainly through state or territorial health agencies.

EPA has set standards for over 90 contaminants organized into six groups: microorganisms, disinfectants, disinfection byproducts, inorganic chemicals, organic chemicals and radionuclides. States and territories must implement rules that are at least as stringent as EPA’s to retain primary enforcement authority (primacy) over drinking water. Many states also apply their own state-specific standards, which may be more rigorous or include additional parameters. Many countries look to the standards set by the EPA in the United States for appropriate scientific and public health guidance and may reference or adopt US standards.

World water resources are mainly salty (97.5%) and fresh water (2.5%). Salty water is found inoceans, seas and some lakes while fresh water is either stored underground (30%) or in the formofice/snowcoveringmountainousregions,AntarcticandArctic(70%)butonly0.3%isusablebyhumans.

Water Purification Methodologies

The objective of any water purification system is to remove contaminants to meet the drinking water standards.

Contaminants in water can be categorized into several different types:

Physical contaminants primarily impact the physical appearance or other physical properties of Examples of physical contaminants are sediment or organic material suspended in the water of lakes, rivers and streams from soil erosion.
Chemical contaminants are elements or compounds. These contaminants may be naturally occurring or man-made. Examples of chemical contaminants include nitrogen, bleach, salts, pesticides, metals, toxins produced by bacteria, and human or animal
Biological contaminants are organisms in water. They are also referred to as microbes or microbiological Examples of biological or microbial contaminants include bacteria, viruses, protozoan, and parasites.
Radiological contaminants are chemical elements with an unbalanced number of protons and neutrons resulting in unstable atoms that can emit ionizing radiation. Examples of radiological contaminants include cesium, plutonium and uranium.

The question is "What is Desalination"

With this limited amount of usable fresh water, desalination offers the means to meet the increasing demand for fresh water. Desalination technologies are divided into three major groups, namely: (1) thermally activated systems in which evaporation and condensation are the main processes used to separate salts from water, (2) pressure-activated systems where a pressure is applied on the salty water that forces it through a membrane, leaving salts behind and (3) chemically-activated methods. Thermally activated systems include: multi-stage flash distillation (MSF), multiple-effect distillation (MED), vapor compression distillation (MVC), humidification – dehumidification desalination (HDH), solar distillation (SD) and freezing (FZ). In these systems, heat transfer is used either to boil or freeze the seawater or brackish water to convert it to vapor or ice so the salts are separated from the water.

Pressure-activated systems use permeable membranes to create two zones where water can pass through leaving salt behind. These technologies consist of reverse osmosis (RO), forward osmosis (FO), electro-dialysis (ED) and nanofiltration (NF).

Chemically-activated systems include ion-exchange desalination (IE), liquid–liquid extraction (LLE) and gas hydrate (G.HYD) or other precipitation schemes. Recently, adsorption technology (AD) has been investigated for desalination application. In this technology an adsorbent material with high affinity to water like silica gel can be used to separate the water from the salts.

Thermal technologies uses a substantial amount of energy since vaporizing 1 lb. of water requires 1,000 Btu of energy. Vapor Compression attempts to energy integrate the energy from condensation of steam to pre-heat the feed water, but it requires steam to pre-heat the feed water. Membranes suffer from fouling and maintenance of these membranes is very expensive. Chemical methods consume chemicals, and adsorption processes only separate small amounts of water. Desalination methods can have many different applications. Brackish water typically contains total dissolved salts (TDS) in the range of 1,000 – 25,000 ppm while seawater has an average of 35,000 TDS concentration. Produced water can have a salinity exceeding 35,000 ppm and can be as high as 250,000 ppm.

Solution

AquaGEOLabs, in partnership with world class experts in water treatments and water solutions has developed the Aqua SEA Process which is capable of taking any type of contaminated water and converting it to drinking water standards. The process consists of filtration followed by Surface Assisted Crystallization called SEAination.

SEAination method uses a specially-prepared material to selectively adsorb salts, even when they are well below their saturation concentration. Sustainable Tech has also developed other separation methods which can selectively remove water-soluble contaminants, such as aromatic hydrocarbons, alkyl fluorinated chemicals, etc.

The performance of AGL’s SEAination process for a typical Produced Water composition given below, and the process was able to recover 98% of the water with a treated water effluent of 1200mg/L (ppm) total dissolved solids.

The plot below shows the cost of treated water ($/m³) for the various Desalination technologies, including SGS’s AQUA-SEA SEAination process.

AQUA-SEA SEAination process is able to produce treated water at a cost comparable to Liquid-Liquid Extraction and Adsorption (AD). Liquid-Liquid extraction uses a solvent, and its energy consumption is significantly larger. Adsorption (AD) can only produce small amounts of desalinated water, while AQUA-SEA SEAination process, a Lego block type system, can be bundled up based upon need for larger flowrates, as in sea water desalination applications.

The AQUA-SEA treatment system can produce from 5 gpm drinking water from non-potable, sea, brackish, river, frac waters etc. The power consumption is estimated to be 120 amperes at 12V DC power supply. The main advantage with this design, is that the system can run on solar panels in absence of grid power or when power supply is an issue as is the case in most developing nations.

SEA WATER DESALINATION- PERFORMANCE

Sea water has salt concentrations of 38,000 ppm, which generates almost 27 atm of osmotic pressure. There are no membranes which can withstand this high pressure. The Aqua-SEA SEAination process can function at a significantly lower pressure and this substantially reduces the investment and operating cost of the desalination process. Most desalination capital costs runs in millions of dollars along with tremendous amount of operating costs.

A single module of the Aqua-SEA SEAination treatment process generates a permeate water flux of 10 LMH and using 5 gpm (19 liters/min or 1136 LMH) as the flowrate of fresh water from the treatment system, ten (10) treatment modules are used to achieve the production rate. Again, with the Lego-block approach of the system, the need defines the how the modularization is done. The capital costs requirements are fractional compared to the traditional desalination systems and operating costs are in pennies for the Aqua-SEA unit.