TECHNOLOGYWATER

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Testing micro-nanobubble generating device at different salinities 

Bubble size is a critical parameter in diffused bubble, aquaculture aeration systems. A study conducted to determine the influence of water with different salinities on performance of nanobubble generating technology (NBT) showed that by using the same amount of power and air flow, the amount of oxygen transferred by NBT into water at a salinity of 30 ppt is 8.5 times that transferred into city (fresh) water.

Aeration in aquaculture

Natural oxygenation by diffusion from the air and photosynthesis by aquatic plants will not meet the combined oxygen demand of the cultured species and the other biota in intensive aquaculture. The efforts to increase dissolved oxygen (DO) concentrations in ponds include partial water exchange to replace the oxygen-deficient water with oxygenated water from the source, addition of fertilizer to stimulate photosynthesis by aquatic plants, applications of compounds such as hydrogen peroxide that release oxygen through chemical reactions, adding pure oxygen gas into pond waters, and use of mechanical aerators. Water exchange and aeration are the most widely used and effective techniques.

In semi-intensive and intensive aquaculture, aerators are necessary to satisfy the oxygen requirements for respiration of the cultured organisms. Sufficient aeration also is essential for ammonia management by promoting nitrification. Different types of aeration are used in aquaculture. Aeration is performed through two methods: splashing water into air with devices such as vertical pumps, pump sprayers and paddle wheels; or releasing bubbles of air into water with propeller-aspirator-pumps and diffused-air systems. There is increasing interest in fine-bubble diffusers as a means of aerating aquaculture system─ particularly in highly-intensive grow-out or holding units.

Micro-nanobubbles

Microbubbles (MBs) and nanobubbles (NBs) are tiny bubbles with a respective diameter of 10–50 µm and <200 nm, and have been explored for various applications. A micro-nanobubble (MNB) is a bubble that ranges in diameter from 0.1 micrometers to 10.0 micrometers. MNBs technology has attracted much interest in bio-related areas such as bioremediation, aquaculture and plant cultivation. MNBs are superior to macro-bubbles because they have larger interfacial area, higher inner pressure, lower rising velocity in water, long lifetime and high mass transfer efficiency. Also, the generation method of MNBs has an impact on their properties. All these factors will dramatically improve dissolved oxygen supply.

Study setup

It is common to report aerator performance parameters at standard conditions to overcome site specific conditions. The aerator performance tests are standard oxygen transfer rate (SOTR) (mass transferred per unit time) kg O2/hr; and standard aeration efficiency (SAE) (mass transferred per unit time per unit power) kg O2/kW-hr. The procedure for conducting the tests followed the protocol suggested by the American Society of Civil Engineers.

Aquaculture is booming: As of 2012, we produce more farmed fish than beef worldwide, some 66 million tons. And while fish farming has a bad reputation, the mangrove-plowing, antibiotic-dosing, overcrowded and under-regulated shrimp- and salmon-farms of the 1980s are — like Members Only jackets and crimped hair — largely relics of those times, with a few heinous exceptions. The New Aquaculture(TM) is sleek and clean, with always-advancing science and technology on hand to help producers keep an eye on sustainability, as well as the bottom line.

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The world is less than 40 years away from a serious problem: producing enough food for 9 billion mouths. But with climate change cutting more than a quarter of crop yields by 2050, innovators must devise strategies to confront dwindling global food supplies.

Enter Forward Thinking Architecture.

On World Water DayLearn about critical issues and help support the Earth Institute

What’s the true cost of water? What does that include beyond the pipes, pumps, reservoirs and treatment plants? How do we value a forest that filters water bound for an underground aquifer? How should we figure the cost of pollution that spoils a freshwater resource? Do we consider the cost of water used in industrial processes, to produce energy or to grow the food we eat? Sunday is World Water Day, a United Nations-sponsored effort to spread the word about how we use water and waste it, and what we can do to ensure water remains a sustainable resource. According to the UN, “Despite impressive gains made over the last decade, 748 million people do not have access to an improved source of drinking water and 2.5 billion do not use an improved sanitation facility.” Improving access for those people can create great economic benefits. Some other water facts from the UN:

More water is used to manufacture a car than to fill a swimming pool; 10 liters of water are used to make one sheet of paper; 91 liters are used to make 500 grams of plastic.

To produce two steaks, you need 15,000 liters of water; 1 kilo of rice requires about 3,500 liters.

On average women in the developing world spend 25 percent of their day collecting water for their families.

Every week one million people move into cities, and the demand swells for better and more efficient water systems.

Taking on America's Water Challenges “Will it take another Dustbowl for Americans to start paying attention to water issues?” That’s a key question posed at a day-long conference sponsored by the Columbia Water Center, where experts from industry, academia, government and non-profit sectors gathered to talk about the challenges facing the United States.

Norman Foster to build Toronto tower with the largest living wall in North America 

 Mies Van der Rohe is famous for his phrase "less is more", but really these days, in cities like New York and Toronto, everybody is channeling Morris Lapidus, architect of flamboyant hotels, who said "too much is never enough." So now we have Norman Foster designing a 72 story tower at the corner of Bloor and Yonge in midtown Toronto (with local Core Architects). That will make it the tallest inhabited structure in Canada.

Soil Remediation- Introduction

Soil remediation, also known as soil washing, is a term that refers to various processes designed to remove contaminants such as hydrocarbons (petroleum and fuel residues), heavy metals, pesticides, cyanides, volatiles, creosote, and semi-volatiles from soil. Soil remediation is needed to clean and maintain high quality standards of soil, water and air that can consequently benefit commercial cultivation, and wild flora and fauna.

Soil Remediation- Types of Techniques

There are four main types of soil remediation techniques for the removal of various pollutants and contamination from soils that have compiled enough documentation to give them prominence in use. These techniques include:

Bioremediation: Bioremediation involves treatment of polluted soils by biological means. The process uses bacterium (aerobic and anaerobic species), particularly targeted to consume and break down hydrocarbons and other pollutants in soil. The advantage of the process also lies in the fact that when contaminate is consumed all the microbes die off. However, note that the process is more successful in soil that maintains 70 degrees F of temperature with sporadic rain for optimal moisture. And for bioremediation to be more effective in colder climates, soils should be properly covered and insulated. This is because the colder the ambient climate will be, the longer the clean-up time the process will take.

Popular Bioremediation Services Providing Companies - Soilutions, Soil Bioremediation Inc.

  Thermal Soil Remediation: This technique includes heating contaminated material into the PTU to evaporate hydrocarbon impurities and water. Here, polluted materials are usually treated at temperatures of 650° F to 900° F, and then discharged from the PTU into a cooling unit, which is either a mixer, or auger where water is added for cooling and dust control. The treated material is then discharged from the cooling unit via a conveying system, ready for testing, and subsequent recycling.    

Popular Thermal Remediation Services Providing Companies - TRS Group Inc., Therma-Flite Inc., Nelson Environmental Remediation Ltd

  Air Sparging: In air sparging, large volumes of air are injected into a polluted soil stratum to force the organic vapors outwards where they are typically treated by carbon filtering. The actual time the process takes in treatment depends upon various factors such as depth of the hydrocarbon pollution, the concentration level of contaminate, pH factor of the soil, and permeability of the soil.  

Popular Air Sparging Remediation Services Providing Companies - EPG Companies Inc., McKenna Engineering & Equipment Co., Inc.

  Encapsulation: The process of encapsulation does not filter contaminants from soil so much as it separates them. This can be done in many ways, but one of the most common ways includes mixing the polluted soil with lime, cement, and concrete, leading to preventing the contaminants from spreading to clean soil. However, this method impedes using the soil for cultivation.