询问膜专家

Ask a Question
Name
Email
Question

Water Treatment Encyclopedia

  • Activated Carbon Filters

    Filtration Theory:For thousands of years filtration has been used to reduce the level of dirt, rust, suspended matter and other impurities from water. This is achieved by passing the dirty input water (influent) through a filter media. As the water passes through the media, the impurities are held in the filter media material. Depending on the impurity impurities and the media, several different physical and chemical mechanisms are active in removing are responsible for the removal of impurities from the water. Some of the equipment used to employ these mechanisms has have changed dramatically over time.The fundamental physical and chemical mechanisms that occur during filtration have become better understood over the years. These advances have allowed water treatment specialists to optimize the removal of impurities from the water. Filtration systems remove particulate matter and, because of the large surface area of filter media, they also can be used to drive chemical reactions that result in the removal of several contaminants. Adsorption Principles: “Adsorption” is one of the most frequently used but least understood terms in discussions of filtration. Adsorption refers to the removal of an impurity from a liquid to the surface of a solid. A water-born, suspended particle adheres…
  • Activated Sludge Process

    Activated sludge process is a process for treating sewage and waste water commonly referred as effluent using bacteria (to degrade the biodegradable organics) and air (Oxygen for respiration). Activated sludge refers to a mixture of microorganisms and suspended solids. The bacterial culture is cultivated in the treatment process to break down organic matter into carbon dioxide, water, and other inorganic compounds. The typical activated sludge process has following basic components: 1) Primary Clarifier to separate the solids carried along with Sewage/Effluent 2) A reactor in which the microorganisms are kept in suspension, aerated, and in contact with the waste they are treating 3) liquid-solid separation; and 4) a sludge recycling system for returning activated sludge back to the beginning of the process. There are many variants of activated sludge processes, including variations in the aeration method and the way the sludge is returned to the process. Activated sludge process offers efficient removal of BOD, COD and nutrients when designed professionally and operated properly. The process itself has flexibility and numerous modifications can be tailored to meet specific requirements (e.g. for nitrogen removal). It is a complex mix of microbiology and biochemistry involving many different sorts of microbes. In the Activated Sludge Plant (ASP) bacteria…
  • Advanced Oxidation Processes

    Advanced oxidation processes (abbreviation: AOPs), in a broad sense, refers to a set of chemical treatment procedures designed to remove organic (and sometimes inorganic) materials in water and waste water by oxidation through reactions with hydroxyl radicals (·OH). In real-world applications of wastewater treatment, however, this term usually refers more specifically to a subset of such chemical processes that employ ozone (O3), hydrogen peroxide (H2O2) and/or UV light. One such type of process is called in situ chemical oxidation. AOPs rely on in-situ production of highly reactive hydroxyl radicals (·OH). These reactive species are the strongest oxidants that can be applied in water and can virtually oxidize any compound present in the water matrix, often at a diffusion controlled reaction speed. Consequently, ·OH reacts unselectively once formed and contaminants will be quickly and efficiently fragmented and converted into small inorganic molecules. Hydroxyl radicals are produced with the help of one or more primary oxidants (e.g. ozone, hydrogen peroxide, oxygen) and/or energy sources (e.g. ultraviolet light) or catalysts (e.g. titanium dioxide). Precise, pre-programmed dosages, sequences and combinations of these reagents are applied in order to obtain a maximum •OH yield. In general, when applied in properly tuned conditions, AOPs can reduce…
  • Aerobic Treatment Package

    Aerobic Treatment Packages for Untreated Water Definitions: Wastewater : water polluted by a mixture of all sorts of inorganic (sand, clay, salts) and organic (proteins, sugars, oils and fats) components;Some of them appear in dissolved form and other in suspended form; Origins: Industrial, Agricultural, or municipal origin. Wastewater Treatment : the process that removes the majority of the contaminants from wastewater or sewage and produces both a liquid effluent suitable for disposal to the natural environment and a sludge. Treatment Methods : Combination of mechanical, physicochemical & biological treatment steps. Biological Wastewater Treatment: Collective name for the processes that eliminate the organic matter using micro-organisms. Nutrients such as N (nitrogen) and P (phosphorus) can also be removed, thereby reducing the eutrophication risk. Biological treatment is actually the accelerated version of nature’s own way of water cleaning. It produces a clear effluent, harmless for the environment, by removing organic compounds from the wastewater, as well as nutrients such as N and P. From the economical point of view biolo­gical treatment is the most feasible method.AES Arabia Ltd systems are an advanced evolution of the most common biological treatment method, using activated sludge. Activated sludge: A variable and mixed community of microorganisms in an aerobic aquatic environment. These…
  • Anaerobic System

    Anaerobic treatment differs from conventional aerobic treatment in that no aeration is applied. The absence of oxygen leads to controlled anaerobic conversions of organic pollutants to carbondioxide and methane, the latter of which can be utilized as energy source. The main advantages of anaerobic treatment are the very high loading rates that can be applied (10 to 20 times as high as in conventional activated sludge treatment) and the very low operating costs. Anaerobic treatment often is very cost-effective in reducing discharge levies combined with the production of reusable energy in the form of biogas. Pay-back times of significant investments in anaerobic treatment technologies can be as low as two years. Anaerobic treatment of domestic wastewater can also be very interesting and cost-effective in countries were the priority in discharge control is in removal of organic pollutants. COD is basically a measure of organic matter content or concentration. The best way to appreciate anaerobic wastewater treatment is to compare its COD balance with that of aerobic wastewater treatment, as shown in Figure below. Anaerobic Treatment:The COD in wastewater is highly converted to methane, which is a valuable fuel. Very little COD is converted to sludge. No major inputs are required…

Case Studies

The Impact of Ferrous Ion Oxidation on Silica Scaling in RO Systems

Controlling Aluminum Silicate Formation in Membrane Separation Processes

An Evaluation of Corrosion Control Additives for Potable RO Permeate

A Relationship Between Phosphate Scales and Silica Fouling in WasteWater RO Membrane Systems

Excessive Sulfuric Acid Dosing Resulting in Irreversible Scale Formation

Optimizing Scale Inhibition Costs in Reverse Osmosis Desalination Plants