SOURCES OF SOLID WASTE: Wastewater. Gas emissions Lecture № 4 SOURCES OF SOLID WASTE: Wastewater. Gas emissions

The main sources of waste water industry enterprises of household purpose; large livestock facilities; large agricultural complexes; waste of the deposits mining; mines and quarries water; processing and alloy products; discharges of water and rail transport; primary flax processing waste, etc.

Состав и происхождение сточных вод Composition and sources of wastewater Состав и происхождение сточных вод Types of wastewater The qualitative composition Phase Composition ATMOSPHERIC (storm) solids petroleum products, fertilizers Suspended substanses organic matter (60%), minerals (40%), microorganisms and bacteria colloids Domestic or municipal Solutions of organic compounds solids Mineral oil and petroleum products, inorganic acids and their salts, alkali, surfactants heavy metal ions Ionic solutions INDUSTRIAL (depend on enterprises)

Types of wastewater pollution Mechanical - high content of mechanical impurities, mainly for surface water; Chemical - toxic and non-toxic organic and inorganic (mineral) substances: acids, bases, salts (arsenic, lead, cadmium, mercury, chromium, copper, fluoride), hydrocarbons of various structures and their derivatives - more than 1 million substances Bacterial and biological - the presence of organic matter in the water (300 - 380 Mt. / year), surfactants, nutrients, a variety of pathogenic microorganisms, fungi and small algae. Radioactive - the presence of radioactive substances in surface water or groundwater; Heat - heated water of thermal and nuclear ES, industrial wastewater

Industrial wastewater formed as a result of water use in various industrial processes and depend on the enterprise The main (foreground) pollutants: mechanical suspension (sand, scale, metal shavings, dust, fluxes, cotton fiber, etc.); mineral oils and other petroleum products; inorganic acids and their salts; alkali; surface-active agents (surfactants); inorganic salts of heavy metals.

Atmospheric sewage or runoff formed from runoff of the rain and snowmelt from an area directly into the water bodies or sewage system. Composition varied: solids (sand, stones, chips, dust, soot, crop residues, etc.) petroleum products, fertilizers, etc. Particularity - low concentrations of pollutants (except HD)

Domestic wastewater or municipal wastewater formed in the process of human life, Have a relatively constant composition: contain about 60% of organic matter, about 40% of minerals, predominant types of microorganisms: Escherichia coli, Salmonella, Staphylococcus, Streptococcus, Enterococcus, Clostridium, Enteroviruses

The content of organic substances in industrial wastewater Pollutants Amount in the world's stock Mt. / year Oil products 26,563 Phenols 0,460 Waste of synthetic fibers 5,500 Plant fossils 0,170 In total 33,273

Chemical contaminants of industrial effluents biologically labile organic compounds; low toxic inorganic salts; oil and oil products; biogenic compounds; substances with specific toxic properties, including heavy metals; biologically hardly decomposed (or nondecomposed) organic synthetic compounds.

The most dangerous and most widespread types of chemical contaminants 1. Heavy metals (mercury, lead, cadmium, zinc, copper, arsenic, chromium, nickel, cobalt, manganese, antimony, tin, bismuth) - persistent chemical contaminants have got cumulative effect of the specific toxic properties Heavy metals ENVIRONMENT COMPONENTS + Connectivity conditions: t, nature of the metal, pH, ionic forms Complexes Oxyhydrates Synergistic mixtures Hydrated ions Ion pairs

The most dangerous and most widespread types of chemical contaminants 2.Oil and petroleum products, metalworking fluids coolant - the main chemical contaminants in the land waters, waters of seas and oceans, 6.1 million tons annually Danger: they have an ability to form stable colloidal systems like micelles Oil globule Na+ dipole emulsifier R-CH2-COO)+Н-

Modern methods of sewage treatment against industrial pollution Wastewater treatment - destruction or removal of the hazardous substances. Destructive methods: the destruction of contaminants or transformation into non-toxic products and the removal of sediments in the insoluble form   Regenerative methods: based on extraction and utilization of impurities. Wastewater treatment can be considered as complex, multi-stage manufacturing process cause it: uses raw materials (waste water) has finished products (purified water) has waste products (precipitation).

Modern methods of sewage treatment (according to the mechanism of action) Biological: filtering fields, biological ponds, aeration, methane tanks, aerotanks, biofilters, Physical: magnetic, ultrasonic, Electro treatment, ionizing radiation Physicochemical: coagulation, floatation, adsorption, ion exchange, extraction, distillation, freezing, electrodialysis, reverse osmosis Sewage treatment Mechanical: settling, filtering, centrifugation, filtration, microfiltration, cleaning in hydrocyclones Chemical: oxidation (chlorination, ozonation, liquid-phase and vapor-phase oxidation), reduction, neutralization, precipitation, complexation

Mechanical methods Removes mechanical impurities (coarsely dispersed particles), depending on the size:  by grilles, screens, sand traps, septic tanks, manure traps of different designs; surface pollution – by oil traps, petrole traps, sumps, etc. allows to select up to 60-75% of insoluble impurities from the municipal sewage, and from industry sewage - up to 95%

Chemical (reagent) methods Purpose - precipitation in the form of insoluble substances: Processes: oxidation, reduction, neutralization Advantages: allow to achieve the efficiency up to 95% of soluble and 25% of insoluble impurities

Physicochemical methods Advantages: remove fine particles and dissolved inorganic impurities; organic matter and hardly oxidizable substances are broken down Apply: electrocoagulation, sorption, extraction, ion exchange, electrofloatation, galvanic coagulation

Floatation (flocculation) Used to treat wastewater from the rough and fine impurities and condensation of suspensions with fine phase. Principle: The formation of particle-bubble complex, bubbles floating and removing of the foam layer containing impurities from the water surface. Advantages: remove fine and colloidal impurities with the help of coagulants and flocculants.

Reverse osmosis (hyperfiltration) the process of the solution separating by filtration through a membrane: pore diameter of about 1 nm pass through water molecules but is impermeable or semi-permeable to hydrated salt ions or undissociated molecules Advantages: selectivity of the membranes; efficiency - up to 99%; provides clean water that can be returned to the water recirculation system

R’H + Na+  R’Na + H+; R’’OH + Cl-  R’’Cl + OH- , Ion exchange Apply: for deep purification of industrial water from heavy metal ions (desalting) and for local systems of metals recovering; Advantages: in some cases can return considerable pert of the water into the work cycle; Ion exchange materials (resins): insoluble polyelectrolytes react (exchange) with the ions of the solution: R’H + Na+  R’Na + H+; R’’OH + Cl-  R’’Cl + OH-  , where R’ and R’’ - solid organic matrix (polystyrene) with cation and anion, respectively; Na+, H+, Cl-, OH- - exchanging mobile ions.

Regenerating solution The scheme of an ion exchange plant № 1, 2, 3 - valves, 4 - tank with regenerating solution Wastewater Regenerating solution Grille and resin layer 1 2 3 4 Pump Working solution

Adsorption method the most affordable and effective method of deep cleaning (post-treatment) of the dissolved organic matter. Applied active sorbents: fine substances with a developed surface - sawdust, ash, peat, clay, coke breeze, activated carbons.

Municipal sewage (domestic waste water) contain large amounts of: synthetic detergents (surfactants); oils and fats, nitrate and nitrite, phosphorus, chloride and sulfate,  vegetable fibers,  faecal matter, food waste.

Methods for biological treatment of municipal wastewater Microorganisms Cleaning equipment Airotanks, methane tanks Anaerobic digestion Bacteria Activated sludge (silt) Biotanks, submerged biofilters Aerobic oxidation Protozoa Biofilm COMPOSITION AND PROPERTIES Biofilters Activated sludge (silt): colloidal system, pH 4 - 9, the negative charge Biofilms: mucous fouling thickness of 1 - 3 mm Biocenosis of: bacteria, fungi, yeast Biocenosis of: bacteria, worms, fungi, yeasts, algae - in total about 12 species, solid substrate General chemical composition of the sludge: C54H212O82N8S7

Agricultural wastewater and livestock enterprises Contain about 60% of organic origin, including: biological contaminants (bacteria, viruses, fungi, algae); pesticides, herbicides, insecticides; chemical fertilizers; Insecticides in the form of suspensions, dissolved in the oil

Classification of gas emissions based on the aggregative state SOLID carcinogens, heavy metals & their compounds organic and inorganic dust soot, tarry materials GASEOUS: sulfur dioxide, oxides of nitrogen & carbon, hydrocarbons LIQUID   Solutions of acid, alkalis, salts

Amount of gas and dust emissions on a global industry Brunch of industry Emisssion, % Energy (thermal power plant) 43,0 Ferrous and nonferrous metallurgy 23,1 Refining industry 10,8 Other brunches

Methods of the air protection 1. Prevention of harmful contaminants and their introduction into the ambient air. 2. Cleaning of the air-gas emissions: mechanical, chemical, physical and chemical. 3. Creation of buffer zones around industrial enterprises

Methods for cleaning of gas & dust emissions from aerosols 1. Mechanical cleaning by dry and wet methods: dry - gravitational settling, inertial and centrifugal dust removal, filtration; wet - centrifugal scrubbers, foam scrubbers, Venturi scrubbers

Gravitational settling dust-filled gas 1 processed gas 2 2 Hollow chamber (long tube or corrugated sleeve) for the deposition of dust: 1 - body, 2 - tanks with hose to remove dust

1-socket, 2-inner cylinder, 3-outer cylinder, 4 – tank for the dust. Purified gas Polluted stream \ 2 1 3 4 dust Construction of cylindrical cyclone: 1-socket, 2-inner cylinder, 3-outer cylinder, 4 – tank for the dust.

"Wet" cleaning of gas and dust emissions from aerosols liquid gas liquid liquid gas gas Sludge Sludge Sludge Scheme of the main ways of dust collection in the wet scrubber: a - in the volume of liquid, b – by a film of liquid, c – by sprayed liquid 1 - gas bubbles, 2 - liquid drops 3 - solids

Physico-chemical treatment of gas and dust emissions from gaseous impurities Chemisorption, adsorption, catalytic and thermal oxidation Absorbents: water solutions of ammonia, carbonates and caustic alkalis, manganese salts, ethanolamines, oil slurry of calcium hydroxide, magnesium sulfate etc. Purified flow Аbsorbent 2 Contaminated flow 1 Retraction to the recovery or recycling Scheme of absorber:   1 - the case of the absorber; 2 - mesh with nozzles