The anaerobic system of biological wastewater treatment and production of biogas.
The anaerobic treatment system effluent allows to reduce effectively the levels of pollution and effluent to biogas, which is an alternative to natural gas. The latter can be used for generation of electric and thermal energy. The anaerobic treatment system effluent has a high level of automation and low operating costs.
Anaerobic system cleaning of drains allows to reduce effectively the level of pollution of wastewater and obtain biogas. The produced biogas is an alternative to natural gas. It can be used for generation of electric and thermal energy, and the resulting residue to use as fertilizer.
Anaerobic treatment method can be considered as one of the most promising in the presence of high concentration of wastewater organic substances or for treatment of domestic wastewater. Its advantages over aerobic methods is the sharp reduction in operating costs (for anaerobic microorganisms do not require additional aeration of water) and the lack of problems associated with the disposal of excess biomass.
Biogas is obtained by anaerobic fermentation of organic materials. As a product of metabolism present in organic waste to methane bacteria, a necessary condition for the production of biogas is the lack of oxygen, PH factor 6.5 to 7.5 and a constant temperature of 15°C to 55°C.
For biogas production it is possible to use the following organic materials:
*in brackets the size of biogas in m3 per tonne of raw material:
– liquid manure, solid compost (20 – 70);
– biological waste collected on farms (100 – 200);
– secondary (secondary grown) raw materials (corn silage, non-food grains);
– sewage and grease sewage (80 – 150);
– old fat (1000);
– biological waste from farms to slaughter cattle (100), Breweries and distillers (20), warehouses for storage of fruit and wine, dairy farms (25), pulp industry and sugar production.
Highly concentrated effluents are averaged, are brought to the desired temperature and served in the preliminary reactor. There are stages preceding smetanoobraznuju ie is the process of preparing for waste feed in the methane reactor.
The prepared wastewater are pumped to a digester, in which the result of bacterial decomposition of organic matter and produces biogas. The methane reactor is gas-tight, fully sealed stainless steel tanks or concrete. To maintain a stable temperature, it is equipped with an internal heating system. To reduce heat loss provided by exterior insulation. The operation of all treatment plants is performed according to the command from the Central software module in a software-timed mode.
After anaerobic treatment stage the level of pollution in waste water COD is reduced by 8-10 times, and they can be directed to biological treatment plants for tertiary treatment and subsequent discharge into the pond. The resulting organic residue can be used on fields as fertilizer.
The resulting biogas consists of approximately 50-70% methane, 30-50% of dioxide of carbon and 1% of various impurities. Biogas is accumulated and averaged on concentration and pressure in the gas tank. After that is cleaned and supplied to the power station. As the HES equipment is used the reciprocating internal combustion engines adapted to work on biogas. Thermal power plant works on the principle of cogeneration of electric and thermal energy. The overall efficiency of this equipment reaches 95%. These engines are currently the most cost-effective way of producing energy.
If the company already has its own boiler room or power station operating on natural gas, full or partial replacement of natural gas by biogas significantly reduces the cost of production of thermal or electric energy.
All equipment and technological processes of anaerobic biological treatment systems are controlled by automatic system (APCS), the cost of human labor is minimized.
– high degree of purification at the COD/BOD;
– small increase of the surplus active sludge in the digester;
– improve vodoohda properties of digested sludge;
– a safe and sanitary in relation to the sludge;
– the production of large quantities of biogas;
– autonomy, energy independence of the enterprise;
– reduction of emissions of harmful substances into the atmosphere;
– long service life of equipment;
– high level of automation;
– low operating costs;
– short payback period.
– alternative use of compost, manure and other organic materials as a source of energy;
– high economic efficiency and short payback period;
biogas replaces traditional fuel;
– high overall efficiency (electrical and thermal) – up to 92%;
the remaining dry residue from the digester can be used as agricultural fertilizer;
– corrosive effect neutralizes high PH;
– waste from fermentation do not contain fragrance;
– helps reduce the influence of factors affecting the greenhouse effect (power generation with reduced CO2 emissions).
Note: the description of technology in example of anaerobic wastewater treatment system with biogas production GazEcos.