Implementation of Biological Sewage Treatment Systems in Afghanistan
Household sewage treatment plants
Household sewage treatment plants are designed to treat waste water from houses, guest houses, lodges and other establishments for 2 to 50 people. Household treatment plant consists of a tank in which there is a non-aerated zone and a separation. Tremendous advantage is that the cleaning operation is stable and the need for service and maintenance is minimal. Household sewage treatment plants occupy a minimum area. Thanks to its small size, odourless and noiseless operation it can be installed close to home. The most commonly are plants placed under the ground, but they can be placed also in home basements.
Technology of household sewage treatment plant is placed into tanks, which may be plastic, stainless steel or composite steel-concrete.
Plastic tank System of Plastic tanks
Brick Tank Steel-Concrete Tanks
The using of Own sewage treatment systems in the underdeveloped system of central wastewater treatment plants have huge advantage for the economy, environmental protection, and not least the health of residents. Environmental advantage of reducing the number of removing waste water in the city of Kabul and near the unprotected landfill can limit adverse health effects on groundwater and inhabitants.
Use of waste water in Herat Use of waste water in Kabul
The Biological Sewage Treatment system has been realized by Temoryan-H, Ltd
- Province Herat
- Provnce Kabul
- Province Mazare Sharif
Small Sewage treatment plant
Small sewage treatment plant is a sewage treatment plant to 500 of population equivalents. Plant purifies wastewater from buildings such as houses, recreational facilities, restaurants, manufacturing workshops, offices, nurseries.
Basic characteristics and division of small sewage treatment plants
Small sewage treatment plants treat the waste water by microorganisms, attached firmly to the base in the form of various systems of biofilters and biodisks drenched by sewage and also by activation systems with sludge in the fluid, in which there are flakes of sludge mixed with waste water and air. Most sewage treatment plants work on the principle of an aerobic treatment system where organic matter is decomposed by a mixture of microorganisms which need oxygen from the air to life.
Basic requirements and conditions for small scale sewage treatment plant
- Purification efficiency of greater than 95%
- Quiet in operation
- Energy consumption less than 1 kWh/m 3 treated water
- Vapour tight excluding odour in the surrounding area
- Long-term functionality without any inflow of sewage
- Ability to handle inrush inflow
- Unattended operation and minimal maintenance costs
- Little or no demand for professional service
- Use of only non-corrosive materials
- Storage of treatment products for at least 3 months of operation.
The degree of biological pollution of wastewater is most commonly expressed by the value of BOD5 (biological oxygen demand). In common sewage it ranges from 200 to 400 mg/l. Discharge from well-functioning sewage treatment plant has values 15 to 30 mg/l. For discharge into water body are for the household wastewater treatment plant required values below 50 mg/l and for infiltration into the ground it is usually below 8 mg/l.