Turkish Regulations...

Turkish Regulations for Design of Sewers...

According to Directions No.3, one of the regulations of Iller Bank which is responsible for the infrastructure systems in Türkiye, hydraulic design of the sewer systems must be met the following criteria.

Design Flowrate...

First step is to calculate Flowrate of Potable Water Distributed to City using the following equation.

"Potable Water Flowrate"...

Second step belongs to calculation of Wastewater Flowrate via the following relationship.

"Wastewater Flowrate"...

The last step is involved with calculation of Unit Wastewater Flowrate using the following equation.

"Unit Flowrate"...

Hydraulic Design Equation...

Currently, the Manning equation is used most commonly for the design of sanitary sewers. The recommended n value for the design is 0.015.

"Manning Equation"...

Sewer Pipe Materials and Sizes...

The principal materials used in the manufacture of sewer pipe are asbestos cement, ductile iron, reinforced concrete, prestressed concrete, PVC, and vitrified clay. In Türkiye, prestressed concrete is being used. Minimum sewer sizes are usually specified in local building codes. The smallest sewer used should be larger than the building sewer connections so that objects passed through the building sewer will not clog the municipal sewer.

According to Directions No.3 of Iller Bank, minimum size of building sewer connections and gravity sewers must be 150 mm and 200 mm, respectively.

Minimum and Maximum Velocities...

When the velocity of flow in a sewer is low, there is a tendency for the solids present in wastewater to settle out. The minimum velocity must be equal or higher than 0.50 m/sec. To avoid damaging sewers it is recommended that the maximum flow velocities be limited to values equal to or less than 3.00 m/sec.

Minimum and Maximum Slopes...

Minimum slopes are often used to avoid extensive excavation where the slope of the ground surface is flat. Maximum slopes are generally applied in case of falling. According to Directions No.3, minimum and maximum slopes should be determined by the following criteria.

"Min. & Max. Slopes"...

Construction of Sewers...

There are many ways in which the actual construction of a sewer system may be accomplished, depending on the soil conditions encountered and the construction equipment available for the job. The important thing is that the finished sewer perform the function for which it is intended with a minimum of maintenance cost. To attain this and, three conditions should be met.

"Sewer Ditch"...

Sampling and Flow Measurement Directions Stated on Turkish Water Pollution Control Regulation...

"Frequency of Flow Measurement & Sampling"...

"An Example for Receiving Media Discharge Standards"...

"Categorization of Surface Waters"...



Turkish Discharge Standars...

Turkish Water Pollution Control Regulation...

According to The Environment Law (Public Law 2872) became active on August 9, 1983, The Turkish Goverment established The Water Pollution Control Regulation which declares standards for wastewater discharges, on September 4, 1988. Current standards require that as a minimum all municipal wastewater be treated to secondary standards shown below. Secondary treatment of municipal wastewater is generally assumed to include settling, biological treatment, and disinfection, along with sludge treatment and disposal. Thus, the principal components of municipal wastewater, suspended solids, biodegradable material, and pathogens should be reduced to acceptable levels through secondary treatment.

"Receiving Media Discharge Standards for Municipal Wastewater"...

The Turkish regulations define receiving streams as either effluent - limited or water quality - limited. An effluent - limited stream is a stream which will meet its in - stream standards if all discharges to that stream meet the secondary - treatment and best - available - technology standards. Municipalities and industries discharging to effluent-limited streams are assigned discharge permits under the regulations. Water quality - limited standards (Turkish Regulation) for sea - side used for recreational purposes, were shown below.

"Discharge Standards for Recreational Areas"...

A water quality - limited - stream would not meet its proposed in - stream standards even if all discharges met secondary - treatment and best - available - technology criteria. Discharges to these streams may be required to meet effluent conditions more stringent than secondary - treatment and best - available - technology.

Effluent standards, potable - water standards, and in - stream standards are obviously interrelated. Enforcement of effluent standards, along with the control of nonpoint sources of pollution, should result in the attainment of in - stream standards. The improvement of in - stream quality should result in a better raw water for potable supplies. However, it is impractical to expect surface waters, even if in - stream standards are met, to meet all of the maximum contaminant levels imposed by the potable - water standards. Treatment of surface water for potable use will always be required, the nature and level of treatment depending on the in - stream quality of the water source.

"IZSU" Wastewater Discharge Regulation...

"IZSU", General Directorate of Water and Sewer Systems of Metropolitan City of Izmir, was built on December 4, 1991 to establish standards related to municipal and industrial discharges into metropolitan sewer system and to control them.

More stringent standards may be imposed where necessary, and in some cases less stringent standards may be permitted for small flows. Industrial discharges are required to treat their wastewater to the level obtainable by the best - available - technology for wastewater treatment in that particular type of industry. If industry discharges to a municipal wastewater collection system, the industrial waste must be pretreated so as to be compatible with the untreated municipal wastewater. Discharge standards for municipal sewer system of Metropolitan City of Izmir are shown below.

"Discharge Standards for Municipal Sewer System of IZSU"...

If industry does not meet the aforementioned discharge standards, it is charged by "IZSU" via following equation called Share for Pollution Prevention.

"Share for Pollution Prevention"...

Turkish Regulations for the Reuse and Disposal of Sludge...

According to The Environment Law (Public Law 2872) became active on August 9, 1983, The Turkish Goverment established The Solid Waste Pollution Control Regulation which declares standards for collection, transportion, and ultimate disposal of solid wastes, on March 14, 1991. Regulations related to wastewater treatment sludges are given below.