Mashabei Sade, Israel
3600 m/day (0.95 MGD)
One of the major projects that will change the face of Israel throughout the ages is the relocation of the IDF training bases to the Negev desert. Thousands of soldiers and officers of the army will move south to develop the Negev and make available expensive land in the center of the country. This sudden increase in the population of the Negev requires a solution to the wastewater created by the transition. To date, the wastewater from Revivim, Ramat Negev Regional Center, Retamim, Tlalim, Ashalim and Bir Hadaj, and wastewater from a number of dairy farms, gas stations, industrial zones, etc., were given only primary treatment and contributed to the pollution of the Negev.
The WwTP must receive wastewater from various sources, with different qualities, different flow rates, at different times, at different peak hours. Moreover, the wastewater flows from six different pumping stations.
Shtang not only took responsibility for the design and construction of the plant; it is also in charge of operating the plant (through O & M, a sister company in TGW) for the next 15 years. The Company will operate the sewage treatment plant and pumping stations to meet the stringent requirements despite differing sewage quality and quantity and provenance. The effluent is destined to irrigate olive groves.
The extremely arid region in which the Mashabim plant is situated, called for an appropriate solution for the treated effluent, in order to avoid evaporation and loss of precious water.
Shtang Engineering & Construction built a facility of uncompromising quality, which includes pre-treatment with fine filtration and removal of sand, grit and oil; a raw sewage flow equalization tank; a biological treatment system based on conventional activated sludge technology; a secondary effluent reservoir; a tertiary filtration system and contact cell; a sludge treatment system (including thickening, aerobic stabilization and centrifuges); a drain water collection system; an emergency reservoir and administrative buildings.
Despite the plant's isolated location in the desert, a proper odor neutralization system was installed, not only for the pre-treatment facility and the equalization tank, but also for the sludge treatment facility. The control unit treats odor via a biological filter with a synthetic substrate and polished by activated carbon.
Phosphorus removal is obtained via a biological system. However, due to uncertainty in the amount and composition of sewage, an additional removal system by chemical means was also designed. If necessary, a coagulant (iron or aluminum salts) dosing unit will be added to the anaerobic basin for excess phosphorus binding.
Evaporation was avoided by pumping the effluent through a sealed pipe to a 9,600 m3 operational reservoir, lined with high density polyethylene (HDPE) sheeting and covered with a floating reinforced polypropylene (RPP) geo-membrane cover. This cover not only avoids drying, but serves to prevent birds from congregating in the area in search of water and posing a danger to IDF aircraft training in the area.
The future development of the WwTP was considered during the construction process and the areas and facilities were allocated for a further expansion to 4,800 m3/d and later to 7,200 m3/d.