Amani Jabari

The accelerated expansion and development in Palestine, has resulted in increasing of water consumption, and consequently in generation of large quantities of wastewater from various sources. This wastewater has been seeping into the ground, which leads to the problems of ground water, soil, health and environment. These problems must be reduced and need a serious solution. Building wastewater treatment plants is the most suitable solution.

In the whole water-wastewater cycle, wastewater treatment systems considering as the most energy consuming part. The energy demand of wastewater treatment systems depends on the site of the plant, type of the treatment process, aeration system, and its size (population served, organic or hydraulic load), age of the plant, experience of its managers, effluent quality requirement, etc. All stages of wastewater treatment plants and sludge treatment require energy for pumping, mixing and aeration of wastewater and sludge disposal.

In Palestine there are several determinants related to the field of energy used as a result of many factors, such as the energy prices which considered as the highest in the world, and the other effective factor is the fully controlled of energy sector by Israeli occupation, where the Palestinian people are exposed to daily violence committed. The most important challenge facing the wastewater treatment plants is the amount of energy consumed specifically operational cost (most of treatment plants have an operational cost reach to 70%from total cost) .For all this reasons, we should find the best possible ways for optimization of energy consumption in wastewater treatment plants, at the same time this ways should be environmentally friendly. As a case study, the wastewater treatment plant in Jericho was taken.

In this research the main aim is to optimize and reduce the energy consumption in Jericho wastewater treatment plant, and the specific objectives are (1)use the best way to increase energy efficiency in the Jericho wastewater treatment plants.(2) Identify areas for conservation and to determine where energy is being used inefficiently, and trying to find suitable way to make energy efficiency through energy management, improving equipment, run the equipment for fewer hours.(3) Finding suitable design to decrease the energy consumption in Palestinian wastewater treatment plants.

The general findings of this research are: (1) the amount of wastewater influent to Jericho wastewater treatment plant had been very low in 2015and this is due to the low number of building connected to sewer network, it served 3200 capita, but the influent increased in WWTP due increasing of connection rate it reaches 1250 house connections, approximately 6250 capita served. In 2020 it is expected to connect all the city and served 36000 capita and the annual amount of treated wastewater will reach around 311000 m3 and can cover most of the agricultural lands at the east of Jericho city, which famous with palm trees planting.

(2) In Jericho WWTP the energy consumption (kWh/m3) considered to be high in the first operational year, which means that the WWTP working inefficiently at first. But it was noticed that the energy consumption decreased with years, this is due to the increase of the number of population served by WWTP, thus growing in the influent of the WWTP, and therefore the energy consumed is divided by a larger quantity of flow rate, and this is confirmed with the concept of (economies of scale).

(3) When the energy consumption compared in two years 2015 (the first operating year) and 2016 the second year, taking in consideration that the total load of wastewater entered to the WWTP hugely increased, it has been observed in contrast of expectations that the energy consumption decreased despite the increasing of the total load of wastewater entering the WWTP, this marked decrease due to the organization of the operation of the WWTP, and had an efficiency operational plan of the WWTP.

(4) The WWTP divided into seven stages; grit chamber, reactor, final clarifier, disinfection, utility facility, gravity thickener, garden facility. The energy consumption in each stage was calculated for years (2015, 2016), and 2020 target year. It is clear that the reactor stage, which contain aeration blower is the most energy consuming stage, according to the energy consumption value and literature, it reaches 465 (kWh/day),  the reactor represents 68% of the total consumption, while the other stages represent together 32%. In WWTP there are four aeration blowers, only two of them work all the time, while the other two are rarely turned on.

(5)From the calculation of energy consumption for every Kg of water quality the results are obtained show that the most energy consumption between the three water qualities is total Nitrogen (TN), it consumed energy18 times more than the other wastewater quality for one kilogram. It was noticed that the WWTP has a very good effluent quality corresponded with the Palestinian recommendations and guidelines.