Sludge Management, Treatment, and Reuse at Northern Gaza Emergency Sewage Treatment (NGEST)

The project was implemented in 2019 by Oxfam in partnership with UCAS aiming at studying the methods and alternatives of sludge management, treatment, and reuse at NGEST under the WASH program.

Project-Specific objectives:

To investigate and study the current practices concerning sludge management, treatment and reuse at the NGEST.

·         To propose effective options for sludge management, treatment and reuse at the NGEST.

·         To utilize sludge as fertilizer for selected crops (lettuce, mint, squash and alfalfa).

·         To assess the environmental and health impacts associated with sludge reuse as an agricultural fertilizer.

Project summary:

The project team assessed the treatment and disposal process of sludge at NGST considering the existing documents, their technical experience and raw sludge testing results, but they found that the sludge treatment methods at NGST need improvement and modification.

Accordingly, they used the treatment technology simulating the drying beds technique to treat the sludge using a specific portion of the University College of Applied Sciences roofs that have been selected and prepared to receive the sludge for treatment. The sludge was spread on the roof with a thickness of 15 – 20 cm and directly exposed to the sun. The treatment process stopped after 1.5-month exposure to the sun, as the faecal coliform and E-coli completely disappeared from the sludge. The treated sludge was tested on a weekly basis covering the E-coli, TDS, PH, Nitrogen, Potassium, Sodium, O.M, Water content, Sand, PO4, SAR, FC, Helminth, Eggs and C/N. Different sludge samples with different treatment periods were stored to be utilized as fertilizers in the subsequent project phases. Additionally, 400m2 of the greenhouse was selected at the UCAS campus in Kan Younis City and was ploughed and prepared for planting. The project team used different types of local and commercial fertilizers including commercial fertilizer, cow manure and chicken manure were obtained and tested for different parameters. All of them were applied in the greenhouse and in isolated pots; Including treated sludge, commercial fertilizer, cow manure, chicken manure, 50% sludge + 50% commercial fertilizer, 50% cow manure + 50% sludge, 50% chicken manure + 50% sludge, and blank soil without any fertilizer as a control one. The overall process was supervised and monitored directly by the relevant stakeholders and experts. Additionally, a monitoring program for soil, water and crops was implemented for 6 weeks and documented for comparing purposes. The investigated parameters included: plant length, leaf length, leaf width, leaf number, growth status, production/yield, nutritional status, leaf area, leaf colour and visual damage. The monitoring program continued for 5-6 weeks. By the end of this period, the majority of plants were completely developed and yielded products. The crops had been harvested successfully and sent to the laboratory for testing. Six weeks later, tomato and cucumber plants start to yield products, while other plants including squash, lettuce, and Rocca started to yield after three to four weeks. In the case of eggplant, it took about ten weeks to yield.