maryam zulkifli, hassimi abu hasan, siti rozaimah sheikh abdullah, mohd hafizuddin muhamad.  (2022).  a review of ammonia removal using a biofilm-based reactor and its challenges.  - journal of environmental management.  1-24. 

siti noor khaleeda mhd syahri, hassimi abu hasan, siti rozaimah sheikh abdullah, ahmad razi othman, peer mohamed abdul, raja farzarul hanim raja azmy, mohd hafizuddin muhamad.  (2022).  recent challenges of biogas production and its conversion to electrical energy.  - journal of ecological engineering.  251-269. 

mohanad j. m-ridha, muna faeq ali, ahmed hussein taly, khalid m. abed, sabah j. mohammed, mohd hafizuddin muhamad, hassimi abu hasan.  (2022).  subsurface flow phytoremediation using barley plants for water recovery from kerosene-contaminated water: effect of kerosene concentration and removal kinetics.  - water.  1-12. 

mohammed a. ibrahim, mohammed ali a. shaban, yaseen rashid hasan, mohanad j. m-ridha, haitham a. hussein, khalid m. abed, sabah j. mohammed, mohd hafizuddin muhamad, hassimi abu hasan.  (2022).  simultaneous adsorption of ternary antibiotics (levofloxacin, meropenem, tetracycline) by sunflower husk coated with copper oxide nanoparticles.  - journal of ecological engineering.  30-42. 

donald anak juan, hassimi abu hasan, mohd hafizuddin muhamad, siti rozaimah sheikh abdullah, siti nur hatika abu bakar, junaidah buhari.  (2021).  physico-chemical and biological techniques of bisphenol a removal in aqueous solution.  - journal of ecological engineering.  136-148. 

hassimi abu hasan, jahira alias, farahanim nabila arbain, siti rozaimah sheikh abdullah, nor azman kasan, mohd hafizuddin muhamad.  (2021).  reusing sago mill effluent as a substrate for bio-based polymeric flocculant fermentation: optimisation of operational conditions.  - environmental technology & innovation.  1-11. 

ahmad razi othman, hassimi abu hasan, mohd hafizzudin mohamad, nur izzati ismail, siti rozaimah sheikh abdullah.  (2021).  microbial degradation of microplastics by enzymatic processes: a review.  - environmental chemistry letters.  3057-3073. 

hassimi abu hasan, nuradila jamal, siti rozaimah sheikh abdullah, siti nur hatika abu bakar, mohd hafizuddin muhamad, xiangkun li.  (2021).  effective iron-accumulating bacteria isolated from chemical laboratory drainage for iron removal.  - journal of ecological engineering.  187-194. 

siti nur hatika abu bakar, hassimi,abu hasan, siti rozaimah sheikh abdullah, nor azman kasan, mohd hafizuddin,muhamad, setyo budi kurniawan.  (2021).  a review of the production process of bacteria-based polymeric flocculants.  - journal of water process engineering.  1-13. 

mohd hafizuddin muhamad, siti rozaimah sheikh abdullah, hassimi abu hasan, siti nur hatika abu bakar, setyo budi kurniawan, nur izzati ismail.  (2021).  a hybrid treatment system for water contaminated with pentachlorophenol: removal performance and bacterial community composition.  - journal of water process engineering.  1-14. 

atyaf farooq alshekhli, hassimi abu hasan, mohd hafizuddin muhamad, siti rozaimah sheikh abdullah.  (2020).  development of adsorbent from phytoremediation plant waste for methylene blue removal.  - journal of ecological engineering.  207-215.