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Lagooning and bio-consortium optimisation for secondary level remediation of simulated sugar factory wastewater

Sugar factories are a significant source of water pollution, particularly in developing countries such as Pakistan, where the sugar industry is the second largest after tanneries. The wastewater is disposed of untreated to the environment, since traditional wastewater treatment processes are capital-intensive, energy-demanding and complex in operation. The common approach is to use waste stabilization ponds or lagoons mostly operated on complete retention basis. This work is an attempt to highlight the possibility of effectively applying wastewater lagooning process utilizing the inherent organic contents of sugar factory wastewater with the aid of an algae-bacterial consortium (ABC) to investigate its capacity to utilize this resource to produce renewable fuel while de-polluting wastewater rather than it being a liability to be disposed of. A lagoon photo tank (LPT) resembling a prototype raceway lagoon was designed and used to carry out mass cell cultivation on a sugar-oriented medium for the assessment and inter-optimization of the process conditions such as temperature, incident light (IL), pH, dissolved oxygen (DO). The evaluation of the process performance was observed via the analyses of parameters such as chemical oxygen demand (COD), total organic carbon and cell mass growth. The first part of this study was related with the baseline assessment of LPT process conditions using distilled water as well as sucrose solution or sugar water to establish basis for a priori analysis of simulated sugar factory wastewater (SSFW) carried out in the second part. The suitability of the dosing of copolymer Polyacrylate polyalcohol was optimised through a series of trial runs to aid in the immobilization of mono or mixotrophic cultures of green algae Chlorella Vulgaris and bacteria Pseudomonas Putida at the surface of LPT in order to influence reduction in the organic concentration of SSFW. This research study has contributed to the knowledge base of the concerned area of study with respect to hitherto unknown application of copolymer Polyacrylate polyalcohol, which showed viable characteristics in the cultivation medium in terms of cell immobilization at the surface of LPT resulting in the formation of growth-conducive copolymer-algae matrices leading to the rapid growth of the cell mass with increased process efficiency. This process optimisation resulted in SSFW depollution by around 89% along with energetic biomass growth with a calorific value of 27 kJ g1 and at an optimum growth rate of 1.2 d1 suggesting towards the potential of copolymer addition in the system to enhance the efficiency of the organisms inducing optimum substrate utilization.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:555515
Date January 2011
CreatorsRehman, Abdul
PublisherUniversity of Nottingham
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://eprints.nottingham.ac.uk/14578/

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