Knowledge Globalization Conference, 13th International Knowledge Globalization Confernece 2018

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A Review on Advanced Resource Recovery Options from Wastewater

Mohammad Abu Hashnat Badsha

Last modified: 2018-01-09

Abstract


In the coming days, advancing resource recovery options could be one of the priorities to the environmental scientists while advancements in the wastewater treatment technologies will be taking place in parallel. The old fashioned and common recovery options from wastewater, either in the form of energy like biogas or animal feed or bio-compost, are no more wonders to us. Therefore, we have to take microscopic look into wastewater and improve technologies then huge opportunities will be opened in front of us to recover thousands and millions of valuable resources.

With the technological advancements the scientists are always curious to introduce us new and advanced resource recovery options; for instance, recovery of nutrients in the form of struvite, bioplastic in the form of polyhydroxyalkanoates (PHAs), bio-hydrogen, chromium salts, biodiesels, cellulose, protein, hormone, etc. Among these advanced technologies, a good number of researchers attempted to find a reliable option to recover nutrients in the form of struvite from human urine and wastewater. EAWAG has even tried to implement a model of circular green economy for the recovered struvite in Nepal, considering nutrient content in human urine (1 L urine = 5 g of nitrogen, which is equivalent to 10 g of urea fertilizer that contains similar amount, 46% of 10 g urea ~ 5 g N). According to EAWAG, maximum 90% of phosphorous can be achieved from urine using low-cost chemical precipitation method. Other studies and their maximum recovery rates are also included in this report, for instance, Forward Osmosis (FO), where ammonium nitrogen recovery rate was found 50 to 80%, whereas phosphate and potassium more than 90%). In contrast, ammonia separation from urine could be achieved up to 99% in a vacuum membrane distillation (MD) process. But, the cost of recovery of nutrient using membrane process has not been studied yet. In addition, new nanocomposite material was studied to recover phosphate from wastewater using magnetic particles where the maximum adsorption rate was observed 88% and 95%, while using the same material for real sewage wastewater the result was worse and significantly decreased. However, religious custom of the different communities is a great challenge to ensure reusability of the recovered nutrients, for example, the Muslim community believes urine as impure so no one should get contact with it according to their religious custom.

Apart from this, a very few of other resource recovery options, such as recovery of bioplastic, biohydrogen, chromium, biodiesels, cellulose, protein, hormones, etc., have shown promising results in terms of their production rates and purities. Among these innovative recovery options, some of them are already studied pilot-scale basis (e.g. cellulose, biohydrogen, etc.) and applied in the industrial-scale (e. g. bioplastic, biodiesel, chromium, protein, hormone, etc.); but most of them are still in their development stages at the laboratories under the different scientists, and giving hopes for the young researchers to bring the technology from laboratory to real life.