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The non-aromatic, heterocyclic hexamine is one of the most refractory pollutants in some industrial effluents and food-grade plastics. This compound and its derivatives harm human health with limited options for eco-friendly biological treatment. This study reports the characterization of two rapid hexamine-removing bacterial isolates, Micromonospora citrea SRCHD01 and Micrococcus luteus SRCHD02, from wastewater of Hexamine producing plant at Vishakapatnam, India. The former is a structured biofilm former while the latter is a weak biofilm former with both isolates dividing faster under immobilized conditions. Isolate SRCHD01 could reduce 200 mg/L hexamine to 84.91 mg/L in 24 h with associated Chemical Oxygen Demand (COD) reduction of 99% from an initial concentration of 8028.93 mg/L within 120 h, making it the fastest hexamine-removing bacteria reported till date. The investigation opens a new avenue for studying the bioremediation of hexamine in biofilm reactors ensuring environmental protection. [ABSTRACT FROM AUTHOR]

Dairy industries are highly polluting, energy and fresh water consuming installations. The present study aims to make dairy effluent treatment plant operation less time consuming with minimal energy consumption while generating a value added product. Analysis of the temporal and spatial variation in performance of a biofilm based plug flow reactor involved in the biotransformation of Dairy Waste Water (DWW) revealed ammonia (57.68 mg L–1) rich liquid biofertilizer production within 4 h, with associated reduction of nitrate (70.77%), phosphate (36.44%), protein (62.87%), Biological Oxygen Demand (BOD) (26.38%) and Chemical Oxygen Demand (COD) (39.59%). The process was 4 times faster than the fastest existing process reported till date. The consortium showed a striking reduction in its doubling time from 78 min 56 sec (in suspension culture) to 17 min 10 sec (as biofilm) upon immobilization. It could produce 734.60 mg ammonia per kg of immobilization matrix from DWW. Metagenomic analysis revealed the robustness of the biofilm based biotreatment system. The novelty of this study is the innovative approach of rapid conversion of the waste from dairy industry into a value added product using microbes from geosphere in an energy efficient manner which would make dairy effluent treatment plant operation self-sustainable and eco-protective. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Municipal wastewater usually contains nitrate and phosphate as major contaminants, and if discharged untreated affects the health of the environment and human population. Currently available treatment technologies to treat municipal wastewater lose the essential growth nutrients ‘P’ and ‘N’ during treatment. This paper presents a strategy of simultaneous sequestration of nitrate and phosphate in biomass, by using a tailor‐made consortium in a biofilm reactor. RESULTS: The consortium comprising of three novel Bacillus strains in a fixed bed biofilm bioreactor maintained at ambient temperature showed reduction up to 94% of nitrate, 68% of phosphate, 93% of chemical oxygen demand, 97% of biochemical oxygen demand, 73% in total organic carbon while maintaining an effluent pH of 6.8 ± 0.02. Response surface methodology revealed maximum reduction at a flow rate of 1.97 L h‐1 with 306.04 mg L‐1 and 19.62 mg L‐1 of initial nitrate and phosphate concentrations respectively. The system was scaled up from 4.5 L to 220 L with the same retention time of 2 h and operated with consistent performance for over 212 days. CONCLUSION: The treated wastewater met the criterion for reuse as non‐potable water for applications like irrigation and aquaculture, hence making it the fastest microbial process for simultaneous nitrate and phosphate removal from wastewater. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]