Assessment of optimum dilution ratio for biohydrogen production by anaerobic co-digestion of press mud with sewage and water.

Anaerobic co-digestion of press mud with water or sewage at ratios of 1:7.5, 1:10 and 1:12.5 were performed in continuously fed UASB reactors for hydrogen production. At a constant hydraulic retention time of 30 h, the specific hydrogen production rate was 187 mL/g volatile solids (VS) reduced during maximum biohydrogen production of 7960 mL/day at a 1:10 ratio of press mud to sewage. Chemical oxygen demand (COD) and VS reductions of 61% and 59% were noted on peak biohydrogen yield. A pH range of 5-6 was suitable at ambient temperature for entire process; a lower pH was inhibitory. Co-digestion of acidic press mud with sewage controlled pH for fermentation. Hence press mud can be exploited for biohydrogen production.

Anaerobic stabilization and conversion of transformed intermediates of antibiotic pharmaceutical effluent in a fluidized bed reactor.

The formulation and implementation of regulatory standards for the ultimate disposal and reuse of transformed products of antibiotic drugs and solvents have been a pending issue in the waste management of pharmaceutical industries especially in the developing countries like India. A case study has been identified and the current issues in one of the major pharmaceutical industry (manufacturing cephalosporin drugs) located in Chennai, India, has been discussed for the possible implementation of anaerobically transformed intermediates of antibiotic pharmaceutical waste sludge. The objective of the study was to determine the effect of bioaugmentation on the convertibility of anaerobically transformed intermediates of antibiotic pharmaceutical waste sludge into residuals and biocompost. Cephalosporin is a common name refers to cephradine (C16H19N3O4S) and cephalexin (C16H17N3O4S.H2O). Based on the critical examination of results, the industry is looking for the alternatives of either direct disposal of 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and phenyl acetic acid or for further degradation and disposal, which will essentially require additional cost and maintenance. The present regulatory standard implemented in India does not envisage such disposal alternatives and hence this would invite suggestions and recommendations of the expertise for the possible implementation on the pending issue in the antibiotic based pharmaceutical industries. The presence of cephalosporin increases total strength (Chemical Oxygen Demand) of the effluent and indirectly increases the cost of the treatment. Hence the biotransformation of cephalosporin either alone or in combination with other energetic compounds, offers the potential for an economical and environment friendly disposal alternative for the anaerobically transformed intermediates of antibiotic pharmaceutical waste sludge.

Effect of loading rate and HRT on the removal of cephalosporin and their intermediates during the operation of a membrane bioreactor treating pharmaceutical wastewater.

The viability of treating high-concentration antibiotic wastewater by a membrane bioreactor (MBR) was studied using submerged flat sheet membrane. The major problems for these modules are concentration polarization and subsequent fouling. By using gas-liquid two-phase flow, these problems can be ameliorated. A case study has been identified and the current issues in one of the major pharmaceutical industry (manufacturing cephalosporin drugs) located in Chennai, India, has been discussed for the possible removal of anaerobically transformed intermediates of antibiotic pharmaceutical wastewater. The objective of the study was to determine the effect of organic loading rate and hydraulic retention time on the removal of cephalosporin derivative, viz., cephalexin (C(16)H(17)N(3)O(4)S.H(2)O) and the intermediates [7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and acyl group (Phenyl acetic acid)] in the MBR with enhanced biodegradation using bioaugmentation technique. Based on the critical examination of results, the industry is looking for the alternatives of either direct disposal of 7-ADCA and phenyl acetic acid or for further degradation and disposal, which will essentially require additional cost and maintenance. The present regulatory standard implemented at a global level, (meaning the intermediates which are transformed during its course of travel within the industry and in the treatments plants, i.e., in the present study it is, 7-ADCA and phenyl acetic acid are not allowed to discharge on water bodies), does not envisage such disposal alternatives and hence the present study was aimed at the complete removal of intermediates (7-ADCA) and phenyl acetic acid prior to discharge.

Effect of loading rate and HRT on the removal of cephalosporin and their intermediates during the operation of a membrane bioreactor treating pharmaceutical wastewater.

The viability of treating high-concentration antibiotic wastewater by an anaerobic membrane bioreactor was studied using submerged flat sheet membrane. The objective of the study was to determine the effect of organic loading rate and hydraulic retention time on the removal of cephalosporin derivative, viz. cephalexin, and the intermediates 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and acyl group (phenyl acetic acid) in an anaerobic membrane bioreactor with enhanced biodegradation using the bioaugmentation technique. The pharmaceutical industry is looking for alternatives to either direct disposal of 7-amino-3-deacetoxycephalosporanic acid and phenyl acetic acid, or further degradation and disposal, which will essentially require additional costs and maintenance. The present regulatory standard, implemented at a global level, does not allow for such disposal alternatives and hence the present study was aimed at the complete removal of the intermediates 7-ADCA and phenyl acetic acid prior to discharge.

Anaerobic pretreatment and increased solid destruction for vegetable solid waste codigested with cattle slurry.

Municipal solid waste and industrial solid waste are considered to be a large quantity of organic fraction which have contributed to different levels of pollution on land and ground water. The present study was carried out for the determination of characteristics of vegetable solid wastes, cattle slurry and sewage sludge for effective anaerobic co-digestion. The objective of the work was to study the treatability of vegetable solid wastes by co-digestion with municipal sewage and cattle slurry in different ratios. The laboratory batch scale studies were carried out to determine effects of various process parameters on startup and digestion. The pretreatment on solid waste has resulted in effective co-digestion of vegetable solid waste and hence showed increased biogas yield. The optimum ratio of vegetable wastes to inoculum (cow dung and anaerobic sewage sludge in the ratio of 1:1) was found to be 1:2 for effective co-digestion and maximum biogas yield.

Effect of inoculum-substrate ratio on acclimatization of pharmaceutical effluent in an anaerobic batch reactor.

Anaerobic treatment has gained tremendous success over the past two decades for treatment of industrial effluents. Over the past 30 years, the popularity of anaerobic wastewater treatment has increased as public utilities and industries have utilized its considerable benefits. Low biomass production, row nutrient requirements and the energy production in terms of methane yield are the significant advantages over aerobic treatment process. Due to the disadvantages reported in the earlier investigations, during the past decade, anaerobic biotechnology now seems to become a stable process technology in respect of generating a high quality effluent. The objective of the present experimental study was to compare the biodegradability of recalcitrant effluent (pharmaceutical effluent) for various inoculum-substrate ratios. The batch experiments were conducted over 6 months to get effect of ratio of inoculum-substrate on the acclimatization of pharmaceutical effluent. The tests were carried out in batch reactors, serum bottles, of volume 2000 mL and plastic canes of 10000 mL. Each inoculum was filled with a cow dung, sewage and phosphate buffer. The batch was made-up of diluted cow dung at various proportions of water and cow dung, i.e., 1:1 and 1:2 (one part of cow dung and one part of water by weight for 1:1). The bottles were incubated at ambient temperature (32 degrees C-35 degrees C). The bottles were closed tightly so that the anaerobic condition is maintained. The samples were collected and biodegradability was measured once in four days. The bottles were carefully stirred before gas measurement. The substrate was added to a mixture of inoculum and phosphate nutrients. The variations in pH, conductivity, alkalinity, COD, TS, TVS, VSS, and VFA were measured for batch process. The biogas productivity was calculated for various batches of inoculum-substrate addition and conclusions were drawn for expressing the biodegradability of pharmaceutical effluent on acclimatization period and influent COD concentration.

Anaerobic sustainability for integrated biomethanation of sugar mill waste and municipal sewage.

The study investigates the viability of biogas generation by integrating the biodegradable waste product of sugar industry viz., pressmud with municipal sewage using biomethanation process. The total solid content of pressmud and sewage mixture was optimized with respect to maximization of biogas yield with continuous monitoring over several operating parameters. Optimum total solid content of 5% found to yield 80 m3 of biogas per ton of pressmud compared to 65m3 per ton of conventional digestion of pressmud alone. It is estimated that 3.4 x 10(8) m3 of biogas can be generated through integrated biomethanation from the potential of4.2 million tons ofpressmud available annually in India.

Efficiency of chemically modified low cost adsorbents for the removal of heavy metals from waste water: a comparative study.

In this paper, a comparative study of removal efficiency of heavy metals [copper Cu(II), Manganese--Mn(II), Iron--Fe(II), Nickel--Ni(II), Lead--Pb(II) and Zinc--[Zn(II)] from aqueous solution by adsorption on non-conventional materials and on chemically activated non-conventional materials, is presented. It is found that the adsorption potential varies as a function of contact time, concentration, particle size, pH and flow rate. Of all the low cost adsorbents used in the study, saw dust is found to possess greater adsorption efficiency for all metals, than rice husk under identical experimental conditions. Chemically activated saw dust could remove 98.28% of Cu(II); 100% of Mn(II); 96.72% of Fe(II); 96.72% of Cd(II); 75% of Cr(VI); 80% of Ni(II); 95% of Pb(II) and 93% of Zn(II), from the corresponding metal solution taken one at a time.

Anaerobic treatment and biogas recovery for sago wastewater management using a fluidized bed reactor.

Starch manufacturing industrial units, such as sago mills, both at medium and large scale, suffer from inadequate treatment and disposal problems due to high concentration of suspended solid content present in the effluent. In order to investigate the viability of treatment of sago effluent, a laboratory scale study was conducted. The treatment of sago effluent was studied in a continuous flow anaerobic fluidized bed reactor. The start-up of the reactor was carried out using a mixture of digested supernatant sewage sludge and cow dung slurry in different proportions. The effect of operating variables such as COD of the effluent, bed expansion, minimum fluidization velocity on efficiency of treatment and recovery of biogas was investigated. The treated wastewater was analysed for recycling and reuse to ensure an alternative for sustainable water resourse management. The maximum efficiency of treatment was found to be 82% and the nitrogen enriched digested sludge was recommended for agricultural use.

Treatment of anti-osmotic drug based pharmaceutical effluent in an upflow anaerobic fluidized bed system.

During the production of Cephradine (a main constituent of anti-osmotic drug) a large quantity of concentrated effluent was produced. The main polluting compounds in this effluent are osmotic drug, acetic acid and ammonia. The feasibility of using a fluidized bed reactor under anaerobic condition with bioaugmentation to treat anti-osmotic drug based pharmaceutical effluent was evaluated. The main objective of the study was to show that bioaugmentation could be used to promote biological treatment to applications where conventional operation might be difficult or unfavourable. The effluent with chemical oxygen demand (COD) of 14000-18000 mg/l was treated in a fluidized bed reactor with a hydraulic retention time of 3-12 h. The reactor was unable to maintain consistent removal in conventional mode of operation due to an inability to retain and grow biomass. The COD reduction (%) after inoculation from a sequencing batch reactor was related to influent concentration, mass of inoculum and hydraulic retention time characterized by calculating the initial food to microorganism ratio. The role of volatile fatty acid (VFA) as cosubstrate was assessed with respect to COD reduction (%). Continuous COD reduction (%) attained a maximum value of 88.5% using bioaugmentation through periodic addition of acclimated cells every 2 days with 30-73.2 g of cells from an off-line enricher reactor.

Bioaugmentation and anaerobic treatment of pharmaceutical effluent in fluidized bed reactor.

The start-up of an anaerobic fluidized bed reactor was carried out using a single inoculum (supernatant of anaerobic digester) and later on with multiple inoculum (a mixture of supernatant of anaerobic digester and volatile fatty acid (VFA)) to achieve a faster start-up. Then regular experiments were carried out to study the effect of hydraulic retention time (HRT) on COD removal (%) and biogas production. The pharmaceutical effluent with COD of 2000 to 4000 mg/L was treated in a fluidized bed reactor using an enricher-reactor concept with a hydraulic retention times of 3 (Uf = 6 Umf) to 24 (Uf = 1.5 Umf) hr. The maximum COD removal (%) of 91.2 and a maximum biogas production of 5.62 L/d were obtained at 24 hr HRT for a maximum COD concentration of 4000 mg/L corresponding to a fluidization velocity (Uf) of 20 m/hr (1.5 Umf) using a granular activated carbon bed of average size 700 microns.

Bioaugmentation and treatment of cephalexin drug-based pharmaceutical effluent in an upflow anaerobic fluidized bed system.

Cephalexin is a constituent of the cephalosporin group used for the treatment of bronchitis and other heart diseases due to its enhanced oral activity. The effluent from these industries contains a disintegrated form of the drug contributing high chemical oxygen demand (COD), volatile solids and organic solvent. A laboratory-scale study was conducted to evaluate the efficiency of a fluidized bed reactor operated under anaerobic condition with bioaugmentation to treat the cephalexin containing pharmaceutical factory effluent. The main objective of the study was to show that bioaugmentation could be used to promote biological treatment to applications where conventional operation might be difficult or unfavourable. The effluent, with COD of 12,000-15,000 mg/l, was diluted and studied in single and multiple inoculation experiments with hydraulic retention times of 3-12 h. The removal efficiency after inoculation from an anaerobic sequencing batch reactor was related to influent concentration, mass of inoculum and hydraulic retention time characterized by calculating the initial food to microorganism ratio. Continuous COD removal efficiency attained a maximum value of 88.5% using bioaugmentation through periodic addition of acclimated cells every 2 days with 30-73.2 g of cells from an off-line enricher-reactor.