The Cardiology Society of India-Kerala Acute Heart Failure Registry: poor adherence to guideline-directed medical therapy.

AIMS: Data on the burden of acute heart failure (AHF) admissions, practice patterns, and outcomes are rare from India and other low- and middle-income countries. We aimed to describe the baseline characteristics, guideline-directed medical therapy (GDMT) prescribing patterns and 90-day mortality rates in patients admitted with AHF in Kerala, India. METHODS AND RESULTS: The Cardiology Society of India-Kerala Acute Heart Failure Registry (CSI-KHFR) is an observational registry from 50 hospitals in Kerala, India, with prospective follow-up. Consecutive patients with AHF, who consented to participate, were enrolled. The 2016 European Society of Cardiology criteria were used for the diagnosis of AHF. Kaplan-Meier survival analysis and Cox-proportional hazard models were used for data analysis. The variables in the MAGGIC risk score were used in the multivariable model. A total of 7507 patients with AHF (37% female) participated in the CSI-KHFR. The mean age was 64.3 (12.9) years. More than two-third had reduced ejection fraction (EF) (67.5%). Nearly one-fourth (28%) of patients with heart failure (HF) with reduced EF received GDMT. Overall, in-hospital and 90-day mortality rates were 7% and 11.6%, respectively. Prescriptions of different components of GDMT were independently associated with 90-day mortality. CONCLUSION: The CSI-KHFR recorded an in-hospital and 90-day mortality of 7% and 11.6%, respectively. Only one of four patients received GDMT. AHF mortality was independently associated with GDMT initiation. Quality improvement initiatives that focus on increasing GDMT prescription may improve the survival of HF patients in India.

Effect of a Quality Improvement Intervention on Clinical Outcomes in Patients in India With Acute Myocardial Infarction: The ACS QUIK Randomized Clinical Trial.

Importance: Wide heterogeneity exists in acute myocardial infarction treatment and outcomes in India. Objective: To evaluate the effect of a locally adapted quality improvement tool kit on clinical outcomes and process measures in Kerala, a southern Indian state. Design, Setting, and Participants: Cluster randomized, stepped-wedge clinical trial conducted between November 10, 2014, and November 9, 2016, in 63 hospitals in Kerala, India, with a last date of follow-up of December 31, 2016. During 5 predefined steps over the study period, hospitals were randomly selected to move in a 1-way crossover from the control group to the intervention group. Consecutively presenting patients with acute myocardial infarction were offered participation. Interventions: Hospitals provided either usual care (control group; n = 10 066 participants [step 0: n = 2915; step 1: n = 2649; step 2: n = 2251; step 3: n = 1422; step 4; n = 829; step 5: n = 0]) or care using a quality improvement tool kit (intervention group; n = 11 308 participants [step 0: n = 0; step 1: n = 662; step 2: n = 1265; step 3: n = 2432; step 4: n = 3214; step 5: n = 3735]) that consisted of audit and feedback, checklists, patient education materials, and linkage to emergency cardiovascular care and quality improvement training. Main Outcomes and Measures: The primary outcome was the composite of all-cause death, reinfarction, stroke, or major bleeding using standardized definitions at 30 days. Secondary outcomes included the primary outcome's individual components, 30-day cardiovascular death, medication use, and tobacco cessation counseling. Mixed-effects logistic regression models were used to account for clustering and temporal trends. Results: Among 21 374 eligible randomized participants (mean age, 60.6 [SD, 12.0] years; n = 16 183 men [76%] ; n = 13 689 [64%] with ST-segment elevation myocardial infarction), 21 079 (99%) completed the trial. The primary composite outcome was observed in 5.3% of the intervention participants and 6.4% of the control participants. The observed difference in 30-day major adverse cardiovascular event rates between the groups was not statistically significant after adjustment (adjusted risk difference, -0.09% [95% CI, -1.32% to 1.14%]; adjusted odds ratio, 0.98 [95% CI, 0.80-1.21]). The intervention group had a higher rate of medication use including reperfusion but no effect on tobacco cessation counseling. There were no unexpected adverse events reported. Conclusions and Relevance: Among patients with acute myocardial infarction in Kerala, India, use of a quality improvement intervention compared with usual care did not decrease a composite of 30-day major adverse cardiovascular events. Further research is needed to understand the lack of efficacy. Trial Registration: clinicaltrials.gov Identifier: NCT02256657.

Team based collaborative care model, facilitated by mHealth enabled and trained nurses, for management of heart failure with reduced ejection fraction in India (TIME-HF): design and rationale of a parallel group, open label, multi-centric cluster randomised controlled trial.

Background: Heart failure (HF) is a debilitating condition associated with enormous public health burden. Management of HF is complex as it requires care-coordination with different cadres of health care providers. We propose to develop a team based collaborative care model (CCM), facilitated by trained nurses, for management of HF with the support of mHealth and evaluate its acceptability and effectiveness in Indian setting. Methods: The proposed study will use mixed-methods research. Formative qualitative research will identify barriers and facilitators for implementing CCM for the management of HF. Subsequently, a cluster randomised controlled trial (RCT) involving 22 centres (tertiary-care hospitals) and more than 1500 HF patients will be conducted to assess the efficacy of the CCM in improving the overall survival as well as days alive and out of hospital (DAOH) at two-years (CTRI/2021/11/037797). The DAOH will be calculated by subtracting days in hospital and days from death until end of study follow-up from the total follow-up time. Poisson regression with a robust variance estimate and an offset term to account for clustering will be employed in the analyses of DAOH. A rate ratio and its 95% confidence interval (CI) will be estimated. The scalability of the proposed intervention model will be assessed through economic analyses (cost-effectiveness) and the acceptability of the intervention at both the provider and patient level will be understood through both qualitative and quantitative process evaluation methods. Potential Impact: The TIME-HF trial will provide evidence on whether a CCM with mHealth support is effective in improving the clinical outcomes of HF with reduced ejection fraction in India. The findings may change the practice of management of HF in low and middle-income countries.

Impact of COVID-19 on heart failure hospitalization and outcome in India - A cardiological society of India study (CSI-HF in COVID 19 times study - "The COVID C-HF study").

OBJECTIVES: The presentation and outcomes of acute decompensated heart failure (ADHF) during COVID times (June 2020 to Dec 2020) were compared with the historical control during the same period in 2019. METHODS: Data of 4806 consecutive patients of acute HF admitted in 22 centres in the country were collected during this period. The admission patterns, aetiology, outcomes, prescription of guideline-directed medical therapy (GDMT) and interventions were analysed in this retrospective study. RESULTS: Admissions for acute heart failure during the pandemic period in 2020 decreased by 20% compared to the corresponding six-month period in 2019, with numbers dropping from 2675 to 2131. However, no difference in the epidemiology was seen. The mean age of presentation in 2019 was 61.75 (±13.7) years, and 59.97 (±14.6) years in 2020. There was a significant decrease in the mean age of presentation (p = 0.001). Also. the proportion of male patients decreased significantly from 68.67% to 65.84% (p = 0.037). The in-hospital mortality for acute heart failure did not differ significantly between 2019 and 2020 (4.19% and 4.,97%) respectively (p = 0.19). The proportion of patients with HFrEF did not change in 2020 compared to 2019 (76.82% vs 75.74%, respectively). The average duration of hospital stay was 6.5 days. CONCLUSION: The outcomes of ADHF patients admitted during the Covid pandemic did not differ significantly. The length of hospital stay remained the same. The study highlighted the sub-optimal use of GDMT, though slightly improving over the last few years.

Pulmonary Hypertension Registry of Kerala, India (PRO-KERALA): One-year outcomes.

BACKGROUND: Short term outcomes of patients with pulmonary hypertension are not available from low and middle-income countries including India. METHODS: We conducted a prospective study of 2003 patients with pulmonary hypertension, from 50 centres (PROKERALA) in Kerala, who were followed up for one year. Pulmonary hypertension (PH) was mainly diagnosed on the basis of Doppler echocardiography. The primary outcome was a composite end-point of all-cause death and hospital admission for heart failure. All cause hospitalisation events constituted the secondary outcome. RESULTS: Mean age of study population was 56 ± 16 years. Group 1 and Group 2 PH categories constituted 21.2% and 59% of the study population, respectively. Nearly two-thirds (65%) of the study participants had functional class II symptoms. 31% of Group 1 PH patients were on specific vasodilator drugs.In total, 83 patients (4.1%) died during the one-year follow-up period. Further, 1235 re-hospitalisation events (61.7%) were reported. In the multivariate model, baseline NYHA class III/IV (OR 1.87, 95% C.I. 1.35-2.56), use of calcium channel blockers (OR 0.18, 95% C.I. 0.04-0.77), vasodilator therapy (OR 0.5, 95% C.I. 0.28-0.87) and antiplatelet agents (OR 1.80, 95% C.I. 1.29-2.51) were associated with primary composite outcome at one-year (p < 0.05). CONCLUSION: In the PROKERALA registry, annual mortality rate was 4%. More than half of the patients reported re-hospitalisation events on follow up. Uptake of guideline directed therapies were suboptimal in the study population. Quality improvement programmes to improve guideline directed therapy may improve clinical outcomes of PH patients in India.

A multicentric, 2 × 2 factorial, randomised, open-label trial to evaluate the clinical effectiveness of structured physical activity training and cognitive behavioural therapy versus usual care in heart failure patients: a protocol for the PACT-HF trial.

Background: Heart failure (HF) is a multi-morbid chronic condition, which adversely affects the quality of life of the affected individual. Engaging the patient and their caregivers in self-care is known to reduce mortality, rehospitalisation and improve quality of life among HF patients. The PACT-HF trial will answer whether clinical benefits in terms of mortality and hospitalisation outcomes can be demonstrated by using a pragmatic design to explore the specific effects of physical activity, and cognitive behavioural therapy in HF patients in India. Methods: We will conduct a 2 × 2 factorial, randomized, open-label trial, which aims to see if rehabilitation strategies of structured physical activity training and cognitive behavioural therapy for depression and self-management reduce the risk of repeat hospitalisation and deaths in HF patients in India. Patients will be randomised to (1) physical activity + usual care (2) cognitive behaviour therapy + usual care, (3) physical activity + cognitive behaviour therapy + usual care, and (4) usual care at 1:1:1:1 ratio. Time to mortality will be the primary outcome. A composite of mortality and hospitalisation for HF will be the main secondary outcome. Additional secondary outcomes will include 'days alive and out of hospital', cumulative hospitalisation, quality of life, Minnesota Living with Heart Failure questionnaire score, depression score, six minutes walking distance, handgrip strength, and adherence to medicines and lifestyle.  The effects of intervention on the primary outcome will be estimated from Cox proportional hazard models. For the continuous secondary outcome variables, differences between randomised groups will be estimated from linear mixed models or generalised estimating equations (GEE) as appropriate. Discussion: PACT-HF is designed to provide reliable evidence about the balance of benefits and risks conferred by physical activity and cognitive behavioural therapy-based cardiac rehabilitation for those with HF, irrespective of their initial disease severity.

Clinical characteristics and 30-day outcomes in patients with acute decompensated heart failure: Results from Indian College of Cardiology National Heart Failure Registry (ICCNHFR).

BACKGROUND: Acute decompensated heart failure (ADHF) is a challenging medical emergency with high mortality and its prevalence is increasing in India. There is paucity of data on ADHF in the country. METHODS: Indian College of Cardiology National Heart Failure Registry (ICCNHFR) is an on-going observational registry on ADHF contributed by 22 hospitals across India; and we present the in-hospital and 30-day outcomes of ADHF patients enrolled from August 2018 to July 2019. Major objective included capturing demographics, comorbid conditions, aetiology, prescription patterns and assessing clinical outcomes. RESULTS: Of 5269 patients (mean age: 61.90 ± 13.85 years) enrolled in this study, males were predominant (67.09%). Mean duration of hospitalization was 5.74 ± 4.74 days. Ischemic heart disease was the most common (75.44%) aetiology. Abnormal electrocardiogram readings were found in most patients (89.86%). LVEF of ˂40% was found in 68.29% of patients. In-hospital mortality rates were 6.98%. The 30-day cumulative mortality was 12.35% and 30-day rehospitalization rate was 7.98%. At discharge, all guideline-based medical therapy (GDMT) were prescribed only to 24.99% of patients and 23.72% adhered to the prescription until 30 days. Older age, high serum creatinine levels and poor LVEF contributed to high mortality and rehospitalization. CONCLUSION: Patients with ADHF were younger and predominantly males. Usage of GDMT in ADHF patients was low (24.99%) and the in-hospital mortality was high. Older age, high serum creatinine levels, poor LVEF contributed for 30-day mortality and rehospitalization. This data on ADHF, could help in developing strategies to improve outcomes for HF patients in India.

Effect of a quality improvement intervention for acute heart failure in South India: An interrupted time series study.

BACKGROUND: Although quality improvement interventions for acute heart failure have been studied in high-income countries, none have been studied in low- or middle-income country settings where quality of care can be lower. We evaluated the effect of a quality improvement toolkit on process of care measures and clinical outcomes in patients hospitalized for acute heart failure in 8 hospitals in Kerala, India utilizing an interrupted time series design from February 2018 to August 2018. METHODS: The quality improvement toolkit included checklists, audit-and-feedback reports, and patient education materials. The primary outcome was rate of discharge guideline-directed medical therapy for patients with heart failure with reduced ejection fraction. We used mixed effect logistic regression and interrupted time series models for analysis. RESULTS: Among 1400 participants, mean (SD) age was 66.6 (12.2) years, and 38% were female. Mean (SD) left ventricular ejection fraction was 35.2% (9.7%). The primary outcome was observed in 41.3% of participants in the intervention period and 28.1% of participants in the control period (difference 13.2%; 95% CI 6.8, 19.0; adjusted OR = 1.70; 95% CI 1.17, 2.48). Interrupted time series model demonstrated highest rate of guideline-directed medical therapy at discharge in the initial weeks following intervention delivery with a concomitant decline over time. Improvements were observed in discharge process of care measures, including diet counseling, weight monitoring instructions, and scheduling of outpatient clinic follow-up but not hospital length of stay nor inpatient mortality. CONCLUSIONS: Higher rates of guideline-directed medical therapy at discharge were observed in Kerala. Broader implementation of this quality improvement intervention may improve heart failure care in low- and middle-income countries.

Acute decompensated heart failure (ADHF) during COVID-19 pandemic-insights from South India.

AIM: This retrospective study compares admissions and outcomes due to acute decompensated heart failure (ADHF) during the COVID-19 pandemic from 25 March to 25 July 2020 with the historical patient control who were admitted during the same period in 2019. METHODS AND RESULTS: Data of the participating hospitals was collected and analysed from the ICC NHFR (Indian College of Cardiology National Heart Failure Registry) for 2019 and 2020. Total number of ADHF admissions, demographics, aetiology, co-morbid conditions and in-hospital mortality was compared and analysed. A significant decrease in the number of hospital admissions due to ADHF from 2019 to 2020 (1056 vs. 526 respectively) was noted. Incidence of admissions with <40% ejection fraction (EF) reduced in 2020 (72.4% and 80.2% in2020 and 2019)and >40% (EF) increased (27.6% and 19.8% in 2019 and 2020 respectively, p = 0.0005). Ischemic heart disease (IHD) was the most common aetiology (78.59% in 2019 and 80.98% in 2020, p = 0.268). The in-hospital mortality was numerically higher in 2020 (10%) than in 2019 (8%), but not statistically significant (p = 0.161). CONCLUSION: This study from the registry shows that the incidence of ADHF admissions during COVID-19 lockdown significantly reduced compared to the previous year. Demographic patterns remained similar but patients presenting with de-novo HF increased; IHD was the most common cause. The in-hospital mortality was numerically higher during the lockdown. The impact of lockdown perhaps led to fewer hospitalisations and this is to be factored in future strategies to address health care delivery during such crises.

Presentation, Management, and In-Hospital Outcomes of Patients with Acute Heart Failure in South India by Sex: A Secondary Analysis of a Prospective, Interrupted Time Series Study.

Background: Sex differences in presentation, management, and outcomes of heart failure (HF) have been observed, but it is uncertain whether these differences exist in South India. Objective: We describe sex differences in presentation, management, and in-hospital outcomes in patients hospitalized with HF in South India and explore sex-based differences in the effect of the quality improvement intervention in a secondary analysis of a prospective, interrupted time series study. Methods: The Heart Failure Quality Improvement in Kerala (HF QUIK) study evaluated the effect of a quality improvement toolkit on process of care measures and clinical outcomes in patients hospitalized with HF in eight hospitals in Kerala using an interrupted time series design from February 2018 to August 2018. The primary outcome was guideline-directed medical therapy (GDMT) at hospital discharge for patients with HF with reduced ejection fraction (HFrEF). We performed sex-stratified analyses using mixed effect logistic regression models. Results: Among 1,400 patients, 536 (38.3%) were female. Female patients were older (69.6 vs. 65 years, p < 0.001), were less likely to have an ischemic etiology of HF (control period: 78.2% vs. 87.5%; intervention period: 83.6% vs. 91.5%; p < 0.05 for both) and were less likely to undergo coronary angiography or percutaneous coronary intervention. The quality improvement intervention had similar effects on the odds of GDMT at discharge in females with HFrEF (adjusted OR 1.79, 95% CI 0.92, 3.47) and males with HFrEF (adjusted OR 1.68, 95% CI 1.07, 2.64, pinteraction = 0.69). Conclusions: We observed sex-specific differences in presentation and procedural management of patients with HF but no differences in the effect of the quality improvement intervention on discharge GDMT rates. Both male and female patients with HFrEF remained undertreated in the study intervention period, demonstrating the need for implementation strategies to close the HFrEF treatment gap in South India.

One-year clinical outcome of patients with nonvalvular atrial fibrillation: Insights from KERALA-AF registry.

BACKGROUND: We report patient characteristics, treatment pattern and one-year clinical outcome of nonvalvular atrial fibrillation (NVAF) from Kerala, India. This cohort forms part of Kerala Atrial Fibrillation (KERALA-AF) registry which is an ongoing large prospective study. METHODS: KERALA-AF registry collected data of adults with previously or newly diagnosed atrial fibrillation (AF) during April 2016 to April 2017. A total of 3421 patients were recruited from 53 hospitals across Kerala state. We analysed one-year follow-up outcome of 2507 patients with NVAF. RESULTS: Mean age at recruitment was 67.2 years (range 18-98) and 54.8% were males. Main co-morbidities were hypertension (61.2%), hyperlipidaemia (46.2%) and diabetes mellitus (37.2%). Major co-existing diseases were chronic kidney disease (42.1%), coronary artery disease (41.6%), and chronic heart failure (26.4%). Mean CHA2DS2-VASc score was 3.18 (SD ± 1.7) and HAS-BLED score, 1.84 (SD ± 1.3). At baseline, use of oral anticoagulants (OAC) was 38.6% and antiplatelets 32.7%. On one-month follow-up use of OAC increased to 65.8% and antiplatelets to 48.3%. One-year all-cause mortality was 16.48 and hospitalization 20.65 per 100 person years. The main causes of death were cardiovascular (75.0%), stroke (13.1%) and others (11.9%). The major causes of hospitalizations were acute coronary syndrome (35.0%), followed by arrhythmia (29.5%) and heart failure (8.4%). CONCLUSIONS: Despite high risk profile of patients in this registry, use of OAC was suboptimal, whereas antiplatelets were used in nearly half of patients. A relatively high rate of annual mortality and hospitalization was observed in patients with NVAF in Kerala AF Registry.

Microeconomic Costs, Insurance, and Catastrophic Health Spending Among Patients With Acute Myocardial Infarction in India: Substudy of a Randomized Clinical Trial.

Importance: Ischemic heart disease is the leading cause of death in India, and treatment can be costly. Objective: To evaluate individual- and household-level costs and impoverishing effects of acute myocardial infarction among patients in Kerala, India. Design, Setting, and Participants: This investigation was a prespecified substudy of the Acute Coronary Syndrome Quality Improvement in Kerala study, a stepped-wedge, cluster randomized clinical trial conducted between November 2014 and November 2016 across 63 hospitals in Kerala, India. In this cross-sectional substudy, individual- and household-level cost data were collected 30 days after hospital discharge from a sample of 2114 respondents from November 2014 to July 2016. Data were analyzed from July through October 2018 and in March 2019. Exposures: Health insurance status. Main Outcomes and Measures: The primary outcomes were detailed direct and indirect cost data associated with acute myocardial infarction and respondent ability to pay as well as catastrophic health spending and distress financing. Catastrophic health spending was defined as 40% or more of household expenditures minus food costs spent on health, and distress financing was defined as borrowing money or selling assets to cover health costs. Hierarchical regression models were used to evaluate the association between health insurance and measures of financial risk. Costs were converted from Indian rupees to international dollars (represented herein as "$"). Results: Among 2114 respondents, the mean (SD) age was 62.3 (12.7) years, 1521 (71.9%) were men, 1144 (54.1%) presented with an ST-segment elevation myocardial infarction, and 1600 (75.7%) had no health insurance. The median (interquartile range) expenditure among respondents was $480.4 ($112.5-$1733.0) per acute myocardial infarction encounter, largely driven by in-hospital expenditures. There was greater than 15-fold variability between the 25th and 75th percentiles. Individuals with or without health insurance had similar monthly incomes and annual household expenditures, yet individuals without health insurance had approximately $400 higher out-of-pocket cardiovascular health care costs (median [interquartile range] total cardiovascular expenditures among uninsured, $560.3 [$134.1-$1733.6] vs insured, $161.4 [$23.2-$1726.9]; P < .001). Individuals without health insurance also had a 24% higher risk of catastrophic health spending (adjusted risk ratio, 1.24; 95% CI, 1.07-1.43) and 3-fold higher risk of distress financing (adjusted risk ratio; 3.05; 95% CI, 1.45-6.44). Conclusions and Relevance: The results of this study indicate that acute myocardial infarction carries substantial financial risk for patients in Kerala. Expansion of health insurance may be an important strategy for financial risk protection to disrupt the poverty cycle associated with cardiovascular diseases in India.

Biomethanation of poultry litter leachate in UASB reactor coupled with ammonia stripper for enhancement of overall performance.

In the present study possibility of coupling stripper to remove ammonia to the UASB reactor treating poultry litter leachate was studied to enhance the overall performance of the reactor. UASB reactor with stripper as ammonia inhibition control mechanism exhibited better performance in terms of COD reduction (96%), methane yield (0.26m(3)CH(4)/kg COD reduced), organic loading rate (OLR) (18.5kg COD m(-3)day(-1)) and Hydraulic residence time (HRT) (12h) compared to the UASB reactor without stripper (COD reduction: 92%; methane yield: 0.21m(3)CH(4)/kg COD reduced; OLR: 13.6kg CODm(-3)day(-1); HRT: 16h). The improved performance was due to the reduction of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) in the range of 75-95% and 80-95%, respectively by the use of stripper. G/L (air flow rate/poultry leachate flow rate) in the range of 60-70 and HRT in the range of 7-9min are found to be optimum parameters for the operation of the stripper.

pH regulation of alkaline wastewater with carbon dioxide: a case study of treatment of brewery wastewater in UASB reactor coupled with absorber.

Studies were carried out with carbon dioxide absorber (CA) to evaluate the usage of carbon dioxide (CO(2)) in the biogas as an acidifying agent by Up-flow Anaerobic Sludge Blanket (UASB) reactor. Investigation on the 5l absorber revealed that ratio of brewery wastewater (BW) flow rate to biogas flow rate of 4.6-5.2 was optimum for minimum consumption of CO(2) for acidification. The acidified BW after the absorber was treated in UASB reactor with optimum organic loading rate (OLR) of 23.1 kg COD/m(3)/day and hydraulic retention time (HRT) of 2h. UASB reactor exhibited good performance with respect to reduction of chemical oxygen demand (COD) and methane yield. The implications of the present study on the full scale anaerobic reactor of medium scale brewery revealed that sufficient cost savings could be made if CO(2) in the biogas or CO(2) that was being wasted (let out to the atmosphere) can be used instead of sulfuric acid (H(2)SO(4)) for pH control.

Microbial conversion of sulfur dioxide in flue gas to sulfide using bulk drug industry wastewater as an organic source by mixed cultures of sulfate reducing bacteria.

Mixed cultures of sulfate reducing bacteria (SRB) were isolated from anaerobic cultures and enriched with SRB media. Studies on batch and continuous reactors for the removal of SO(2) with bulk drug industry wastewater as an organic source using isolated mixed cultures of SRB revealed that isolation and enrichment methodology adopted in the present study were apt to suppress the undesirable growth of anaerobic bacteria other than SRB. Studies on anaerobic reactors showed that process was sustainable at COD/S ratio of 2.2 and above with optimum sulfur loading rate (SLR) of 5.46kgS/(m(3)day), organic loading rate (OLR) of 12.63kg COD/(m(3)day) and at hydraulic residence time (HRT) of 8h. Free sulfide (FS) concentration in the range of 300-390mgFS/l was found to be inhibitory to mixed cultures of SRB used in the present studies.

High rate biomethanation technology for solid waste management and rapid biogas production: An emphasis on reactor design parameters.

A high rate biomethanation digester was designed and fabricated to study its real field treatment efficiency and simultaneous biogas generation. The major design parameters like self mixing, delinking hydraulic retention time and solid retention time etc. were considered for efficient performance. It was operated with an organic loading rate (OLR) of 1.5kg/m(3)d(-1) with composite food waste for about one year. The maximum treatment efficiency achieved with respect to total solid (TS) reduction and volatile solids (VS) reduction was 94.5% and 89.7%, respectively. Annual mean biogas of about 0.16m(3)/kgVSd(-1) was observed with methane content varying from 56% to 60% (v/v). The high competence of high rate digester is attributed to its specific design features and intermittent mixing of the digester contents and also due to the hydrodynamic principles involved in its operation.

Multi stage high rate biomethanation of poultry litter with self mixed anaerobic digester.

A multi stage high rate biomethanation process with novel self mixed anaerobic digester (SMAD) was developed in the present study to reduce the hydraulic residence time (HRT), increase the volatile solids (VS) loading rate, improve the VS destruction efficiency and enhance the methane yield. Specific design features of SMAD were useful in mixing the digester contents without consuming power and de-alienated the problem of scum formation. In the first phase, poultry litter having 10% total solids (TS) was subjected to high rate biomethanation in multi stage configuration (SMAD-I and II in series with UASB reactor). It was observed that gross VS reduction of 58%, gross methane yield of 0.16 m3 kg(-1) (VS reduced) and VS loading rate of 3.5 kg VS m(-3) day(-1) at HRT of 13 days was obtained. In the second phase SMAD-II was bypassed from the process scheme keeping the other parameters same as in the first phase. The results obtained were not as encouraging as in the first phase. The study showed that multi stage configuration with SMAD design improved the anaerobic digestion process efficiency of poultry litter.