Review Article
A review on evaluation of applied pretreatment methods of wastewater towards sustainable H2 generation: Energy efficiency analysis

https://doi.org/10.1016/j.ijhydene.2020.01.081Get rights and content

Highlights

  • Hydrogen generation was a holistic approach to reduce environmental pollution.

  • Hydrogen generation was accelerated by pretreatment process.

  • Pretreatment process accelerates the hydrogen generation capacity of wastewater.

  • Selection of appropriate pretreatment enhances sustainable hydrogen generation.

  • Commercialization of pretreatment for hydrogen intensification remains provocative.

Abstract

This study reviewed the recent updates on the pretreatment methods employed towards the enhancement of hydrogen production. Low hydrogen yield was considered to be a current obstacle for hydrogen utility on the industrial scale. On pretreating, the wastewater, the structure of the macromolecule gets dissipated and destroyed which reduces the polymerization potency. It favors the availability of monomers for the fermentation process. Various pretreatment methods with operating conditions and parameters were documented along with their pros and cons. Mainly, the pretreatment methods adopted for reducing the toxicity levels of wastewater to enhance biohydrogen production are dealt with in detail. Pretreatment methods have shown a positive impact on most of the cases studied. It acts on various components of wastewater and makes it amenable for the hydrogen-producing microbiome. Energy balance methodologies have also been provided towards the selection of a cost-effective and sustainable approach. Perspectives and recommendations on pretreatment systems were directed towards the development of a successful hydrogen economy. Overall documentation details the significance of pretreatment in the fermentation process for higher hydrogen yield.

Introduction

Innovation in the field of energy systems becomes a major quest due to the high demand and development of various technologies on environmental emphasis. In the worldwide history of human civilization, energy has furthermost essential status towards progress and prosperity. The present outline of energy demand grows tremendously on a global scale to reduce greenhouse gas (GHG) emissions linked with fossil fuel depletion. Major destructive environmental impacts such as climate change, ozone layer depletion, acidification, and air pollution occur on incinerating fossil fuels. Hydrogen energy generation was a holistic approach to reduce environmental pollution and its related issues [1]. Hydrogen is a very light and more abundant element with no odor and no toxic with the highest energy content (122 kJ/g), besides no harmful emissions during its combustion [2]. Similar to electricity, hydrogen is an energy carrier and used in all economic sectors such as transportation, power, industry, and buildings [3]. In addition, this more intense and vast desirable hydrogen energy was utilized in the refining industry, food processing sector, methanol production, ammonia and fertilizer for agriculture, metal and fabrication industry and electronics sector [4]. Also, by using fuel cells, hydrogen can be converted to electricity and operated continuously under hydrogen and oxygen zone. These fuel cells are available from small to very large sizes liberating heat and water as its by-products [5]. Thus, Hydrogen, an industrial gas, has strong fundamentals on a global scale. As per the report of the 2015 IEA technology roadmap for hydrogen and fuel cells, hydrogen has potential characteristics to reduce CO2 emissions.

The rapid industrialization demands high water and energy resource and overconsumption of rich valuable resources affects the ecosystem. This immense development of the industrial sector leads to drastic environmental changes by disposing of the abundance of wastewater without treatment which causes pollution and health hazards [6]. The treatment of wastewater along with the generation of renewable energy resource is an ideal method to tackle the problems nowadays. Presently, the availability of pilot-scale eco-friendly approach is more for yielding bioenergy such as biomethane, biohydrogen and bioethanol from organic wastewater. In recent decades, hydrogen production from wastewater is gaining attention as an emergent technology.

Hydrogen generation can be achieved by various methods such as dark fermentation, photo fermentation, bio photolysis and microbial electrolysis [7]. The photosynthetic bacteria in the wastewater consume organic acids and light energy to generate hydrogen during photo fermentation process. A major limitation of this fermentation process is excess energy demand, removal of ammonia, photobioreactor size and minimum light conversion efficiency affects the hydrogen yield. Bio- Photolysis process make use of green algae and cyanobacteria which may absorb light energy in direct and indirect way and deplete the water molecules through electron transfer. This in turn enhances the hydrogen generation and oxygen. But, the efficiency of the light energy conversion is very less and restricts the hydrogen generation by inhibiting the enzyme hydrogenease and nitrogenase due to oxygen availability. During microbial electrolysis, the volatile fatty acids (VFA) of wastewater was depleted in low voltage and utilized by the acidophilic microbes which liberates the electrons/protons to produce hydrogen. But, co-generation of VFA and alcohol limits the hydrogen yield during this process. This issues was conquered by integrating the process i.e., two-step process such as photofermentation and microbial electrolysis method. This integrated approach effectively enriches the hydrogen yield but consumes high energy. The dark fermentation process was a highly adopted and efficient method [8] which was carried out by fermentative bacteria. This process consumes various carbon sources in the absence of any external light source to produce hydrogen. The usage of raw industrial wastewater for hydrogen production can be a high energy-intensive and low yield process [9]. Since raw industrial wastewater consists of complex and recalcitrant biodegradable compounds that hinders the hydrogen yield and specific hydrogen production rate. Hence to enrich the process feasibility and sustainability, pretreatment process such as physical, chemical, biological and mechanical was incorporated as an additional step. The pretreatment process accelerates the hydrogen generation capacity of wastewater [10]. So far, no review paper has been particularly focused on this aspect, thus, the scope of the review is to study various pretreatment process involved in wastewater treatment which aids in enhancing the hydrogen generation, overview of wastewater detailing necessity of pretreatment, strategies and reactor utilized for the H2 generation enhancement and evaluation required for commercialization. Fig. 1 details the brief description of the review.

Section snippets

Overview of wastewater

Most of the human and industrial activities necessitate high amount of water for existence and that leads to the way for enormous wastewater generation. The majority of wastewater was disposed to the environment without treatment due to not strict regulations in many developing countries [11]. It causes a detrimental impact on human health, economic productivity, freshwater resource quality and ecosystem [12]. Source of wastewater generated includes domestic residence, commercial properties,

Pretreatment of wastewater for H2 production

Pretreatment of wastewater was highly preferred to enhance microbial-substrate accessibility and reaction rate. The pretreatment method has the advantage of improving the rate-limiting step thereby augmenting the biohydrogen production performances. There are several pretreatments adopted to improve surface area of wastewater substrate such as physical method - thermal and microwave treatment [15,16], chemical method-alkaline, acidification and Ozone treatment [[17], [18], [19]], mechanical

Cost and energy evaluation of pretreatment process for H2 production during commercialization

In cost and energetic analysis, operational costs namely: energy consumption, chemical consumption and other for pretreatment of wastewater was taken into consideration for calculation. Energy consumption cost is the major parameter determining the profitability of the treatment process which accounts to be 62% of the capital cost required for the treating wastewater. Based on the research report [[70], [71], [72], [73], [74], [75], [76], [77]], the energy consumption of the pretreatment

Limitation and challenges in pretreatment techniques

Even though there are many reports on viable approaches intended for enhancing biohydrogen production, an intense rise in commercialization that remains almost unachievable. This is mainly due to the long-lasting gap among the researchers and engineers [82]. Hence, this issue necessitates the researcher to procure the perspective of field application towards an economic output that could readily operable by industry. Researchers adopted different pretreatment approaches for biohydrogen

Key issues and future perspectives

Key issues affecting the hydrogen economy were grouped into four components (1) feedstocks preparation for the smooth and efficient treatment process, (2) suitable selection of pretreatment process for hydrogen enhancement, (3) contaminants exist in hydrogen generation need to be purified by downstream processing, and (4) uniform hydrogen supply and appropriate storage. To achieve clean hydrogen, proper monitoring in the above four components was required. The implementation of suitable

Conclusion

The study details the review of the extensive literature on wastewater pretreatment on the features involved in enhancing biohydrogen generation. The study also revealed the efficiency of various pretreatment agents in enhancing hydrogen generation. However, numerous pretreatment techniques have been extensively studied, but lack of concord in opting universally appropriate method. This necessitates lots of research in the future. Variation in metabolic pathways and microbial distribution

Acknowledgment

The authors acknowledge the National Research Foundation of Korea (NRF) grant funded by the Korea Government (Ministry of Science and ICT, NRF-2019M3E6A1103839).

References (90)

  • L. Ozkan et al.

    Effects of pretreatment methods on solubilization of beet-pulp and bio-hydrogen production yield

    Int J Hydrogen Energy

    (2011)
  • F. Battista et al.

    Selection of the best pretreatment for hydrogen and bioethanol production from olive oil waste products

    Renew Energy

    (2016)
  • B. Ramprakash et al.

    Comparative study on the performance of various pretreatment and hydrolysis methods for the production of biohydrogen using Enterobacter aerogenes RM 08 from rice mill wastewater

    Int J hydrogen energy

    (2015)
  • A. Cesaro et al.

    Pretreatment methods to improve anaerobic biodegradability of organic municipal solid waste fractions

    Chem Eng J

    (2014)
  • S. Chang et al.

    Evaluation of different pretreatment methods for preparing hydrogen-producing seed inocula from waste activated sludge

    Renew Energy

    (2011)
  • P. Pagliaccia et al.

    Single stage anaerobic bioconversion of food waste in mono and co-digestion with olive husks: impact of thermal pretreatment on hydrogen and methane production

    Int J Hydrogen Energy

    (2016)
  • F. Battista et al.

    Selection of the best pretreatment for hydrogen and bioethanol production from olive oil waste products

    Renew Energy

    (2016)
  • D. Rorke et al.

    Biohydrogen process development on waste sorghum (Sorghum bicolor) leaves: optimization of saccharification, hydrogen production and preliminary scale up

    Int J Hydrogen Energy

    (2016)
  • Z. Wang et al.

    Pretreatment of vinegar residue and anaerobic sludge for enhanced hydrogen and methane production in the two-stage anaerobic system

    Int J Hydrogen Energy

    (2015)
  • S.S. Yang et al.

    Simultaneous waste activated sludge disintegration and biological hydrogen production using an ozone/ultrasound pretreatment

    Bioresour Technol

    (2012)
  • N. Pisutpaisal et al.

    Improvement of mesophilic biohydrogen production from palm oil mill effluent using ozonation process

    Energy Procedia

    (2014)
  • E. Elbeshbishy et al.

    Enhancement of biohydrogen producing using ultrasonication

    Int J Hydrogen Energy

    (2010)
  • Y.B. Wang et al.

    Effects of pretreatment of natural bacterial source and raw material on fermentative biohydrogen production

    Int J Hydrogen Energy

    (2012)
  • T. Yusaf et al.

    Alternative methods of micro organis disruption for agricultural applications

    Appl Energy

    (2014)
  • S. Kavitha et al.

    Accelerating the sludge disintegration potential of a novel bacterial strain Planococcus jake 01 by CaCl2 induced deflocculation

    Bioresour Technol

    (2015)
  • K. Tamilarasan et al.

    Synergistic impact of sonic - tenside on biomass disintegration potential: acidogenic and methane potential studies, kinetics and cost analytics

    Bioresour Technol

    (2018)
  • S. Kavitha et al.

    Impact of thermo – chemo – sonic pretreatment in solubilizing waste activated sludge for biogas production: energetic analysis and economic assessment

    Bioresour Technol

    (2016)
  • P.M. Budiman et al.

    Ultrasonication pre-treatment of combined effluents from palm oil, pulp and paper mills for improving photo fermentative biohydrogen production

    Energy Convers Manage

    (2016)
  • J.X.W. Hay et al.

    Improved biohydrogen production and treatment of pulp and paper mill effluent through ultrasonication pretreatment of wastewater

    Energy Convers Manag

    (2015)
  • E.P. Leano et al.

    Effects of pretreatment methods on cassava wastewater for biohydrogen production optimization

    Renew Energy

    (2012)
  • M.A.Z. Bundhoo et al.

    Effects of pre-treatment technologies on dark fermentative biohydrogen production: a review

    J Environ Manag

    (2015)
  • S. Kavitha et al.

    Effect of NaCl induced floc disruption on biological disintegration of sludge for enhanced biogas production

    Bioresour Technol

    (2015)
  • U. Ushani et al.

    Sodium thiosulphate induced immobilized bacterial disintegration of sludge: an energy efficient and cost effective platform for sludge management and biomethanation

    Bioresour Technol

    (2018)
  • X.Y. Cheng et al.

    Fungal pretreatment enhances hydrogen production via thermophilic fermentation of cornstalk

    Appl Energy

    (2012)
  • S.H. Chen et al.

    Biosorption and biodegradation potential of triphenylmethane dyes by newly discovered Penicillium simplicissimum isolated from indoor wastewater sample

    IntBiodeterior Biodegradation

    (2015)
  • S.H. Chen et al.

    Bio decolorization and biodegradation potential of recalcitrant triphenylmethane dyes by Coriolopsis sp. isolated from compost

    J Environ Manage

    (2015)
  • J. Liu et al.

    Fungal pretreatment of raw digested piggery waste water enhancing the survival of algae as biofuel feedstock

    Bioresour Bioprocess

    (2017)
  • L. Zhao et al.

    Fungal pretreatment of cornstalk with Phanerochaete chrysosporium for enhancing enzymatic saccharification and hydrogen production

    Bioresour Technol

    (2012)
  • R. Lakshmidevi et al.

    Enzymatic saccharification and fermentation of paper and pulp industry effluent for biohydrogen production

    Int J Hydrogen Energy

    (2010)
  • V. Golob et al.

    Efficiency of the coagulation/flocculation method for the treatment of dyebath effluents

    Dyes Pigments

    (2005)
  • Y.H. Seo et al.

    Pretreatment of cheese whey for hydrogen production using a simple hydrodynamic cavitation system under alkaline condition

    Fuel

    (2015)
  • E. Eroglu et al.

    Microalgal hydrogen production research

    Int J Hydrogen Energy

    (2016)
  • J. Wang et al.

    Fermentative hydrogen production using various biomass-based materials as feedstock

    Renew Sustain Energy Rev

    (2018)
  • D.H. Kim et al.

    Experience of apilot-scale hydrogen producing anaerobic sequencing batch reactor (ASBR) treating food waste

    Int J Hydrogen Energy

    (2010)
  • A.P. Eswari et al.

    H2O2 induced cost effective microwave disintegration of dairy waste activated sludge in acidic environment for efficient biomethane generation

    Bioresour Technol

    (2017)
  • Cited by (36)

    View all citing articles on Scopus
    View full text