Biotreatment of Industrial Waste Water in Petroleum Industry - Coursework Example

Author’s Affiliation:

E-mail:

Abstract

The main theme of this paper was to provide a detailed understanding of the biotechnology that became popular to treat wastewaters with special reference to the petroleum industry. Thus, this paper entailed primarily a brief understanding of the industrial wastewaters, the historical evidence of its treatment through biotechnology and the growing importance of bio-treatment of the petroleum industry’s wastewaters in the recent years. Thereafter, conclusions were drawn along with certain recommendations to increase its implementations in the near future.

Keywords: industrial wastewaters, biological treatment, petroleum industry.

1. Introduction

In general, wastewater has been generating from two main sources, one being the human sewage and the other source being the manufacturing industry that is through its method of processing. These waste materials if untreated and directly discharged in the water can create waste-borne diseases and pollution in the environment. In order to treat, especially the industrial wastewaters, biological treatment method was introduced in the twentieth century and from then, it has become one of the popular types of treatment of wastewaters in the world. This biological basis of treatment involved bacteria which naturally occur to be confined in the tanks at a high concentration involving biological mechanism. These bacteria are put together with microbes and protozoa to make the activated sludge. Thereafter, the bacteria become active and start removing the carbon molecules in the wastewaters which can hence, be disposed of in the sea or river without posing any harm. However, depending upon the quality, costs, level of mechanization and operations, the treatment processes may vary accordingly [1]; [2]. Thus, the objective of this paper is to critically evaluate the biological treatment processes and discuss this type of industrial wastewater treatment particularly focusing on the petroleum industry.

2. Industrial Wastewaters

Industrial wastewaters in general terms were the toxic effluents that resulted in the activities of humans in the process of manufacturing and raw-material processing in the industries. These wastewaters if left untreated can cause water pollution and correspondingly raise various issues, problems, and water-borne diseases. Thus, industrial wastes comprise chemical, electrochemical, petrochemical, pharmaceuticals and chemicals from food processing [3]. These wastes, if present in the form of water being termed as ‘industrial wastewaters’ wherein it was noted that in certain instances it contained an alarming amount of grease and oil content and some components were highly toxic in nature. Not only the disposal of wastewaters into the receiving water bodies had physical effects such as water quality and clarity, it also had other major effects. Hence, to be precise, pilot-scale wetland system can also be implemented for the treatment of these pollutants, especially with the usage of the biochemical processes [4].

These included increased levels of oxidation, inhibition of toxic chemicals, eutrophication (increased discharge of nitrogen and phosphorus in the water bodies) as well as the creation of pathogens, increasing the disease-causing organisms, which were highly infectious in nature. Thus, the main pollutants that resulted in such wastewaters from industries were organic pollutants. However, the model pollutants that were considered included carboxylic acids, phenolics, and compounds containing nitrogen [5]. It can further be noted that the wastewaters were produced from continuous treatment through oil-degrading bacterium in an oilfield. Moreover, with the usage of immobilized cells, the chemical oxygen demand (COD) can be reduced along with the reuse of these cells, in order to treat oily wastewaters [6].

3. Biological Treatment of Industrial Wastewaters

Industrial wastewaters were different from the sewage disposals because of their compositions and discharge patterns. However, various industrial treatment plants utilized the biological process for the treatment of sewage treatment plants. The concept of biological treatment is simple but its control is highly complex in nature. This complexity is increased with the incorporation of variables, which can affect the entire treatment process. The possibilities of variables that can be involved were changed in the bacterial flora compositions in the treatment tanks and hence the sewage passage process in the plant can also vary. There was also another possibility that the plants that have been assigned to the biological treatment can be overburdened because of the presence of various harmful chemicals. If the concentration of these recalcitrant chemicals were high, the treatment process needs to be slowed down. If those chemicals were highly toxic, the bacteria can be killed and unknowingly the manufacturing unit may dispose of their wastewaters and untreated effluents directly into the natural environment. All these possibilities must be kept in mind and regular checks must be made so that dead bacteria can be removed and replaced with new seeds in the tanks. Hence, it can be implied that it is important to have a regular check on the compositions of the toxic effluents in the wastewaters and its disposal in the water bodies. Hence, in the global context, the effluent’s composition that can be discharged into the water bodies has been regulated by the agencies of the national environment [2]; [7].

Corresponding to the biological treatments, there were various methods that were utilized in the past years. Among all the methods and techniques used, some of them have been discussed herein such as Membrane Bioreactor, Bimetallic Zero-Valent Iron, and anaerobic-aerobic treatment. In order to upgrade the treatment processes and make it efficient and optimally effective, there was the adoption of various biotreatment methods by evaluating the practical possibilities. Based on the Membrane Bioreactor (MBR) technology, the operation of aerobic treatment was facilitated in three different types of industries namely, paper mill, food production plant and port fuel production plant. This step was undertaken only after the treatment plants were facing difficulties in separating bio-solid waste and biological sludge. It was also reported that with the usage of MBR treatment for the petrochemical wastewater, its efficiency was high and the removal of 85% of toxic chemicals was also noted. Hence, the usage of MBR increased micro-organisms’ removal with greater efficiency and the removal of chlorinated aromatics. Along with these efficiencies, the enzymes used for degrading cellulose, grease, and oil was also prominent with this method. With such implementation, it was observed that wastewater containing effluents that had hydrophobicity and lower bio-degradability could also be successfully treated with this method. It was also suggested that with the usage of MBR operations, these types of industries should use the lower time for cell residence and mixed liquor volatile suspended solids (MLVSS) in their bioreactors. Besides, industries should accordingly increase the number of biosolids [8]; [9].

Similarly, according to Sharghi & Bonakdarpour [10], the MBR treatment can be regarded as more efficient for the removal of organic waste materials. At the time of high concentration of pollutants in the waste waters, the most feasible technique turned out to be the anaerobic processes, which could convert organic pollutants into smaller molecules. Thus, especially in the petroleum industry, it showed a high level of feasibility, when used with micro-electrolysis for the treatment of wastewaters produced from oilfields [11]. Similarly, according to Shpiner, Liu, Stuckey [12], it was treated with the usage of ‘waste stabilization ponds’ which in simple terms facilitated the biodegradation of waste materials that was petroleum driven along with the materials such as heavy metal removal [12]; [13].

With the passage of time, there were various innovative techniques used such as Zero-Valent Iron (ZVI) in North America. This technique was used to enhance the biotreatment of the industrial wastewaters as it was mainly used to reduce chlorinated compounds, which were organic in nature. Hence, considering its efficiency, it was incorporated in the biological treatment processes wherein the ZVI reactors were connected to the treatment plants. The positive results of this incorporation made this process popular, as a result of which the settling characteristics of the effluents increased to a large extent. Therefore, it was further incorporated in various other industries such as textile industries, paper and printing industries, petrochemical refineries and iron and steel industry. Hence, this process design in the treatment plant resulted in the optimization of system performance and potential investment as well as regulatory risks [9].

Another such prominently employed treatment system was anaerobic-aerobic treatment, by which both the municipal and industrial wastewaters were treated. This was also upgraded and accordingly, high rate of anaerobic-aerobic bioreactors was utilized, wherein high COD was to be treated. Hence, this integration of aerobic as well as anaerobic degradation process in a bioreactor had the capability to enhance the degradation efficiency of the entire wastewater. Another such efficient method that was used comprised continuous biodegradation with the help of packed-bed bioreactor which was as efficient as the other methods. Therefore, utilizing integrated methods in a single bioreactor was further incorporated with a stacked configuration which proved to be immensely advantageous for the treatment of highly concentrated wastewaters. It required minimal space and even incurred a lower capital cost, thereby enhancing the removal of COD efficiently. Similar was the effect of anaerobic baffled reactors while treating oily wastewaters contained higher amount of pollutants [14]; [15]; [16]. Considering the biological treatment and the components of pollutants, Natural Rubber Waste Serum (NRWS) can be considered as one of the major pollutants generated from rubber industries [17]. Particularly referring to the context of Greece, there was a study upon the quality of surface water and it was found that ‘anthropogenic-toxic’ materials such as Zinc (Zn) were found generating from industrial effluents and metal activities [18].

4. Specific Reference to its Implications in the Petroleum Industry

The petroleum industry has been utilizing all these treatment plants and techniques for years because of its nature of production. Since petroleum industry is the part and parcel of the oil and gas sector, a major challenge that it has been facing was the contamination of various water bodies. The wastewater generated from the industries of the oil and gas resulted in one of the largest waste rivers. Hence, to reduce its harmful effects on the environment as well as the living beings, it can be suggested that one of the cost-effective methods i.e., biological pretreatment is used for treating the oil wastewater [19].

It was also reported that water-oil emulsions occurred through the activities of petroleum industries, for which the most effective treatment method was observed to be the use of chemical and physical treatment. These processes efficiently broke the emulsions of water and oil with the usage of the de-emulsifying bacterium [20].

These contaminations were caused due to the exposure of various hazardous and oily fluids as well as radioactive elements, which must be carefully treated, handled and disposed of. With further research, it was evident that the untreated disposal of petroleum pipes created external and internal radiations especially amid the workers and therefore, strict measures and efficient treatment processes must be taken into consideration to eliminate the hazardous impact of untreated petroleum wastewaters [21]. According to Helmy & Kardena [22], the wastes generated in Indonesia included various pollutants such as hydrocarbons, chemicals, biocides, heavy metals and the like. This was studied according to the six stages, which included seismic survey (S), exploratory drilling (D), construction (C), production (P), maintenance (M) and abandonment (A) The results can be better illustrated by the following table.

Table 1: Common wastes in exploration (E) and production (P) operations

Source: [22].

Instances of 2014. A significant amount of crude oil is said to have been trapped in the petroleum reservoirs, which was unrecoverable with the use of conventional methods. In particular, the industry was facing challenges while removing various materials from the crude oil such as metal, nitrogen, sulfur and organic compounds. To curb this problem, secondary recovery methods were used such as gas and water injections in order to increase productivity. However, to remove inorganic toxins, various physical and chemical refinery processes were used such as hydro-desulfurization, hydro-treatment with high temperature and high pressure as well as desalting. However, with the increasing standards and demand for petroleum products, the environmental laws were more strictly implemented due to its harmful effects. Therefore, the petroleum production companies were forced to increase their efficiency in removing the effluents and reduce the concentration of sulfur, nitrogen, and metal to the lowest possible ppm level. Thereafter, the usage of Microbial Enhanced Oil Recovery (MEOR) increased, which was an alternative method of recovery of such materials and utilized micro-organisms as well as their metabolic products. In the process of implementing this method, there were various challenges which must be taken into account to attain success in a commercial manner. Furthermore, it was found that after its implementation, either it was used as a supplement for physicochemical processes or was fully supplemented. However, the complexity that remained in an individual project varied with the level of its usage and success [23].

Instances of 2015. In case of Indonesia, there was growing concern about the increase in demand of petroleum products and energy consumption. As a result of which the exploitation and production also were seen to increase, which in turn created varied environmental accidents. In the environmental concerns, the petroleum industry activities were the result of oil spills, an increase of residue from waste disposal plant and cleaning activities as well as materials released from leakage. All these accidents can create great harm to the environment as well as the health and safety of human beings. However, some of the companies used bioremediation, which was one of the cost-effective technologies to treat different environmental problems. It was also noted that ‘oily sludge management’ was the common method that used biological agents for the treatment, which was environment-friendly in nature. This usage of microbes to degrade petroleum hydrocarbons was also known as bioremediation. Therefore, treating these waste materials so that harmful materials will not get exposed to the water bodies has become the latest concern. On an overall basis, it was noted that there was a lack of infrastructure and low level of waste management done that restricted the disposal bio-treatment options in the Indonesia. Thus, there were certain parameters, based upon which the standard of the water quality was established to control the wastewater contamination of petroleum industries that were terminal based. It has been illustrated below in the form of a table [22].

Table 2: Parameters for Maintaining the Standards

Sources: [22]

Instances of 2017. More evidence of such implementation was seen in the recent scenario wherein, there were developments observed for the application of the technology, in which Sequencing Batch Reactor (SBR) was used. According to Jafarinejad [23] the process in the wastewater treatment of oily materials must comprise four general processes namely pretreatment, primary, secondary and tertiary treatments (also called polishing). It was further observed that the biological treatment method was highly challenging as per the type of industry and the inclusion of complex chemicals that needed to be treated. These challenges were prominent due to the level of toxicity and inhibition of the complex compounds in the process of serving as microbial substrates. However, the usage of SBR technology was incorporated for better successful endeavors related to the treatment process. It was further observed that this method promoted the mineralization of wastewaters which contained toxic components. Moreover, it was widely used for removing dissolved oil from the wastewaters, and therefore, the companies should adopt this technology considering various factors. These factors include its economic feasibility, appropriate design, the rate of sludge generation, site applicability as well as regulatory requirements to possess an optimum utilization of this technology. Hence, it was further suggested that understanding the basic principles and modifying this technology would be highly beneficial for the industry. However, limited application of SBR system was observed in the petroleum industry thus with more research and upgradation, and this method can be best suited for the wastewater treatment [23].

Putting the further light on the oily wastewater treatment, Yu, Han & He [24] stated that petroleum refineries unavoidably generated a huge amount of oily wastewaters. The current challenge that the world is facing because of the activities of this industry was the oily wastewaters disposal in the environment, which had adverse effects on nature and the living beings. Therefore, there were greater concerns for its treatment because it has become an alarming issue, which must be explored and proper solutions must be generated so that each and every refinery and Petroleum Company can use them. Hence, the development status of the methods of such treatment was properly studied and examined from various aspects namely, flotation, biological treatment, coagulation, combined technology, technology for membrane separation and the advanced process of oxidation. Thereafter, conclusions were drawn that advancements were efficient enough to treat the effluents but were not according to the increasing environment requirements. Hence, more research and further improvements were necessary to a large extent for effective and efficient bio-treatment methods especially for the petroleum industry [24]; [25].

Conclusion and Future Recommendations

On an overall basis, it can be concluded that with continuous improvements in the existing treatment methods, the quality and efficiency of the treatment of effluents can be improved in compliance with the current regulations and requirements concerning people and the environment as a whole. Hence, for more improvements, it can be recommended that optimization of research and development of processes should be encouraged for avoiding their limitations. Furthermore, the in-depth study would be necessary on the mechanism for the degradation of oily wastewaters, thereby increasing the efficiency and reducing processing costs. Therefore, to develop an environment-friendly approach, secondary pollution must be avoided considering automatic control over the rate of wastewater treatment, in turn bringing about a prominent increase in the potential for future developments.