Treatment Of High-strength Wastewater Research Articles

Treatment of high-strength saline bilge wastewater by four pilot-scale aerobic moving bed biofilm reactors and comparison of the microbial communities

ABSTRACT Four Pilot-scale Moving Bed Biofilm Reactors (MBBRs) were operated for the treatment of real, saline, bilge wastewater. The MBBRs were connected in pairs to create two system configurations with different filling ratios (20%, 40%) and were operated in parallel. The inflow organic loading rate (OLR) varied from 3.6 ± 0.2 to 7.8 ± 0.6 g COD L−1 d−1, salinity was >15 ppt and three hydraulic residence times (HRTs) were tested 48, 30 and 24 h. In both systems, the first-stage bioreactors (R1 and R3) eliminated the higher part of the organic load (57%–65%). The second-stage bioreactors (R2 and R4) removed an additional fraction (18%–31%) of the organic load received by the effluent of R1 and R3, respectively. The microbial communities of the influent wastewater, suspended, and attached biomass were determined using 16S rRNA gene amplicon sequencing analysis. The evolution of the microbial communities was investigated and compared over the different operational phases. The microbial communities of the biofilm presented higher diversity and greater stability in composition over time, while the suspended biomass exhibited intense and rapid changes in the dominance of genera. Proteobacteria, Bacteroidetes and Firmicutes were highly present in the biofilm. The genera Celeribacter, Novispirillum, Roseovarius (class: Alphaproteobacteria) and Formosa (class: Flavobacteriia) were highly present during all operational phases. Principal Component Analysis (PCA) was used to identify similarities between samples, exhibiting high relation of samples according to the series of the bioreactor (1st, 2nd).

Application of a membrane-less air cathode microbial fuel cell to treat municipal waste composting leachate

The adverse effects of high strength wastewaters on the microbial activities have created a challenge to biological treatments. Microbial fuel cell has been considered as a promising process because the electrical potential generation can stimulate microorganisms and overcome the inhibitory effect. However, several issues (e.g., scalability, high costs and maintenance) have prevented the process from the industrial applications. Elimination of the proton exchange membrane has been suggested as a remedy to the mentioned problems. In this work, a membrane-less microbial fuel cell was modified by putting the cathode within a thin sand layer (instead of the proton exchange membrane) to treat a high strength wastewater sample. The influences of the feed organic load and time of treatment in the modified system were studied in batch and continuous operations. It was revealed that the batch operation efficiency was higher for the lower feed loadings as a 5-day batch treatment removed 66 ± 4% of the 15,000 ± 500 mg/L initial chemical oxygen demand while the continuous process efficiency with 9-day hydraulic residence time was slightly more than 50%. However, the efficiency of the continuous operation for treatment of higher initial loading values was better than the batch mode with the removal efficiency of 41 ± 2% versus 12 ± 2% for a more concentrated leachate feed (45,000 ± 1000 mg/L). Finally, it was disclosed that the modified membrane-less MFC employed in this work can be effective in treatment of high strength wastewaters in larger scales with lower costs.

Enhanced biohydrogen production in a membraneless single-chamber microbial electrolysis cell during high-strength wastewater treatment: Effect of electrode materials and configurations

The selection of better electrode material and studies of the electrocatalytic activities of the electrodes are crucial to increasing biohydrogen production in a microbial electrolysis cells (MEC). In the present work, we studied biohydrogen production and electrocatalytic activities using a membraneless single-chamber MEC fed with high-strength wastewater, using different electrode materials (metal and carbon electrode), configurations and electrode distance. The electro-fermentation (EF) process showed a significantly higher biohydrogen production and COD removal, compared to conventional dark fermentation reactor (DF). The maximum hydrogen production rate (HPR) obtained was 314 m3 H2/m3R.d with an overall biohydrogen recovery (rH2) of 340% using the electrode configuration stainless steel 304 pleated mesh 60 as anode and stainless steel 304 flat mesh 60 as cathode at 4 cm of electrode distance. The onset potential for the hydrogen evolution reaction (HER) with metal electrode was significantly lower than carbon electrode.

Anaerobic membrane bioreactor for carbon-neutral treatment of industrial wastewater containing N, N-dimethylformamide: Evaluation of electricity, bio-energy production and carbon emission

The feasibility of anaerobic membrane bioreactor (AnMBR) for the treatment of N, N-dimethylformamide (DMF)-containing wastewater was theoretically compared with the conventional activated sludge (CAS) process in this study. The electricity consumption and expenditure, bio-energy production and CO2 emission were investigated using the operational results of a lab-scale AnMBR operated in a long-term operation. The AnMBR was capable of producing bio-methane from wastewater and generated 3.45 kWh/m3 of electricity as recovered bio-energy while the CAS just generated 1.17 kWh/m3 of electricity from the post-treatment of excessive sludge disposal. The large quantity of bio-methane recovered by the AnMBR can also be sold as sustainable bioresource for the use of household natural gas with a theoretical profit gain of 29,821 US$/year, while that of the CAS was unprofitable. The AnMBR was also demonstrated to significantly reduce the carbon emission by obtaining a theoretical negative CO2 production of −2.34 kg CO2/m3 with the recycle of bio-energy while that for the CAS was 4.50 kg CO2/m3. The results of this study demonstrate that the AnMBR process has promising potential for the carbon-neutral treatment of high-strength DMF-containing wastewater in the future.

Nitrification resistance and functional redundancy maintain the system stability of partial nitrification in high-strength ammonium wastewater system

The sudden change of ammonia loading in high-strength ammonium wastewater treatment can directly affect the system stability by altering microbial community dynamics. To maintain the system stability, the effects of ammonia shock loading on microbial community dynamics must be studied. Two sets of sequencing batch reactors were operated with 6 shock cycles (maximum volumetric loading rate of 1928 mg N/(L·d)). CN system contained both organic carbon and ammonia and N system contained only ammonia. Comparing with N system, CN system operated more stably and had higher nitrite accumulation rate. Free ammonia (FA) was the select stress for the turnover of CN microbial communities, while the N communities didn t shift much. The increase of Nitrosomonas and the appearance of heterotrophic nitrification-aerobic denitrification bacteria in CN system presented its resistance and redundancy against FA impact, while the increase of functional genes exhibited functional genes redundancy which maintained the system stability.

Simultaneous methanogenesis and denitrification coupled with nitrifying biofilm for high-strength wastewater treatment: Performance and microbial mechanisms

A combined system consisting of an upflow blanket filter (UBF) and a moving-bed biofilm reactor (MBBR) was developed for the simultaneous removal of organic matters and ammonia from high-strength wastewater. With a constant COD of approximately 2000 mg/L and ammonium nitrogen in a series of concentrations (e.g., 50, 200 and 400 mg/L in stages I to III) of the influent wastewater, the removal efficiencies of COD, ammonium nitrogen and total nitrogen reached 96.10%-98.19%, 100%, and 79.12%-82.15%, respectively. With the increase of influent ammonia nitrogen concentration, the specific methanogenic activity of the UBF granules decreased significantly, while the specific denitrification rates of the UBF granules and specific nitrification rates of the MBBR biofilms increased significantly. Microbial community analysis showed that Methanobacterium and Methanosaeta were the dominant methanogens in the UBF granules, while Candidatus Competibacter, Thauera and Acinetobacter were identified as dominant denitrifiers. In addition, nitrifiers were enriched in MBBR biofilms at 11.33% and 13.87% of the average abundance of Nitrosomonas and Nitrospira, respectively, at stage III (influent ammonium at 400 mg/L, COD/NH4+-N = 5). The ecological network analysis, including full-networks and sub-networks, indicated that the interactions between methanogens and denitrifiers in the UBF granules were strong when the influent ammonium concentration reached 400 mg/L. No intensive interactions were observed among the functional bacteria in the MBBR biofilms over the entire operation. Overall, this study provides a new strategy for the application and construction of efficient biological processes to achieve simultaneous removal of organic matter and nitrogen for high-strength wastewater treatment.

High robustness of attached Chlorella sp. on semi-continuous low strength effluent polishing under axenic and xenic conditions

Chlorella is widely applied in various wastewater streams of different strengths. Utilization of attached Chlorella biofilm for satisfactory high strength wastewater treatment have been frequently reported, yet the performance of Chlorella biofilm for low strength effluent polishing is still ambiguous. This study first explored the preference of relatively low concentrations of nitrogen sources by attached Chlorella sp. under batch cultivation, then compared the growth and nutrients removal of the biofilm under axenic and xenic conditions in semi-continuous mode, i.e. running the attached system at hydraulic retention time of 2 days and biomass harvest interval of 4 days, treating synthetic effluent with 15 mg/L NO3−-N as the sole nitrogen pollutant representing the nitrogen profile of municipal secondary effluent. Results showed that NO3−-N and NH4+-N were preferred over others under batch cultivation, with up to 99.2 % N removed from the synthetic effluent. EPS content and particularly EPS polysaccharides content were highly significantly correlated to Chlorella sp. biofilm growth, with EPS polysaccharides to protein ratio being >1.8 when fed with NO3−-N in batch culture. Throughout the 48-day semi-continuous operation, because of the high robustness of attached Chlorella sp. biofilm, the biomass harvest rate, EPS content, biomass composition, and nutrients removal were similar under axenic and xenic conditions, yielding 1.2–1.6 g/m2/d attached biomass, >73 % nitrogen removal and > 90 % phosphorus removal. A new finding of three-fold extracellular protein content increase was observed under semi-continuous operation comparing with batch culture, leading to mostly <1.0 EPS polysaccharides to protein ratios, while intracellular lipid content significantly reduced (from 20.8 to 23.8 % to 13.6–17.0 %). Overall, results of this study suggested that biofilm of the ubiquitous Chlorella sp. biofilm could be applied not only for nutrients rich wastewater treatment, but also for advanced nutrients removal from low strength effluent under xenic conditions.

Erratum for “Integrated Approach to Treatment of High-Strength Organic Wastewater by Using Anaerobic Rotating Biological Contactor” by Milad Ebrahimi, Hamidreza Kazemi, S. A. Mirbagheri, and Thomas D. Rockaway

Erratum for “Integrated Approach to Treatment of High-Strength Organic Wastewater by Using Anaerobic Rotating Biological Contactor” by Milad Ebrahimi, Hamidreza Kazemi, S. A. Mirbagheri, and Thomas D. Rockaway

Numerical Analysis of a Full-Scale Thermophilic Biological System and Investigation of Nitrate and Ammonia Fates

Thermophilic biological processes proved to be effective in aqueous waste (AW) and high-strength wastewater treatment. In this work, the monitoring of a full-scale aerobic thermophilic biological plant treating various high-strength AW in continuous mode is reported. This paper aims to: (i) provide models to help the AW utility manager in predicting the load of fed pollutants and performances, and (ii) fully investigate nitrogen transformations in biological reactor. Based on the results, the thermophilic sludge in the studied plant was able to degrade Chemical Oxygen Demand (COD) and remove nitrate nitrogen with very high efficiency (79.3% and 97.1, respectively). The monitoring was conducted following a statistical approach and searched for the possible correlations between the input parameters and the efficiency of removal of the plant. Moreover, a multivariate linear regression was carried out highlighting that the yield value of the removal of COD and nitrogen forms, apart from ammonia, was well explained (R2 = 0.9) by the linear regression against the other monitored parameters. As far as nitrification is concerned, there was, on the one hand, an increase in ammonium ions due to the hydrolysis of the organic substance that occurs in the reactor, and on the other hand, a stripping of the same ammoniacal nitrogen in the form of NH3. While nitrates were effectively removed, according to fluorescent in situ hybridization tests, sludge proved to be formed by minute flocs, where bacteria responsible for the oxidation of ammonium and nitrite seem to be unable to grow.

A review of modified and hybrid anaerobic baffled reactors for industrial wastewater treatment

This review discusses high-strength wastewater treatment using anaerobic baffled reactors (ABRs) and modified ABRs. The research findings and applications of ABRs in treating various types of high strength wastewater generated from food companies, livestock, and industries were summarized and reported. Measurement parameters affecting the performance of ABRs are briefly discussed. The state-of-the-art laboratory studies are compiled and critically reviewed. Critical challenges and suggestions for future investigation are also addressed.

Simultaneous production of hydrogen-methane and spatial community succession in an anaerobic baffled reactor treating corn starch processing wastewater

Corn starch processing wastewater (CSPW) is a high-strength organic wastewater and biological treatment is considered as the dominant process. The present work investigated the effects of pH on the bioenergy production and spatial succession of microbial community in an anaerobic baffled reactor (ABR) treating CSPW. The results showed that above 90.5% of COD removal and above 16.6 L d−1 of methane were achieved at the influent pHs of 8.0 and 7.0 under organic loading rate of 4.0 kg COD·m−3·L−1 condition. Further decreasing the influent pH to 6.0 resulted in the COD removal decreased to 89.7%. Besides, 9.2 L d−1 of hydrogen and 13.0 L d−1 of methane were obtained. There was significant difference in the volatile fatty acids profiles during the variation of pH. Illumina Miseq sequencing showed that Clostridium, Ethanoligenens, Megasphaera, Prevotella and Trichococcus with relative abundance of 2.1%∼28.1% were the dominant hydrogen-producing bacteria in C1. Methanogens (Methanothrix and Methanobacterium) dominated in the last three compartments. Function predicted analysis revealed that the abundance of metabolic-related gene families containing carbohydrate, amino acids and energy in the last three compartments were higher than that in C1. A deduced biodegradation model of CSPW in ABR revealed that the anaerobic sludge in C1 mainly produced hydrogen. Microbial population in C3 was responsible for COD removal and methane production. The redundancy analysis revealed that hydrogen production was highly correlated with some hydrogen-producing bacteria in C1, whereas methane production was positively correlated with microbial group in C2∼ C4.

Synergistic effect of activated charcoal and chitosan on treatment of dairy wastewaters

This research investigated the feasibility of using hybrid system based on coagulation and adsorption for high-strength dairy wastewater treatment. Activated charcoal was used a non-toxic adsorbent and chitosan as a natural coagulant for the removal of odor, chemical oxygen demand (COD), total nitrogen (TN), and total phosphorous (TP) from raw dairy effluents. The surface morphology of the adsorbent and coagulant were characterized by scanning electron microscope (SEM). Bench-scale jar test experiments were conducted to evaluate the performance of the integrated treatment system to treat real wastewater with different experimental conditions. Results of the study showed that about 68% and 74% COD was removed by using adsorption and coagulation method respectively. However, a high COD removal efficiency of 90% was achieved, when the coagulation process was coupled with the adsorption process. An in-depth analysis of contaminants present in the dairy effluents after treatment were studied by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The obtained results demonstrated that the organic compound like lipids, carbohydrates and proteins were drastically reduced which in turn lowered the COD level by employing the hybrid treatment system. The above outcomes suggested that combining naturally occurring sorbents and coagulants can greatly enhance the dairy wastewater pre-treatment performance in small scale treatment plants.

Dynamic model of algal-bacterial shortcut nitrogen removal in photo-sequencing batch reactors

This study investigated algal-bacterial shortcut nitrogen removal (SNR) in photo-sequencing batch reactors (PSBRs) for treatment of high ammonium strength wastewater using both experimental and modeling approaches. Bench-scale PSBR studies were carried out under alternating light and dark cycles, provided aerobic and anoxic conditions that promoted nitritation/ denitritation. Total nitrogen removal efficiencies >90% were achieved when favorable operating conditions, including solids retention time (SRT) and organic and inorganic carbon availability, were applied for the functional microorganisms. A dynamic model was developed to simulate conversions of species and the activity of algae, ammonia oxidizing, nitrite oxidizing and heterotrophic bacteria. In addition, biomass wasting during each cycle was estimated by the model to maintain the targeted SRT. The model was able to capture the dynamics of nitrogen removal, substrate utilization and biomass generation under varying operating conditions and can potentially be used for large scale PSBR design and optimization.

Performance intensification of constructed wetland technology: a sustainable solution for treatment of high-strength industrial wastewater.

The objectives of this study were to: (1) assess the intensification of chemical oxygen demand (COD) and phosphate (PO4-P) removal; and (2) generate a set of rate constants of COD degradation (kCOD) and phosphate (kPO4-P) removal for the treatment of industrial wastewater (WW) using intensified adsorption beds. Two horizontal subsurface flow constructed wetlands (HSSFCWs) filled with coal ash and alum sludge and two conventional HSSFCWs packed with gravels were operated with different loadings of COD and PO4-P at a hydraulic retention time (HRT) of 24 hrs at water depth of 0.40 m. The bed performance was analysed for COD and PO4-P removal efficiency. The intensified HSSFCWs outperformed the control beds by a mean COD and PO4-P removal efficiency of 43 and 49%, respectively. The progression of COD and PO4-P removal along the system was fitted into the first-order plug flow model (K-C model). In this study the kCOD values ranged from 0.36 to 0.65 m/d with a mean of 0.46 ± 0.08 m/d (n = 30). The kPO4-P values ranged from 0.74 to 1.76 m/d and averaged to 1.23 ± 0.37 m/d (n = 30), irrespective of the condition applied. Hence, these data can be used for future projects using HSSFCWs to treat industrial wastewater.

Effects of organic carbon and sulfide on the anammox reaction in the anoxic column in the SRDAPN process for treating high-strength wastewater

Low energy consumption treatment of high-strength wastewater is crucial in controlling groundwater pollution and eutrophication in closed waterbodies. In this study, the sulfate reduction, denitrification/anammox, and partial nitrification (SRDAPN) process, which is an effective organic carbon and nitrogen removal process with low energy consumption for low strength wastewater, was applied to treat livestock wastewater with high COD and sulfate concentration, and microbial reaction and community were examined using an anaerobic–anoxic biological filter reactor that simulates circulation from an aerobic reactor. At a total organic carbon loading rate of 2.7–5.8 kgC/m3·day, sulfate reduction and methane production occurred simultaneously in the anaerobic column of the reactor. Specifically, sulfate reduction resulted in organic matter removal rates of 38 and 26% at ambient temperature and 25 °C, respectively. Furthermore, both heterotrophic and autotrophic denitrification occurred in the anoxic column, and when the organic loading rate in the anoxic reactor was below 0.2 kgC/m3·day, 33%–37% of ammonium and 33%–34% of nitrite were removed by the anammox reaction. Heterotrophic denitrification bacteria (Thauera, Comamonas, and Denitratisoma) and sulfur denitrification bacteria (Sulfurimonas denitrificans) grew in the lower and middle parts of the anoxic column, whereas anammox bacteria (2.5% of Candidatus Brocadia at ambient temperature and 9.4% of Candidatus Kuenenia at 25 °C) grew in the upper part of the anoxic column. These results indicate that the SRDAPN process based on sulfur cycle and anammox is useful for treatment of high strength wastewater with low energy consumption.

Predicting membrane fouling in a high solid AnMBR treating OFMSW leachate through a genetic algorithm and the optimization of a BP neural network model

Anaerobic membrane bioreactors are a promising technology in the treatment of high-strength wastewater; however, unpredictable membrane fouling largely limits their scale-up application. This study, therefore, adopted a backpropagation neural network model to predict the membrane filtration performance in a submerged system, which treats leachate from the organic fraction of municipal solid waste. Duration time, water yield flow, influent COD, pH, bulk sludge concentration, and the ratio of ΔTMP to filtration time were selected as input variables to simulate membrane permeability. The membrane pressure slightly increased by 1.1 kPa within 62 days of operation. The results showed that the AnMBR membrane filtration performance was acceptable when treating OFMSW leachate under a flux of 6 L/(m2·h). The model results indicated that the sludge concentration largely determined the membrane fouling with a contribution of 33.8%. Given the local minimization problem in the BP neural network process, a genetic algorithm was introduced to optimize the simulation process, and the relative error of the results was reduced from 5.57% to 3.57%. Conclusively, the artificial neural network could be a useful tool for the prediction of an AnMBR that is so far under development.

Advanced treatment of hydraulic fracturing flowback water using a novel combined process

A novel process was proposed for treating heavily polluted hydraulic fracturing flowback water from oil/gas production with an initial chemical oxygen demand (COD) of 8850 mg/L. The process was comprised of gel breaking, cavitation-impinging stream/iron-carbon micro-electrolysis (CIS/ICME) and electro-Fenton. The viscosity of the wastewater was reduced from 6.20 to 1.09 mPa•s after 90 min of gel breaking treatment using sodium hypochlorite at a dosage of 3.0 g/L. The CIS technology solved the passivation and hardening problems of traditional ICME technology, enhancing COD abatement by 48.2% points and increasing iron utilization from 36.8% to 82.4%. The results show that, under the optimum conditions, the effluent COD was reduced to around 170 mg/L with a removal efficiency of 98.1%, and the reduction ratios of oil, color, corrosion rate and suspended solids reached 100%, 95.2%, 94.0% and 97.7%, respectively. The quality of final effluent could meet the national discharge standard of China. The CIS/ICME process removed a considerable proportion of COD and oil, while the electro-Fenton unit played an important role in post-polish of final effluent. This study shows that the hybrid system has the potential to be applied for the advanced treatment of high-strength oilfield wastewater.

Industrial Wastewater Treatment Efficiency of Mixed Substrate (Pumice and Scoria) in Horizontal Subsurface Flow Constructed Wetland: Comparative Experimental Study Design

The discharge of untreated wastewater causes serious public and environmental health problems. Hence, the present study aimed to evaluate the combined adsorption potential of the two substrates (Pumice and Scoria) in a horizontal subsurface flow constructed wetland. The substrates were collected from the Ethiopian rift belt. Composite samples from tannery wastewater before and after treatment of four different retention times (RT) were collected and analyzed. Chrysopogon zizanioides was planted in one of the mixed substrate beds and grown for 5 months before running wastewater for the treatment. The maximum removal efficiency of the planted bed revealed that BOD5 at RT 7 days effluent concentration of 59.33 mg/L (96.38% removal), COD at RT 7 days 129.33 mg/L (98.14% removal), NO3-N at RT 7 days 0.28 mg/L (99.76% removal), TN 27.33 mg/L (95.80% removal), PO4-P RT 9 days 0.01 mg/L (99.9% removal), TP at RT 7 days 6 mg/L (95% removal), Sulfide at RT 7 days 0.27 mg/L (99.9% removal), sulfate at RT 9 days 87.9 mg/L (91.8% removal), and total Chromium at RT 7 days 0.1 mg/L (99.45% removal) respectively. The efficiency of the study and control beds was tested by a Two-Sample t-Test. The result showed that there was a significant difference at a 95% confidence interval, p-value = .002. Hence, the mixed substrate with plants performs better than the unplanted one, which means it can be effective for the treatment of high-strength industrial wastewater using horizontal subsurface flow constructed wetland.

Synthesis of Atmospherically Stable Zero-Valent Iron Nanoparticles (nZVI) for the Efficient Catalytic Treatment of High-Strength Domestic Wastewater

Here, we report the fabrication of nZVI by the wet chemical technique in the presence of ethanol using ferric iron and sodium borohydride as the reducing agents under ambient conditions. The obtained nZVI particles are mainly in a zero-valent oxidation state and do not undergo significant oxidation for several weeks. The structural and morphological parameters of nZVI were investigated by using UV, XRD, SEM, EDX, TEM, and DLS analysis. The optical nature, bandgap energy, and absorption edge were all revealed by the UV–visible spectrum. The phase development and crystallinity of nZVI particles were shown by the XRD pattern. The morphological investigation revealed that the nanoparticles were spherical with an average size of 34–110 nm by using ImageJ software, and the elemental analysis was analyzed using EDX. Furthermore, the catalytic treatment performance of domestic wastewater was evaluated in terms of pH, COD (chemical oxygen demand) solubilization, total solids (TS), volatile solids (VS), phosphorous, and total nitrogen (TN) reduction under aerobic and anaerobic operating conditions. The effluent was subjected to a process evaluation with a different range (100–500 mg/L) of nZVI dosages. The COD solubilization and suspended solids reduction were significantly improved in the anaerobic condition in comparison to the aerobic condition. Furthermore, the effect of nZVI on phosphorous (PO43−) reduction was enhanced by the electrons of iron ions. The high concentration of nZVI dosing has a positive impact on COD solubilization and phosphorous removal regardless of the aeration condition with 400 mg/L of nZVI dosage.

Decentralized high-strength wastewater treatment using a compact aerobic baffled bioreactor

Decentralized wastewater treatment is a potential solution to the economic and sustainability issues associated with current wastewater infrastructure requirements for rural and expanding urban settings. However, wastewater produced from small-scale operations (domestic, industrial, agricultural, defense, etc.) are often found to have higher pollution concentrations than municipal wastewater and is referred to as “blackwater” in the study. A baffled bioreactor (BBR) was employed to carry out blackwater treatment. The results of this study showed the removal of organic content and inorganic nitrogen was high in all of the feed amounts tested and increased corresponding to an increase in feed amount. Microbial diversity results supported that the feed amount was the most important factor in treatment performance. The microbial community was more diverse at higher feed amounts than lower feed amounts. A non-metric multidimensional scaling (NMDS) analysis revealed that higher feed amounts enriched Verrucomicrobiaceae, unclassified Sphingomonadales, unclassified Burkholderiales in the microbial community, and facilitated the removal of total solids, total nitrogen, and NO3−. The energy and exergy analyses showed the consumption of 5.02 Wh/L wastewater energy with a universal exergy efficiency of 61% at the feed amount of 3750 LPD. An economic analysis further delineated the treatment cost profiles of the decentralized unit under four different energy case scenarios of electricity from the grid, propane gas engine for remote rural communities, diesel engine (I) using standard U.S. market diesel fuel costs for remote rural communities and scientific research bases, and diesel engine (II) using the fully burdened cost of diesel fuel for military contingency bases and other extreme environmental scenarios.