Chemically enhanced primary treatment (CEPT) process have advantages of low pollution load and low costs, it can greatly improve the removal efficiency of organic matter by primary treatment , so the process has been studied widely and intensively. In this thesis, the mechanism, coagulant type, dosage and precipitation time were studied.

The Northeast Ohio Regional Sewer District has initiated an investigation into the feasibility of implementing chemically enhanced primary treatment (CEPT) and high rate disinfection (HRD) of its wet weather flows at its three wastewater treatment plants in the greater Cleveland Metropolitan area. The first two parts of this project have been completed, namely, the jar testing of CEPT–HRD and the design of facilities to implement pilot- and field-scale demonstrations of these technologies at the three plants. Of the five coagulants tested, ferric chloride was the most consistent in performance requiring on the order of 30 mg/L in concert with 1-2 mg/L of very high molecular weight anionic polymer to achieve the size and strength of floc required in these applications. Removals of approximately 80 percent of TSS and BOD were achieved with a residual TSS concentration of approximately 10 mg/L, well within the targeted value of 40 mg/L. Chlorine disinfection jar tests with raw sewage and CEPT supernatant showed that E. coli concentrations of No Reference information available - sign in for access. No Citation information available - sign in for access. No Supplementary Data. No Article Media No Metrics

Primary and chemically enhanced primary wastewater treatment with microsieving (disc or drum filtration) was studied at the large pilot scale at seven municipal wastewater treatment plants in Europe. Without chemical dosing, the reduction of suspended solids (SS) was (on average) 50% (20–65%). By introducing chemically enhanced primary treatment and dosing with cationic polymer only, SS removal could be controlled and increased to >80%. A maximum SS removal of >90% was achieved with a chemical dosing of >0.007 mg polymer/mg influent SS and 20 mg Al3+/L or 30 mg Fe3+/L. When comparing sieve pore sizes of 30–40 μm with 100 μm, the effluent SS was comparable, indicating that the larger sieve pore size could be used due to the higher loading capacity for the solids. Phosphorus removal was adjusted with the coagulant dose, and a removal of 95–97% was achieved. Moreover, microsieving offers favourable conditions for automated dosing control due to the low retention time in the filter.

Anaerobic digestate from cattle manure fermentation may pose a threat to the environment. How to stabilize the digestate’s characteristics so that they do not disturb the bio-system is a critical issue for digestate management. Chemically enhanced primary treatment (CEPT) was investigated as a pretreatment option for digestate treatment. The performance of CEPT for digestate management was carried out under rapid mixing (200 r/min) and slow stirring (40 r/min), respectively. The optimal dosage of ferric chloride (FeCl₃) was 40 mg/L. The combination of FeCl₃ and anionic polyacrylamide (APAM) had no obvious influence on TP removal, while COD removal efficiency was improved by 15.4%. The digestate pH and temperature remained stable for CEPT application and required no adjustment. The results indicate that CEPT was effective and feasible in enhancing the removal of COD and TP for digestate pretreatment by using FeCl₃ and APAM.

The Northeast Ohio Regional Sewer District (District) is currently implementing pilot- and full-scale demonstrations for the chemically enhanced primary treatment (CEPT) and high rate disinfection (HRD) of its wet weather flows at its three wastewater treatment plants in the Greater Cleveland Metropolitan area in response to a Consent Decree (CD) entered into with the Environmental Protection Agency. During wet weather conditions, operations staff members are deployed to operate and measure the performance at each of the facilities. A number of challenges exist, including inherent intermittent operations, unpredictable wet weather, and changing influent water quality characteristics, all of which can adversely impact performance of these facilities. Despite these challenges, performance results demonstrate an average effluent TSS of less than 40 mg/L at all three plants at sustained surface overflow rates (SORs) ranging from 81.5 to 415.5 m/d (2,000 to 10,200 gpd/sq ft). HRD testing results conducted to date show the capability to achieve 126 CFU/100 mL at dosages of 6 mg/L of chlorine at contact times of less than 10 minutes. By demonstrating performance criteria can be met, the District will have flexibility and maximize existing infrastructure during full-scale implementation and save more than $200 million in capital and operating costs when compared to the CD stipulated alternative treatment technology. Further cost savings can be realized by maximizing the removal performance at high SORs and low disinfection contact times.

Jar tests were conducted to investigate the performance of enhanced primary treatment processes for low-concentration municipal wastewater from South China by using composite flocculant combined with bio-flocculants Pullulan and poly-aluminum-chloride (PAC). The optimum dosage for composite flocculant and conditions for flocculation were determined. The experimental results indicated that composite flocculant had high efficiency for removing over 95% of turbidity, over 58% of COD_Cr (chemical oxygen demand determined with potassium dichromate), over 91% of TP (total phosphate), and over 15% of NH₃-N. Moreover, it could improve sludge settling and dehydration properties, and decrease the treatment cost.

Investigating the potential impact of the trivalent coagulant cations on the removal mechanisms, removal efficiencies and removal patterns of antibiotic resistance genes (ARGs) during anaerobic digestion (AD) of chemically enhanced primary treatment sludge (CEPTS) was performed using polyaluminium chloride (PACl), ferric chloride (FeCl₃) and mixed FeCl₃-PACl. The removal efficiency of the total 23 ARGs and intI1 improved to 72.1% in AD of primary sludge with 100 mg/L FeCl₃ and was the lowest (only 54.4%) in AD of primary sludge with 25 mg/L PACl. The removal of ARGs in AD of CEPTS with addition of single or mixed types of Al-based coagulant began to increase rapidly at the onset of batch operation. On the other hand, the rapid increase in the removal efficiency of ARGs in AD with FeCl₃ began somewhat later than in other ADs and the maximum removal efficiency was reached later than in other ADs.

A novel wastewater treatment process, which couples chemically enhanced primary sedimentation (CEPS) of sewage with acidogenic fermentation of sludge in tandem, has recently been developed to improve the removal of pollutants and nutrients, and recover valuable resources such as phosphorus and organics. This study represented the first laboratory-based examination on the level and removal of the emerging contaminants, including retinoids (i.e., retinoic acids (RAs) and their metabolites) and oestrogenic endocrine disrupting chemicals (EDCs; e.g., 4-nonylphenol, bisphenol A, etc.), in sewage, sludge and its supernatant during this novel wastewater treatment process. The results showed that 65% of retinoids and 73% of EDCs were removed from sewage after aluminum (Al) based CEPS, while 80% of retinoids and 72% of EDCs were removed after iron (Fe) based CEPS. After acidogenic fermentation of the CEPS sludge, 50% and 58% of retinoids, and 50% and 47% of EDCs were further removed in the supernatants of Al-sludge and Fe-sludge, respectively. While there were comparable removals for these two classes of emerging contaminants during Al- and Fe-based CEPS and sludge fermentation, Fe-based CEPS of sewage and sludge fermentation should be preferentially considered, given the relatively lower production of Fe-sludge and lower accumulation of retinoids in Fe-sludge. The levels of retinoids and EDCs in the supernatant and sludge changed during acidogenic fermentation of Fe-sludge. The removals of at-4-oxo-RA (i.e., the dominant retinoid) and bisphenol A (i.e., the dominant EDC) in the supernatant followed the pseudo first-order reaction model, with a half-life of 1.62 days (in the first two days) and 1.55 days (in the whole experiment of seven days), respectively. The results demonstrated the effective removal of emerging contaminants from the sewage and the supernatant during the CEPS and acidogenic sludge fermentation.

Chemically enhanced primary sedimentation (CEPS) technology has been widely applied in Hong Kong, exhibiting excellent performance in contaminants removal from sewage. The generated CEPS sludge contains abundance of organics which could be recovered as volatile fatty acids (VFAs) by fermentation for further utilization. In this work, the effect of calcium peroxide (CaO₂) on the fermentation of FeCl₃ based CEPS sludge was investigated. The feasibility of utilizing the fermentation liquor as substrate for polyhydroxyalkanoates (PHAs) biosynthesis was also evaluated. Results demonstrated that CaO₂ addition facilitated the disintegration of CEPS sludge and enhanced VFAs production. The maximum VFAs yield of 455.8 mg COD/g VSS was obtained with the dosage of 0.1 g CaO₂/g SS, improving by 44.7% compared with the control sludge. Acetic and propionic acid were the predominant components of the VFAs. Microbial analysis indicated that CaO₂ induced microbial reduction of Fe(III), accelerating the initial disintegration of FeCl₃ based CEPS sludge. Microbial communities with hydrolysis and acidogenesis functions were enriched effectively. CaO₂ treatment had no significant influence on the release of ammonia nitrogen (NH₄⁺-N), while reduced the concentration of orthophosphate (PO₄³⁻-P) and ferrous (Fe²⁺) in fermentation liquor, that was beneficial to the further utilization as substrate for PHAs biosynthesis. The VFA-rich fermentation liquor was proved to be a suitable substrate for PHAs biosynthesis. After cultivation, the PHAs content in activated sludge reached 22.3%, which was comparable to those obtained using waste materials as carbon source. This integrated technology could be a superior alternative of realizing sludge disposal and bioplastic production simultaneously.

An investigation was made to study the feasibility of recovering the Alum from coagulation sludges and reusing it in chemically enhanced primary treatment (CEPT) process to make the CEPT more cost-effective and recover the resource (Alum) efficiently. The optimum condition and efficiency of the acidification method for Alum recovery from coagulation sludge were investigated in the test. The results show that when the recovery rate of Alum reaches its highest level, 84.5%, the reduction rate of sludge is 35.5%. It turns out that the capability of recovered coagulant to remove turbidity, UV₂₅₄ and COD are 96%, 46% and 53%, respectively. The results prove that the recovered coagulants could be used in CEPT and the efficiency of recovered coagulant to remove pollutants is similar to that of fresh coagulant. Although some substances will be enriched during recycle, they have little effect on the quality of treated wastewater. The experiments verify that it would be an advisable and cost-effective way to recover Alum from coagulation sludges in water treatment and chemical wastewater treatment, and it could be then recycled to CEPT as well as reduce sludge volume.

Conventional wastewater treatment processes require extensive energy inputs for their operations. Biologically enhanced primary treatment (BEPT) is a promising technology to capture incoming organics that may be utilized to produce biogas and potentially hydrogen with further downstream processing. This study involved a biologically enhanced primary treatment (BEPT) of raw wastewater at bench and pilot-scale using activated sludge (AS) addition and dissolved air flotation (DAF) using raw wastewater at a municipal wastewater facility in Western Australia with average chemical oxygen demand of ~800 mg/L. The results of pilot-scale testing showed an improved removal performance for total chemical oxygen demand (COD-T), soluble chemical oxygen demand (COD-S), and total suspended solids (TSS) compared to conventional primary treatment (PT). Specifically, average COD-T, COD-S and TSS removals for BEPT were 33.3%, 13.5% and 45%, respectively which was 10%, 100% and 6% higher than PT. Moreover, the sludge produced from BEPT had a high solids content of 4.8 g/L, which might not need further thickening prior to anaerobic digestion. It is important to note that no chemicals were used during BEPT testing, which makes the process very cost-effective.

Wastewater treatment plants (WWTPs) are intended to be transformed from energy consumers into sources of energy. This experimental study assessed the performance, sludge and methane production, and energy content of a chemically enhanced precipitation treatment (CEPT) reactor compared with a conventional primary sedimentation treatment (CPST) reactor. The optimization of operational factors such as coagulant (alum (AlSO4)), coagulant aid (polyelectrolyte), sedimentation time, and pH were analyzed by the response surface method (RSM). The results of the CPST reactor indicated that the TS, VS, TSS, VSS, and COD removal rates were 60%, 43%, 69%, 8.96%, and 45%, respectively. Meanwhile, the CEPT reactor was able to remove a high percentage of all pollution (94.99% TS, 50.79% VS, 98.92% TSS, 95.40% VSS, and 95.70% COD) in optimum operation conditions, including sedimentation time 150 min, pH 7.9, coagulant aid 2.5 mg/L, and coagulant 106.2 mg/L.

The recent trend of turning wastewater treatment plants (WWTPs) into energy self-sufficient resource recovery facilities has led to a constant search for solutions that fit into that concept. One of them is chemically enhanced primary treatment (CEPT), which provides an opportunity to increase biogas production and to significantly reduce the amount of sludge for final disposal. Laboratory, pilot, and full-scale trials were conducted for the coagulation and sedimentation of primary sludge (PS) with iron sulphate (PIX). Energy and economic balance calculations were conducted based on the obtained results. Experimental trials indicated that CEPT contributed to an increase in biogas production by 21% and to a decrease in sludge volume for final disposal by 12% weight. Furthermore, the application of CEPT may lead to a decreased energy demand for aeration by 8%. The removal of nitrogen in an autotrophic manner in the side stream leads to a further reduction in energy consumption in WWTP (up to 20%). In consequence, the modeling results showed that it would be possible to increase the energy self-sufficiency for WWTP up to 93% if CEPT is applied or even higher (up to 96%) if, additionally, nitrogen removal in the side stream is implemented. It was concluded that CEPT would reduce the operating cost by over 650,000 EUR/year for WWTP at 1,000,000 people equivalent, with a municipal wastewater input of 105,000 m3/d.

Removal of micropollutants in wastewaters has gained importance in recent years. Advanced treatment processes such as ozone oxidation, activated carbon adsorption, and membrane filtration are required to remove the micropollutants from wastewaters. In this study, extended ozonation was applied at different stages of a wastewater treatment plant (WWTP) to determine its effect on the removal efficiencies of both macro and micropollutants. At the first experimental study, wastewater that was obtained from the effluent of the aerated grit chamber of a conventional full-scale municipal WWTP, was treated with a concentration of 30 mg/L FeCl₃ through a laboratory scale jar test system followed by a laboratory-scale ozonation unit. According to the results, chemically enhanced primary treatment (CEPT) achieved removal efficiencies over 75% for chemical oxygen demand (COD), 50% for total phosphorus (TP) and 90% for total-suspended solids (TSS), while ozonation followed by the CEPT resulted with an overall COD removal efficiency up to 93%. As a second experimental study, effluent of the overloaded conventional activated sludge (CAS) system of the same WWTP was solely post ozonated. 90 min of post-ozonation resulted with a decrease by 70% and an increase by 50% in ammonium and nitrate concentration, respectively. Over 99% removal efficiency of diclofenac was achieved in each experimental study (CEPT+O₃ and CAS+O₃). Results of each experimental study were evaluated in terms of both efficiency and feasibility. Since the ozonation results with an increase in the concentration of oxidized nitrogen; applying ozonation to a preliminary-treated wastewater after CEPT can be advantageous in some cases, where nitrate can be used as electron acceptor in anoxic environments for deep-sea discharges.

In this study, an ammonia nitrogen (NH₄⁺-N) ion exchange (IE) and regeneration (AIR) was constructed, and the chemical enhanced primary treatment (CEPT), AIR and biological aerated filter (BAF) were coupled in series to construct a novel CEPT-AIR-BAF process for efficient pollutants removal. At total hydraulic retention time of 4.6 h, the pilot-scale CEPT-AIR-BAF system obtained effluent with chemical oxygen demand of 17.9 ± 6.0 mg/L, NH₄⁺-N of 0.5 ± 0.3 mg/L, total nitrogen of 2.4 ± 1.0 mg/L and total phosphorus of 0.08 ± 0.05 mg/L. AIR module achieved outstanding NH₄⁺-N IE performance with NaClO-NaCl regeneration, and long-term regeneration increased surface area and mesopore of zeolites. Faster-growing heterotrophic bacteria, such as Pseudomonas and Comamonas, were enriched in BAF. The CEPT-AIR-BAF system saved at least 60% of land occupation and upfront investment, and the treatment cost ($ 0.155/m³) should be further reduced by investigations on the regeneration of loaded zeolite.

Background: “Chemically enhanced primary treatment” (CEPT) is an approach to wastewater treatment. It can be utilized as a specially designed step in “biological” secondary treatment processes. The aim of this study is to create an empirical model of separation efficiency for wastewater chemically enhanced primary treatment. Methods: The empirical model is undertaken using the simulation of the data obtained from pilot plant experimental studies using different types of coagulant (FeCl₃, alum, lime, and Magna-floc155). The empirical modeling techniques used multivariate regression model. Different values of BOD₅, COD, TSS, as well as separation efficiencies for COD and TSS were investigated in accordance to achieve final effluent results that would meet the Egyptian standards limit. Results: Multiple regression analysis showed that removal efficiencies of COD and TSS can be predicted to be (R² = 0.973 and 0.978, respectively). Conclusion: The present work provides an approach for using chemically enhanced primary treatment of wastewater. The obtained results showed that the empirical model can predict removal efficiencies with R² = 0.973, and 0.978 for COD and TSS. The advantage of this model is that it would allow better process control and treatment efficiency. The results show that chemically enhanced primary treatment method can be used as an efficient method in conventional municipal wastewater treatment plants to reduce the organic load of biological treatment and enhance nutrients removal.

Novel wastewater treatment plants (WWTPs) are designed to be more energy efficient than conventional plants. One approach to becoming more energy efficient is the pre-concentration of organic carbon through chemically enhanced primary treatment (CEPT) or high-rate activated sludge (HRAS). This study compares these approaches in terms of energy demand, operational costs, organic micropollutants (OMP), and virus removal efficiency. A CEPT pilot-scale plant was operated at a hydraulic retention time (HRT) of 30 min, and a lab-scale HRAS reactor was operated at an HRT of 2 h and a solid retention time (SRT) of 1 d in continuous mode. A minimum dose of 150 mg/L ferric chloride (FeCl3) was required to achieve a threshold chemical oxygen demand (COD)-to-ammonium ratio below 2 g COD to 1 g of NH4+ -N (fulfilling the requirement for a partial nitritation-anammox reactor), reaching high phosphate (PO43-)-removal efficiency (>99%). A slightly lower COD recovery was attained in the HRAS reactor, due to the partial oxidation of the influent COD (15%). The lower PO43- removal efficiency achieved in the HRAS configuration (13%) was enhanced to a comparable value of that achieved in CEPT by the addition of 30 mg/L FeCl3 at the clarifier. The CEPT configuration was less energy-intensive (0.07 vs 0.13 kWh/m3 of wastewater) but had significantly higher operational costs than the HRAS-based configuration (6.0 vs 3.8 c€/m3 of wastewater). For OMPs with kbiol > 10 L/gVSS·d, considerably higher removal efficiencies were achieved in HRAS (80-90%) than in CEPT (4-55%). For the remaining OMPs, the biotransformation efficiencies were generally higher in HRAS than in CEPT but were below 55% in both configurations. Finally, CEPT was less efficient than HRAS for virus removal. HRAS followed by FeCl3 post-treatment appeared to be a more effective alternative than CEPT for COD pre-concentration in novel WWTPs.

In this study, alkaline fermentation was applied to promote organics and P recovery from polyaluminum chloride (PACl)-enhanced primary sedimentation sludge. Coagulant results demonstrated that the optimum PACl dosage of 100 mg/L resulted in the effective concentration of 73% of organic matter and 90% of P from wastewater into sludge. Batch fermentation results highlighted the ability of alkaline fermentation in improving the biodegradability of PACl sludge. More specifically, at pH 11, 43.3% of soluble organics and 36.49% of P were released to the fermentation supernatant. Furthermore, P fractionation fermented sludge results revealed that partial Al-P dissolution and organic phosphorus hydrolysis were the main drivers of the released P. Finally, at pH 11, 85% of P was recovered as magnesium ammonium phosphate from the fermentation supernatant at the 2:1 Mg/P molar ratio. In conclusion, 24.9% of organics and 27.9% of P from raw wastewater were converted to valuable products via alkaline fermentation.

A study to evaluate the effect of ozone on solids removal during the coagulation-flocculation of wastewater from Mexico City drainage (including domestic and industrial) was conducted. Results of this study show significant improvements in the effluent quality with small ozone doses. The optimum ozone dosage was found to be 3.32 mg L⁻¹ ± 0.20. With this dosage it is possible to reduce the coagulant concentration from 50 mg L⁻¹ to 40 mg L⁻¹ without affecting the effluent quality. When coagulant dose is not reduced, an increase in the flocs' settling velocity due to a larger average size (with a decrease in TSS) is observed before and after filtration. In all cases, reductions in turbidity and color levels are seen when polyelectrolytes are used. The best results are achieved using a relation of ≈ 0.02 g O₃/g TOC.

Iron-based chemically enhanced primary sedimentation (CEPS) is increasingly adopted for wastewater treatment in mega cities, producing a large amount of sludge (Fe-sludge) with a high content of organics for potential organic resource recovery. In this experimental study, acidogenic fermentation was applied treat FeCl₃-based CEPS sludge for production of volatile fatty acids (VFAs) at different pHs. Batch fermentation tests on the Fe-sludge with an organic content of 10 g-COD/L showed that the maximum VFAs production reached 2782.2 mg-COD/L in the reactor without pH control, and it reached 688.4, 3095.3, and 2603.7 mg-COD/L in reactors with pHs kept at 5.0, 6.0 and 8.0, respectively. Analysis of the acidogenesis kinetics and enzymatic activity indicated that the alkaline pH could accelerate the rate of organic hydrolysis but inhibited the further organic conversion to VFAs. In semi-continuous sludge fermentation tests, the VFAs yield in the pH6 reactor was 20% higher than that in the control reactor without pH regulation, while the VFAs yield in the pH8 reactor was 10% lower than the control. Illumina MiSeq sequencing revealed that key functional microorganisms known for effective sludge fermentation, including Bacteroidia and Erysipelotrichi, were enriched in the pH6 reactor with an enhanced VFAs production, while Clostridia became more abundant in the pH8 reactor to stand the unfavorable pH condition. The research presented acidogenic fermentation as an effective process for CEPS sludge treatment and organic resource recovery and provided the first insight into the related microbial community dynamics.

Anaerobic digestion (AD) of chemically enhanced primary treatment (CEPT) sludge and non-CEPT (conventional sedimentation) sludge were comparatively operated under mesophilic and thermophilic conditions. The highest methane yield (692.46±0.46mL CH4/g VSremoved in CEPT sludge) was observed in mesophilic AD of CEPT sludge. Meanwhile, thermophilic conditions were more favorable for the removal of total antibiotic resistance genes (ARGs). In this study, no measurable difference in the fates and removal of ARGs and class 1 integrin-integrase gene (intI1) was observed between treated non-CEPT and CEPT sludge. However, redundancy analysis indicated that shifts in bacterial community were primarily accountable for the variations in ARGs and intI1. Network analysis further revealed potential host bacteria for ARGs and intI1.

The City of Columbus, Ohio has two consent orders with the Ohio Environmental Protection Agency to address wet weather flows. A decade after the plan, a new approach is being taken, incorporating green infrastructure and high-rate treatment technology in substitution for large storage tunnels. The City of Columbus studied proprietary high-rate treatment technologies during the development of the initial plan; however studies are now focused on chemically enhanced primary treatment. Jar testing and full scale pilot testing indicated that with addition of coagulant and flocculant the necessary treatment required by the Ohio Environmental Protection Agency could be achieved. Testing also indicated that the combined effluent from the chemically enhanced primary treatment facility and existing plant effluent would achieve all discharge limits.

Fly ash was adopted to prepare a composite coagulant containing Al and Fe salts by acid leaching. The concentrations of Al and Fe salts in the coagulant and the conversion efficiencies of Al and Fe oxides in fly ash are strongly affected by L/S ratio (defined as the ratio of volume of acid solution to mass of fly ash, ml/g), reaction temperature, and H₂SO₄ concentration. At L/S ratio of 3 ml/g, H₂SO₄ concentration of 4 mol/L, the prepared fly ash-based coagulant after heating and cooling of 0.5 h achieves maximum concentrations of 0.137 mol/L Al³⁺ and 0.0464 mol/L Fe³⁺+ Fe²⁺. At a dosage of 3.2 ml/L, coagulation of domestic wastewater results in removal efficiencies of 92% SS, 65% COD, and 98% -P. The prepared coagulant proves to be an effective agent in terms of pollutant removal and exhibits comparable performance with conventional and polymer Al and Fe coagulants. This could be ascribed to charge neutralization by Al and Fe salts, and bridging effect with the aid of solubilized silicic acid and residual particles.

Over the last two decades, the use of coagulation and flocculation has been emphasized for the enhancement of primary sedimentation in municipal wastewater treatment plants. This work is concerned with the development of an approach for the simulation and optimization of a chemically enhanced primary treatment (CEPT)/activated sludge scheme for municipal wastewater treatment using ferric chloride as a coagulant. A mathematical model has been developed which comprises empirical relations for the CEPT stage based on reported experimental data. The activated sludge model has been based on reported rules of thumb. Optimization has been undertaken using the BOX Complex Routine to minimize a cost objective function with controlling parameters. The effect of varying operating cost components on the cost function has been also assessed via sensitivity analysis. Results indicate that, for small communities, the addition of a CEPT stage is recommended based on technical and economic consideration for current and prospective costs and prices.