BOTSFORD, J.

In July of 2008, the plaintiffs filed an appeal in the Superior Court from a decision of the defendant board of health of Southbridge (board) approving a "minor modification" to the site assignment for an existing landfill and related processing facility in that town under G.L. c. 111, § 150A (§ 150A).3 The plaintiffs brought their appeal pursuant to G.L. c. 30A, § 14. In response to a motion to dismiss, two judges in the Superior Court ruled that as parties before the board, the plaintiffs had standing to bring their complaint for judicial review to the Superior Court. However, the second judge (motion judge) concluded that the plaintiffs' challenges to the board's decision failed on the merits. Final judgment entered on December 16, 2009, affirming the board's decision.

We transferred the plaintiffs' appeal from the judgment to this court on our own motion to consider in particular the issue of the plaintiffs' standing to seek judicial review in the Superior Court of the board's decision. However, there is a threshold issue whether the appeal must be dismissed because the plaintiffs' notice of appeal was not timely filed in the Superior Court. For the reasons we shall discuss, we conclude that Mass. R.A.P. 4(a), as amended, 430 Mass. 1603 (1999), did not authorize the allowance of the plaintiffs' motion to file their notice of appeal late, and consequently their appeal must be dismissed. Nevertheless, because the parties have fully presented and briefed both the standing issue and the plaintiffs' substantive challenges to the board's decision, we review both of these issues in this opinion. We conclude that on the record before the court, (1) the plaintiffs lacked standing to seek judicial review of the board's decision in the Superior Court; and (2) the plaintiffs' substantive challenges to the decision lack merit.4

1. Background.

The basic background facts are not in dispute.5 The defendant Southbridge Recycling and Disposal Park, Inc. (SRDP), operates a landfill and an associated processing facility at 165 Barefoot Road in Southbridge. On February 27, 2008, SRDP filed an application for a minor modification of its existing site assignment with the board pursuant to § 150A and 310 Code Mass. Regs. §§ 16.00 (2001), the implementing regulations of the Department of Environmental Protection (department). At that time, SRDP was operating both the landfill and the processing facility under a site assignment decision of the board issued in April, 1999.6 The minor modification SRDP requested had two components: (1) to reallocate a specified number of tons per year of waste from the processing facility to the landfill, thereby increasing the volume of waste accepted by the landfill and decreasing by a corresponding amount the volume of waste accepted by the processing facility; and (2) to allow the landfill to accept waste from the processing facility regardless of its geographic origin.

Between March 27 and May 21, 2008, the board held a public hearing on SRDP's modification request. On March 27, the first of what turned out to be eleven hearing dates, the hearing officer admitted the plaintiff ten-citizen groups (citizen groups) as "Parties" to the hearing with the right to participate fully in it. See 310 Code Mass. Regs. § 16.20(9), (10)(e). Through their counsel, the citizen groups did so by presenting and cross-examining witnesses, presenting and responding to motions, making opening and closing statements to the board's hearing officer, and submitting a proposed decision. At the hearing, approximately sixty witnesses testified, and seventy-two exhibits were admitted as well as seven chalks. The board issued its decision on June 9, 2008. It granted SRDP's application for a minor modification of the site assignment, but with fifty-eight specific conditions imposed. The plaintiffs timely filed their complaint for judicial review in the Superior Court on July 8, 2008, naming the board and SRDP as defendants.7

2. Timeliness of the plaintiffs' notice of appeal.

a. Facts.

The Superior Court judgment entered on December 16, 2009. Under rule 4(a), the plaintiffs were required to file their notice of appeal in the Superior Court within thirty days of that date.8 The plaintiffs apparently mailed their notice of appeal to the Superior Court on January 15, 2010, but the court did not receive or docket the notice until January 19 (January 18 was a holiday), more than thirty days after the date of the judgment.

On February 3, 2010, SRDP and the board jointly moved to strike the notice of appeal as untimely filed. At the hearing on the defendants' motion, held on March 23, the motion judge permitted the plaintiffs' counsel to make an oral motion to enlarge the time to file the notice of appeal under Mass. R.A.P. 4(c), as appearing in 378 Mass. 928 (1979).9 On April 1, the motion judge allowed the motion to enlarge and denied the defendants' motion to strike. The plaintiffs' appeal was entered in the Appeals Court on May 14. On May 17, the defendants moved to dismiss the appeal based on what they claimed was the late filing of the notice of appeal. On June 4, 2010, a single justice of the Appeals Court entered an order denying the motion and stating that the untimely filing "may be raised as an issue in appellee's brief."

b. Discussion.

Acting on the invitation of the single justice, SRDP and the board press their claim that the plaintiffs' appeal must be dismissed because the motion judge did not have the power to allow the plaintiffs' motion to enlarge the time for filing the notice of appeal. We agree. Under rule 4(c), a lower court judge may extend the time to file only if the request to extend is made within sixty days of entry of the judgment to be appealed—that is, within thirty days from the expiration of the thirty-day period prescribed by rule 4(a). See, e.g., Shaev v. Alvord, 66 Mass.App.Ct. 910, 910-911 (2006) ("Having missed the thirty-day deadline, the plaintiff was required, under Mass. R.A.P. 4[c] ... to file a motion seeking leave to file an appeal late within the next thirty days"). See also Commonwealth v. Boutwell, 21 Mass.App.Ct. 201, 205 (1985) ("it is clear that a trial judge does not have the power to permit a defendant to file a notice of appeal beyond the sixty-day period"); Commonwealth v. Lopes, 21 Mass.App.Ct. 11, 16 (1985) (where trial judge purported to allow defendant to claim appeal from conviction well beyond sixty-day period permitted by rule 4(c), judge's action was "nullity"). Here, the plaintiffs did not move to enlarge until March 23, 2010, more than ninety days after entry of the Superior Court judgment.10 The motion judge had no authority to allow the motion to enlarge, and as a consequence, the plaintiffs' appeal is subject to dismissal. Nevertheless, as stated at the outset, we exercise our discretion to consider the remaining issues presented in this appeal.11 The question whether the plaintiffs qualify as "aggrieved" parties with standing to bring this appeal is one of general importance to the review of administrative agency proceedings, and in any event it is appropriate to bring a final resolution to this case. See, e.g., Guardianship of Erma, 459 Mass. 801, 804-805 (2011); Commonwealth v. Balboni, 419 Mass. 42, 44 (1994). See also Wellesley College v. Attorney Gen., 313 Mass. 722, 731 (1943).

3. The plaintiffs' standing to seek judicial review.

a. Facts.

On or shortly before the first hearing date on SRDP's modification application, the plaintiffs filled out and submitted to the board registration forms entitled, "Registration of 10-Citizen Group." Each form contains an identical printed statement purporting to explain how the individuals signing the form as members of the citizen group would be affected by the proposed site assignment modification.12 The hearing officer, whom we infer was acting pursuant to the department's site assignment regulations, admitted the citizen groups as full interveners in the matter, entitled to all rights of a party to call and cross-examine witnesses, introduce exhibits, and present arguments. See 310 Code Mass. Regs. § 16.20(9)(a), (c).13

After the plaintiffs filed their complaint for judicial review in the Superior Court, SRDP and the board moved to dismiss, claiming that the plaintiffs were not persons "aggrieved" by the board's final decision, and therefore lacked standing to bring an action under G.L. c. 30A, § 14, and § 150A. A Superior Court judge other than the motion judge denied the defendants' motion, reasoning that because the plaintiffs had been afforded full party status in the board's proceedings, they were entitled automatically to bring an action for judicial review of the board's decision as "aggrieved" persons. Later, in ruling on the plaintiffs' motion for judgment on the pleadings, the motion judge rejected the defendants' argument that the plaintiffs lacked standing for the same reason.

b. Discussion.

To set a framework for consideration of the standing issue, we begin with a review of the pertinent statutory and regulatory provisions.

The siting and permitting of landfills and related facilities is governed by § 150A and the department's site assignment regulations, 310 Code Mass. Regs. §§ 16.00. Under § 150A, a person seeking to operate a site for a new landfill (or processing) facility or to expand an existing facility must submit a site assignment application to the appropriate local board of health, which is required "to hold a public hearing satisfying the requirements of [G.L. c. 30A]." Id. An owner or operator of an existing facility requesting a "minor modification" of the site assignment is not required to submit a full site assignment application, but the board is required to hold a public hearing on the request. 310 Code Mass. Regs. § 16.22(3). The department's regulations include a section prescribing "public hearing rules" to govern the public hearing process. See id. at § 16.20. One of these, § 16.20(9)(a), sets out requirements for party intervention in the proceeding before the board. This regulation provides that persons may intervene as parties if they make a written request and are considered by the hearing officer to be "specifically and substantively affected." It goes on to state that any citizen group of ten or more persons (ten citizen group) "shall be considered to be specifically and substantially affected" and entitled to register as a "party" to a public hearing where damage to the environment "is or might be at issue." See note 13, supra.14, 15

The final relevant statutory provisions relate to appeals. Section 150A states that "[a]ny person aggrieved" by the board's siting decision may appeal pursuant to G.L. c. 30A, § 14, and "[f]or the limited purposes of such an appeal," the board's final decision "shall be deemed to be a final decision in an adjudicatory proceeding." G.L. c. 111, § 150A. General Laws c. 30A, § 14, in turn, provides that judicial review is available to "any person ... aggrieved by a final decision of any agency in an adjudicatory proceeding."16

As the statutory provisions just quoted indicate, understanding the meaning of the term "person ... aggrieved" in c. 30A, § 14, is critical. "In order to maintain an action for review [under c. 30A, § 14], a party must be aggrieved in a `legal sense' and show that `substantial rights' have been `prejudiced.'" Group Ins. Comm'n v. Labor Relations Comm'n, 381 Mass. 199, 202-203 (1980), quoting Duato v. Commissioner of Pub. Welfare, 359 Mass. 635, 637-638 (1971).17 Cf. Ginther v. Commissioner of Ins., 427 Mass. 319, 323-324 (1998) (participants in public hearing held on proposed insurance company merger did not have standing to seek judicial review because, inter alia, there was no showing they suffered "direct and certain injury" from commissioner's decision and therefore were persons aggrieved).

It is true that some of our decisions contain language suggesting an agency's designation of a person as an intervener with the right to participate fully as a party brings with it the right to seek judicial review of the agency decision as an "aggrieved person." See, e.g., Save the Bay, Inc. v. Department of Pub. Utils., 366 Mass. 667, 672-673, 676 (1975) (Save the Bay).18 However, in Save the Bay, the court was discussing intervention in an administrative agency's "adjudicatory proceeding" as defined in G.L. c. 30A, § 1, that is, an agency proceeding in which the rights of "specifically named persons" are adjudicated. Under G.L. c. 30A, an agency conducting an adjudicatory proceeding may "allow any person showing that he may be substantially and specifically affected by the proceeding to intervene as a party in the whole or any portion of the proceeding." G.L. c. 30A, § 10(4). As that language reflects, such a determination of intervening party status is based on individual facts establishing the substantial and specific effect that the proceeding may have on the individual or entity seeking to intervene. If an agency decides that a particular person is "substantially and specifically affected" by a proceeding to a degree warranting intervention as a party, it is likely the person also will be able to establish that he or she qualifies as a person "aggrieved" for purposes of obtaining judicial review of the agency's decision.19

The public hearing before the board, however, was not an adjudicatory proceeding, as 310 Code Mass. Regs. § 16.20(1), states explicitly,20 and as the plaintiffs correctly acknowledge. Under the department's site assignment regulations, 310 Code Mass. Regs. § 16.20(9), citizen groups such as the plaintiffs acquire party status automatically, at least where, as here, there are claims of damage to the environment. See id.; note 15, supra. In other words—as is borne out by the record in this case—the board makes no individualized determination of how the specific group or any of its members may be affected by the proceeding, but is directed by the regulation to treat the group as a full party simply because it is a citizen group.

The grant of full party status to citizen groups under 310 Code Mass. Regs. § 16.20(9) presumably is designed to enable the board to receive relevant information about environmental effects of proposed siting decisions from a broad array of persons. But the regulation and its purpose do not themselves entitle the plaintiffs to seek judicial review of the board's final decision as persons "aggrieved." See Ginther v. Commissioner of Ins., 427 Mass. at 324 ("Mere participation in the administrative process does not confer standing to raise a claim in the Superior Court").21 Rather, it is necessary to determine whether any of the plaintiff citizen groups, or, more particularly, any individual members of the citizen groups, have shown or even alleged prejudice to their own substantial rights. See Duato v. Commissioner of Pub. Welfare, 359 Mass. at 637. Put another way, have any of the citizen group members shown or alleged "substantial injury" to themselves that would result directly from the board's approval of the proposed site assignment modification? See Ginther, supra at 322, quoting Harvard Law Sch. Coalition for Civ. Rights v. President & Fellows of Harvard College, 413 Mass. 66, 69 (1992). See also Goldberg v. Board of Health of Granby, 444 Mass. 627, 631-632 n. 8 (2005).22

The administrative record does not support a conclusion that any of the plaintiffs will suffer prejudice to their individual rights. The only record evidence on the issue is the set of registration forms. These reflect that the plaintiffs live in the "vicinity" of the landfill, although not necessarily in Southbridge itself.23 But regardless whether they live in Southbridge or a neighboring town, there is no indication of how close any of the members of the citizen groups may live to the landfill, and therefore, no indication as to what direct or specific impact the proposed modification of the landfill may have on any of them. The identical statement of how the plaintiffs are "substantially [and] specifically affected" on each of the registration forms (see note 12, supra) is essentially a general and collective assertion of injury. Because neither the registration form nor any other part of the record contains information describing the specific relationship of any plaintiff to the landfill—whether by physical proximity or otherwise—it is impossible to conclude that any of the plaintiffs may claim injury that is special to them and different from a generalized concern of the community. Contrast Save the Bay, 366 Mass. at 674-676 (although unincorporated association participating in agency proceeding could not be party to judicial appeal from agency decision, one of its members who owned property abutting facility at issue had standing as aggrieved party). Cf. Standerwick v. Zoning Bd. of Appeals of Andover, 447 Mass. 20, 27-28, 33 (2006) (discussing standing as "person aggrieved" under zoning and comprehensive permit statutes, G.L. c. 40A and c. 40B).24 Cf. also Harvard Law Sch. Coalition for Civ. Rights v. President & Fellows of Harvard College, 413 Mass. at 68-69 (discussing requirements for establishing standing as "persons aggrieved" under G.L. c. 151B, § 9).25

To summarize: although, pursuant to 310 Code Mass. Regs. § 16.20(9), the plaintiffs qualified as interveners with full party status before the board, the record does not support their claim that they have standing to appeal to the Superior Court as persons "aggrieved." As interveners, the plaintiffs would have the right to intervene in an appeal brought by an aggrieved person whether or not they were aggrieved themselves, G.L. c. 30A, § 14(2), see note 16, supra, but on the present record they were not entitled directly to initiate an action for judicial review. The defendants' motion to dismiss the plaintiffs' complaint should have been allowed for lack of standing. Nevertheless, for reasons stated earlier, we turn briefly to the merits of the plaintiffs' challenge to the board's decision.

4. Merits.

At issue is the board's decision to grant SRDP a minor modification to its existing site assignment.26 The burden is on the plaintiffs, as the challenging parties, to prove that the decision is not supported by substantial evidence, based on error of law, arbitrary or capricious, or an abuse of discretion. G.L. c. 30A, § 14(7). "In our review of administrative agency decisions, we generally defer to the experience, technical competence, specialized knowledge, and discretionary authority of the agency." Heublein, Inc. v. Capital Distrib. Co., 434 Mass. 698, 705 (2001), citing Seagram Distillers Co. v. Alcoholic Beverages Control Comm'n, 401 Mass. 713, 721 (1988).

The plaintiffs assert that the board's decision should be reversed because it is based on two errors of law. In particular, they claim that the board (1) erroneously expanded the acreage that previously had been site assigned, based on SRDP's misrepresentation of that area in its application for a minor modification; and (2) incorrectly approved a modification for the processing facility even though that facility is not (a) located on land that was properly site assigned, or (b) a permitted accessory use of an existing site assigned area. These claims are without merit.

Contrary to the plaintiffs' repeated assertions, the record demonstrates that both the landfill and processing facilities are located on land that was site assigned either in 1979 or in 1999. The plaintiffs argue that only 20.6 acres of land was site assigned in the 1979 site assignment. However, that site assignment was not for a specifically delineated acreage, but for "a tract of land presently owned by George Corriveau in the Barefoot Road section of Southbridge." In 1979, before the town of Southbridge changed its boundaries (see St.1993, c. 210), the tract in question was approximately sixty-four acres. The site assignment designated 20.6 acres of it for waste disposal, but the over-all site assignment was for the bigger tract, namely, the full sixty-four acres of land previously owned by Corriveau and located in Southbridge.27 With respect to 1999, the plaintiffs similarly confuse the acreage designated for waste disposal with the entire portion of land being site assigned.28 SRDP did not misrepresent the acreage of site assigned land in the 2008 request for minor modification at issue here, and the board did not make its decision based on an incorrect determination of that acreage.

Turning to the plaintiffs' argument focused on the processing facility, to the extent it depends on the claim that the facility is not on site assigned land, it must fail because, as just discussed, both the landfill and processing facilities are located on land that was properly site assigned in 1979 and 1999. The plaintiffs' additional claim that "processing" is not a properly approved use of the site also must be rejected: the processing activity undertaken at this facility was and is a recognized exception to the general prohibition, spelled out in 310 Code Mass. Regs. § 16.21(3), against conducting a different solid waste activity on an area site assigned for a specific solid waste purpose. See 310 Code Mass. Regs. § 16.21(3)(a) (1994) ("Recycling or composting may be approved at any assigned, permitted active disposal or handling facility without requiring a new or modified site assignment when such activity is integrated into the assigned solid waste management operation and the tonnage limits ...").29 Substantial evidence in the record, including the department's site suitability report prepared in connection with the earlier, 1999 application for a major modification to the 1979 site assignment, shows that the processing facility was designed to increase recycling and would be integrated into the existing landfill facility. Furthermore, in connection with the review it undertook in 2008 (see note 27, supra), the department concluded that the board's approval of the name change for the landfill facility (see note 29, supra) was proper and the processing facility was not operating without a valid site assignment.

The plaintiffs' final argument is that the modification sought by SRDP in 2008 in substance was a "major" modification, and the board improperly treated it as a "minor" modification, thereby permitting SRDP to avoid the more rigorous review that § 150A and the department's regulations called for. The claim cannot succeed because it necessarily depends on acceptance of the plaintiffs' position that the landfill and processing facilities currently operate on land that has not properly been site assigned—a position that we have rejected.

5. Conclusion.

For the reasons discussed in this opinion, the plaintiffs' appeal must be dismissed.

So ordered.